Become a Tuning Pro: hpcdmy.co/dr4a Support the channel by shopping through this link: amzn.to/3RIqU0u Patreon: www.patreon.com/d4a There's a mistake in the compression ratio calculations when the volume increases by 5cc at 00:54. The total volume increases by 5 too so it becomes 505/55 and not 500/55 which means the result is 9.18 and not 9.01. The example obviously still works and the logic is the same but the number isn't correct. Thank you to @sagi fern for pointing this out.
No Bro... you were right. Sorry, and @sagi (sorry sagi) was wrong: the displacement of a cylinder is NOT the total volume of the cylinder/chamber system. The displacement of an engine is the result of the volume determined by (bore x stroke). The displacement change only if you modify the cylinder bore or increasing the stroke by changing of crankshat.👍
Good save. When all else fails, check the math several times... Proper Head Prep is really important. Not just in short term, but long term also. Some people think it's a waste of time, but there are lots of reasons to do it right from the start. Ever have to yank the heads off to correct a problem that should have been done before bolting everything together... oops. Always amazes me that some people don't have the time to do these steps first, but have the time later to remove heads and do it anyway.
I always found this debate interesting. I think it's useful to think in terms of swept volume and to keep in mind that static and dynamic compression ratios vary throughout the rpm range and are different and same based on the volumetric efficiency of your combo at any given rpm. Great vid as usual.
I purchased an '88 MR2 a few weeks ago that sat for a few years with a broken timing belt. Brought it back to life, now starting to work through the kinks that it has due to its age. Your videos are a godsend, and an inspiration for what I hope to do with mine in the future. Thanks!
I would add to get the rough chamber work as close as possible between each chamber. Then get the cylinder head resurfaced before finishing the chambers and getting everything dialed in and equal. The removal of material from the head gasket surface on the cylinder head will reduce the volume in the chambers, so it's good to do it prior to the finished work.
For future reference, if anyone wants engine displacement tool. It’s actually a burette, your nearest high school might tell you where they buy it from. Should be inexpensive no more than 20-30 bucks. Glad I paid attention during chemistry lectures 😂😂😂😂
You cant, but you cant reduce an engines tendency for pre ignition by grinding away the quench zones that were engineered in to do specifically just that either. Shrouded valves... Toyota didnt put that material there to hurt engine performance.
Re: the large syringe at 34 cc initial fill. There are cheap digital scales easily available that can measure mass down to 0.01g (or even 0.001g). So it would be easy to use a scale to ensure that the 34 cc syringe initial fill is consistently identical across the four chambers. The point here is consistency, not anything directly related to accuracy (except the improved consistency). Cheers.
A slight improvement on his approach, but not quite perfect. Follow all the steps up to filling the chambers with water. At that point, fill the large syringe with REFRIGERATED DISTILLED water and weigh it with a gram scale. Fill one chamber with water and then weigh the syringe again. The weight difference in grams is equal to the volume of the chamber in cubic centimeters. (well...technically 1cc of distilled water weighs 0.9982g, but that difference is too tiny to matter.) Refill the syringe, re-weigh it on the gram scale, fill the next chamber, and calculate the weight difference again. Repeat for all chambers.
@@drajo123 No, they aren't. Where exactly do you have problems? Maybe I can help you out. I routinely make perfectly repeatable measurements down to +/- 5mg, +/- 2mg if I take the time, that's the limit of the scale I'm using. And as stated, they're repeatable even after weeks. Having things more than accurate enough for measuring out your combustion chambers to 0.1cc in a rather short timeframe shouldn't be a problem at all. I'm too lazy to calculate it rn, but I think even rather substantial temperature swings won't cause enough difference in density to actually matter much.
@@drajo123 bruh if i can use a mg scale drugged out of my mind to measure mg scale stuff then idk what to say about ur scales but maybe get better ones
@@deusexaethera . It is my recollection , that the Metric Weights and Volumes are thus . One Cubic Centimetre of pure water , at 4 degrees C , the highest density point , is the DEFINITION of One Gram . 1.00000g Ergo , One Litre = One Kilogram and 1000 Litres = One Metric Tonne . The Scale definitions based off the Standard Metre .
