HOW and WHY to EQUALIZE combustion chamber volumes CC - Project Underdog #10

[@d4a]

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.

[@chupachups6098]

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.👍

[@EquiliMario]

@@chupachups6098 Total volume = (bore x stroke) + comb. chamber vol. So if combustion chamber volume increases, total volume increases equally

[@carlcoolamon7146]

... thickness of the head gasket my dude, adds to chamber volume as well as total volume.

[@SJR_Media_Group]

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.

[@Pappaoh]

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.

[@matel9985]

bro this is hands down THE best car channel on youtube

[@UNLOCKCONNECTIONS]

Facts!!!!

[@bigcazza5260]

d4a is a more entertaining and not slow version of james may

[@sicstar]

Bump!

[@massimobattaglia5093]

agreed. and I'm not even into cars!

[@enginy.5328]

trueeeee

[@JxH]

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.

[@deusexaethera]

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]

smal digital cheap scales are wery dificult to use acuratly and consistently.

[@heinzhaupthaar5590]

@@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.

[@amicloud_yt]

@@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

[@johncunningham4820]

@@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 .

[@chewykarma]

Always fun to discover a golden nugget like this channel. Your ingenuity and patience are truly impressive. Your explanations, clear and concise. Thank you.

[@franciscodieguez5187]

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.

[@SamichHunter]

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.

[@DaftFader]

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!

[@SJR_Media_Group]

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.

[@deusexaethera]

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]

@@SJR_Media_Group does small varyations i chaimber shape not matter, as long as volyme is the same?

[@SJR_Media_Group]

@@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.

[@reallifeengineer7214]

@@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.

[@LightningStrike50]

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!

[@mikeygroves9921]

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.

[@skylinefever]

If you have enough money, you can pay someone to do this stuff. Some shops can even use a CNC machine for the best accuracy possible.

[@maxxod1]

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.

[@jdmking4776]

I know these videos don't always get as many views and such but, I'm so glad you make them. They are some of my favorite videos on your channel.

[@markmetzger5430]

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 :))

[@maxcactus7]

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!!

[@deusexaethera]

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.

[@davidelliott5843]

Weight measurement is far more accurate than volume measurement.

[@ubewood499]

My 1st car is using the 4AFE engine. Super reliable and durable!!!

[@enso3140]

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

[@astonswai798]

7 hours of measurements and cutting now that's a super weekend

[@rezavarghayi8181]

This will be like the most sophisticated home made build on the planet. Everything is so accurate and beautifully done. Can't wait for the end result

[@d4a]

You should see some of the stuff people do on the DIY.. I'm a joke compared to some of that.

[@rezavarghayi8181]

@@d4a dude you're like an A grade full on engineer. Most diy KZbinrs that build cars don't have nearly as much knowledge as you do. Every video i learn something new. Amazing stuff

[@yosoydpfknr2855]

Wow just wow !!! You need time, patience, knowledge, patience and more patience to do something like this. This hands down is one of the best if not the best car performance channel in KZbin.

[@marchutchings8834]

Your videos are the most informative videos on automotive engineering I have seen. Congratulations and keep them coming.

[@someidiot1984]

Turned out waaaaaayyyy better than my attempt years ago. Guess my patience is much more limited. Good on you.

[@SamBrickell]

I don't even change my own oil, yet I watch these videos.

[@Naggstek]

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.

[@angelikamerker4006]

👌👍👌That's the absolutly best I've seen in 40 years about explanations how to make motors. I am car mechanic, have 60 years and made several engines. Your channel is very to recomand. 👌👍👌🙋🏼🐺i

[@jamppa4693]

I'm building a bmw m20b25 stroker engine, your videos have been a great benefit to me, thank you

[@wackydriver]

e30?

[@jamppa4693]

@@wackydriver yep

[@Sylvan_dB]

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.

[@The5hit]

great video! Can't wait for more videos as this engine comes together.

[@crxtodd16]

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!

