Just looked for the data on my Cosworth 2.2L stroker and Big Valve Head

as follows

Bore - 86mm
Stroke - 94mm
Head Volume 46.8cc
Volume above Piston - 25.9cc

Comp Ratio ~ 8.5:1

hope this helps

cheers

John

 

Thanks John!

 

What do you mean with volume above the piston?

 

Tim when you said 0.74 clearance... with what gasket?
Because if you use Mitsubishi 5 layer OEM gasket then the piston should come higher that the top of the block (0.06-0.26 at least depends on gasket thickness) !!!!
Right?

 

IM sorry for the confusion I meant that the piston should be at approx zero deck height and that there should be approx 1MM piston to head clearance.

 

Volume in top of piston recess - Piston dish
Volume from top of Piston to deck height - Deck Relief
Volume attributed to Gasket (1.3mm in my case) - Gasket
all added and called Volume above Piston (Terminology could be misleading)

Do not have the individual volumes to hand - sorry

John

 

So Cosworth Head is 46.8cc for sure?
How much volume does OEM has?

 

dude install the head and have a good day-JOEYD

 

keep this on topic guys. its a legit question and everyone is trying to learn engine math. Some of the best techs in the business are answering, try to follow along.

 

Degreing the cams is not a big deal and is easily accomplished with inexpensive adjustable cam gears and a timing wheel.

You can either go with a different piston or deck the head or block of both

Don't forget to check piston to valve clearance with clay

Al

 

This is similar to the Buschur pistons as I asserted on page 1 - zero deck height

I would suggest that the OP conisder Buschur or AMS pistons

Al

 

I already spoke with Ken Anderson from Cosworth USA and he told me that the Cosworth pistons have this issue with the height from the factory.
The CR of my motor will be 8.37:1 if I will use Cosworth pistons.
So the only solution is to buy a new set of pistons from Buschur Racing (JE pistons) or AMS (Ross pistons) that had zero height difference....
So I guess my motor will be half Cosworth half Buschur...
The 8.8:1 that cosworth said on their spec is wrong.
The real spec is 8.61:1 for cosworth pistons and stock head and 8.37:1 with cosworth pistons and cosworth head....
The only way to make a full cosworth motor is to buy custom cosworth pistons....

The best thing with Cosworth pistons is that the pin is not at the center of the piston and that they use 2618 forged material.
Is there any other brand with this characteristics?

Please help me to decide A.S.A.P. for a new piston set.
1000+ WHP capable,as light as possible.
Which piston set is top notch?

 

About head gasket for my Evo 9....
Do you know which is the thiner gasket that I could install?
I am searching for a 0.8mm gasket cause the one that I have now is 1.2mm (I think) OEM Mitsubishi Metal HG.

 

Have a look at www.jacksonautomachine.com they will help you out with your build.

 

I STRONGLY recommend you go with AMS' products...

-E