To learn electronics in a very different and effective way, and gain access to Mr Carlson's personal designs and inventions, visit the Mr Carlson's Lab Patreon page here: www.patreon.com/MrCarlsonsLab
@@Daveyk021 on a 4 stroke engine it takes 2 revolutions of the crankshaft to fire all the cylinders. the configuration makes no difference. 3 cylinders fire on a 6 cylinder engine per revolution and 4 on an 8 cylinder.
@@richardcranium5839 Thank you. Also the distributor runs off the crank. I think this morning, I was in lala land thinking the cam shaft. Since a V engine has two, I was thinking that would change the math. I thinker on cars and small engines (when I have time). I need to check the math to test a TAC and DWELL meter I have (it is digital, so it is probably dead nuts on??). I still like the idea of an analog meter for it. I think that is better to watch the needle swing. I may get on ebay and order and old analog tac/dwell meter before they are all over $1000 after too much of the public see this video.
@@Daveyk021 V engines can also have only one camshaft. They were the older engines that had pushrods and lifters. The camshaft was in the block right over the crankshaft.
Knowing that you have moved the labs all around, it feels a little funny to see the old main lab in the intro and outro! Sears always had major manufacturers make their house brand devices. It is possible that the design really is a SUN product though it really does not matter. Nice job as is your normal! Even my "old" truck (1973) has electronic ignition so the dwell function to me is not needed. So many people today look down on the old way to do things. A needle is much easier to use when doing things like setting RPM as it is the way our brain works, analog not digital. Great job on a device I had totally forgotten about! NOW TO THE UFO device!!! :D
Just finished fixing up a Canadian made Tuffy Tool model 1813 Tach-Dwell meter , thanks to this video. Having access to a function generator was able to calibrate rpm and dwell accurately. Was out by a bit due to out of tolerance resistors , linearity is perfect across the whole span of the meter. I use this for my Canadian ' 66 Malibu SS . Still running points as the car still has its original 283. Great Job Paul !
This is all new to me and I've driven lots of old cars. I'm off to a new video to fill that gap. Need to learn about dwell. I never fail to learn something new from these videos.
Hi Paul. Many years ago now, I used to be employed as supervisor of a small group of calibrators of mechanical meters. The device should really be calibrated and used in the same way, that is, if it is to be used standing up, it should be calibrated so, or if used lying on its back, then calibrate it in that position. With a good meter, any difference should be very small, but nevertheless when we issued a calibration certificate it would only guarantee the stated accuracy if used the same way it was calibrated.
@@geraldstewart very few mechanical meters will give precisely the same reading in ALL positions. Hence, a tolerance is given, and the instrument is tested in only the positions it is expected to be used. For example, a mechanical AVO meter could be calibrated both vertically and laid on its back. If then used on its side for example, it could be outside tolerance.
For those wondering why 'dwell' matters in old cars with breaker point ignitions: The dwell angle is the number of degrees of crankshaft rotation in which the points are closed. During this period, the magnetic field in the primary winding of the ignition coil is building. When the points open, the magnetic field collapses quickly generating a brief high voltage, which is stepped up even more in the secondary coil eventually arcing across the spark plug gap. The longer the dwell angle (i.e. points closed), the more time there is to build a magnetic field in the primary - an increase in this magnetic fields leads to a higher voltage at breakdown and a better spark. The dwell angle is set by adjusting the breaker point gap - i.e. how far apart the points are when they're pushed open by the cam lobe. A larger gap implies a smaller dwell (inverse relationship) because the breaker points in the small dwell case are adjusted such that they open sooner on the cam lobe and are ultimately pushed farther apart at the top of the lobe. Because breaker points can be pitted due to arcing, adjusting the points gap distance (with feeler gauges) is relatively inaccurate (as the points faces may not be flat) and having a dwell meter does a much better job at getting a proper adjustment. Incidentally, I believe vintage race cars occasionally used dual point systems (and possibly additional coils ?) to maximize coil charging at high rpms - a scheme where every other ignition cycle would take place on the alternate coil/points set that would be fully charging during the previous cycle. I may have the details of this last part wrong. Anyway, I hope this is interesting/helpful to someone out there :-)
The ignition dwell angle isn't derived from crankshaft rotation. It's is derived from distributor rotation. Crank rotates twice the speed of the cam. For example a 4 banger has breaker lobes that are 90 degrees apart, so the dwell angle would be around 45 degrees.
blobscot It is not actually a secondary winding in the coil. It is an overwind -- much as the overwind in LOPT [Line Output Transformers Transformer] used in devices employing a CRT Other than this small error in your description, all is accurate
Also.... Being that this meter is so accurate, Is there any way to mod it ? So that you could use it for 1,2,3 and 4 cylinder engines ? And to also increase the max rpm to 24,000 for motorcycle mechanics ?? It would be a great tool for finding or setting up the powerband, because there isn't much if any lag-time ! Love your channel !
Gearhead for all my life. Mostly sports cars but also motorcycles. My dad was a mechanic all his life. I have most of those tools. Glad I won't be using them anytime soon as I sold all of the ICE cars and bought an EV in 2018. More fun to drive and will blow most muscle cars off the road. Don't miss the gas station or the smell. Great video though. Brings back memories of tuning old cars to pass emissions.
@@MrCarlsonsLab LOL. I enjoyed seeing that this morning. That was quite the lesson; thank you. I tinker with my 1949 CJ3A (which I repaired and installed the engine myself back in 2007) and I need to put the motor back together on my 1974 Beetle. For that I need to set the tac and dwell, That I have no real idea how to do properly. In the '49, I adjusted the points and turned the distributor until the motor ran its best and sounded the best. A 2.2liter Go Devil engine is not too picky. The beetle on the other hand is. I did but a digital tac/dvm about a year ago. I will be testing it the way you taught in this video; thank you! Now let's see you tune up a car with that thing (I know it really isn't what you do on UA-cam, but you would do it in such a way, that we could understand what it really being done.
Marcos Souza Those that dislike the video presentation are likely those who have little to no knowledge on the subject matter, and perhaps have the attention span of a house-fly. One cannot teach those who choose to live a life of ignorance. The tragedy is that they take pride in their ignorance.
@@andrew_koala2974 I think you got it spot on. I don't have the hands-on knowledge on the subject-matters Mr. Carlson shows us (very little practice, I only got the theoretical electromagnetism part of it), but I admire the simplicity and practicality he demonstrates in every video. Also, I really appreciate the old and new equipment he shows and restores (we never saw 99% of those brands and products in Brazil).
You have to remember that this meter was made during a time when Sears cared about making products well instead of today's habit of making things cheap and customers having to come back to replace it much quicker.