[@dragan3290]

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

[@jonathanhurdthe]

Beautiful end result, awesome walkthrough 🙏

[@robertb3409]

What a great video. You are one of the most informative car guys on you tube. I love your DIY approach.

[@natelasaede8296]

@ 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.

[@dominik230900]

You just could’ve bought a titration Burette, they are way cheaper than the Kits from the US and More precise

[@timgriffiths2505]

Around 10 quid for a 150ml and 9 quid for the stand.

[@brendanjones3395]

What is a titration Burette ?

[@dominik230900]

@@brendanjones3395 A Burette that is used for titration. It’s laboratory equipment which is used to dose a certain liquid (mostly acidic or Bases)

[@brendanjones3395]

Thank you for the explanation I never heard of this tool I will research more into it.

[@aldenconsolver3428]

When I did a similar job without chamber volume correction on a small block chevy I was really surprised by how much good it did the engine. Even by eye it was possible in this case to make a smoother running engine. I don't know if it was the work on the gas passages or the cylinder head itself but the engine was significantly improved. This exercise was also very good for two-stroke engines, the passages between the crankcase and the combustion chamber were messy and of unequal volume, once more just cleaning up the mess made for a much more enjoyable ride.

[@natanaelonate5193]

I lowkey want this channel to stay underrated so no one else gets smart and i can continue to grow my knowledge, lol but fr tho this guy deserves an award

[@macthemec]

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

[@802Garage]

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!

[@slohachi6433]

The syringe method is pretty good. I've used it when cc'ing ACVW heads.

[@Wagonman5900]

This is proper craftsmanship.

[@indopleaser]

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

[@bobsponge6609]

Awesome video. It is extremely well explained as always. You should have at least 1M subscribers. Thank you for the video.

[@canadatransistor]

the head gasket thickness and evenness as well can contribute to compression ratio discrepancies. Cool video - enjoyed it.

[@danielrus7117]

Wow! So much dedication and hard work! Kudos! It shine's beautiful and must perform better now!

[@jozsefizsak]

Nice to see it progressing.

[@calumward1192]

This is what I’ve been struggling with! Thank you!

[@AlessandroGenTLe]

I remember when I had to do this for my Malaguti Fifty TOP equipped with a 75cc aftermarket Morini cylinder... I was 15 and I not only had to check the compression ratio, but also the squish area which is paramount in a 2T high performance engine. For that I was pouring candle melted wax into the spark plug hole with the engine mounted and piston at TDC, then remove everything again to check the squish area was effective and finally re-melt the wax into a siringe in order to get its amount and get the volume of the combustion chamber. Such a tedious job, considering that every time the squish wasn't what I expected I also had to re-do all after having lowered the cylinder base gasket (if not put it in the machine to cut away few 1/10s of mm to get it right)...

[@xhf8yxhf8y9]

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.

[@d4a]

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.

[@andrewmartin8816]

@@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

[@slightlyinsaneraf]

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

[@daggepopnit]

A god and fast way to clean the head for this kind of work is a fresh knife honing stone and wd40. if its a cast deck you use atf instead of wd40.

[@davidparker9676]

There is so much wrong with this video it is comedy for anyone who knows what they are doing.

[@bobfearick2297]

My only comment is i respect your detailing, toward blueprinting, which is what you need to be the winner at the end, nothing you do is wasted, Thank you.

[@glensubtorq]

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!

[@xyjoshxy]

One of the best vids I've seen. Never thought about doing this myself. No I want to try this.

[@peterwill9660]

You make the best videos! Great work👍

[@Dom-ny9dt]

Now that I know this kinda stuff exists I wanna do it myself. I could even do the measuring very precise at work!

[@thepaperboy9009]

Good stuff. I love your vocal delivery and emphasis on certain key words! Well done. I wish to channel and osmose your motor nerdness into my brain. 👍👍👍

[@yellowbird8690]

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]

So if you want to usethe plasticine then why not just measure its mass with some cheap jewellery weighing scale?

