Puzzling head feature

[davep]

I've had new valve guides installed recently and I've noticed that an area around each combustion chamber is recessed a few thou, each area corresponds to the cylinder/piston circumference:



Does anyone have any idea why the recesses are there? They are 4.3 BV heads (1.69"/1.46") and have been extensively worked on so my initial thought was CR adjustment maybe.

[davep]

Thanks for the responses guys. Where is Spend these days?

If I fit composite gaskets am I going to hit problems?

[davep]

The recesses or groves where there before the valve guides where done. Composite gaskets came off and the block face has no corresponding grove, the gaskets where in good order.

Read some info on Wills Rings and high CR on the V8 Owners Forum, blimey you learn something new everyday!

[davep]

An optical illusion in the pic, it's a 2-3 thou groove and like the guys said above I now know they're there to locate wire compression rings. There were no rings in place when the heads were taken off and no gasket problems. The heads have a casting number ERC 0216 and no injector notches in the inlet ports but the ports have been enlarged.

[davep]

Thanks for the advice carsy. Like I said earlier there are no corresponding grooves in the block face.

The engine was rebuilt due to slipped liners ten years ago using a V8 Dev 4.6 performance short engine and the original BV heads, but, interestingly, the car came from the factory as a standard 4.3. I've read a previous post by Spend on TVR BV heads and I must agree there has been extensive porting and flow work done, however I cannot be sure that this was originally done by TVR Power or as part of an upgrade between 1992 - 2001.

[davep]

Grifter, thanks for the advice. When you did your engine upgrade did you do the head assembly and wire work yourself. If so, what gaskets did you use and did you do any before and after compression checks?

How's that B9 of yours, missing the Griff yet?