Gregory Thomas The CORPORATE Empire which now controls and operates a de facto Government with its BS HQ in Pennsylvania Avenue in the District of Corruption - You may have heard reference to it as DC -- The Currency you work for goes Directly there. They are connected to SkyNet and have their hands in your pockets and have made your employer to act as their collection agent. You may be a GT but you cannot outrun DC Good luck and goodbye
I'm sure that 'Sears' as it existed back in the day, still cares about good products. The problem is that all the people and ethics associated with Sears as it used to be have retired, been pushed out or otherwise replaced with sociopathic greed-mongering hyper-capitalists. It might be money that's the problem, or perhaps it's just unethical folks that just want to use us all to make a quick buck. In many ways life in 2021 is of a much higher quality than in 1960, but our money buys so very little now. I was born in 1990 and even I've seen a drastic down-turn in my 31 years, in the quality of products. We have to bring back more stringent product quality regulations and penalize outsourced production, while incentivizing local production sources.
I work 6 mechanics. Not a single one knows what a dwell meter does. I had to teach all of them how to set points with a feeler gauge. The younger generation. Yikes!
@@MrCarlsonsLab Wait till you have to teach them how to strip, clean and align a pair of SU carburettors. More so if you have to show them how to set up a bike with individual carburettors per cylinder, and balance them.
Feeler gauge? An old timer once taught me that if you ever got in a jam, use a book of matches. One side for points, fold it over for the spark plugs. It wouldn't be accurate, but it will get you home. Not really realavent today, but if you own a classic, it comes in handy.
@@MrCarlsonsLab Sometimes I feel like a Tetradactyl at a petting zoo. The kids are scared and cry out old and ugly. But I’ve lived long and was built for functionality.
@@VitoVeccia Also you really need to know what more modern vehicles use the same points, plugs and capacitor as your classic vehicle. Many spares suppliers only have a look up book that covers the last 40 years of vehicles, so if you drive something from the 1960's, you will get the "we do not have any" response, but if you ask for the more modern one they find they actually do stock it, and you get the last one or two, that have been on the shelf for 3 decades.
Thanks for the video. Sears tune up equipment was always very accurate OoB. I owned several over the years. In the 60's, the name they were sold under was Penske, as in Penske Racing Working on small sports cars, the most important readings were usually for low idle speeds. High speeds were not used as much, except for maybe checking your tachometer. The dwell meter was especially useful as that was the function that indicated the quality of your distributor bearings and points-springs. I was kind of hoping you were going to have to build in some calibration controls if this didn't have any originally. Please set aside some time in the future, to do one of those too. Thanks again.
love the video but i might suggest that a brief description of how the circuit converts hz to meter movement for rpm and duty cycle is converted for dwell
How ironic that you did this video as I just recently found a really nice Sears unit in someone's trash that does all these tests plus it has all the plug in test cables with it. Unit is in great shape. I'll probably never use it other than maybe the voltmeter and ampmeter. Looks good for the bench though. Also got a near mint complete old g.e. beige plastic portable record player. Can't wait to check it out.
It has other uses believe it or not. It can be used to retrieve codes from OBDI Ford's, and it can be used to place a load test on circuits. Before condemning a purge solenoid, you can put the meter in its place, and it load tests the circuit so that you don't need to do voltage drop tests.
Speaking of Sears Roebuck and Co, some decades ago you could buy from them model T spark coils. We bought one as kids to use for making a Tesla coil. That was around 70 years ago.
There is no "big thumbs icon" so I will let you know in write I REALLY ENJOY YOUR VIDEOS !!!! thanks a lot for taking the time with this great, educational and quality produced videos!!!
Hi Paul, Had the same unit. Saw less use when the HEI distributors started making an appearance. Don't know where my unit is now. I sold my shop when I retired in 2018 and closed down my trucking company. Enjoyed the video. You and the family stay safe. 73 WJ3U
When I started doing mechanic work over 50 years ago that was the tool to have to get your car is running great. I really enjoyed this video. It’s because of videos like this that I became a patron sometime ago. The only thing I can use my old dwell tachometer on is the tractor.🤣👍 I look forward to all your videos. Keep safe Paul.
Fine work, Paul. I thought, this thing will show/ give bad numbers by its nature of construction. But i was proven wrong. May I ask you something? Can you imagine to layout an build a special tool nobody ever made available , but a lot people need? I talk about an instruction or tool to check and calibrate wattmeters für HF and maybe VHF, too. Something to check an align in the 1W to 10W range, 100W will be a problem i think...? That will be a real great thing worldwide.. 73 de Olaf, Cologne-Germany
I just calibrated a somewhat similar unit to the one in the video (a hand held style) that was also sold by Sears (Made in Japan). It could only read up to ~1000 RPM on the V8 scale even at the highest setting of the calibration potentiometer. I opened it and found a single electrolytic capacitor (47uF/10V) which is laughable since the unit normally run in a 12V-14V environment. I replaced the capacitor with a 47uf/50V and it worked beautifully and calibrated accurately throughout the whole range. Thought of sharing this for anyone who may contemplate such calibration.
On a 4-stroke engine, each cylinder fires every 720°. The ignition system fires every 720°/(# of cylinders); Let's call this the "firing angle". A 4-cylinder has a firing angle of 180°, a 6-cylinder has a firing angle of 120°, and an 8-cylinder has a firing angle of 90°. The dwell angle is the rotational angle of the distributor the points are closed and the coil is storing up energy (magnetic flux) for the next spark. The tricky thing to remember, is that the distributor (and cam shaft) spins at 1/2 the speed of the crankshaft. The voltage on the coil's low terminal is small (near ground) during the dwell time because the points connect the low side of the coil to ground, or ground through a low valued resistor. For calibrating a Dwell Meter with a pulsed signal of variable duty cycle, the dwell angle is the fraction of the distributor rotation angle where the waveform is "low" (near 0V). Distributor Rotation Angle = 1/2 Crankshaft Rotation Angle Dwell Angle = (1/2)*(Firing angle)*(1-Duty_Cycle) For the 6-cylinder case with a 50% duty cycle, the Expected Dwell Angle displayed on the meter would be Dwell Angle = (1/2)*(120°)*(1-0.5) = (60°)*(0.5) = 30° It's not 50*(0.6) gets you the same answer, but I think you switched the decimal points around on the two numbers. I thought your viewers might appreciate a more detailed explanation. The dwell angle can be controlled by adjusting the "points gap". Side Note: PWM methods (frequency to voltage conversion, and duty cycle measurements) generally have excellent linearity.
The reason for the wedge shaped circuit board? My guess is that the manufacturer used the same board for the handheld model where the board is mounted in the handle with the meter movement above it.
or it allowed more circuit boards condensed into same physical size board. rotate every other circuit layout 180 degrees, then angle cut between them. :)
Excellent. I have a Dwell/Tach meter that is much cheaper than this lovely thing and have used it since the 90s. Now I need a function generator to test it! There's always something 😄
I had a Sears VOM back in the early eighties and it was a pretty good meter. Not Simpson quality but plenty good for general use. I don't know if it's still spot on anymore but I'm not surprised your meter came back around with a little tlc.
