Measuring volume (cc's) of a pop up piston. Read description for answer.
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- Опубликовано: 2 окт 2024
- I'm measuring the cylinder volume in cc's of a 351 Cleveland engine with pop up pistons. I failed to do the math in the video but the answer is 7.23cc's for the pop up piston top volume.
I measured 147cc's with piston .730" down in the cylinder. 63cc's with the piston .365" down. The difference is 84 cc's. 84 cc''s minus 63 cc's is 11cc's.
The piston is 0.018" down at TDC. The volume of a cylinder 4.033" in diameter and 0.018" high is 3.77 cc's.
11cc'c minus 3.77cc's is 7.23cc's. So the volume of the pop up piston top is 7.23cc's.
My heads are 75 cc. The Gasket is 12 cc. After using compression ratio calculators, this engine with the pop up pistons and open chamber heads has 10.15:1 compression.
When I use my Closed Chamber heads the compression goes up. The CC heads are 66 cc's, resulting in 11.35:1 compression.
Thanks for explaining this, i was having a hard time figuring it out lol. Was almost going to make a reverse mold of the piston, that would not have been fun.. anyway, i checked your math, and it all makes sense! My only problem is how you calculated the compression height in the bore for your final cc measurement. Truly the dome is 11 cc's, and its reliant on the builder to set the compression height. That calculation is easily done separately. Also im curious, is that gasket you used .050 or thicker? Common .040 x 4.100 gasket calculates to 8 or 9 cc's, and picks the compression up almost half point in your example. But that gasket isn't a symmetrical round bore either, so it might be more?
On a Cleveland the head gasket is bigger than on a Windsor. A Cleveland doesn’t have a perfect circle for the cylinder opening. I made a video of when I measured the cc’s of the gasket. It is 12 cc’s. Watch the video on it. Thanks.
@@dansmessygarage6720 I will, thank you! That is very good info to know!
Didn't it take a bit more than 147 cc? i could see some air under the plate
No. Watch the video again. You can see the air bubble getting bigger after I stopped filling it. The liquid was draining out thru the ring gaps. It most likely was draining out the entire time I was refilling the burette. That means it took less than 147 cc's. For my messy garage tactics, 147 is close enough.
Did you make good power with those pop up pistons on those open chamber heads.
It makes about 475 hp on 93 octane pump gas. Nothing crazy. It is N.A. no blower, no turbo, no NOS, just a single 750 carb. Today it is called a boring engine :-(
@@dansmessygarage6720all these modern engines, people have a helluva motor with just a cam, exhaust, and computer tune. It's still fun to take a motor with mediocre heads and show up some "big hp" motors.
Edit: not that cleveland heads are mediocre, just by today's standards.