head chamfer for 3.2ss

gestalt1 · 10-08-2005, 01:46 PM

i got a nice set of ported sc heads and hey were chamfered for 100mm cylinders. i am building a 3.2 short stroke and the cylinders are 98mm. i measured the chamfer outside edge diameter and it is just under 100mm, more like 99mm. is this going to be a problem for my 98mm cylinders? i am not using a head gasket.
thanks.

Mark McClure · 10-09-2005, 06:11 PM

I just had the same issue with my 3.0. The heads have been chamfer to 98. I have sent mine away to be welded and machined.

The issue that I see is that the chamfer creates a larger deck height at the very edge of the piston. On my measurements I had 1.5mm head to piston and 2.0 deck height. Try this on yours to see! from asking around it makes sence that it will promote detonation in that area.

So you can either weld and machine or buy 100mm P&C's.

Hope that this helps.....

Cheers

Mark.......

davidppp · 10-10-2005, 12:44 AM

Hello Gestalt.

I would not worry much.

I have on my bench in front of me a 2.2 Cylinder head I took from a virgin unopened 2.2T Sporto with 65k miles which I'm doing the top end on.

The diameter of the chamber is 85.6mm..

The bore is of course 84mm..

but, at the top of the bore is also a small chamfer...

Welding heads is not only costly, but prone to distortion, and will definitely set up stresses ...

Kind regards
David

gestalt1 · 10-10-2005, 03:16 PM

thanks guys, i think you are both right. the over chamfer would promote detonation but i am going to have twin plugs. i would also assume the wedge shape of the chamfer would create greater stress on the head to cylinder seal. there is a small chamfer at the top of the cylinders on my max moritz P&C set. i really do not want to go with the 100mm cylinders because i just got the case machined and do not want send it out again to have the bores enlarged and deal with larger copper base gaskets. would going from 3.2L with 9.5:1 CR to 3.3L and 10.2:1 CR add much power?