Just finished installing my freshly reworked head on the TR6. There was
nothing wrong with the old head other than worn valve guides and the nasty
smell that comes with raw oil being introduced (via the valve guides) into
the exhaust stream. And the fact that it is a later style head (73 by my
guess since it has no EGR valve port but you can see where it goes) and the
7.75 : 1 compression ratio.
I took an early head to the machine shop and had bronze sleaves installed
in the old valve guides, the guides were cut and stem seals installed, .060
was shaved off the head in hopes to get another point of compression ratio,
and he radius'd the sharp edges in the combustion chamber.
Whilst cleaning the top of the block I did something I have never done
since I bought this engine (used) some 12 years ago: I read the engine
number and it turns out to be a CC engine (CC85xxx). So, it appears that
somewhere along the line a PO had popped a later head on an early block.
Thus I had the worst of both worlds: The lower compression head on a block
with the more pedestrian camshaft. I must have had the worlds only 90 HP
TR6. Not any more.
Initial driving impressions: No great shakes. Any difference is subtle.
It runs about like before but it may have more torque which is what I was
looking for anyway. I say "may" because it may be the placebo effect
kicking in. One interesting thing, however - I transfered the carbs from
one manifold to the other without touching a setting. It now idles at 950
- 1000 RPM whereas before it idled at 800.
But best of all the foul smell is gone.
Dave
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