IS THIS REALLY FAIR! for a old school car guy this is like hiding peas in mashed potato's. twisting electronics with automotive, I love your videos this one made me think of all the times working on cars with a meter like that.
Ive been looking for how to do this for ages. I have 2 of these. One is accurate and the other not and I didn't know how to fix it. I'm impressed with how easy this is to do. Thanks.
Mr. Carlson, I’m sure that you are aware that companies are not going to spend the time and the extra 5 cents to solider connections correctly. They are all about PROFIT. They make things now as cheap as possible and sell them for as much as possible. Products like this are made on a assembly line as fast as possible and as cheap as possible.
I was going to congratulate you on 300k subscribers last week and didn't get around to it. So, congratulations on 301k subscribers! Thanks for your great videos!
with these d'arsonval needles I also check needle balance {weight at end of needle}. This is done in horizontal and vertical position of meter to check that 'zero' position doesn't change. AAAHHHH memories.
Back in the day we used to buy open frame 1mA movements from Farnell (IIRC), and they'd arrive in all sorts of states!.....requiring spindle adjustment top and bottom to keep the coil level as well as adjusting the freeness of the movement. Yes, it was an art to get it all adjusted perfectly and linear.
FYI, one would use a dwell meter while cranking the engine, usually with plugs remove, and set the gap while watching the meter. This also avoids getting oil on the point faces since you are not using feelers. Nice vid man
Please don't keep us in the dark. What kind of car are you working on? I have a 1933 Plymouth, a 1950 Ford and a 1968 Corvette. So I am very interested in vintage cars.
I will probably pull the radio this winter and do a restoration on it. (I'm always to busy to do restorations for myself it seems.) I will reveal the car at that point. Thanks for your interest. Your 33 sounds very neat!
You always impress me. There are times I laugh. You are a very good technician. As a retired Broadcast Engineer who cut my teeth on valve technology, I feel that you are a little bit excessive on the safety of high voltage circuits. It is still better to be safe. On transmitters we ALWAYS did several things. Remove all jewelry. Keep one hand in a pocket. Us the shorting stick to verify the power supply is discharged. Good work! Excellent audio! As always, nice production.
Robin Cross Exactly. When I was studying Electronics Engineering and Electro-Mechanical Engineering. (during my 30-year long Military career - Airforce) - The practical side of things was done with PHILIPS who were building the avionics systems for our U.S. built fighter jets. My then Mentor suffered a cardiac arrest when the metal bracelet on his watch attracted an arc from an EHT lead that had been punctured by an unknown technician -- presumably to measure the EHT voltage. I learned from his experience and never wore a watch or a ring after that. Besides keeping one hand 'in pocket' It also pays to stand on a rubber mat. Rubber car mats are under $6 and a potential lifesaver. I had the opportunity years ago. mid-1990s to visit a sign manufacturing business, where they were making NEON signs - and one of their benches was a salvaged Stainless Steel bench presumably from a commercial kitchen or Butcher - I was horrified when I checked it to discover it was not earthed. - Suffice to say that the shop proprietor is Lebanese. Perhaps he obtained the table from a Lebanese bakery.
The circuit board shape prob comes from its use in a hand held usage as I am sure one of the big tool brands did a hand held dwell meter with a smaller case but same gauge and function.
Great video! I just bought a vintage Snap-on tach-dwell meter. It needs re-wired, but your video will definitely help if I need to adjust it. Thanks for sharing.
It has a thin angular circuit board because the same circuit board was used in a smaller handheld version that the circuitry was in the handle and above it was the meter gauge.
Impressed is somewhat miss-understated, I really did not expect this 'Pro'! meter to be anywhere near as accurate, (so much is labelled 'Pro' now days and it means crap really) hats off to the designer and manufacturer, they really came up with something quite special, obviously the meter movement is of quite high quality not something you would get today unless you pay 'think of a number and double it' price, the old school stuff wins again, thanks very much for showing this Paul it was VERY interesting to watch and see it truly shine at the end!
I've been a backyard mechanic since the 1970s. Over the years, I've collected several of these - '50s sun diagnostic analyzer, '60s Allen diagnostic analyzer, '70s Marquette diagnostic analyzer, '60s craftsman tach/dwell, '50s allstate tach/dwell, '70s sun tach/dwell, '80s sears charging system/tach/dwell. Wish I could post pictures here. Long term goal is to clean them all up & have them on display. Never even thought about checking their accuracy. Starting to get into arduinos, and have picked up some low cost electronics equipment, including the xr2206 function/signal generator kit. Would that work for this process?
I can understand your skepticism working on a Sears branded piece of equipment. It works the opposite way, also. 25 years ago, my cousin handed me a top of the line Carver receiver to repair. I was excited to get my hands on it. It turns out, the receiver was actually made by Pioneer, which was a bit of a let down. I did get it repaired and back to my cousin.
Sorry Paul, I tried to follow your maths on dwelling, starting with 60°, and then.... 50% x .6 = 30°. I lost track of the way you use these numbers. I could understand 50% of 60° = 30°. The .6 totally escapes me. Maybe it is the USA school way of teaching percentages ?
Hi Erik. The easy way to remember is the full scale reading. V8 Dwell has the maximum scale as 45° so you use X .45. The V6 scale has a maximum as 60° so you use X .6 The 50% shown is the duty cycle to get your reading.
Thanks Paul! Got out my old ArcherKit Engine Analyzer to check the calibration and sure enough it was off! That kit had you do the CAL of the tach using a line cord with a few 56K resistors in series with the Hot and Neutral. You plug it in the wall socket and attach your test leads to the ends of the resistors to get 60Hz (ish) line frequency. Got you close, thanks for the video and math to check the other RPMs!
Hi Paul, I was a little surprised when you soldered the first electrolytic cap, sans rosin flux. I learned from you how important flux is for every joint. Mmmm, just asking? I hope don't unfriend me for this. BTW I love flux and how well adds to the performance for soldering on anything that will take solder. Still love your videos Paul. Thanks for all you do. Gary ;-)
BTW I have two 32 oz. Rosin flux bottles #835 lol I missed out on buying the Wavetek, DOD instrument for $120.00 plus some easy shipping costs 4 years ago. Paul said it was a good device, makes me sad to know I should have bought it. Still I have have amazing HP devices for the same thing.
Good timing! I use my old Sears unit (later model than this one) but just bought a Heathkit Automotive Scope to test the dwell accuracy thus calibrate - I should have just waited for this video!!
Paul, I look forward to learning from your adapter for this dwell/tach meter for it to work with 6V vehicles. Please show enough detail so that I can adopt _that_ to an 8V vehicle (i.e., a 6V Willys that starts a _whole_ lot better on 8V than it does on its original 6V! ;). I've got an "old" Sears dwell/tach test tool that I purchased in the mid-'70s that I'm sure needs a similar calibration like you've shown here.
