Datsun L-series Valve Adjustment
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- Опубліковано 17 жов 2024
- I did these videos several years ago. I had previously only put them up on my photobucket account and then on Ratsun.net. I just came across them again, so I thought I'd combine them and post them to youtube. Not sure about the vid quality from the old camera, but it should still be helpful.
Further tune up info I posted on Ratsun a few days ago
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Ready to show my trucks’ valves some lovin! Thanks mate.
Cool. :) If it's a Datsun, you can download the factory manual for free...here..... www.bluehandsvideo.com/manuals.html
This hands-on video was invaluable to helping me adjust my valves on my L28. It's so nice to actually see it and almost have a feel for it ahead of time. Thank you!
Incidentally the bolts were so tight on the valvetrain I needed a 1/2" breaker bar to loosen them. That was the special tool I actually needed to do this job. I know the motor hadn't run in 10 years because it was my car, but I had no idea how long it had been since the valves were adjusted. Someone could have King-Konged them so tight or they were just frozen in time. I used a 3/8" torque wrench to turn the crankshaft bolt. I didn't have to jack the car up either...I just crawled under the front of the car and turned the crank 1/20th a rotation at a time (or as much as I could click it before it hit the floor -- it can't be accessed from the top due to the fan etc) and after finding TDC, following the firing order in the cylinders from there worked out really well for me. It took me a few hours, I was careful with every move I made and I did it cold, but I did it right, and the car responded very well. I'm getting 17.5-18inHg at the intake manifold now and the car is running great. it was a long incremental journey to that from the 10.5in I started with when I first got the motor running but the valve adjustment made the biggest single difference.
Incidentally, the torquier (sp) motor after the valve job was making my slightly loose fan belt slip on the pulley when I was on the throttle and the noise was making me cringe until I found out what it was. ;)
That's awesome!!!! Thank you so much for letting me know. I'd love to do a newer version of it, but it's gonna be awhile before I'm under the hood of a Datsun again. Any chance you're on the west coast? We have guys from CA and Canada come to the 2 day Canby event every year.
Thanks!!!
Mike
bluehandsvideo
East coaster unfortunately but thank you! This video is pretty much textbook imho. The L28 lash adjust worked exactly the same as this, there's just more of the same to deal with. I was nerdy about it and used a clipboard with a pen in my shirt to keep my E's and my I's straight as I went along the valvetrain. Actually I had a minor problem on one of the valves where the head of the crowfoot was making contact with a head bolt when I was trying to get it around the adjustment bolt. I've heard of people breaking the tops of studs before so I was careful not to put too much if any real pressure on it. I ultimately couldn't use the breaker bar on this particular valve and had to use a regular (thinner) wrench like you did, but with a hammer and some light tapping included.
I'm still very much enjoying having added those last two inches of vacuum. The car is purring thank yous your way too. The perspective and intuition and confidence from your video truly helped. I watched your entire video two maybe three times before doing the job. Thanks again!
heymisterderp
Thank you!!! I really appreciate your feedback!!! :)
Maybe I should be doing car vids....they seem to help the most. :)
I'll be restoring an 83´ 280 ZX Turbo over the summer, your videos will be very helpfull! Thank you!!
You're more than welcome! I wish I'd had the better camera back then :)
Nice video. To make things go easier and faster I'd recommend buying a special wrench the Datsun Z vendors sell that enable you to do the job without having to lay two wrenches on top of one another. Makes it much easier to maintain the proper setting when tightening things up. Also, you don't have to pull the plugs and crawl under your car to turn the crank to rotate the cam. Just jack up the passenger rear wheel, put the car into fifth-gear, release the parking brake, and rotate the tire by hand to precisely place the cam at TDC, then just follow the firing order as you go through the valves. Goes much, much, faster, which isn't such a deal on L motors that are adjusted cold, but is a deal on other Datsun motors which are adjusted hot (e.g. U20).
John Baker Great information John! Thanks!
Awesome! Thanks for coming back and posting the info! :)
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So if I wanted to waste time... I make the first lobe towards the front of the car pointing up check and adjust it. Go to second lobe, point it up check and adjust and so on? Am I checking every one when it is straight up? Looks like some of the ones you did were still canted sideways...
