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Lol, be sure to dust the scale and measure atmospheric pressure between each measurement too, right? And recalibrate the scale for each measurement, lol
@@VndNvwYvvSvv can’t tell if you’re being sarcastic… if you are then this is tenths if grams that he’s talking about so yes letting the shavings fall inside the piston and not blowing them off will skew the measurement.
since im not a machinist, I would try to mix the wrist pins, like the heavy wrist pin in the lightest piston and vice versa, untill you get an a closer average, ( my comment was made at nine minutes) but yeah good stuff.
I used use a sharp knife to remove aluminum. It's cheap and accurate. Works for porting aluminum cylinder heads too until you need to work the valve seat area
Small tip if you want any and it's purely subjective but I'd cut some of the more boring parts. 23 seconds lost watching pistons weighed . All I want to know is how much they weighed.(for example) Subbed
Cheers for the feedback Maverick! We get people asking for that footage when we cut it out of the course material (they want to see every little bit) which is where this video is from, but you're right for UA-cam we should probably do it a little differently in the future. Appreciate your time =) - Taz.
Handy. I'll need this in a couple weeks when I'm assembling my RB25 Build, which is on my channel. Excellent video. Where do i get a highly accurate scale like that though, had trouble finding that.
@@DaveMcLain ya, even in a world where an ICE doesn't develop a little carbon buildup, just the minor amount of difference of surface oil retention on each piston could give you a gram either direction. But that's why I go to the hundredth.... which is quite the pain in the ass.
I was about to drill a small dimple on top of the piston. Heck, drill 15 dimples to remove 15 grams from the piston. Then to complement the reduction in piston weight, increase the boost by 15 psi.
Nice tutorial Andre! I have a question for you - when I designed pistons for a project, I spoke to the design engineers at Mahle about piston balancing. They told me to categorically never remove material from the underside, and only remove material from the crown area. This leads me down the path of settling the combustion chamber volume first, and balance after. Balancing the gudgeon pin/ wrist pin seems like the only viable option once you've set the compression chamber volume?
A friend of the family did this in a VW back in the day with... Are you ready? ... Are you really ready? A coathanger. Worked really well. I did a similar thing with 50/50 resin mixing once too
I've just done my Hayabusa engine build using standard pistons, there was 4 grams difference between the lighter one and heavier one? What a ball ache to match to the lightest one. I think if doing it again I would get another set of pistons that I can choose closer weighted ones.
0.01 Grams don't sound like much until you take into account how many G's a piston Experiences as it switches from going up and down TDC & BTC The piston itself will weigh upto 10 Tonnes (10,000KG) During Peak G-forces as it changes direction in the thousands of G's 0.01 grams becomes 20-30kg of unbalanced weight on piston
So i weigh out my pistons, pins etc. and my rods for the piston side (oscillating weight) and crank side (rotating weight). Now I matched the rods to the pistons (clips, rings and pins have exactly the same weight, so they don't matter), can I use it like that? My rods just have a difference of 0.2g, my pistons have a difference of 1g lightest to heaviest. Rotating mass of the rods have a difference of 0.2g (measured everything a hundred times). I wanted to get an overall difference of 0.3g max.
Amazing video. I have a suggestion/question: When pairing pistons with pins, instead of going for "heaviest with lightest" there might be a combination where you could pair them such that two pistons pin combos could have the same weight while being the lightest ones. This could make it so that you would only have to remove material from the other two pistons. My example is based solely on adding up the individual weight measurements from the pistons and the pins (I understand that weighing them as a pair could provide a slightly different weight due to rounding): Going piston 3 + pin 1 as well as piston 4 + pin 4 would give them both a combined weight of 450.2 g. While the remaining two combinations will be 450.5 g and 450.7 g. Do you think it is worth to go the extra effort to try and create pairs (or groups) of piston-pin combos with the lowest weight possible? So that you are actively balancing less pistons and/or pins? I suppose this will not always be possible, but I am curious if this is something people do.
Ideally you're trying to do it so you're removing the least amount of material rather than working on the least amount of pistons. When you're doing it yourself rather than being billed by the hour too an extra 15 mins or so really doesn't matter as it isn't a hugely time consuming process compared to other aspects of engine building, but at the end of the day you of course are free to do whatever you thinks makes the most sense and works the best for you personally - Taz.
@@hpa101 Makes sense. Thank you guys. These videos are amazing and I'm learning so much. And the fact that you're replying to questions from 2 year old videos. You are incredible!
You can do this to diesel pistons as well. Same rules apply when it comes to the fact there are areas where you want to avoid taking material from and others where it is acceptable remembering you balance to your heaviest piston to match them rather than getting them all to your lightest as that will see you needing to remove more material - Taz.
Love all your videos @hpacademy - can you recommend affordable scales to use? Given the total weight is not necessarily important, just the matching of weights between components, I suspect anything that measures to 2kg in 0.1 grams would be acceptable if it nets repeatable results?
100%, it's hard to see in this video but Andre directs the shavings from the dremel to go outside and away from the piston, not directly into it :) - Taz.
Great vid! 🤩 one question: we have anyway to take the conrod out, so it would not be also a good idea to weight them and match it, like the conrod and piston weights the same? Thanks and keep going to make videos like this!