My lifetime career was in electronics! 3 years at Westinghouse, 18 at Kodak and 12 at Rochester Institute of Technology! Loved my life’s work! Over those years I collected dumpster dive test instruments bound for the recycler! Most need repairs!! Want to fix them! Ha ha! Thanks for the videos!
@@MrCarlsonsLab I have a 67 Mustang and 72 VW beetle and I still have my old Dixco tach/dwell meter to adjust ignition timing! Now I know how to calibrate it! THX! I’m also restoring a C64 and disc drive, fixing some old cb radios and building cb antennas! I’ve been retired 8 years but I try to learn something new every day! Thanks for that!!!
I'll be honest, as much as I love older motors and older electro-mechanical systems, this stuff is why I'd much prefer to drive a vehicle with an electronic ignition haha. Great tutorial though, I'm sure this will come in handy due to my fetish for old automobiles!
All of the timing on my race car is done in the ignition box. My Dad and brother have a race pak in their car and we can change the timing during the run. I do have a dwell meter and a timing light in the garage in a box. I should dig in out and give it a go through. Congratulations on 300K Paul!!
In the old service station I worked in back in the day, we had a big "SUN" cart with several types of portable meters you could select. The only one I ever saw any mechanic use was the Tach/Dwell meter. I was well worn while all the others looked brand new. It took a lot of punishment. No idea how accurate it actually was. LOL!
Really a great educational video Mr C. on this type gear! I have a lot of Snap On electronic gear from my fathers garage that could use an alinement and refurbishment!
Had one in the early 80's with the wedge shaped circuit board. It was also a Sears but was a hand held unit. The circuit board was in the handle and the top was a meter. Looks like when they made that model you had they could not be bothered making up a new board for it. Great video as always Paul.
Now now, Mr. Carlson, there's no need to mock the dead... though it's pretty funny. 🤣 RIP Sears, the once-great retailer bean-countered to death. Do you have a vehicle with a 6-volt electrical system? 👍
Great topic. I have a vintage SUN dwell/tach meter and I just didn't feel like digging in the math to figure out how to simulate pulse train that will simulate engine RPMs or dwell timing. It is pristine except for some slight surface scuff in the paint. Internally it is totally clean. Not sign of any battery corrosion at all ever
Just curious why you would say this would not work on 6 volts? Just the nature of the way it works I would not think that it would be very voltage sensitive. I have a Niehoff T-70 Dwell/Tach meter that I use on my 48 ford pickup that is still 6 volt and it seems to work just fine. I will be checking the calibration on it now. However it did appear to be working pretty accurately. You do have to wrap your head about the positive ground aspect of it when you connect it up however :-)
Hi Jimmy. This meter has no internal battery, so the circuit is powered by the distributor. This limits the internal circuits function. You may want to check the accuracy of your Niehoff, as most dwell-tach meters will read at 6 volts, but with accuracy issues.
Glad I don't use points anymore, ie, gained 40km per tank-full switching to electronic. Now, how can we test if our cheap timing-lights have lag, ie, read late - lol -.
My father had a tach/dwell meter, (which is still (probably) in his garage ;-), that he used to make fine adjustments to the points on his 69 Imperial. They used to call me "Mic Eye" when I was younger cause I could adjust the points without a feeler gauge. (I couldn't really tell the gap, but I had done it so much that I could get it REALLY close, so close that dad rarely had to adjust them once I'd set them) Thanks for the trip back in time Mr Carlson!!! I sure do miss my dad!!!
Please do a reverse-engineering video on this. I’m especially interested in how the “dwell” function works. I would have expected an integrator to convert PWM->analog voltage, but that would make the low end (15 degrees) to be at the left of the meter scale, and the high end (45 degrees) to be at the right end (full deflection) of the meter scale.
To learn electronics in a very different and effective way, and gain access to Mr Carlson's personal designs and inventions, visit the Mr Carlson's Lab Patreon page here: www.patreon.com/MrCarlsonsLab
Love your video's Mr C !!
V6s and V8s share the same crankshaft but opposite of each other, so v6=3 and v8=4. What about an in-line 6 cylinder, is that divide by 6 or 3?
@@Daveyk021 on a 4 stroke engine it takes 2 revolutions of the crankshaft to fire all the cylinders. the configuration makes no difference. 3 cylinders fire on a 6 cylinder engine per revolution and 4 on an 8 cylinder.
@@richardcranium5839 Thank you. Also the distributor runs off the crank. I think this morning, I was in lala land thinking the cam shaft. Since a V engine has two, I was thinking that would change the math. I thinker on cars and small engines (when I have time). I need to check the math to test a TAC and DWELL meter I have (it is digital, so it is probably dead nuts on??). I still like the idea of an analog meter for it. I think that is better to watch the needle swing.
I may get on ebay and order and old analog tac/dwell meter before they are all over $1000 after too much of the public see this video.
@@Daveyk021 V engines can also have only one camshaft. They were the older engines that had pushrods and lifters. The camshaft was in the block right over the crankshaft.
Knowing that you have moved the labs all around, it feels a little funny to see the old main lab in the intro and outro! Sears always had major manufacturers make their house brand devices. It is possible that the design really is a SUN product though it really does not matter. Nice job as is your normal! Even my "old" truck (1973) has electronic ignition so the dwell function to me is not needed. So many people today look down on the old way to do things. A needle is much easier to use when doing things like setting RPM as it is the way our brain works, analog not digital. Great job on a device I had totally forgotten about! NOW TO THE UFO device!!! :D
Just finished fixing up a Canadian made Tuffy Tool model 1813 Tach-Dwell meter , thanks to this video. Having access to a function generator was able to calibrate rpm and dwell accurately. Was out by a bit due to out of tolerance resistors , linearity is perfect across the whole span of the meter. I use this for my Canadian ' 66 Malibu SS . Still running points as the car still has its original 283. Great Job Paul !
I like restoration of old Devices in your lab
Thanks!
I love Mr Carlson's Lab!
This is all new to me and I've driven lots of old cars. I'm off to a new video to fill that gap. Need to learn about dwell. I never fail to learn something new from these videos.
Glad it was helpful!
Hi Paul. Many years ago now, I used to be employed as supervisor of a small group of calibrators of mechanical meters. The device should really be calibrated and used in the same way, that is, if it is to be used standing up, it should be calibrated so, or if used lying on its back, then calibrate it in that position. With a good meter, any difference should be very small, but nevertheless when we issued a calibration certificate it would only guarantee the stated accuracy if used the same way it was calibrated.
You need to adjust the meter movement so it works right in all positions
@@geraldstewart very few mechanical meters will give precisely the same reading in ALL positions. Hence, a tolerance is given, and the instrument is tested in only the positions it is expected to be used. For example, a mechanical AVO meter could be calibrated both vertically and laid on its back. If then used on its side for example, it could be outside tolerance.
