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Old 06-07-2009, 06:35 AM
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Default Re: What is wrong with my motor? Figure this one out!!

Rich;

Normally the pistons don't hit very bad, just enough to leave witness marks in the domes that are maybe .010-.020" deep...but that's still more than enough to create a h*lluva racket when the engine's running. Needless to say this isn't good for the engine, so I would strongly advise against running it any further. I would advise discussing this issue with your builder before doing anything else.

If there is any "good news" to the situation, it's that the problem can be alleviated by slightly relieving either the domes or the chambers at the point(s) of interference. Other than that, the only choice is to remove the L78 pistons and install the correct L34 style units with a smaller dome which is designed for the oval port heads.

One other thing to consider is that the L78 pistons will give you close to 11-1 compression, so you'll have to run good gas should you decide to leave them in.

Give me a call monday if you wish and I can give you some more details.

Eric
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