Some Surestart engines have SPI

Cox International Thu Jan 24, 2013 11:30 am

There have been numerous reports of 10% or more in performance variations for these engines. Matched/unmatched cylinder and pistons may be a contributor but we recently discovered something else.

Some of the Surestart engines have SPI, which would increase RPM. I took some measurements and found OEM pistons that are .002” shorter than normal and cylinders that have the exhaust cutout .003” lower than normal, matching up with the .005” SPI gap.

**Cribbs74** Thu Jan 24, 2013 11:53 am

That makes some sense as it would have been less costly to reconfigure between runs.

I have always wondered what it took to make an engine? As in what procedures were used and what equipment to make the individual pieces.

Ron

Cox International Thu Jan 24, 2013 12:06 pm

We know what tooling is required and what the procedures are and it's a lot in both cases.

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Some Surestart engines have SPI

Some Surestart engines have SPI

Re: Some Surestart engines have SPI

Re: Some Surestart engines have SPI

Re: Some Surestart engines have SPI