Thanks for the response Randall.
I hadn't thought about the volume that the wet-test oil takes up, but I
guess it would increase the compression ratio. Good point. So would the wet
test for rings only be valid for a cylinder with a very low pressure
relative to the others?
Cylinder 4 may indeed be causing me a problem. My statement about strong
running wasn't entirely accurate. The vehicle stumbles intermittently when
cruising at 60 mph or over. I can't tell if its something slipping in the
driveline or a misfire. Maybe it's cylinder# 4.
I was planning on doing the valves over the winter. It looks like rings can
be done with the engine in place. Do you think it would it be worth the
effort? Anything else I should look at when I have the cylinder head off?
Regards,
Hugh Fader
72 TR6
> Hugh :
>
> My guess would be worn intake valve guides instead, with the
> majority of
> the oil going through #4. The pitting would be detonation
> under cruise
> conditions, caused by the octane-lowering effect of the oil. The
> increase in 'wet' compression is probably caused by the oil taking up
> part of the combustion chamber, in effect temporarily increasing the
> compression ratio. It's unusual for rings to wear that
> evenly, and even
> ring/cylinder wear would not explain the increased oil in #4 and #6.
>
> In any case, it's a lot easier to change the valve guides.
> You may even
> be able to temporarily add valve stem seals without removing the head,
> both as a band-aid and to verify the problem. You'll need an airline
> and adapter to pressurize the cylinder and hold the valve up while you
> remove the spring, install the seal, and replace the spring. I don't
> know the sizes for a TR6 offhand, but I was able to buy 'teflon' type
> seals over the counter at a local speed shop, given the guide
> od and the
> stem od. About $1/each.
>
> Randall
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