Cylinder head Volume??

[Red21]

Just been looking through the engine build spec for my 21t and I am getting conflicting information regarding the combustion chamber volume in the head,
Now the little Renault data book indicates a Combustion chamber volume of about 58cc where's the build sheet for my engine says standard is appox 43cc but a writen mark on the head is 59cc?
Now the head has been modified with the removal of the additional wedge by the inlet valve so this will increase the chamber volume, but what to?

Now I could measure the volume by the liquid methed but I am going to ask first for the correct CC on a standard head as shown in the attachment.
(Mine to follow later)

 

[DaveL485]

I Have no idea.

Break out the burette :icon_biggrin:

 

[Red21]

I Have no idea.

Break out the burette :icon_biggrin:

I might have to!! but here is a pic of the chamber on the head from my 21.

 

[-Jo-]

diff to explain this in english but turbo engine's prefer small combustionchamber. If you want to optimise it, make sure you have a longer stroke.

Small combustion + long stroke = ai caramba on torque figures !

 

[Andyquadra]

I might have to!! but here is a pic of the chamber on the head from my 21.

Thats right for a prima low compression head, I had one off them a long time ago. They grind away the section of the chamber opposite the spark plug.

However I'v done the opposite. Why have most of the fuel/air mix on the other side of the chamber to the spark plug? So I had it welded in.

Andy

 

[Red21]

diff to explain this in english but turbo engine's prefer small combustionchamber. If you want to optimise it, make sure you have a longer stroke.
Small combustion + long stroke = ai caramba on torque figures !

I know where you are coming from Jo.
After a lot of measuring and calculations the standard head volume is appox 58cc to obtain a comp ratio of 8:1, then I found this online calculator
http://www.csgnetwork.com/compcalc.html which confirmed what I worked out.
But I will still have to get the old measuring burett out to see what cc my cylinder head is but it looks like a 7.5:1 CR (64cc volume)

 

[-Jo-]

its worth to try it :icon_wink:

I'm with Andy on this one...seen many ported-flowed-drilled-skimmed-whatever heads but none off them worked as promised.

The old-new engine from craig has a real cup head, prepared by Raepers. It did 256@ the wheels with a half mapping (bearings fooked) and .48 ex.housing (cossie turbo) and way to small injectors (803's) :icon_eek:

Also, fooling arround with the head is a complicated proces. You need a cam that match you're calculation. Its worthless to enlarge combustion when you're cam doesnt pump enough air true. Thats what i got at the moment, techniprofil stage 4 cup profil and more then 20 at the wheels less then with the cheap pipercam (wich is one off the best cams i ever tested with my setup)

 

[Red21]

Jo, This is what engine spec I have at present and is obtained whilst doing routine mantenance over the years and the head cc & CR is one of the last things to find out.

Kent F528 camshaft
Valve clearance 0.25mm (0.010?)
Inlet cam lift 5.69mm (0.224?)
Exhaust cam lift 5.69mm (0.224?)
Duration @ 0.25mm valve clearance 278 d
Duration @ 1.0mm valve clearance 219 d
Full lift @ 110 d ATDC
Low compression, polished & ported cylinder head with 1.6mm (0.0625?) valve seat contact face,
standard valve guides.
Cylinder head volume 58.5cc (43.93cc standard) ? ((58.15) ?)
Compression ratio??

This engine when new coupled with an MD80 turbo & with 500 miles on it gave appox 260hp @ 1.1bar (95ron fuel :icon_eek and 397nm torque, but since then another 5000 miles and a different turbo plus one of Henks early ecu's and a few other bits on it,
it could be time for another RR just to see how wear & tear has affected it.
Once I put it back together.

 

[-Jo-]

realy nice figures, i also got a Kent cam avaible but lost all the dimensions and technical sheet (doh!).

Maybe you can send Henk an email, he can prob. answer you're question on the comb.-issue. He went to the states to do his examination for SAE Race Engine Calibration Certificate and passes. Very clever guy that Henk.

http://www.fastchip.nl/