Hey there DrSiech. Yes sir, your conrods can and should also be balanced. You avoid doing them with the pistons as an entire unit and I'll pop a few links here that will help cover this and it is also in the engine building course material. Quick video: ua-cam.com/video/TViHBkLZnx8/v-deo.html Some more details here: ua-cam.com/video/0tXbCqA2QHI/v-deo.html Webinar lesson on this specifically (paid content): www.hpacademy.com/previous-webinars/193-2/ Course material this is included in (paid content): www.hpacademy.com/courses/practical-engine-building/ Hope that all helps you out - Taz.
can you use the *small-end rod* weights to balance the piston weights? ( example: +1piston&+0rod and +0piston&+1rod) I have a piston thats like 2g overweight, all my pins and rings are all the same. i took out some material from piston, but i dont want to remove too much. so can i include the small-end rod weights when balancing? or is it better to just grind pistons and rods *Separately* to match smallest weight
Hey there Andrewdini :) 2g is not an excessive amount to remove from your piston, and your pistons and rods should be balanced independently. Your connecting rods will be balanced at both the big and small ends, so taking excess off one for the sake of your piston would actually see you taking off even more material to balance that out across your rods, which is something you don't want to do. Just remove the material from the correct location as shown and you will be find :) - Taz.
so i found alot of people talking about removing the material from the piston/ wrist pins. someone online removed material by the bottom off the piston, and you removed the inner sides of the piston material. will this be better on how u did it to reduce the cause of engine failure?
Hey Brandon, Great question. In our opinion where we have removed the material from is the safest place, however, by nature, you have a few options on a piston that won't be detrimental when compared to something like conrods where you have to be very calculated and careful where and how you remove the material. Cheers! - Taz.
Late reply but if it's an aftermarket piston I would be returning it for a replacement. 2.14g out of weight with the rest isn't great QC. Generally any half decent piston manufacturer should be matching their piston weights across production such that a particular set doesn't have that much variance.
Enjoyed the video, very informational. One question on rounding to the nearest tenth of a gram. If you round, it's possible that you end up with piston/pin combos that are .18 gram different. For example a piston/pin are 450.36 grams (rounded to 450.40) and another piston/pin is 450.60 and by grinding material off we get it to 450.52 (rounded to 450.50). These two pistons are a tenth of a gram when rounded, but in actuality are .16 gram different. Is that difference acceptable? Or do you try to get closer than a rounded tenth?
Hey, after going through a couple of $300-$400 USD scales from a company that will remain nameless, we ended up with more repeatable results with this set from Amazon of all places. It's important to note that consistency is more important than the actual weight since you're focusing on the weight difference - Taz.
Hey John, this is discussed in the video along with where on the wrist pin you should remove it from. Ideally though where possible you want to remove less material, not more. By matching the lightest piston with the heaviest wrist pin and then balancing via removal of material from an unstressed area on the piston, this is achieved - Taz.
Wouldn't it be easier to remove the material from the very bottom edge of the skirt? Seems like that would be the lowest stress area of the entire piston, and easiest to do.
No, thats actually one of the high stress area, the skirt is the part that keeps the piston straight up by rubbing the cylinder wall, with oil squirted on them of course. I wouldn't mess with something that has a very important job
I am planning to rebuild my 2008 Honda City 1.3MT Engine, Cylinder no 2 is weak, Engine burning 0.5_0.7 Liter between every oil change. I hope my C-2 will be doubLe in weight LOL.
I think I would degrease the components before weighing them. Not for the weight of the grease but to ensure that any ground off material doesn’t stick to the grease and affect the weight.
Another grate video! Some questions... Is there any reason to such a precision? The acceleration of a piston in a performance engine is what? 200000 m/sec². With a 0.5 grams of imbalance we are looking at 100 N of force differential. Is it enough to cause problems or to make a difference in the performance of the engine? What an imbalance o a gram for example would do to a performance engine?
It's up to you, Andre does mention at the start it might be other kill for some however you're balancing your pistons anyway and all it costs you to be a little bit more pedantic about the weight difference is really a few minutes of time, nothing else, so it's something Andre always does for this reason - Taz.
You are 100% correct. Balancing pistons is just 1 of 17 essential steps. If you're interested in learning the other 16 steps, including rod balancing, take a look at our engine building courses here - bit.ly/engbuil - Taz.
See that's what I thought. I always filed rings installed the rings into the piston. Installed the rod and everything then just measured all 4 in that sense. Then balanced the 4 to each other. Is there a benefit to doing each part separately?
Yes, you're weighing engine components, not tins of paint 😎 We actually went through (returned) a few expensive US made scales before we tried these out of frustration and found them to be better. Won't always be the case, there are some awesome scales out there, but again just shows you need to trust but verify, even if it is a well known brand name - Taz.
1/10 of a gram is useless. You will have oil splashing under the piston,being trapped in the pin,and soot deposits on the top of the piston after 5 minutes. it wil be out of balance constantly. a gram or half a gram is more than enough.
Oil, unlike the piston is fluid and will, thank to inertia not change direction as rapidly as the piston and mechanical components, this will mean the load it imparts is minimal in turn it's effect on balance will be minimised.
Oil is projected under the piston while it's going up or down,the cranckshaft is constantly rotating. it's completly doing the same stroke as the piston. that mean it's making more mass going up,and then is projected in the oil pan when the piston is finished going down. the fact it's fluid do not change the fact it's adding weight during the stroke up. if you have not the same volume of oil going under each piston (wich is always the case ),there is unbalance.
Fluids behave like fluids mate. It will not affect the balancing of the assembly. Else the air itself that the assembly rotates though would be factor at high rpm. Fluid dynamics bro.
So,if i pour 20 grams of oil in your left hand palm,and 5 grams of oil in your right hand palm,and ask you to lift and lower your arms they both the same weight ?
michaelovitch if you pour them on the side of my hands and it runs off...yeah especially at 80 to 90 degress where its about as viscous as water. Now if i start thrashing them up and down a few thousand times a minute, there will be almost none of any of it on either. Make my hands from polished metal... even less.