Always fun to discover a golden nugget like this channel. Your ingenuity and patience are truly impressive. Your explanations, clear and concise. Thank you.
I enjoy your videos a lot. Over the past year or so you have enlightened me about a lot of things involving engines and the engineering behind them. At my age I am past doing this myself but when I was younger I would have killed for these types of videos. And we, your viewers, really appreciate all the time it takes to record these wonderful videos, so please keep up the good work and again thank you! Be safe and stay well.
I've never heard about equalizing combustion chamber volumes! I just assumed they were precision made and would already be equalized. Good to know it's something worth checking on second hand engines you are building. TY!
All cast pieces; blocks, heads, intake manifolds, etc. are mass produced using sand molds. There is lots of variation between parts. You probably can custom order heads and blocks already prepped to your specifications. If not, some good old fashion elbow grease, knowledge gained from reputable web sites, and time can result in higher performance, better fuel economy, and a feeling of satisfaction.
In a stock engine it's close enough, but a modified engine is by definition not a stock engine. The modifications are what cause the problems in the first place, so more modifications are needed to fix the problems.
@@DaftFader it's almost impossible to get exact shapes of the combustion chambers , but today with special CNC (Computer numerical control), they can get really close. Old timers spent hours, even days to match combustion chambers, intake and exhaust ports. I would have taken mine to a speed shop and let them do it.
@@DaftFader The approach (working assumption) is basically: those small variations in combustion chamber shape is too small and can be ignored. Think in terms of “signal over noise”. Whatever variations, if the “signal difference” between those variations is smaller than the “environmental noise”, then those tiny variations don’t matter.
The thing I love the most about this channel is the topics it covers. You just don't think these as something you would do to your car, but after the video it's like a "totally obvious" thing to do. Plus, it goes beyond the typical bolt-on turbo, catalog cams and such. One of the best channels about cars, if not the best.
ALTERNATE APPROACH THAT IS LESS FUSSY: Follow all the steps up to filling the chambers with water. At that point, fill the large syringe with REFRIGERATED DISTILLED water and weigh it with a gram scale. Fill one chamber with water and then weigh the syringe again. The weight difference in grams is equal to the volume of the chamber in cubic centimeters. (well...technically 1cc of distilled water weighs 0.9982g, but that difference is too tiny to matter.) Refill the syringe, re-weigh it on the gram scale, fill the next chamber, and calculate the weight difference again. Repeat for all chambers.
I really like your videos... so thorough... However, in this one, why did you not deck/clean the head surface first?? So you had a truly flat surface for the plexiglass to sit on when taking the measurements.
Yes, that would be the typical approach, but when you're grinding the bit can sometimes skip and you can accidentally gouge the deck. The old gasket material remains are incredibly thin but are a great layer of protection and I feel more comfortable with them because I'm a bit clumsy sometimes. Petroleum jelly will seal even against dirt and debris and the difference in chamber volume after decking will likely be minimal.
@@d4a sorry need to disagree with this , yes i wouldn't deck the head but you really do need to scrap all the gasket material off. you can see a big clump of gasket which could be 1mm which would make a difference. also we use a thicker bit of perspex so to not have any sag. P.s, great videos
This will likely come down to "how well I want it done", if you want absolute accuracy, you can resurface the head, but like it's said in video, this is enthusiast home build, you ideally wanna save some money, especially with the grinder that hes using
You definitely covered the basics nicely. Not too many people even think about cylinder heads other than how much they can flow. The one suggestion I have is that you can use the Vaseline after the valves are in and fill the largest volume combustion chamber with body filler ( or something else like it ) then you will have a template for the other chambers. I usually use differential gear marking paste on the template to see what needs work and where.