I'm guessing I don't need to answer this a year late...dang YT notifications. :( ...... When you look at the cam lobe, you'll see that it's the same diameter for an 1/8-1/4? of the rotation. Straight up would definitely be optimum, but pointing the lobe to 11 or 1 oclock should still be okay.
Thank you for the posts and all the advice/suggestions
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You're more than welcome :)
Hmmm.....I have zero experience with the 240Z, but it should be the same motor, just longer. The 4cyl L-series manuals are on the Tech page of olddatsunsdocom You might check in there and see if they call for the same tool. I don't remember any special tool being called for. At least not for the adjustment. If you're changing lash pads, there most likely is.
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there is a special "wrench" for torquing the adjustment lock-nuts
If either of the carb butterflies are open too much at idle, that can cause run-on(dieseling) too. More correctly.....it adds to the causes of dieseling. For the engine to diesel, it has to still be getting fuel somehow and then it has to have something igniting the fuel. A mis-adjusted carb can cause the fuel issue and carbon deposts can create the hot spots(act like a glow plug). I posted a wordy carb adj procedure on ratsun just a few days ago.....
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i need help with my 280z.
before take out the head i aline the #1 from the timing chain to the camshaft point but i saw its was in intake stroke. what shoul i do.or any recomentation..
I wish I could be more help, but I haven't turned a wrench on a car in at least 5 years. lol I'm not at all familiar with the 6 cyl engine. There's lot's of guys on Ratsun.net that are. Do you have a manual? You can download any manual you need at datsunforums.com www.nicoclub.com/datsun-service-manuals
I'm guessing that you're trying to get the crank lined up before you remove the head. The crank's TDC mark will pass it's pointer twice for every one time the camshaft turns. You may need to just turn it around one more time. You can also check your distributor to see if it's pointing at cyl 1 spark plug to help confirm.
thanks alot.
you're welcome :)
down 'n dirty: mark the cam sprocket tooth that mates the marked chain link. Pay attention to dowel hole in middle of cam sprocket (number) Replace in exact same relationship. Also, get or make "chain wedge" so you don't have to take the front off the engine. Distributor will only go on one way
you should "feel" for the lowest spot on the cam "heel" (by rocking the enginge back and forth),for an accurate adjustment
Ok.
Feel free to do a video showing that technique and send me a link...I'll put it in the description box at the top.
You're more than welcome. :)
I messed up on my reply....it looks to be at the top.
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So I have a 1980 720 4x4, carb., l20b, factory everything. It runs fine, and reliably, except for an annoying ticking noise as you accelerate (basically anything over 2000rpm, but not at idle.) It has had all hoses/fluids replaced, the ignition timing has been correctly adjusted, it has the correct (new) spark plugs. Would the valve adjustment be the cause? If not I would apreciate any suggestions.
It also diesels sometimes when you turn it off, dont know if that helps...
Thank you for the video
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run a tank of Chevron premium through it. Clean the combustion chambers. Try reducing the timing a few degrees to see if it helps. Might be "pinging"
ever take it out on the freeway? (clean it out). How did the old plugs look?
Did the wrench sizes in this video work for your 240Z head by chance ? I need to adjust my 240Z head as well i can fit a ton of feelers stacked up in the gap between the cam and pad..
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wrenches the same. "Z"s have cam spary bar which 510' don't. Same head, just 2 cyls longer
If you you're keeping the stock exh mani, I have a 3/8" downpipe flange available on my site. Link posted above.
:)
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I put a link to the post in the description above since I can't put it here.
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Will this work for a 79 datsun 620 5-speed? I think its a L20B....
Should. The technique will be the same, but the lash spec might be slightly different. Are you familiar with olddatsuns.com?
www.davidcmurphy.com/olddat/html/tech/620L20.htm
Yes; specs may be different
I do it this way; put the 1 cilinder on compresion and 0 degree on the crank and so the admision and exaust valves will be closed 100%. Then you adjust admision and exaust from cil 1; adm from 2 exaust from 3 and none from cil 4. After that rotate 360 on the crankshaft and adjust the remaining valves.
+Mauricio Nuñez That way works just fine too. Without watching the vid again, I couldn't tell you how I did it in the vid. No time to watch it again. Thanks!