Zero and then calibration the scale before measuring. If you are doing the same for clearances then it should apply to balancing. If you have all the fancy equipment such micrometers, bore gauges, and calipers and are not properly calibrating before using then whats the point? It can be off just one time but that one time can be catastrophic. In this case calibration doesn't ensure precision, but if a scale is inaccurate I wouldn't trust it for balancing to a tenth of a gram.
If you were going for a specific weight, we would agree, however you just need the scales to be repeatable,, so if it's out by 5 grams so long as it's out by 5 grams every time it doesn't matter for this application - Taz.
@@hpa101 I agree if it is precise, and will consistent enough for everything to be balanced. Hypothetically, if the scale was reading heavy 0.53 grams every time and engine builder decided to subtract 0.53 grams from the balancing numbers. Once you take stuff out and find everything is 0.53 grams lighter would you trust that engine builder if he says the scales just always reads heavy without any proof? That is why during calibration they even write the difference in readings.
André, what I still do not comprehend entirely is when we use pistons and rods that are of different weight compared to the factory piston weight. The crankshaft obviously is balanced in itself. How does heavier / lighter rod&pistons affect the entire rotating assembly? TIA Dom
Balancing to a tenth of a gram is a fools endeavor when masses orders of magnitude greater than that in the form of oil, carbon, etc are uncontrollably and unevenly distributed on the rotating and reciprocating components of an engine. Also, any set of pistons or rods that isn't sufficiently balanced from the factory aren't worth buying and using in the first place!
Unless you're in Formula 1, you don't have the ability to accurately calculate and measure oils influence or carbon weights etc. There are some things that are simply outside of our control, so instead we focus on what we can control and do it to the best standard we can. To balance to the degree Andre has here, and he did address this in the actual video, it could be considered a little overkill, but it only takes a few more minutes than it would to do things to a lesser standard. For balancing from factory, it's all a matter of degrees of balance and you could quite easily run this kit as delivered. We tend to be extremely fussy so our target balance is just tighter than those of the parts manufacturer. We find that all of the aftermarket parts we use are outside of our personal targets if that makes you feel any better - Taz.
Absolutely agree that +/- 0.1 gram is a waste of time. Unless your reciprocating mass is extremely light, or your RPM's are extremely high, you do not need to balance to better than +/- 0.5 gram.
@@bunnyrabbit4972 what's the time difference between 1g, 0.5g and 0.1g when it comes to balancing? I think you will find it is negliable, but everyone is free to do things to their preference on their own builds for sure - Taz
@@hpa101 A typical high performance STREET engine will not have a peak piston deceleration rate exceeding 3000 G's approaching TDC at operational redline. 0.5 grams * 3000 = an instantaneous imbalance of 1.5 kg. This is nothing to worry about, and when you marry the light pistons with the heavy rods, and vice versa, the overall error is reduced further, below +/- 0.5 g.
Hard to see in the video but when you're doing this you're holding the Dremel in such a way all of the shavings are not going into the piston, they're going straight out. We just assumed this little tidbit would be common sense sorry, but I'll add a note to the description. Once you dive in yourself you will see exactly how that works :) Enjoy! - Taz.
You can speed up the videos on UA-cam (and also in the courses on our website) via the 'cog' button on the bottom right of the video window. I usually set it to 1.5 myself as because of our accent Andre does talk a bit slower and clearer than he would in normal conversation just to help those who are not native English speakers understand him better. Hope that helps! - Taz.
Sir i have royal enfield bullet machismo 350 cc it is passing through big problem pls help me. Oil comes from breather pipe what can i do for this problem i have opened head but when i kick the bullet engine oil comes from breather pipe
im tired of buying scales... i dont even know where to get a scale that can measure the weight of a piston and still be accurate to a tenth of a gram...
You need accuracy in the differential of weight, not the actual weight. You are trying to get them all to the same weight, not a set one, so repeatable results are what you're after. We spent a lot of money on scales before finding some cheaper ones did this best for us, but some HPA commenters have also mentioned that painters scales can be very accurate, a good size and also a good price for this usage ;) - Taz.
We did spend 200-300 USD each on two other sets from a reputable US company that surprisingly (and frustratingly!) didn't give correct or repeatable results, whereas these scales might not be 100% accurate if you were trying to get a specific weight, however they are accurate between weights (the difference) which is what we're after for this task. We do know that painters scales are also a good choice 👍 - Taz.
Ahhh sir... you ground the piston down at the wrong place and weakened it. Sorry but warranty is void now even though the piston is indeed defective. Sir, would you like to buy another one?
You can call your supplier before you balance your pistons to be safe and double check where they wish you to take the material from. This isn't something new or unknown to them, in fact in some advertising they will possible boast as getting their own product weights very close so that it is less work for you to balance yourself, which acknowledges their understanding that it is done and required for and by many :) - Taz.
@@hpa101 yeah I hear ya, was just joking around. Btw, is it required to balance the pistons? I've got a set coming in for my engine, didn't really want to do this unless it's necessary.
@@garyr7027 ahh sweet, sorry man, it's hard to tell sometimes with just the text as we get some surprising comments haha If you don't plan to balance your pistons and rods the way we do for high performance builds, say if you're just rebuilding a low power application for your daily driver, then at the very least you should still weigh and pair them in such a way to get them as close as possible as sets. This would see your heaviest rod with the lightest piston etc. It's your build so at the end of the day you can do as much or as little to it as you like 😎- Taz.