For those wondering why 'dwell' matters in old cars with breaker point ignitions: The dwell angle is the number of degrees of crankshaft rotation in which the points are closed. During this period, the magnetic field in the primary winding of the ignition coil is building. When the points open, the magnetic field collapses quickly generating a brief high voltage, which is stepped up even more in the secondary coil eventually arcing across the spark plug gap. The longer the dwell angle (i.e. points closed), the more time there is to build a magnetic field in the primary - an increase in this magnetic fields leads to a higher voltage at breakdown and a better spark.
The dwell angle is set by adjusting the breaker point gap - i.e. how far apart the points are when they're pushed open by the cam lobe. A larger gap implies a smaller dwell (inverse relationship) because the breaker points in the small dwell case are adjusted such that they open sooner on the cam lobe and are ultimately pushed farther apart at the top of the lobe.
Because breaker points can be pitted due to arcing, adjusting the points gap distance (with feeler gauges) is relatively inaccurate (as the points faces may not be flat) and having a dwell meter does a much better job at getting a proper adjustment. Incidentally, I believe vintage race cars occasionally used dual point systems (and possibly additional coils ?) to maximize coil charging at high rpms - a scheme where every other ignition cycle would take place on the alternate coil/points set that would be fully charging during the previous cycle. I may have the details of this last part wrong. Anyway, I hope this is interesting/helpful to someone out there :-)
Very well said!
The ignition dwell angle isn't derived from crankshaft rotation. It's is derived from distributor rotation. Crank rotates twice the speed of the cam. For example a 4 banger has breaker lobes that are 90 degrees apart, so the dwell angle would be around 45 degrees.
blobscot
It is not actually a secondary winding in the coil.
It is an overwind -- much as the overwind in LOPT
[Line Output Transformers Transformer] used in
devices employing a CRT
Other than this small error in your description, all
is accurate
@@MrCarlsonsLab No points in todays cars ???
Thanks for the explanation because I was wondering about dwell angle!
Super fun. Thanks Mr. C. It is appreciated.
Also.... Being that this meter is so accurate, Is there any way to mod it ? So that you could use it for 1,2,3 and 4 cylinder engines ? And to also increase the max rpm to 24,000 for motorcycle mechanics ?? It would be a great tool for finding or setting up the powerband, because there isn't much if any lag-time ! Love your channel !
Gearhead for all my life. Mostly sports cars but also motorcycles. My dad was a mechanic all his life. I have most of those tools. Glad I won't be using them anytime soon as I sold all of the ICE cars and bought an EV in 2018. More fun to drive and will blow most muscle cars off the road. Don't miss the gas station or the smell. Great video though. Brings back memories of tuning old cars to pass emissions.
Nice video, does the square wave swing from positive to negative or just positive to zero volts? thanks.
It's goes from zero to positive, no polarity change.
10:25 - That look like gain-inaccuracy as opposed to linearity; the error increases with frequency.
Probubly a hex
Precision! Lmfao. Love it.
No battery required. :)
Now we wait for 45096 to go for >$1000 on ebay - lol
It's unfortunate that this happens when ever I restore something.
@@MrCarlsonsLab LOL. I enjoyed seeing that this morning. That was quite the lesson; thank you. I tinker with my 1949 CJ3A (which I repaired and installed the engine myself back in 2007) and I need to put the motor back together on my 1974 Beetle. For that I need to set the tac and dwell, That I have no real idea how to do properly. In the '49, I adjusted the points and turned the distributor until the motor ran its best and sounded the best. A 2.2liter Go Devil engine is not too picky. The beetle on the other hand is. I did but a digital tac/dvm about a year ago. I will be testing it the way you taught in this video; thank you!
Now let's see you tune up a car with that thing (I know it really isn't what you do on UA-cam, but you would do it in such a way, that we could understand what it really being done.
I wonder how can someone dislike a video with this level of knowlege and care. Congrats, Mr. Carlson. Your content and you are simply awesome.
Trolls...every channel has them....🙂
Marcos Souza
Those that dislike the video presentation are likely those who
have little to no knowledge on the subject matter, and perhaps
have the attention span of a house-fly.
One cannot teach those who choose to live a life of ignorance.
The tragedy is that they take pride in their ignorance.
@@andrew_koala2974 I think you got it spot on. I don't have the hands-on knowledge on the subject-matters Mr. Carlson shows us (very little practice, I only got the theoretical electromagnetism part of it), but I admire the simplicity and practicality he demonstrates in every video.
Also, I really appreciate the old and new equipment he shows and restores (we never saw 99% of those brands and products in Brazil).
Jealous trolls that will never amount to anything is how dislikes happen. They have nothing better to do but what they do best. Troll
This is unique, always surprised by how your acumen in electronics applies to so many different fields.
Thanks for your kind comment Jim!
I have a Hawk hand held dwell tach meter and the casing is exactly the same shape as that circuit board so, mystery solved.
Nice catch !....cheers.
I was just going to post the same.
Now we know who made it for Sears
My old man taught me this, on a Craftsman in the late 70's early 80's..He's missed. Thanks for this
Glad you enjoyed Charles!
You have to remember that this meter was made during a time when Sears cared about making products well instead of today's habit of making things cheap and customers having to come back to replace it much quicker.
Absolutely!
Gregory Thomas
The CORPORATE Empire which now controls and operates a de facto Government
with its BS HQ in Pennsylvania Avenue in the District of Corruption - You may have
heard reference to it as DC -- The Currency you work for goes Directly there.
They are connected to SkyNet and have their hands in your pockets and have made your
employer to act as their collection agent.
You may be a GT but you cannot outrun DC
Good luck and goodbye
I'm sure that 'Sears' as it existed back in the day, still cares about good products. The problem is that all the people and ethics associated with Sears as it used to be have retired, been pushed out or otherwise replaced with sociopathic greed-mongering hyper-capitalists. It might be money that's the problem, or perhaps it's just unethical folks that just want to use us all to make a quick buck. In many ways life in 2021 is of a much higher quality than in 1960, but our money buys so very little now. I was born in 1990 and even I've seen a drastic down-turn in my 31 years, in the quality of products. We have to bring back more stringent product quality regulations and penalize outsourced production, while incentivizing local production sources.
Great video. Thanks.. The wedge shaped PCB is probably because the same board was used in a hand-held device variety of the same meter. Just a guess..
You're probably right!
I work 6 mechanics. Not a single one knows what a dwell meter does. I had to teach all of them how to set points with a feeler gauge.
The younger generation. Yikes!
Yes, we are dinosaurs now :^) Wait until you have to teach them float level and float drop adjustments... That will be fun.
@@MrCarlsonsLab Wait till you have to teach them how to strip, clean and align a pair of SU carburettors. More so if you have to show them how to set up a bike with individual carburettors per cylinder, and balance them.
