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Re: Tom Johnson's Rebuild??
Paul_G._Christie@intouch.mpx.com.au (Paul G. Christie) correctly said:
>> firstname.lastname@example.org,Internet writes:
>> HOWINHELL can it be an ignition problem?? Can't Happen!!! The
>> ignition has NOTHING to do with mechanical wear in the cylinder
>> walls. It has to do with igniting the fuel/air mixture at the
>> right time.
> I agree with the rest of your post but the ignition has a hell of a lot to do
> with mechanical wear. detonation (pre ignition) will play havoc with
> rings,cylinder walls and pistons to the point wear it can burn a hole in the
> top of a piston etc. Also a simple thing like retarded timing will cuase the
> motor to run exceccissvly hot and damage rings and bores etc.
> I'm not saying that this was the fellows problem just that things should be
> understood before advice is given so as not to confuse people. I notice this
> goes on a lot in this mailing list.
WELL put! But let me state a counter-argument and my reasons for it.
I considered ignition but still think that it is highly
unlikely to affect the rings. **As far as I am aware** (note
qualifier, as I am not an expert in this area) detonation would first
damage the piston tops and probably melt through them before
affecting rings. Ring problems, *in my interpretation* would be a
much later effect of excessive detonation.
You are 100% right about heating - but in my experience, an engine
has to get REALLY, REALLY hot before getting hot enough to take the
temper out of the oil rings, which can certainly cause excessive oil
consumption. I have seen this happen, but NEVER to an owner who was
not aware that he/she had gotten the engine much hotter than was
I have never heard of an engine getting hot enough to lose the temper
from the main rings. Therefore, while I certainly agree that timing
problems, epecifically excessive detonation or grossly innacurate
timing, could cause damage to pistons, I think it highly unlikely
tht damage would PREcede such severe damage to the pistons that the
rings would be the most suspect item. Nor do I think that he could
get the engine hot enough to damage the rings without knowing full
well that he had done so.
O'course, this is theorizing. The proof will come when he pulls the
head and sees the piston tops.
BTW: I have seen a Ford 302 V-8 get SO hot that the babbit material
from the main bearings ran ito the pan and formed pellets - so hot
that every major component was warped and not one major part was
salvageable. But it ran well - until they turned it off....then it
was toast. Had to sit for three hours before we could remove the
radiator cap, and even then it shot a geyser!
I say the above not to pick a fight, but to explain the reasoning
behind my comment. YOU may have it exactly right! It will be
interesting to hear the outcome.
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