This is only to make super OCD people feel like they're doing something good. Lexus balances to plus or minus 0.5g...which means they only need a scale that measures to a whole gram! Go find something to do that uses your time better. Our shop balances rotating assemblies. We leave the crank a few grams heavy, so +/- 1 g on the reciprocating mass doesn't affect anything. You may need finer balances on 14k bike engines with very small rotating mass. Most aftermarket parts come within a gram on the heavier bits. 1g on an 1700g bob weight (typical for a modern V8) is nothing. Besides, the crank goes through different balances at different rpm, plus harmonics. Get a Fluidampr. It damps vibrations across the entire rpm range, versus elastomer ring style which work within a narrow band.
If you watch the video again you'll hear us cover the weight difference near the start, and as for Lexus, a high-performance engine is generally running a much higher output than it ever was from factory so unless you're trying to build a factory spec engine, if you're doing things exactly as they did you're doing it wrong :) Two different focuses there - Taz.
Nice fake shop in the background.... Also, where are the con rods? As someone else pointed out, part of the rotatating assembly and should be balanced with pistons.
Hey Steffen! Thanks for your comment. I'll have to correct you there sorry, NO, your connecting rods should not be balanced with your pistons. As we point out in the video description this is just 1 of 17 steps and conrods are just one of those other steps. Also a lot of care must be taken when you balance your rods, and you need to balance each end across your set, not just to total rod weight. As to being fake, it's not a shop and we're not a shop. This is our engine building room, and that's what we call it :) You can watch an engine being built from start to finish in this room via the course material if you want to learn about why you shouldn't balance your rods with your pistons and all of the other detailed steps, or you can come and ask at our next free live lesson - www.hpacademy.com/free-engine-building-lesson/ - Taz.
Is it really that important? A gram is like the weight of a paper clip... I can't imagine that being a big deal. When companies like SCAT/Wiseco and Eagle sell sets of rods or pistons they're matched +/- 1 gram. I figured that was good enough.
Right at the start Andre mentions that you could get away with less, but also in the same token once you're doing it you're not really going to spend much more time being more precise, so why wouldn't you? We have never heard of an engine being 'overbalanced' =) - Taz.
I agree with modern manufacturing the balance isnt as important as it once was. However if you are building a motor that is going to see very high rpms balance issues can escalate.
With in a gram or 2 is fine. If it's revving over 7k+ then you might want to get more anal. But other that. In a street motor, this is pointless. Especially when you think about how much oil CLINGS, to the crank shaft throwing off this balance. Now you can polish the crank to reduce the clinging. But unless you are are constantly revving this engine, and or looking for a slight advantage over the competition in your class. It's pointless.
You can only control so much, so why not do it right rather than worry about what you can't change? We've never heard of an engine failing due to having the pistons balanced and it only takes a few extra minutes to do it more precisely than 2g, however, everyone's build is their own and they're free to do it to whatever standard they wish. Nothing wrong with that - Taz.
![Get This Wrong and You'll Destroy Your Engine! | Piston Ring Gaps [FREE LESSON]](http://i.ytimg.com/vi/8ke229_cb2U/mqdefault.jpg)
![Get This Wrong and You'll Destroy Your Engine! | Piston Ring Gaps [FREE LESSON]](/img/tr.png)
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Remember to blow the shavings away with compressed air before weighing the piston again
Tristian Anderson spell check is your friend
Lol, be sure to dust the scale and measure atmospheric pressure between each measurement too, right? And recalibrate the scale for each measurement, lol
@@VndNvwYvvSvv can’t tell if you’re being sarcastic… if you are then this is tenths if grams that he’s talking about so yes letting the shavings fall inside the piston and not blowing them off will skew the measurement.
@@aafmirq777 yes he was trolling
I love the fact that I can go back through your video catalog and brush up onmy knowledge
Great tutorial. I'm sure one day I will find a way to put it to good use.
Quality of this info/video is excellent. Really well explained.
16:58 holy shit, add a 4-4 beat to that and youve made an edm burning man banger
These are great, thanks Andre'
Great teacher.
Very good tutorial, thanks!
since im not a machinist, I would try to mix the wrist pins, like the heavy wrist pin in the lightest piston and vice versa, untill you get an a closer average, ( my comment was made at nine minutes) but yeah good stuff.
Your correct this guy does not know what he is talking about
He did
@@danstomber1664 did you even watch the video
I used use a sharp knife to remove aluminum. It's cheap and accurate. Works for porting aluminum cylinder heads too until you need to work the valve seat area
I've been working with aluminum lately ,and it's kinda neat you can whittle it like wood with an old razor knife.
Small tip if you want any and it's purely subjective but I'd cut some of the more boring parts. 23 seconds lost watching pistons weighed . All I want to know is how much they weighed.(for example)
Subbed
Cheers for the feedback Maverick! We get people asking for that footage when we cut it out of the course material (they want to see every little bit) which is where this video is from, but you're right for UA-cam we should probably do it a little differently in the future. Appreciate your time =) - Taz.
Handy. I'll need this in a couple weeks when I'm assembling my RB25 Build, which is on my channel. Excellent video. Where do i get a highly accurate scale like that though, had trouble finding that.
My engines piston and con-rod assemblies are balanced to 0.02g across the board. The differences get multiplied once you're revving 7k+
What Engine/Car?
Cool story bro your honda must love that
How close are they after they have been run in an engine and have some carbon build up? Are they within one gram? Probably not...
@Sho Yu Weeni You're nuts.
@@DaveMcLain ya, even in a world where an ICE doesn't develop a little carbon buildup, just the minor amount of difference of surface oil retention on each piston could give you a gram either direction. But that's why I go to the hundredth.... which is quite the pain in the ass.
I was about to drill a small dimple on top of the piston. Heck, drill 15 dimples to remove 15 grams from the piston. Then to complement the reduction in piston weight, increase the boost by 15 psi.
