Hi,

just measured my 20V head and 16VE pistons, results below:

chamber volume: 43,5cc
gasket volume: 7,05cc (assuming it is 1,2mm compressed, 86,5mm bore)

(volume of piston 2 wall clearance to the first ring) MINUS piston dome: -6,1cc

swept volume, as always, 499,6cc

So, (499,6+43,5+7,05-6,1)/(43,5+7,05-6,1) = 12,24 CR

All data except swept volume and gasket volume is measured with water by myself. Measured many times to be sure. Gasket thickness 1,4mm uncompressed. Thinking it is 1,2mm compressed.

Anyone stated 13,6 CR VE with 16VE pistons???

BTW, I think chamber volume is the same for old-school SR20VE.

I got 12.37 with an engine calculator program if deck clearance is 0mm and that includes gasket volume etc

virtualengine2000.com and download the free calculator ;)

I don't need a "free" calculator. I have a master degree in field of physics. ;-)
Which values are you using while calculating your data? Mine values?

86mm bore
86mm stroke
43.5cc Combustion chamber volume
86.5mm Gasket Bore
1.2mm Gasket Thickness
6.1cc Piston dome
0mm deck clearance
Result: 12.37

If deck height is not 0mm then:
0.5mm deck clearance = 11.67
If piston sits 0.5mm above deck height then = 13.17

swept vol = pi()*43*43*86/1000=499,56
gasket vol = pi()*43,25*43,25*1,2/1000 = 7,05
all the other items are measured. see my first post.

deck height is 0mm.

After some chamber job, chamber volume will rise, so I think CR will come to desired 12:1.


BTW, SR16VE piston laying in chamber gives 4,5mm piston2valve clearance. Add another 1,2mm gasket height, and we are getting 5,7mm valve clearance at TDC! It is the stock pistons!!!!

Hi, my friend has a SR16VE and he put some sr20de crank and rods, but using the SR16 pistons, so the compression is at 13.5.1 and want to lower that to 11.0.1 with a thick custom cometic headgaskit, anyone know the thicknes he can use?? like 1.2 or 1.8 or 2.2 please help. thanx...

SRC calculated it to 12.85 with SR16 pistons on DE crank and rods.

Hi, my friend has a SR16VE and he put some sr20de crank and rods, but using the SR16 pistons, so the compression is at 13.5.1 and want to lower that to 11.0.1 with a thick custom cometic headgaskit, anyone know the thicknes he can use?? like 1.2 or 1.8 or 2.2 please help. thanx...

See above.

It is not 13.5:1, its closer to 12.5:1 which means if you fit a 1.6mm gasket(Tomei and Cometic sell them off the shelf) then you should get a lot closer to what you wanted. No point going to 11:1 as thats achievable on stock pistons with a head shave

Updated data...

I just bought a new set of precise medical syringes and I use another thick piece of Plexiglas, so it doesn't bend while measurements are taken. I've got next measurements last time:


1 cyl.: 43,11 | 43,17
2 cyl.: 43,40 | 43,41
3 cyl.: 43,10 | 43,12
4 cyl.: 43,22 | 43,14

piston dash (in bore): 6,795 | 6,731


Great precision of measurements I think.

Remember my combustion chamber is highly modified. So now I admit my mistake of first measurements. Unfortunately, I can't measure stock 20V combustion chamber volume now.

And what we get:

if we take into consideration 40,5 сс volume (more_fasterer's data) for stock 20V head, we will get 13,2:1 CR using 16VE pistons. +1mm notched pistons will bring you 12,77:1 CR.

if we take into consideration 41,8 сс volume (Andreas' data) for stock 20VE head, we will get 12,87:1 CR using 16VE pistons. +1mm notched pistons will bring you 12,42:1 CR.

My modified 43,15cc combustion chamber will bring me 12,5:1 CR using stock 16VE pistons. +1mm notched pistons will bring me 12,07:1 CR.

I think I will be happy with 12:1 CR. I'm thinking now on which cams will suit this setup.

Hi SRC

Im getting similar figures to you.

People on the other forum say compression using SR16 VE pistons are up and over 13. Ive tried to see how this is possible - but piston CC would have to be up near 10cc alone to achieve thi


Going by your figures, and what iver ran so far, the N1 piston would be in the mid 11.7 range for compression. I will try and calculate CC on the N1 piston later.

Calm down sssanctum 5speed never called you stupid. If your calculations are right just prove it no big deal. A lot of people just take it as gospel and don't try new things. Hell I'd be more than happy if my SR16 pistons are not 13.1 lol I would rest a little easier.

so how do you guys measure the volume of the dome on the piston?