[@VaSKovach]

Omg its smart. I like the productivity and open mind thinking no one would of thought about that

[@DL101ca]

@@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.

[@deusexaethera]

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.

[@glennchartrand5411]

@@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.

[@houseofcars6998]

I couldnt wait to the end of the vid to tell you mate you’re absolute genius. This is the shit little kids dreams are made of! I had no idea of this just wow!

[@BudgeChem]

A digital postal weight scale can help a lot with measuring the combustion chamber volume. If you weighed your water container first, then fill the CC to the brim, then weigh the water you have left, the difference is weight of the water in the CC ( assuming you didn't drip or spill ). Then convert that weight to volume ( adjusting for temperature, too if you want SUPER accurate ) .

[@anthonylove6639]

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. 👍😊

[@JeffReeves]

Nice video! It's cool to see how sometimes we need to alter our approach in order to get the results we want, such as moving the holes for filling the chambers to a spot where it's easier to get air out of. A couple of things I'd like to mention as a former basic chemistry student: significant digits and margin of accuracy/error. The short version of both is that not every measuring device is truly accurate, and not every measurement can be correct to the smallest digit available by the measuring devices. That said, the measurements you were doing should be good enough for enthusiast work because you are chasing a power level easily obtainable by your overall setup and not making a 1K HP drag machine.

[@alejandro52612]

Great explanation!! So excited to see this project moving forward!!

[@terraraptorgaming6781]

Awesome video. It was very informative.

[@bubot17]

Great video, keep it up, let your videos guide the younger generation

[@brianmaynard7320]

Love your approach!! Double the work for a V8!! Now I HAVE to do it!!

[@gavinwilkes3702]

Amazing bit of information great work 👏 👍 and very informative keep it coming 👍

[@spaight711]

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.

[@davidelliott5843]

After the initial measuring of all chambers, you can speed up the measurement of each cylinder for correction by using a separate glass for each one.

[@SE45CX]

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.

[@skylinefever]

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.

[@zacbailey6112]

just want to applaud your dedication, one day I'll do this!

[@altairtodescatto]

Will do on my 2 cylinder motorcycle, that girl is in desperate need of a rebuild, but will be my learning bench =D

[@shanepowers7566]

An old dirt track trick: on a V-8, the back cylinder on each side have pistons 1/2 of a compression ratio higher than the other 6 cylinders. Example; front 6 - 10 1/2 to 1, the back 2, 11 to 1.

[@JettaSt0ned]

Wicked stuff! Was wire tucking my g5 cleaning it all up and now might go and equalize the head 😂😂

[@derekfromtauranga6012]

I have done this many years ago when I was racing and rallying cars. You should surface the head and grind and lap the valves and seats first. Use old valves to protect the valve seats while you are grinding the chambers. Number all the valves so they are all matched to their seats. I seem to remember I used kerosene to measure the volumes. It’s quite a time consuming process but when you are trying to gain every possible HP out of the engine every bit helps. I remember checking cam timing and shimming the sprocket key way to correct cam timing. I even use to lighten and balance pistons and Conrods, lighten the flywheel and have the engine fully balanced.

[@lobuxracer]

Sure. Lap the valves and see a 5% decrease in flow. So 20th century.

[@bojned]

Good one, I admire your patience :)

[@corollaae8645]

Great explanation of port and polish!

[@steveadams5190]

Great job! Next, the runners!

[@LikeZO]

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.

[@AndrewShingange]

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 😁👍🏾👍🏾👍🏾👍🏾

[@kevinghifari2330]

Thank you soo much for this, I've been meaning to purchase the CC kit but shipping cost a fortune, I'm surely gonna try this syringe method for my motobikes P. S Superb video, salute

[@geoffmooregm]

If you need a valve job then you should factor that into your work plan. Depending on the decision to just cut or replace and cut (if they are replacable) the seats will affect the chamber volume as the valves sit higher or lower on their seats. It is also worth mentioning to the machine shop that you want all the seats at identical height so find the lowest seat first and cut to that.