Pro Tip From a Medical Professional: Use the smallest syringe you can. Volume and precision vary inversely with syringes. If you want a super accurate number, use a 1cc syringe 36 times…. I personally wouldn’t trust a 30cc syringe to be precise within less than 2ml.
Of course you have the same bore and stroke in each cylinder... Back when my cousin was working his way through an automotive tech school he bought as a project a 1962 car from my father. It had a straight six chevy 261 (like the truck motor, but canadian so it had hydraulic lifters) which ran, but was burning oil almost as fast as it streamed out past the rear main seal. Being a student with limited means, he ended up rebuilding that straight six with new rings for all six cylinders, three original pistons, but one cylinder needed bored 0.040 over and two were okay with 0.020 over and those three needed new pistons. Obviously not built for performance, but it ran great with the expected straight-six smoothness. That car became a daily driver for a few years plus we put thousands of miles with multiple 1000+ mile road trips driving at high speeds while burning multiple tanks of fuel to reach our destination. We'd leave after school on Friday needing to be back on Monday or Tuesday at the latest.
I might have another way; Use plasticine. Push enough in, to completely fill each camber, using a rolling pin to get it level with the face. Next, get a glass and a tray. Put the glass on the tray. Fill the glass with water right up to the rim. Pull the plasticine out of the chamber. Roll it into a ball and slowly put it into the water. Because of displacement, the water will run out, onto the tray. Measure the water in the tray to get your volume.
@@Bialy_1 maybe while compressing it with a roller, you could end up with parts that have higher density and therefore higher weight while still having equal volume.
Plasticine can't get into the hollow space inside the sparkplug. (yes, that tiny little bit does matter.) Here is the best approach: Follow all the steps up to filling the chambers with water. At that point, fill the large syringe with REFRIGERATED DISTILLED water and weigh it with a gram scale. Fill one chamber with water and then weigh the syringe again. The weight difference in grams is equal to the volume of the chamber in cubic centimeters. (well...technically 1cc of distilled water weighs 0.9982g, but that difference is too tiny to matter.) Refill the syringe, re-weigh it on the gram scale, fill the next chamber, and subtract the weight difference again. Repeat for all chambers.
@@deusexaethera Use a 14mm bolt instead of spark plugs. And petrobond casting sand. You could weigh the sand , and since it forms a perfect impression , you could take the one from #1 cylinder and set it in #3 to see where they differed. That way you can match volume , shape and valve seating.
Nice job on the head but what about piston compression height variances? A 1000th inch (0.025 mm aprox.) difference in piston compression height in an 80 mm bore (common for I4 engines) is 0.125 cc. The same would be true for connecting rod center to center distance variability and crank throw variability. If you truely want equal compression ratio across all cylinders you may actually want slightly different combustion chamber volumes to account for these other variances in your engine parts.
Absolutely, 100% agree. Piston casting variations, head gasket, connecting rod, crank and crankshaft bore. And probably other stuff. The only way to get a true number is with the engine assembled. All of those errors are going to stack.
@@joels7605 Thx, problem is while you can kinda get piston compression height measurements the crank and rod measurements are extremely hard to get without very specialized equipment.
Amazing DIY video, thank you for taking the time for making this tutorial. I had no idea that such small changes in cylinder head volume made such a great difference in compression ratio. Please continue with this series on your engine build :))
Amazing video as always but i would like to point out a couple things were missing 1- for diyers you could easily buy a burette sold on chemical supply stores for a fraction of professional kits 2- if you plan on getting your head decked do this before trying to equalize you combustion chamber volumes 3- generally is better to use a single piece of thicker glass with a hole could be bought cheaply at a glass store and make it a little more accurate
You better be upgrading the suspension and swaybars to handle all that mad power that car gets. Or did you unbox parts for that in your last video? I'm gonna go watch that now…
I didn't. Suspension is koni yellows and eibachs, but brakes will likely need upgrading. I won't be entering mad power realms, 200-300hp is where I'll be dwelling.