Just a Datsun enthusiast and hobby machinist. :)
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Actually the manifold is probalby the only thing besides the cat converter (depending on how clean it is) I will keep. The rest of the piping and muffler are going (replaced probably by a glasspack for more flow). Currently I am running my first tank of the concentrate cleaner, if the second doesnt clear it up I will decide if I want to tear it down and clean it myself or just take it to the mech. in town and get him to clean the whole thing. But I will look into the flanges
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Thanks for the info Thejimmyyyc and bluehandsvideo.
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How do you adjust them hot?
quickly! LOL But seriousely....the manual will state a "hot" and a "cold" gap. My preference is to do them cold. Once you stop the hot motor and take the valve cover off, you start losing heat. If you can't do the adjustment very quickly, the gap will vary from the first valve you adjust to the last because the motor cools. So....adjust them while the motor is cold. Once you're done, warm the engine up to operating temp and then "check" the valves to make sure they are within the "hot" settings. You spend all your time driving with the motor hot, so you want them set correctly at full temp. I just don't recommend trying to set them while it's hot. Set them with the motor cold and then verify they're correct when it's hot.
same as cold. Be prepared for hot oil on your hands; You have to do it a couple of times because it cools off too quickly.
Yeah I can imagine it needs a good cleaning, the carb is just about spotless, but when i removed the hose feed on the top of the valve cover to the carb pan, i could see grimy build up just through that quarter-sized hole. I will look into the chevron super, if that doesnt do it, I will break out the ratchets and toothbrush. Either way the click must go, I plan on rebuilding the exhaust (needs it anyway) for more output and dont want it sounding like a machine gun going down the road.
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I would clean or replace the PCV.
as i recal
in the book it was .30mm on the exhaust and .25mm on the intake
+Faisal Abdulaziz Been years since I did any valve adjustments. I don't remember what I set these to, but I'm sure I got the specs from a manual at the time. They did vary a bit between years and engine size.....and this wasn't the original engine to this car. Thanks!
Mike
Sounds like a question for a real mechanic. I just play one on youtube! :) lol
The ticking could be valve adjustment....possibly detonation too. You might try running two tanks of Chevron Super through your rig. It will clean out the fuel system and top end as well or better than any additive in a bottle. If you have carbon deposits built up, that could cause detonation and the dieseling. The other cause of dieseling can be the anti-dieseling solenoid not working or being hooked up.
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An upcoming project is going to be some aluminum landing gear for a friends RC Heli...... :)
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I set mine one thou tight cold. Recheck hot. A thou doesn't matter? Why bother doing it?
A thou is 1/3rd the thickness of a human hair. The gap could change that much due to temp change if someone is setting them hot......by the time they set the first one to when they set the last, the temp drop could cause more change than that. I understand what you're saying and why it's better to check it cold(more consistent), buy on a motor this old, the tolerances weren't that tight when they were made.
OK, then why bother with the recommended "settings"? Why not 20 thou, or 6 thou? There is a reason.@@bluehandsvideo
@@donwest5387 I agree.....to a point. On an engine this old, I don't believe a thousandth change in the lift will be noticeable on a 50 year old motor. Feel free to do a video proving your point
Excellent video!
Thanks!
Nice Z! No vids of it. :(
hopefully soon good sir!
does this work on a 1972 datson 510
McMlx PlayzXD
I actually shot this vid on my 70 510 wgn. All the L-series are the same, but the specs change slightly over the years and motor sizes. The specs I'm using in the vid are L16.
K
This is a L20b yall not a L28 dunno is the clearances are identical though soo it MAY not matter but this is NOT a l28
It's actually an L16. I don't think I ever refer to it as an L28, but I'd have to watch the entire video to be sure. I know some of the commenters said it helped them with their L28's since it's very similar....just has two more pistons.
Awesome video
Thanks!
I need to do this but I'm too chicken to try it
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I think you're probably asking 'thejimmyyyc', but if he doesn't respond, you might try getting in touch with DTP or Skib on community dot ratsun dot net
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.010 for intake and .012 exhaust
Those are the WARM specs. I was doing it cold.
@@bluehandsvideo gotcha yeah makes sense now 👍
@@koheartsgpadatslocos8320 They cool off too fast trying to do them warm.....so I just do them cold.....but it's been many years since I've touched a valve train. LOL
cold: one thou tight(er)@@bluehandsvideo