Feeler gauge? An old timer once taught me that if you ever got in a jam, use a book of matches. One side for points, fold it over for the spark plugs. It wouldn't be accurate, but it will get you home. Not really realavent today, but if you own a classic, it comes in handy.
@@MrCarlsonsLab Sometimes I feel like a Tetradactyl at a petting zoo. The kids are scared and cry out old and ugly. But I’ve lived long and was built for functionality.
@@VitoVeccia Also you really need to know what more modern vehicles use the same points, plugs and capacitor as your classic vehicle. Many spares suppliers only have a look up book that covers the last 40 years of vehicles, so if you drive something from the 1960's, you will get the "we do not have any" response, but if you ask for the more modern one they find they actually do stock it, and you get the last one or two, that have been on the shelf for 3 decades.
Thanks for the video.
Sears tune up equipment was always very accurate OoB. I owned several over the years. In the 60's, the name they were sold under was Penske, as in Penske Racing
Working on small sports cars, the most important readings were usually for low idle speeds. High speeds were not used as much, except for maybe checking your tachometer.
The dwell meter was especially useful as that was the function that indicated the quality of your distributor bearings and points-springs.
I was kind of hoping you were going to have to build in some calibration controls if this didn't have any originally. Please set aside some time in the future, to do one of those too.
Thanks again.
love the video but i might suggest that a brief description of how the circuit converts hz to meter movement for rpm and duty cycle is converted for dwell
How ironic that you did this video as I just recently found a really nice Sears unit in someone's trash that does all these tests plus it has all the plug in test cables with it. Unit is in great shape. I'll probably never use it other than maybe the voltmeter and ampmeter. Looks good for the bench though. Also got a near mint complete old g.e. beige plastic portable record player. Can't wait to check it out.
It has other uses believe it or not. It can be used to retrieve codes from OBDI Ford's, and it can be used to place a load test on circuits. Before condemning a purge solenoid, you can put the meter in its place, and it load tests the circuit so that you don't need to do voltage drop tests.
This is like apprenticing to Gandalf. All the old knowledge, spells, but most importantly, wisdom. You cannot buy this anywhere.
I wish I knew half of what he forgot in electronics.
I don't think he has forgotten anything
I think the last time I used one of these was probably 1983 and yes, it was from Sears! That and the stroboscopic timing light. Fun times.
Speaking of Sears Roebuck and Co, some decades ago you could buy from them model T spark coils. We bought one as kids to use for making a Tesla coil. That was around 70 years ago.
Hi Paul. You have just made lot's of shade-tree mechanic's and hometown racing team's Very Happy !!!
There is no "big thumbs icon" so I will let you know in write I REALLY ENJOY YOUR VIDEOS !!!! thanks a lot for taking the time with this great, educational and quality produced videos!!!
Thanks for your kind words Edgar!
Hi Paul,
Had the same unit. Saw less use when the HEI distributors started making an appearance. Don't know where my unit is now. I sold my shop when I retired in 2018 and closed down my trucking company. Enjoyed the video. You and the family stay safe. 73 WJ3U
When I started doing mechanic work over 50 years ago that was the tool to have to get your car is running great. I really enjoyed this video. It’s because of videos like this that I became a patron sometime ago. The only thing I can use my old dwell tachometer on is the tractor.🤣👍 I look forward to all your videos. Keep safe Paul.
Thanks 👍
Bradley Leben
Becoming a patron was an excellent decision.
There is always something one can learn,
irrespective of age or experience.
It might be interesting to also have the complimentary video: How to Tune an Engine with an Oscilloscope. : )
That is the cleanest dwell meter I've ever seen in my life lol didn't know it can go out of spec sitting in a box.
Fine work, Paul. I thought, this thing will show/ give bad numbers by its nature of construction. But i was proven wrong. May I ask you something? Can you imagine to layout an build a special tool nobody ever made available , but a lot people need? I talk about an instruction or tool to check and calibrate wattmeters für HF and maybe VHF, too. Something to check an align in the 1W to 10W range, 100W will be a problem i think...? That will be a real great thing worldwide.. 73 de Olaf, Cologne-Germany
Thanks for your input Ole!
I just calibrated a somewhat similar unit to the one in the video (a hand held style) that was also sold by Sears (Made in Japan). It could only read up to ~1000 RPM on the V8 scale even at the highest setting of the calibration potentiometer. I opened it and found a single electrolytic capacitor (47uF/10V) which is laughable since the unit normally run in a 12V-14V environment. I replaced the capacitor with a 47uf/50V and it worked beautifully and calibrated accurately throughout the whole range. Thought of sharing this for anyone who may contemplate such calibration.
On a 4-stroke engine, each cylinder fires every 720°. The ignition system fires every 720°/(# of cylinders); Let's call this the "firing angle". A 4-cylinder has a firing angle of 180°, a 6-cylinder has a firing angle of 120°, and an 8-cylinder has a firing angle of 90°. The dwell angle is the rotational angle of the distributor the points are closed and the coil is storing up energy (magnetic flux) for the next spark. The tricky thing to remember, is that the distributor (and cam shaft) spins at 1/2 the speed of the crankshaft. The voltage on the coil's low terminal is small (near ground) during the dwell time because the points connect the low side of the coil to ground, or ground through a low valued resistor.
For calibrating a Dwell Meter with a pulsed signal of variable duty cycle, the dwell angle is the fraction of the distributor rotation angle where the waveform is "low" (near 0V).
Distributor Rotation Angle = 1/2 Crankshaft Rotation Angle
Dwell Angle = (1/2)*(Firing angle)*(1-Duty_Cycle)
For the 6-cylinder case with a 50% duty cycle, the Expected Dwell Angle displayed on the meter would be
Dwell Angle = (1/2)*(120°)*(1-0.5) = (60°)*(0.5) = 30°
It's not 50*(0.6) gets you the same answer, but I think you switched the decimal points around on the two numbers. I thought your viewers might appreciate a more detailed explanation.
The dwell angle can be controlled by adjusting the "points gap".
Side Note: PWM methods (frequency to voltage conversion, and duty cycle measurements) generally have excellent linearity.
The reason for the wedge shaped circuit board? My guess is that the manufacturer used the same board for the handheld model where the board is mounted in the handle with the meter movement above it.
You are probably correct.
Wedge shape: probably a board from a hand-held model.
or it allowed more circuit boards condensed into same physical size board. rotate every other circuit layout 180 degrees, then angle cut between them. :)
Excellent. I have a Dwell/Tach meter that is much cheaper than this lovely thing and have used it since the 90s. Now I need a function generator to test it! There's always something 😄
I had a Sears VOM back in the early eighties and it was a pretty good meter. Not Simpson quality but plenty good for general use. I don't know if it's still spot on anymore but I'm not surprised your meter came back around with a little tlc.