Some people won't do it because if they slip up, they might ruin the machine work, and have to do it again. This is especially bad news if you engine has a very short piston to valve clearance, or the manual does not allow much to be milled off the head. Still, to get the best results, milling the head first is best.
My wife looked at me funny when I told her I was going into the garage to put vaseline on my head and measure how much water could fit inside then rub it til it was smooth. I should tell her to watch this video.
I'll never do this because I have no patience but your determination and passion shines through so this was good to watch and I hope you achieve your car dreams.
I think ima do this with my 4b11t cuz the same cylinder keeps throwing rods on me I’ve changed everything but I never ported the head I wanna test this
Awesome video as always! I'm always surprised I don't see a lot of people do this with their builds. I guess they assume whoever refreshes their heads does it, but I'm betting that's a faulty assumption. Others probably don't know they should do it. I supposed in a completely unmodified head other than being resurfaced you shouldn't need to, but still, I'd wanna know. I like the syringe idea over the burette! Feels like it would give more control. My excitement over this engine keeps building!
That is true. However, many people won't do it because they fear they light slip and ruin the freshly machined surface. Ther are aluminum deburring tools lik this that make it nearly foolproof: www.mscdirect.com/product/details/05751003
Love this channel! Hey btw if you decide to port and polish. Leave the intake sides semi rough like 400 grit and smoother on the exhaust ports like 800-1200 grit. Then polishing slightly but not like your combustion chambers are. Sure CNC porting is best. But unless your building a completion engine? There is no need. 👍😊
i prefer the wax method, you melt wax and pour it in the head, cut it flush then melt each cast in a beaker, or put the wax pieces in water and measure the excess
I tried that once. It's a good methodology but I'm too clumsy for it. I started loosing pieces of wax here and there and had debris stick to it so I gave up 😂
Yes. Usually when you buy a performance piston, they tell you how many CCs the valve relief and dish subtract, or how much the dome adds. However, this test should still be performed, as not all pistons are perfect duplicates of each other.
My brother rebuilt a performance 202 holden for my Torana. He did similar things to this but high compression! Interesting video. I never knew the process. But it was very quick as he had it up to get Xu1 specs. Cheers
Hey mate, Just a tip for next time... rather than using the scale on the syringe to measure the volume I've found it much easier to buy a precision set of scales and measure the syringe before and after you fill the chamber. Even cheap (under $30) precision scales will measure down to .01 grams which is more accurate but mostly its just easier as you don't need to try and keep track etc. Just fill the syringe, 0 the gauge, fill the chamber, remeasure the syringe and do a simple calculation. Cheers
Why didn't you have the head face machined first as machining it afterwards will change the compression ratio yet again. The resulting ratio will be higher than that which took so much effort to establish. Machining the head would also recreate sharp edges/hot spots to the outside of the chambers.... Just asking. Keep up the great work. 8-))
Wait, Your not in the United states and still able to hold a conversation in English and have a sough after skillset...I think the conservative news may have lied to me about the rest of the world... Just kidding. Great channel lots of good info and great presentations.
Happy D4A Sunday to all! The best educational automotive channel on the interwebs! Very impressive work on your cylinder head. I can't wait for the test drive video of your MR2!!
Nice work! You can also get 1cc medical syringes (usually used for insulin injections) to get that final fine tuning if you want. Thanks for breaking it down for us!
I tried to mention, that we use the burettes you showed in schools for titration and they are not that expensive. Apparently, people rename them and sell them for higher prices to car enthusiasts? It seems like the comment got deleted, maybe because it contained a link?
If you slip up while doing this, you ruin the machining of the deck and have to do it over again. This becomes an even bigger problem if your head does not allow much to be milled off, or your piston to valve clearance is extremely small.
Yes I get that, but cleaning and milling are two different things. I would think that you would like to have a completely flat surface to check the compression ratio versus having leftover head gasket material on the head. Just sayin'
all the m3's i ever bought had overheated and warped the head like a rainbow, i faced the heads afterwards and it made like a point and ahalf more compression on 1 and 6 lmao
Wow! That's certainly a lot of work, but it's worth it for the peace of mind from a tuning stand point. I have seen other videos about dimpling the intake runners in the head. I was curious if this was something you were considering. It appears to be a lot of work for very little benefit unless it's on a very high performance race engine.
