Cylinder head mod?

[Keith]

After 115,000 miles and 22 years I've got the head off the TR and it all looks in remarkably good nick, even the valve seats look perfect and barely need a re-grind.
I had it converted to unleaded shortly after I bought the car by a certain TR performance specialist and he seems to have done a remarkably good job (unlike most of the other 'performance' bits he sold me which have long since given up and gone for scrap, but that's another story!)
Anyway, when he did the unleaded conversion he fitted slightly larger valves, and I've always thought this was slightly counter productive as the larger inlet valve is shrouded by the walls of the combustion chamber. The Kastner book describes a mod to improve this and I'm contemplating doing this. The mod involves opening open up the valve pocket and chamfering the top of the cylinder liner to allow better flow round the valve. This requires a head gasket which allows for this, but the 'standard' copper gasket I bought seems to have this.
So on the plus side, it could free up the flow and improve power and efficiency, on the minus side, once you grind metal off you can't put it back!
Any thoughts or experience out there?

Keith

[JohnD]

Keith,
I inherited a head in which someone had undermined the chamber sides to reduce valve shrouding - at least I can think of no other reason for doing so.   I carefully built up an engine for this head - and it blew the gasket first time out!    A rebuild with a new gasket lead to exactly the same thing.   I suspect that the edges of the chambers where the head and block faces meet are so thin that they are more flexible than they should be, so that a proper seal is impossible.  That head is going into my Black Museum!

John

[Andy Flexney]

Keith,

When I had my TR4 head converted about 20 years ago I stood before the same question and decided not to remove any metal from the head. However I did notice that the combustion chamber sides have been hollowed out slightly i.e. they are not straight but bowed (think of a barrel, but a short one). This was only done where the wall was closest to the valve. I am not sure if this was done when the valves were put in or if it is standard on a TR$ head. Yes I have a TR4 head on the TR3.  :)

Anyway I left the head as it was and have not been disappointed with the performance of the car. I am sure if you were racing and needed those extra 2 or 3 HP it would be worth the risk but otherwise don’t bother.

Have fun
AndyF