Very nice avatar Deacon Blue! I love my Simpson too. BTW: My SG membership card labels me as a "Healer of Appliances".
Bravo!
IS THIS REALLY FAIR! for a old school car guy this is like hiding peas in mashed potato's. twisting electronics with automotive, I love your videos this one made me think of all the times working on cars with a meter like that.
Ive been looking for how to do this for ages. I have 2 of these. One is accurate and the other not and I didn't know how to fix it. I'm impressed with how easy this is to do. Thanks.
You are welcome!
Mr. Carlson,
I’m sure that you are aware that companies are not going to spend the time and the extra 5 cents to solider connections correctly. They are all about PROFIT. They make things now as cheap as possible and sell them for as much as possible. Products like this are made on a assembly line as fast as possible and as cheap as possible.
I was going to congratulate you on 300k subscribers last week and didn't get around to it. So, congratulations on 301k subscribers! Thanks for your great videos!
Wow ,I haven't opened a Sears Dwell meter , I didn't realize how much adjustment was avalible,Great video,
with these d'arsonval needles I also check needle balance {weight at end of needle}. This is done in horizontal and vertical position of meter to check that 'zero' position doesn't change. AAAHHHH memories.
Hey Paul. Now that you are using my kind of precisin tools do you need a new ball pein hammer? Hi Hi 73 W5DN
Back in the day we used to buy open frame 1mA movements from Farnell (IIRC), and they'd arrive in all sorts of states!.....requiring spindle adjustment top and bottom to keep the coil level as well as adjusting the freeness of the movement. Yes, it was an art to get it all adjusted perfectly and linear.
FYI, one would use a dwell meter while cranking the engine, usually with plugs remove, and set the gap while watching the meter. This also avoids getting oil on the point faces since you are not using feelers. Nice vid man
If you think about this cheap supermarket little instrument, actually it is applied analog computing.
Please don't keep us in the dark. What kind of car are you working on? I have a 1933 Plymouth, a 1950 Ford and a 1968 Corvette. So I am very interested in vintage cars.
I will probably pull the radio this winter and do a restoration on it. (I'm always to busy to do restorations for myself it seems.) I will reveal the car at that point. Thanks for your interest. Your 33 sounds very neat!
@@MrCarlsonsLab My Dad bought the 33 Plymouth in 1954, right after he got out of high school, and my parents went on their first date in this car.
I rebuilt my serious exhaust gas analyzer and got It working flawlessly once again
You always impress me. There are times I laugh. You are a very good technician. As a retired Broadcast Engineer who cut my teeth on valve technology, I feel that you are a little bit excessive on the safety of high voltage circuits. It is still better to be safe. On transmitters we ALWAYS did several things. Remove all jewelry. Keep one hand in a pocket. Us the shorting stick to verify the power supply is discharged. Good work! Excellent audio! As always, nice production.
The main thing here is that he has to be careful about safety warnings because he doesn't want to get into trouble if someone does something silly.
Robin Cross
Exactly.
When I was studying Electronics Engineering and Electro-Mechanical Engineering.
(during my 30-year long Military career - Airforce) - The practical side of things was
done with PHILIPS who were building the avionics systems for our U.S. built fighter jets.
My then Mentor suffered a cardiac arrest when the metal bracelet on his watch attracted
an arc from an EHT lead that had been punctured by an unknown technician -- presumably
to measure the EHT voltage.
I learned from his experience and never wore a watch or a ring after that.
Besides keeping one hand 'in pocket' It also pays to stand on a rubber mat.
Rubber car mats are under $6 and a potential lifesaver.
I had the opportunity years ago. mid-1990s to visit a sign manufacturing business, where
they were making NEON signs - and one of their benches was a salvaged Stainless Steel
bench presumably from a commercial kitchen or Butcher - I was horrified when I checked
it to discover it was not earthed. - Suffice to say that the shop proprietor is Lebanese.
Perhaps he obtained the table from a Lebanese bakery.
Sears is a way better department store then CA ever had! The first Amazon. Where could you purchase a kit house in the 1920 in CA?
The circuit board shape prob comes from its use in a hand held usage as I am sure one of the big tool brands did a hand held dwell meter with a smaller case but same gauge and function.
Great video! I just bought a vintage Snap-on tach-dwell meter. It needs re-wired, but your video will definitely help if I need to adjust it. Thanks for sharing.
Glad to help Frank!
Being a car mechanic , its been a very very long time i checked ther dwell angle on a vehicle, ahh the good old days.....
It has a thin angular circuit board because the same circuit board was used in a smaller handheld version that the circuitry was in the handle and above it was the meter gauge.
Nice job. Good to stray out of radios and such. Maybe work on a cool old timing light next?
Impressed is somewhat miss-understated, I really did not expect this 'Pro'! meter to be anywhere near as accurate, (so much is labelled 'Pro' now days and it means crap really) hats off to the designer and manufacturer, they really came up with something quite special, obviously the meter movement is of quite high quality not something you would get today unless you pay 'think of a number and double it' price, the old school stuff wins again, thanks very much for showing this Paul it was VERY interesting to watch and see it truly shine at the end!
Thanks for your kind comment Keith, and taking the time to write too!
I've been a backyard mechanic since the 1970s. Over the years, I've collected several of these - '50s sun diagnostic analyzer, '60s Allen diagnostic analyzer, '70s Marquette diagnostic analyzer, '60s craftsman tach/dwell, '50s allstate tach/dwell, '70s sun tach/dwell, '80s sears charging system/tach/dwell. Wish I could post pictures here. Long term goal is to clean them all up & have them on display. Never even thought about checking their accuracy.
Starting to get into arduinos, and have picked up some low cost electronics equipment, including the xr2206 function/signal generator kit. Would that work for this process?
The XR2206 will work in the appropriate circuit, but you will need a scope that will read negative duty cycle and frequency.
I can understand your skepticism working on a Sears branded piece of equipment. It works the opposite way, also. 25 years ago, my cousin handed me a top of the line Carver receiver to repair. I was excited to get my hands on it. It turns out, the receiver was actually made by Pioneer, which was a bit of a let down. I did get it repaired and back to my cousin.
"Is that a REAL poncho or a SEARS poncho" - Frank Zappa :)
Sorry Paul, I tried to follow your maths on dwelling, starting with 60°, and then.... 50% x .6 = 30°. I lost track of the way you use these numbers. I could understand 50% of 60° = 30°. The .6 totally escapes me. Maybe it is the USA school way of teaching percentages ?
Hi Erik. The easy way to remember is the full scale reading. V8 Dwell has the maximum scale as 45° so you use X .45. The V6 scale has a maximum as 60° so you use X .6
The 50% shown is the duty cycle to get your reading.
I liked this Vid I Have a Sears Tack/Dwell meter it is a dual meter it also has a ohm/volts meter
Learned a few things on this video. Strangely not about electronics but motors!
You Or Genius Sir Very Detail Explain & nice Video Sir.