Dimpling can consistently be done only using a CNC. Obviously this isn't cheap but it's a very similar aerodynamic logic as the surface of a golf ball. I think there are some benefits to it but I never saw a dyno of an absolutely identical engines with and without dimples. Obviously nobody removes and rebuilds an engine just to dimple it, there's always other mods too, so it's really hard to tell what and how much dimples alone do. I've seen 1000hp and beyond with and without dimples, they were all very fast 😂
Great video. Will help in my project to build 300whp Cruze. Can you do a video on the difference between a turbo with a pressure wheel vs as volume wheel. I remember I was going to turbocharge my s10 and I was looking around for turbos from a Saab and they would ask the question if a I wanted a high pressure wheel or low pressure. I assumed the high pressure wheel just meant higher boost level. If that's all it means then I have answered my own question. But someone told me it wasn't quite that simple.
What you need to do is determine the mass of air the turbo flows and the mass of air the engine would suck in when in NA form. Then calculate boost. Also, you would need to get the right exhaust manifold with the right turbo flange. The early 900 used a Garrett T3 flange, but I don't know what others used. Pressure is determined by how you set the wastegate to open.
I’m super interested to see what your power and torque numbers come out to. Im running an economy Honda K series engine (k24a8) on the maxpeedingrods gt3071 and the torque is through the roof. Making about 350 whp / 300 whtq on 14 psi
Those special kits sold in de USA are nothing more than a normal laboratory burette and a small lab stand. Both can be bought easily and cheaply in the EU as separate items.
Don’t use water unless you use a water wetter because the surface tension is too high. Use alcohol and use a little dye (food coloring works very well) it makes it easier to see and has much lower surface tension for better accuracy
From your channel's About tab- "Location: United States" _Anakin Skywalker voice_ LIAR!! :P Interesting how combustion chamber volume measurement tools are really only sold in the US. That's kind of a bummer for folks like the people on this channel. :( Edit: Great video and channel by the way! If you happen to read this, what effect do pistons with non-flat tops have on this process? Or do you find that most road car engines come with pistons uniform enough that it makes no difference?
@ driving 4 answers . Love that you are doing it yourself & show good improvisation, thank you for sharing with us all. I always enjoy & look forward to all your uploads. I always learn something.
Best to use a fuel additive to help keep carbon at Bay. On motorcycle we just whip head off reclean on singles or twin cylinders. This is for racing bikes
Great video. I think I first do a "simple" head gasket replacement. So, I wouldn't end up in such a pickle a many others at my DIY car repair shop. Who did bite of more then they could chew.
Sometimes you can buy a used head, do the work to it, then install it when you are ready. Later, you can sell your original head to someone else. Either that, or you can buy an "As-cast" rebuilt head from your local auto parts store and work that over, then turn in your existing head for the core charge. However, you only get about 30 days to return your existing head as a core. That method may actually be better, since the valves and valve seats have already been reground or replaced, and the deck has already been milled.
that moment when you realize this doesnt need to be done in a diesel engine but then remember diesel has its own bag of pains... insert backward vegeta meme
in a diesel engine it is done on the piston head (wich is the combustion chamber) you then weight the piston and measure the cc of the combustion chamber but it is most of the time useless compared to doing it on a gasoline engine
@@Julesvale exactly why i said "it doesnt need to be done" you most certainly can but why lower the so important compression needed for ignition?, well theres definitely a place i dont know of where this makes sense on a diesel...