Just as well you saw this video then eh Quang! - Taz.
It lets me rev to 15,000 ripums.
Balance anything that moves and it will run like a sewing machine! 👍🏼
With the piston / pin combo, why don't you remove the weight from the pin instead of the piston?
I recommend using a de-burring wheel, very lightly
Nice tutorial Andre! I have a question for you - when I designed pistons for a project, I spoke to the design engineers at Mahle about piston balancing. They told me to categorically never remove material from the underside, and only remove material from the crown area. This leads me down the path of settling the combustion chamber volume first, and balance after. Balancing the gudgeon pin/ wrist pin seems like the only viable option once you've set the compression chamber volume?
yeah, the underside is under tension, cracks may start there, the top side is in compression,no cracks can originate from the top
Would you do a video on the benefits of cryogenic metal treatment? What sanctioning race bodies allow it?
Thank you
A friend of the family did this in a VW back in the day with... Are you ready? ... Are you really ready?
A coathanger.
Worked really well. I did a similar thing with 50/50 resin mixing once too
What . . . ?!?
You balanced pistons with a coat hanger and resin . . . ? What the heck are you talking about?
I've just done my Hayabusa engine build using standard pistons, there was 4 grams difference between the lighter one and heavier one? What a ball ache to match to the lightest one. I think if doing it again I would get another set of pistons that I can choose closer weighted ones.
Fantastic video. FANTASTIC!! : )
Thank you sir! Glad you enjoyed it :) - Taz.
You're welcome! : ) I'm glad that there are videos like that on youtube.
0.01 Grams don't sound like much until you take into account how many G's a piston Experiences as it switches from going up and down TDC & BTC
The piston itself will weigh upto 10 Tonnes (10,000KG)
During Peak G-forces as it changes direction in the thousands of G's 0.01 grams becomes 20-30kg of unbalanced weight on piston
One minor point. The rings should be gapped, and matched with their pistons, before weighing if you are balancing to 0.1 grams.
Very smart, never thought of that
remember to make sure no aluminum dust or shavings are not on the piston after each grind before weighing.
Just lick them off
I really like how you pronounce Engine, Ingen ahah
So i weigh out my pistons, pins etc. and my rods for the piston side (oscillating weight) and crank side (rotating weight). Now I matched the rods to the pistons (clips, rings and pins have exactly the same weight, so they don't matter), can I use it like that?
My rods just have a difference of 0.2g, my pistons have a difference of 1g lightest to heaviest. Rotating mass of the rods have a difference of 0.2g (measured everything a hundred times).
I wanted to get an overall difference of 0.3g max.
Probably good to clean the shavings out of the piston before re-weighing. Might mess up your results.
Amazing video. I have a suggestion/question:
When pairing pistons with pins, instead of going for "heaviest with lightest" there might be a combination where you could pair them such that two pistons pin combos could have the same weight while being the lightest ones. This could make it so that you would only have to remove material from the other two pistons.
My example is based solely on adding up the individual weight measurements from the pistons and the pins (I understand that weighing them as a pair could provide a slightly different weight due to rounding): Going piston 3 + pin 1 as well as piston 4 + pin 4 would give them both a combined weight of 450.2 g. While the remaining two combinations will be 450.5 g and 450.7 g.
Do you think it is worth to go the extra effort to try and create pairs (or groups) of piston-pin combos with the lowest weight possible? So that you are actively balancing less pistons and/or pins?
I suppose this will not always be possible, but I am curious if this is something people do.
Ideally you're trying to do it so you're removing the least amount of material rather than working on the least amount of pistons. When you're doing it yourself rather than being billed by the hour too an extra 15 mins or so really doesn't matter as it isn't a hugely time consuming process compared to other aspects of engine building, but at the end of the day you of course are free to do whatever you thinks makes the most sense and works the best for you personally - Taz.
@@hpa101 Makes sense. Thank you guys. These videos are amazing and I'm learning so much. And the fact that you're replying to questions from 2 year old videos. You are incredible!
It's ok to dril diesel piston to remove weight?
You can do this to diesel pistons as well. Same rules apply when it comes to the fact there are areas where you want to avoid taking material from and others where it is acceptable remembering you balance to your heaviest piston to match them rather than getting them all to your lightest as that will see you needing to remove more material - Taz.
@@hpa101 thank you
Love all your videos @hpacademy - can you recommend affordable scales to use? Given the total weight is not necessarily important, just the matching of weights between components, I suspect anything that measures to 2kg in 0.1 grams would be acceptable if it nets repeatable results?
www.amazon.com/dp/B01E6RE3A0/ref=dp_prsubs_1 This is the scale he is using. At $15, that should meet your budget.
Blowing the shavings away from the piston is very important
100%, it's hard to see in this video but Andre directs the shavings from the dremel to go outside and away from the piston, not directly into it :) - Taz.
I would take meat out of the wrist pin instead, good stuff.
Great vid! 🤩 one question: we have anyway to take the conrod out, so it would not be also a good idea to weight them and match it, like the conrod and piston weights the same?
Thanks and keep going to make videos like this!
Hey there DrSiech. Yes sir, your conrods can and should also be balanced. You avoid doing them with the pistons as an entire unit and I'll pop a few links here that will help cover this and it is also in the engine building course material.
Quick video: ua-cam.com/video/TViHBkLZnx8/v-deo.html
Some more details here: ua-cam.com/video/0tXbCqA2QHI/v-deo.html
Webinar lesson on this specifically (paid content): www.hpacademy.com/previous-webinars/193-2/
Course material this is included in (paid content): www.hpacademy.com/courses/practical-engine-building/
Hope that all helps you out - Taz.