Thanks Paul! Got out my old ArcherKit Engine Analyzer to check the calibration and sure enough it was off! That kit had you do the CAL of the tach using a line cord with a few 56K resistors in series with the Hot and Neutral. You plug it in the wall socket and attach your test leads to the ends of the resistors to get 60Hz (ish) line frequency. Got you close, thanks for the video and math to check the other RPMs!
Glad it helped Mike!
Hi Paul, I was a little surprised when you soldered the first electrolytic cap, sans rosin flux. I learned from you how important flux is for every joint. Mmmm, just asking? I hope don't unfriend me for this. BTW I love flux and how well adds to the performance for soldering on anything that will take solder. Still love your videos Paul. Thanks for all you do. Gary ;-)
BTW I have two 32 oz. Rosin flux bottles #835 lol I missed out on buying the Wavetek, DOD instrument for $120.00 plus some easy shipping costs 4 years ago. Paul said it was a good device, makes me sad to know I should have bought it. Still I have have amazing HP devices for the same thing.
Good timing! I use my old Sears unit (later model than this one) but just bought a Heathkit Automotive Scope to test the dwell accuracy thus calibrate - I should have just waited for this video!!
The tapered PCB is probably the same as used in the meters that had a tapered handle with meter display at the top.
Paul, I look forward to learning from your adapter for this dwell/tach meter for it to work with 6V vehicles. Please show enough detail so that I can adopt _that_ to an 8V vehicle (i.e., a 6V Willys that starts a _whole_ lot better on 8V than it does on its original 6V! ;). I've got an "old" Sears dwell/tach test tool that I purchased in the mid-'70s that I'm sure needs a similar calibration like you've shown here.
Will do Bob. Should be an easy circuit.
...Sticky movement or static electricity on plastic lens. Easily removed but some moisture, soapy water, dryer sheet, etc. Thumbs up!!
Ooo. Couple of good nuggets there. Thank you RMO
How about fixing an old a/c spark plug oscilloscope
i had at one time a hand held one with the same board . that's why the board is not square so it con fit in the handle
My lifetime career was in electronics! 3 years at Westinghouse, 18 at Kodak and 12 at Rochester Institute of Technology! Loved my life’s work! Over those years I collected dumpster dive test instruments bound for the recycler! Most need repairs!! Want to fix them! Ha ha! Thanks for the videos!
Glad you enjoyed Bob!
@@MrCarlsonsLab I have a 67 Mustang and 72 VW beetle and I still have my old Dixco tach/dwell meter to adjust ignition timing! Now I know how to calibrate it! THX!
I’m also restoring a C64 and disc drive, fixing some old cb radios and building cb antennas! I’ve been retired 8 years but I try to learn something new every day! Thanks for that!!!
I learned smth new again 😊👍 TY Paul!
I'll be honest, as much as I love older motors and older electro-mechanical systems, this stuff is why I'd much prefer to drive a vehicle with an electronic ignition haha. Great tutorial though, I'm sure this will come in handy due to my fetish for old automobiles!
Thanks mr. Carlson. Interesting as always. That studio mike is a gem, excellent sound quality too. I'd love to see the electronics of that.
All of the timing on my race car is done in the ignition box. My Dad and brother have a race pak in their car and we can change the timing during the run. I do have a dwell meter and a timing light in the garage in a box. I should dig in out and give it a go through. Congratulations on 300K Paul!!
Yet another great video and Paul your knowledge knows no bounds !!
Thanks 👍
Always excited to watch another video of you!
In the old service station I worked in back in the day, we had a big "SUN" cart with several types of portable meters you could select. The only one I ever saw any mechanic use was the Tach/Dwell meter. I was well worn while all the others looked brand new. It took a lot of punishment. No idea how accurate it actually was. LOL!
Really a great educational video Mr C. on this type gear! I have a lot of Snap On electronic gear from my fathers garage that could use an alinement and refurbishment!
Glad it was helpful!
I have an old, different Sears Tach-Dwell meter too. I think I'll be doing this now. Thank You!
Glad it helped Bill.
Had one in the early 80's with the wedge shaped circuit board. It was also a Sears but was a hand held unit. The circuit board was in the handle and the top was a meter. Looks like when they made that model you had they could not be bothered making up a new board for it. Great video as always Paul.
Thanks for stopping by Buddy!
Now now, Mr. Carlson, there's no need to mock the dead... though it's pretty funny. 🤣 RIP Sears, the once-great retailer bean-countered to death. Do you have a vehicle with a 6-volt electrical system? 👍
Hi Ted, Yes I do. You will get to see the radio get restored one day too :^)
@@MrCarlsonsLab Awesome!!! Looking forward to it.
Great video, thanks for sharing!
Great topic. I have a vintage SUN dwell/tach meter and I just didn't feel like digging in the math to figure out how to simulate pulse train that will simulate engine RPMs or dwell timing. It is pristine except for some slight surface scuff in the paint. Internally it is totally clean. Not sign of any battery corrosion at all ever
Just curious why you would say this would not work on 6 volts? Just the nature of the way it works I would not think that it would be very voltage sensitive. I have a Niehoff T-70 Dwell/Tach meter that I use on my 48 ford pickup that is still 6 volt and it seems to work just fine. I will be checking the calibration on it now. However it did appear to be working pretty accurately. You do have to wrap your head about the positive ground aspect of it when you connect it up however :-)
Hi Jimmy. This meter has no internal battery, so the circuit is powered by the distributor. This limits the internal circuits function. You may want to check the accuracy of your Niehoff, as most dwell-tach meters will read at 6 volts, but with accuracy issues.
@@MrCarlsonsLab Will do, Thanks!
Glad I don't use points anymore, ie, gained 40km per tank-full switching to electronic.
Now, how can we test if our cheap timing-lights have lag, ie, read late - lol -.
Very interesting and a very good video, Paul; much enjoyed.
Glad you enjoyed it!
I always ask "if it says professional, Is it?"
Great video! Once again I learned a lot from your videos. Thanks, Mr. Carlson!
Thanks for the feedback Robert!
My father had a tach/dwell meter, (which is still (probably) in his garage ;-), that he used to make fine adjustments to the points on his 69 Imperial. They used to call me "Mic Eye" when I was younger cause I could adjust the points without a feeler gauge. (I couldn't really tell the gap, but I had done it so much that I could get it REALLY close, so close that dad rarely had to adjust them once I'd set them) Thanks for the trip back in time Mr Carlson!!! I sure do miss my dad!!!
Thanks for sharing your story Brian!
Please do a reverse-engineering video on this. I’m especially interested in how the “dwell” function works. I would have expected an integrator to convert PWM->analog voltage, but that would make the low end (15 degrees) to be at the left of the meter scale, and the high end (45 degrees) to be at the right end (full deflection) of the meter scale.
Excellent video! I am really looking forward to the analog instrument movement.