Paul writes :
> Anyway, I have a couple of questions for you TR6 gurus. I
>think I'm going to have to take my head off at some time in the near
>future and replace some valves/guides. Whilst carrying out this
>activity, I would also be interested in increasing the compression of
>the engine (US spec) - possibly up to 10:1. I realise that I will have
Why do you want to increase the compression ratio ?
How good is the petrol where you are ?
Are you ever going to use the car in the former Eastern Blok (quality of petrol
here is atrocious - at least it was the last time I was there) ?
I think raising the CR causes more problems than it solves. I raised
the CR on my Midget to 11:1 and although now I have a good, strong engine,
I also get a lot of problems with bad quality gas. I can't remember what
the octane rating was in the UK, but here in the US, 94 is the highest
commonly available. To stop my engine from pinging, I have to add 1 gallon
of Cam2 (100 octane), every time I fill up. If I am in an area where there
is no Cam2 available, I either have to driving gingerly or reset the ignition
timing (which kills performnace).
Increasing the CR will producing A LOT more heat in the engine - how is your
cooling
system ?
Increasing the CR will producing A LOT more strain on the crank/rods/bearing -
how
is you bottom end ?
> I think I am right in saying that the compression can be increased merely by
> shaving the head and not by shaving the block - is this correct and if so,
>does
IF you do decide to increase the CR, I would do it by using different pistons or
by milling the head. I would leaving the block alone (unless you need to deck
the pistons). Cylinder heads are easier to come by than blocks - so if you
screw up, you only need to get another head.
> Does anybody know if the 2500 and TR6 heads are compatible in terms of valve
> sizes and chamber shapes etc.
Call TriumphTune in the UK, they probably have the answers to all their
questions. They
are based in Richmod, Surrey.
Gerry
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