Wouldn't you want the entire rotating assembly balanced as well? (not sure if there's a video that covers this)
Yup, you balance more than just the pistons, this is just one step of the engine building process :) - Taz.
can you use the *small-end rod* weights to balance the piston weights?
( example: +1piston&+0rod and +0piston&+1rod)
I have a piston thats like 2g overweight, all my pins and rings are all the same. i took out some material from piston, but i dont want to remove too much. so can i include the small-end rod weights when balancing? or is it better to just grind pistons and rods *Separately* to match smallest weight
Hey there Andrewdini :)
2g is not an excessive amount to remove from your piston, and your pistons and rods should be balanced independently.
Your connecting rods will be balanced at both the big and small ends, so taking excess off one for the sake of your piston would actually see you taking off even more material to balance that out across your rods, which is something you don't want to do.
Just remove the material from the correct location as shown and you will be find :) - Taz.
الحمدلله
شكرا
what about adding the rod to the total weight and then measuring, wouldnt rod go into the total weight measurement ?
Rods are balanced separately =) - Taz.
And how to check in bore piston and rings are good
you sound like John Cambell mate. So where are you from Wellington or north of the Bombay's
so i found alot of people talking about removing the material from the piston/ wrist pins. someone online removed material by the bottom off the piston, and you removed the inner sides of the piston material. will this be better on how u did it to reduce the cause of engine failure?
Hey Brandon,
Great question.
In our opinion where we have removed the material from is the safest place, however, by nature, you have a few options on a piston that won't be detrimental when compared to something like conrods where you have to be very calculated and careful where and how you remove the material.
Cheers! - Taz.
I have a piston that is 2.14 grams lighter than the rest. Can I even remove that much material safely?
Late reply but if it's an aftermarket piston I would be returning it for a replacement. 2.14g out of weight with the rest isn't great QC. Generally any half decent piston manufacturer should be matching their piston weights across production such that a particular set doesn't have that much variance.
Enjoyed the video, very informational. One question on rounding to the nearest tenth of a gram. If you round, it's possible that you end up with piston/pin combos that are .18 gram different. For example a piston/pin are 450.36 grams (rounded to 450.40) and another piston/pin is 450.60 and by grinding material off we get it to 450.52 (rounded to 450.50). These two pistons are a tenth of a gram when rounded, but in actuality are .16 gram different.
Is that difference acceptable? Or do you try to get closer than a rounded tenth?
Raymond LaCasse
Less than a tenth of a gram, you will probably get that much carbon deposits in the rings after a little running, it's fine.
Where to buy that scale?
Hey, after going through a couple of $300-$400 USD scales from a company that will remain nameless, we ended up with more repeatable results with this set from Amazon of all places. It's important to note that consistency is more important than the actual weight since you're focusing on the weight difference - Taz.
Why not remove the material from the wrist pin instead? It would required approx 2.5 times less material that needs to be removed.
Hey John, this is discussed in the video along with where on the wrist pin you should remove it from. Ideally though where possible you want to remove less material, not more. By matching the lightest piston with the heaviest wrist pin and then balancing via removal of material from an unstressed area on the piston, this is achieved - Taz.
Wouldn't it be easier to remove the material from the very bottom edge of the skirt? Seems like that would be the lowest stress area of the entire piston, and easiest to do.
No, thats actually one of the high stress area, the skirt is the part that keeps the piston straight up by rubbing the cylinder wall, with oil squirted on them of course. I wouldn't mess with something that has a very important job
Has anyone ever re-weighed the pistons after hard use?
I wonder what effect the carbon build-up would contribute.
I am planning to rebuild my 2008 Honda City 1.3MT Engine, Cylinder no 2 is weak, Engine burning 0.5_0.7 Liter between every oil change. I hope my C-2 will be doubLe in weight LOL.
My wiseco pistons in my car is balanced :D
I think I would degrease the components before weighing them. Not for the weight of the grease but to ensure that any ground off material doesn’t stick to the grease and affect the weight.
Another grate video!
Some questions... Is there any reason to such a precision? The acceleration of a piston in a performance engine is what? 200000 m/sec². With a 0.5 grams of imbalance we are looking at 100 N of force differential. Is it enough to cause problems or to make a difference in the performance of the engine? What an imbalance o a gram for example would do to a performance engine?
It's up to you, Andre does mention at the start it might be other kill for some however you're balancing your pistons anyway and all it costs you to be a little bit more pedantic about the weight difference is really a few minutes of time, nothing else, so it's something Andre always does for this reason - Taz.
I was wondering why you don't have the Rods there also as they are part of the total weight.
You are 100% correct. Balancing pistons is just 1 of 17 essential steps. If you're interested in learning the other 16 steps, including rod balancing, take a look at our engine building courses here - bit.ly/engbuil - Taz.
See that's what I thought. I always filed rings installed the rings into the piston. Installed the rod and everything then just measured all 4 in that sense. Then balanced the 4 to each other. Is there a benefit to doing each part separately?
what engine is it? (?? cc)
You do this the same regardless of the engine =) - Taz.
Lol, I recently bough the same scale. Only goes up to 500g...
Yes, you're weighing engine components, not tins of paint 😎
We actually went through (returned) a few expensive US made scales before we tried these out of frustration and found them to be better. Won't always be the case, there are some awesome scales out there, but again just shows you need to trust but verify, even if it is a well known brand name - Taz.
@@hpa101 HP Academy is awesome!! I better continue my education. I purchased two courses :)
1/10 of a gram is useless.
You will have oil splashing under the piston,being trapped in the pin,and soot deposits on the top of the piston after 5 minutes.
it wil be out of balance constantly.
a gram or half a gram is more than enough.
