4E / 5E Combustion chamber CC

finx

finx

Member +
Looking into doing some combustion chamber work on the 5EFHTE. (5efhe base)


So far i have a listing of 39 CC, can anyone who has experiance doing head work on these engines confirm the facotry combustion chamaber CC as thus?
I will be taking preliminary tests of the CC of each chamber on my donor head before i start but i need to calulate how much to take out to attain my optomin compression ratio


Rep for adiquate responce


Thanks
Ryan
 
Last edited:
G

GP82

Member +
I got from 38 and 39cc on a stock unskimmed 4efte head. They were all within 1cc of each chamber!

What kinda C/R are you aiming for?..
 
finx

finx

Member +
Thanks for the responses guys.
Im using an un-skimmed head

Aim is for 9.0:1 compression ratio. Which should equate to 43.5CC chambers if using a base of 39CC with a stock 1mm head gasket (crushed thickness) which seems to be the general starting point.



Ryan
 
weeJohn

weeJohn

Lifer
finx said:
Thanks for the responses guys.
Im using an un-skimmed head

Aim is for 9.0:1 compression ratio. Which should equate to 43.5CC chambers if using a base of 39CC with a stock 1mm head gasket (crushed thickness) which seems to be the general starting point.

Ryan
Click to expand...

Off topic a bit this but while it was mentioned... I am going through the same steps as you at the minute, I have a few used head gaskets in the garage, 2 stock and a few steel ones. The stock ones mic at 1.2mm near enough, and the metal ones mic at 1.4mm which was the size they were listed at.

Have you ever measured a compressed head gasket so that for sure its only 1mm when torqued down? I just cant see the metal rings round the cylinders on the stock gasket increasing by nearly 0.2mm in thickness when removed, its not like the gasket material between the rolled over edge them pushes it back out.
 
weeJohn

weeJohn

Lifer
finx said:
Thanks for the responses guys.
Im using an un-skimmed head

Aim is for 9.0:1 compression ratio. Which should equate to 43.5CC chambers if using a base of 39CC with a stock 1mm head gasket (crushed thickness) which seems to be the general starting point.



Ryan
Click to expand...

I would check the volume of the cylinder below the deck with the piston at TDC first before touching the head. I am getting my block back tomorrow and its the first thing I plan to do.
 
weeJohn

weeJohn

Lifer
I dont have heavily dished pistons so they have the cut outs for the valves, I have also decked the block as well. I want to CC the cylinder to the top of the deck with the piston at TDC and include the volume around the piston crown to the top ring as a CC or 2 makes a difference.
 
S

Skalabala

Member +
Sorry for bringing this up guys.

Might be making a mistake as I am very tired :D
Standard engine CR +-

Head CC: 36cc +-
HG CC: 4cc +-
Piston: 3cc +-

Ratio then is 333cc divide by 43cc and you get a 7.7:1 +-
What am I doing wrong?
 
weeJohn

weeJohn

Lifer
Did you add the 43 on when you calculated the volume at the bottom of the stroke? Also where did you get the 3cc from?
 
weeJohn

weeJohn

Lifer
Skalabala said:
3cc from the piston dish and cut outs.
you lost me on the bottom of the stroke?
Click to expand...

Has that 3cc actually been measured? My 5E with Wossner pistons that have a very small dish like the stock pistons and cut outs measured 6cc when the piston was at TDC, that was with a skimmed block as well.

The 333cc value, how was that calculated I meant. The head gasket and combustion chamber volumes need to be added to the volume of the cylinder displacement in the bore.
 
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