Yb cylinder head skimming??

[wrcjim]

Skimming yb cylinder heads, how far can you go before there scrap??
I know most heads are used well past fords tolerance.

I have a late 2wd head on a our wrc engine measuring 137.6mm.

When is enough,enough

Cheers
Jim

[cossiedavid]

Your there i think mate if not theres not much left for a turbo car

[Joe-Tait]

138.6mm rings a bell for turbo applications

[Davecos 4x4]

they do thicker head gaskets now, wont they be ok to use with your head.

[wrcjim]

Thought as much, starting look for another head then!
Thanks guys

[SCS j1mbo]

As a rally head ive seen them on the seats competing for years!
The early group a heads had 1-1.5mm taken straight off a brand new casing to get the comp ratio up
the myth of a minimum thickness i imagine comes down to someone loosing a seat at a certain thickness at one stage and fords tolerences due to the cr not being adjusted.


A little bit of advice though, get a 4x4 head on there. If your running 10+ wrc cr and 38+psi it will crack, how long it lasts is anyones guess!

[MK Motorsport]

As a rally head ive seen them on the seats competing for years!
The early group a heads had 1-1.5mm taken straight off a brand new casing to get the comp ratio up
the myth of a minimum thickness i imagine comes down to someone loosing a seat at a certain thickness at one stage and fords tolerences due to the cr not being adjusted.


A little bit of advice though, get a 4x4 head on there. If your running 10+ wrc cr and 38+psi it will crack, how long it lasts is anyones guess!

hi jim
I have always wondered about this thickness thing,can you just not machine chambers back out and deepen seats shorten valves so it all stays relative
mark

[SCS j1mbo]

hi mark, the chamber size and valve clearance isnt really the issue, its more to do with the material left around the seat.
pistons can be modified to suit chambers and valve clearance
ps will reply to your text shortly!

[wrcjim]

Cheers Jimbo. The engine was running 9.5-1 @ 38/39psi. It has been ok to be fair, but yes a 4x4 head would be better

Cheers Jim

[markk]

Reclaimed loads of so called under tolerance heads