Oil, unlike the piston is fluid and will, thank to inertia not change direction as rapidly as the piston and mechanical components, this will mean the load it imparts is minimal in turn it's effect on balance will be minimised.
Oil is projected under the piston while it's going up or down,the cranckshaft is constantly rotating.
it's completly doing the same stroke as the piston.
that mean it's making more mass going up,and then is projected in the oil pan when the piston is finished going down.
the fact it's fluid do not change the fact it's adding weight during the stroke up.
if you have not the same volume of oil going under each piston (wich is always the case ),there is unbalance.
Fluids behave like fluids mate. It will not affect the balancing of the assembly. Else the air itself that the assembly rotates though would be factor at high rpm. Fluid dynamics bro.
So,if i pour 20 grams of oil in your left hand palm,and 5 grams of oil in your right hand palm,and ask you to lift and lower your arms they both the same weight ?
michaelovitch if you pour them on the side of my hands and it runs off...yeah especially at 80 to 90 degress where its about as viscous as water. Now if i start thrashing them up and down a few thousand times a minute, there will be almost none of any of it on either. Make my hands from polished metal... even less.
Zero and then calibration the scale before measuring. If you are doing the same for clearances then it should apply to balancing. If you have all the fancy equipment such micrometers, bore gauges, and calipers and are not properly calibrating before using then whats the point? It can be off just one time but that one time can be catastrophic.
In this case calibration doesn't ensure precision, but if a scale is inaccurate I wouldn't trust it for balancing to a tenth of a gram.
If you were going for a specific weight, we would agree, however you just need the scales to be repeatable,, so if it's out by 5 grams so long as it's out by 5 grams every time it doesn't matter for this application - Taz.
@@hpa101 I agree if it is precise, and will consistent enough for everything to be balanced.
Hypothetically, if the scale was reading heavy 0.53 grams every time and engine builder decided to subtract 0.53 grams from the balancing numbers. Once you take stuff out and find everything is 0.53 grams lighter would you trust that engine builder if he says the scales just always reads heavy without any proof?
That is why during calibration they even write the difference in readings.
Undersubscribed channel indeed
André, what I still do not comprehend entirely is when we use pistons and rods that are of different weight compared to the factory piston weight.
The crankshaft obviously is balanced in itself. How does heavier / lighter rod&pistons affect the entire rotating assembly?
TIA
Dom
Balancing to a tenth of a gram is a fools endeavor when masses orders of magnitude greater than that in the form of oil, carbon, etc are uncontrollably and unevenly distributed on the rotating and reciprocating components of an engine. Also, any set of pistons or rods that isn't sufficiently balanced from the factory aren't worth buying and using in the first place!
Unless you're in Formula 1, you don't have the ability to accurately calculate and measure oils influence or carbon weights etc. There are some things that are simply outside of our control, so instead we focus on what we can control and do it to the best standard we can.
To balance to the degree Andre has here, and he did address this in the actual video, it could be considered a little overkill, but it only takes a few more minutes than it would to do things to a lesser standard.
For balancing from factory, it's all a matter of degrees of balance and you could quite easily run this kit as delivered. We tend to be extremely fussy so our target balance is just tighter than those of the parts manufacturer. We find that all of the aftermarket parts we use are outside of our personal targets if that makes you feel any better - Taz.
Absolutely agree that +/- 0.1 gram is a waste of time. Unless your reciprocating mass is extremely light, or your RPM's are extremely high, you do not need to balance to better than +/- 0.5 gram.
@@bunnyrabbit4972 what's the time difference between 1g, 0.5g and 0.1g when it comes to balancing? I think you will find it is negliable, but everyone is free to do things to their preference on their own builds for sure - Taz
@@hpa101
A typical high performance STREET engine will not have a peak piston deceleration rate exceeding 3000 G's approaching TDC at operational redline. 0.5 grams * 3000 = an instantaneous imbalance of 1.5 kg. This is nothing to worry about, and when you marry the light pistons with the heavy rods, and vice versa, the overall error is reduced further, below +/- 0.5 g.
Hey brains how about blowing off the Pistons with air so your not weighing the filings you just ground off.
Hard to see in the video but when you're doing this you're holding the Dremel in such a way all of the shavings are not going into the piston, they're going straight out. We just assumed this little tidbit would be common sense sorry, but I'll add a note to the description.
Once you dive in yourself you will see exactly how that works :) Enjoy! - Taz.
Good job I just wish you was a tad bit faster.
You can speed up the videos on UA-cam (and also in the courses on our website) via the 'cog' button on the bottom right of the video window.
I usually set it to 1.5 myself as because of our accent Andre does talk a bit slower and clearer than he would in normal conversation just to help those who are not native English speakers understand him better. Hope that helps! - Taz.
Slow is smooth.
Smooth is fast.
Sir i have royal enfield bullet machismo 350 cc it is passing through big problem pls help me. Oil comes from breather pipe what can i do for this problem i have opened head but when i kick the bullet engine oil comes from breather pipe
im tired of buying scales... i dont even know where to get a scale that can measure the weight of a piston and still be accurate to a tenth of a gram...
You need accuracy in the differential of weight, not the actual weight. You are trying to get them all to the same weight, not a set one, so repeatable results are what you're after. We spent a lot of money on scales before finding some cheaper ones did this best for us, but some HPA commenters have also mentioned that painters scales can be very accurate, a good size and also a good price for this usage ;) - Taz.
@@hpa101 thanks for the money saving pointer!
don't use Chinese scales. Use a paint mixing scale made in Japan or USA
We did spend 200-300 USD each on two other sets from a reputable US company that surprisingly (and frustratingly!) didn't give correct or repeatable results, whereas these scales might not be 100% accurate if you were trying to get a specific weight, however they are accurate between weights (the difference) which is what we're after for this task.
