Greg, I'll take a stab at answering your questions. You will improve
performance by raising the compression ratio, and 9.5:1 is probably
about as high as you can go on premium unleaded. I'm at 10:1 on pump
gas, but with a pretty aggressive cam with more overlap than stock, so
that lowers the real world compression ratio.
While you don't have to do the cam now, you will have to take the head
off to put a cam in, so you might as well do it now. You'll be saving a
bit of labor and some gaskets. While getting the head milled consider
having a 3 angle valve job and porting (according to Kas Kastner's
instructions) done.
As long as your compression is good, and you're not aware of any
weakness in the bottom end you should be fine. I've been running that
way for a few years, and the bottom end is still fine.
Tom Gentry
Life is too short to drive boring cars!
1996 SVT Cobra, Mystic #1345 of 2000 (mostly stock)
1972 Triumph TR-6 OD (mostly modified)
1959 Triumph Model 10 Sedan (mostly in boxes)
"Hutmacher, Greg" wrote:
>
> I have a completely stock TR6 engine with relatively low (53K) miles on it
> and strong compression and oil pressure. Its only flaws are some oil leaks.
> I am considering pulling the head and having it milled down to achieve 9.5:1
> comp ratio but am not ready to rebuild the lower engine. Here's my
> question: If I do the head mods without doing anything with the cam right
> now, will I achieve any performance gain or will it merely cause
> pre-detonation? Is it possible and/or wise to install a new cam without
> pulling and rebuilding the lower engine? And if I don't change the cam at
> the same time as the head, should I go ahead and install the valve springs
> that are intended for the more aggressive cam? I eventually plan to rebuild
> the lower engine and I plan on going with a little more aggressive cam - not
> a radical cam. Appreciate any info. Regards, Greg
> 76 TR6 (completely stock for now)
> 68 MGB/GT (completely disassembled for now)
--
Tom Gentry
Life is too short to drive boring cars!
1996 SVT Cobra, Mystic #1345 of 2000 (mostly stock)
1972 Triumph TR-6 OD (mostly modified)
1959 Triumph Model 10 Sedan (mostly in boxes)
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