[@heinzhaupthaar5590]

I've got a tip for you that works like a charm and can shave lots of time off the process - just using a proper scale and a syringe. Just use an oversized syringe, draw up a volume to a certain weight, for example 70g, fill the chamber, weight again and note the difference. If you want to be very accurate make sure you keep everything you use in the same room for 24hrs to equalize in temperature and make sure you keep everything out of sun- or spotlights. Even if you're unsure and do every measurement twice that should still be way faster and is plenty accurate. Just make sure your syringe is dry on the outside, your scale isn't utter crap and has a life of its own and keep your phone or other possible sources of radiation away from it. A phone can make scales swing by a lot but you should usually notice it anyway because it won't stabilize. Can't imagine doing it any other way, it's so much wasted time for nothing. A good scale will even be more accurate than the graduations, I've found them to be not as accurate as one might think and differ a measurable bit from model to model even on syringes of quality brand manufacturers.

[@RamPenndragon]

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.

[@joels7605]

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.

[@RamPenndragon]

@@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.

[@errolfeistl1705]

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

[@hanspedersen2326]

Here in europe we use airflow to control the real airflow when the engine is complete. Because there could be slight difference in the casting of the cylinder head

[@MrPowecat]

Great video..... I'm tried this myself. I used Wintergreen Alcohol instead of water

[@gothicpagan.666]

That's the static comp. ratio sorted now for the dynamic. Though for practical reasons, dynamic is usually done first.

[@truegret7778]

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.

[@deusexaethera]

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.

[@ssllhh100]

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

[@d4a]

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 😂

[@ssllhh100]

@@d4a all you had to do is to put the head in the freezer for a few hours, the wax would pop off on its own

[@jameshaulenbeek5931]

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.

[@d4a]

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 😂

[@alejandrocasas1455]

You're right ... This job test your patience... I did it and it was a nightmare... 😫 But worth it 😅 🇲🇽

[@stefanozed868]

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)

[@adrianlala5044]

Keep them coming I am curious how it will turn out

[@josepablofernandez5068]

Nice video as always, cheers from Chile mate!!

[@davidfarmer]

Cool, I actually just cc'd my 3ac-su head. I used a $20 burette, and a cell phone holder arm to hold the burette. my chambers were 31ml on average, but I'm use a 4ac block crank and pistons. they were all within .2 ml, and I suspect the spark plugs may have trapped bubbles, as they are mounted at an angle and they weren't perfectly clean.

[@t115vegaboy28]

I have once overhauled a 4AFE before and we usually have the cylinder gead refaced dew to engine overheat... then sometime we are forced to double the head gaskets when the head already recieved its first refacing... we usually do it cause our customers lack the budget most of the time...

[@Thelemorf]

You should use some other liquid than water, due to the high surface tension of water.

[@alanlee8018]

The only time I ever did this my supervisor (engine builder expert) got me to use kerosene.

[@Flenderr]

Good vid but one remark: by deshrouding those valve recesses, you are also reducing turbulent flow, which helps against knock on a turbo engine. Some prev owner did this also to one of my Kawasaki 750 turbo heads, but only on 1 combustion chamber, so I had to smooth out the other 3 as well.

[@JimmyMakingitwork]

Now we need a way to control cylinder to cylinder temperature variations.

[@Miky9560]

I own an AE111 with 4AFE and 6 speed gearbox so video about turbocharging this engine would be quite interesting to me

[@eTiMaGo]

That's a real labor of love :)

[@DigerCZ]

this was actually really informative and useful video. thank you!

[@Dethjingles995]

We need more videos about project underdog

[@JB82374]

Now that it's so shiny on the inside, you need to put some RGB lighting in there! 😆

[@d4a]

😂

[@deusexaethera]

The combustion itself provides the RGB lighting.