We do know that painters scales are also a good choice 👍 - Taz.
Ahhh sir... you ground the piston down at the wrong place and weakened it. Sorry but warranty is void now even though the piston is indeed defective. Sir, would you like to buy another one?
You can call your supplier before you balance your pistons to be safe and double check where they wish you to take the material from. This isn't something new or unknown to them, in fact in some advertising they will possible boast as getting their own product weights very close so that it is less work for you to balance yourself, which acknowledges their understanding that it is done and required for and by many :) - Taz.
@@hpa101 yeah I hear ya, was just joking around. Btw, is it required to balance the pistons? I've got a set coming in for my engine, didn't really want to do this unless it's necessary.
@@garyr7027 ahh sweet, sorry man, it's hard to tell sometimes with just the text as we get some surprising comments haha
If you don't plan to balance your pistons and rods the way we do for high performance builds, say if you're just rebuilding a low power application for your daily driver, then at the very least you should still weigh and pair them in such a way to get them as close as possible as sets.
This would see your heaviest rod with the lightest piston etc.
It's your build so at the end of the day you can do as much or as little to it as you like 😎- Taz.
@@hpa101 that I can do, and it's a good idea to at least get them close to same weight. One other thing, should the rod be weighed in with it?
For the other 16 steps take a look at our engine building courses here - bit.ly/engbuil
What the heck is a "heevy" piston? 🤔
You'll figure it out =P - Taz
Are you South African?
Same hemisphere. Andre is a New Zealander =) - Taz.
This is only to make super OCD people feel like they're doing something good. Lexus balances to plus or minus 0.5g...which means they only need a scale that measures to a whole gram! Go find something to do that uses your time better.
Our shop balances rotating assemblies. We leave the crank a few grams heavy, so +/- 1 g on the reciprocating mass doesn't affect anything. You may need finer balances on 14k bike engines with very small rotating mass. Most aftermarket parts come within a gram on the heavier bits. 1g on an 1700g bob weight (typical for a modern V8) is nothing.
Besides, the crank goes through different balances at different rpm, plus harmonics. Get a Fluidampr. It damps vibrations across the entire rpm range, versus elastomer ring style which work within a narrow band.
If you watch the video again you'll hear us cover the weight difference near the start, and as for Lexus, a high-performance engine is generally running a much higher output than it ever was from factory so unless you're trying to build a factory spec engine, if you're doing things exactly as they did you're doing it wrong :) Two different focuses there - Taz.
Nice fake shop in the background.... Also, where are the con rods? As someone else pointed out, part of the rotatating assembly and should be balanced with pistons.
Hey Steffen!
Thanks for your comment.
I'll have to correct you there sorry, NO, your connecting rods should not be balanced with your pistons. As we point out in the video description this is just 1 of 17 steps and conrods are just one of those other steps. Also a lot of care must be taken when you balance your rods, and you need to balance each end across your set, not just to total rod weight.
As to being fake, it's not a shop and we're not a shop. This is our engine building room, and that's what we call it :) You can watch an engine being built from start to finish in this room via the course material if you want to learn about why you shouldn't balance your rods with your pistons and all of the other detailed steps, or you can come and ask at our next free live lesson - www.hpacademy.com/free-engine-building-lesson/ - Taz.
Is it really that important? A gram is like the weight of a paper clip... I can't imagine that being a big deal. When companies like SCAT/Wiseco and Eagle sell sets of rods or pistons they're matched +/- 1 gram. I figured that was good enough.
Right at the start Andre mentions that you could get away with less, but also in the same token once you're doing it you're not really going to spend much more time being more precise, so why wouldn't you? We have never heard of an engine being 'overbalanced' =) - Taz.
I agree with modern manufacturing the balance isnt as important as it once was. However if you are building a motor that is going to see very high rpms balance issues can escalate.
@@MrSrt4parts i.e. Honda Type R pistons (+/- 0.1g matched from factory)
@@TheCitizenErazedbecause they are balanced....
@@hpa101 i guess we have; time is money,and you also could damage a piston by grinding on it without polishing the cuts
17.06
He's like...
'Fuck I'm deaf'
What? Type louder! - Taz.
Only just seen this!!!
@@e36racer44 He is still deaf to this day.
Wristbands are too heavy
With in a gram or 2 is fine. If it's revving over 7k+ then you might want to get more anal. But other that. In a street motor, this is pointless. Especially when you think about how much oil CLINGS, to the crank shaft throwing off this balance. Now you can polish the crank to reduce the clinging. But unless you are are constantly revving this engine, and or looking for a slight advantage over the competition in your class. It's pointless.
You can only control so much, so why not do it right rather than worry about what you can't change?
We've never heard of an engine failing due to having the pistons balanced and it only takes a few extra minutes to do it more precisely than 2g, however, everyone's build is their own and they're free to do it to whatever standard they wish. Nothing wrong with that - Taz.
Man, Got to Love Them South Africans.........
Aus or NZ dude...
@@dny9394 No Shit My Man, It's Called Sarcasm and it's what AU & NZ Dish Back & Forth... Just for fun...
Good info but I just can’t listen to another video with that annoying accent...
You clearly don`t know what your talking about
How so Dan? Share some knowledge on what you specifically think is being done wrong here and we'll be happy to discuss =) - Taz.
@@hpa101 Your choice of removal area is not only out of the norm it is ridiculous but thanks for asking
No worries Dan, explain where you take material from and why in that case - Taz.
@@hpa101 on the pin boss above the hole on the in side would be the preferred method