@@Velkanis its to even out the compression ratio as said in the video even tho in the rare case of a performance built diesel engine choosing good pistons from the start is always a better idea
Depends on how much you trust the manufacturer to get head volume, rod length, piston crown volume, stroke, and deck height accurate. These fundamental measurements are not unique to gas or diesel engines. Ideally, whether Kettering ignition or compression ignition, the mechanical elements would be correct. Unfortunately, manufacturers work to tolerance and sometimes those tolerances don't work for you, they actually work against you (see stacked tolerance problems for details) as they did for Suzuki when they produced a number of units with significantly higher compression that design would require some years back. Great for those running super high octane fuel, but horribly destructive for those who ran regular pump fuel.
@@lobuxracer well the sole idea i was running with the comment was to poke some lighthearted fun at the topic.... i had a long ass reply essentially done but decided against it. imma save it for another day...
Great video, reminds me of when i did the same when i was 13 on a lawnmower engine, if anyone is considering this its a great place to start with an engine build, cause your guarunteed to make mistakes and its cheaper if you do it on a lawnmower
The cost of the tool (cc volume tester), that you can use over and over and over, is relatively minor compared to what you gain. Therefore, the cost is minimal, even (especially) for the shade-tree mechanic enthusiast. In my opinion. When I had my stock '69 Camaro motor rebuilt to accept a turbo, I had the heads "cc'ed". It is worth matching ... good video.
You have to value the performance improvement very highly -- or rebuild lots of engines to spread-out the cost -- to claim that the cost is minor compared to the performance improvement.
really cool build. doing alot of stuff i have never heard of before. and doing it yourself to show how low budgets can be optimized. and this build verifies all your technical teaching videos, as in, proof you know what your talking about. have been a viewer maybe since the beginning, so keep up the good content. good luck with your build. from MD, USA
I know you wont see the polished surface once you assemble the engine but it sure looks nice! Seeing you grinding while the head is just wobbling around on the table without some kind of expensive equipment gives me encouragement to try doing more work on my vehicles with what meagre tools I have at home.
Wow! That's a lot of work but very rewarding. I guess you really want to look after that engine now so you don't destroy the head and have to do all that again!
@@cheesemons That's fair enough! I probably haven't used a very nice burette either. I have definitely over squeezed a few syringes. I used to do some lab testing on medical pumps. I had favorite brands and some I hated haha.
I really like your videos, and I have a question could you maybe use a scale to measure the weight before and after and like that calculate the volume of water inside the chamber?
I absolutely love your content, dude. It's inKREdibly informative and educational. Before saying this, I just thought to myself "Why haven't you liked and subscribed yet, then?" so now I absolutely love your content and am a subscribed subscriber who liked the video 😁👍🏾👍🏾👍🏾👍🏾
Great stuff. I've found using laboratory digital balance (0.01g) to weigh by large syringe before and after complete filling the chambers is simpler and quicker. (1gram=1cc)
@@d4a that's really unfortunate I'm really liking your channel and learning a lot of new thing about motors and also opening my mind on motorcycles. Thanks a lot for the work you're doing, hope to see you shine on this platform
Thank you so much D4A for all the content you put out I love all your videos. I am restoring a 1996 corolla DX with the 1.8L 7AFE. maxspeedingrods appears to have forged 7AFE rods. Will this combined with the Toyota 4AGZE 16v pistons you are using in your current project produce the same compression ratio as in your 4AFE project? Also, will you be using the 4AGE oversized valves in your build?
4:19 This equipment just looks like a burette used typically in chemistry and they can be picked up for very cheap anywhere, I had a quick look and they can be bought for less than 20 euros shipped. Definitely shop around before buying chemistry looking equipment sold as engine building tools as often they are the exact same thing resold with engine building in mind for a markup
Well done, however the compression ratio is not 10.0 : 1 as shown, the calculation is incorrect. The initial '500 cc' includes the 50 cc of the combustion chamber, therefore the compression ratio ( SWEPT volume over combustion volume) is actually 450 cc / 50 cc to start with, i.e 9.0 : 1. If you add 5 cc to combustion volume, the new calculation is 450 / 55, i.e 8.2 : 1 Look up Cylinder Volume vs Swept volume vs Combustion volume....you'll see.
