Convert Cat SDP to low compression pistons - TheDieselGarage.com
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post #1 of 9 (permalink) Old 02-06-2017, 11:32 PM Thread Starter
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Convert Cat SDP to low compression pistons

I have a Cat SDP that keeps blowing head gaskets. VVAs are off so the stock high compression pistons are too much. Does anybody know what the Cat part numbers are for the correct low compression pistons? Should I be looking for 15.2:1 or 16:1? I've been told I have 18:1 Pistons now. Serial #SDP04546. All liner protrusions are close to .0045. I'm considering counter boring and shimming to .005. Appreciate any help.
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post #2 of 9 (permalink) Old 02-09-2017, 02:00 AM
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We take .080" off of the tops of 18:1 pistons. That makes them 16:1. You also need to get the liners up to .006" protrusion. Not .005".
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post #3 of 9 (permalink) Old 02-09-2017, 02:10 AM Thread Starter
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Where are you located machinist? I can't find a machine shop in my area that wants to shave the pistons. Is it as easy as taking .080" right of the top or is there more to it than that?
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post #4 of 9 (permalink) Old 02-09-2017, 12:23 PM
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Thats it. Call me 717-368-8532
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post #5 of 9 (permalink) Old 02-10-2017, 12:44 AM
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Quote:
Originally Posted by Pete379X View Post
I have a Cat SDP that keeps blowing head gaskets. VVAs are off so the stock high compression pistons are too much. Does anybody know what the Cat part numbers are for the correct low compression pistons? Should I be looking for 15.2:1 or 16:1? I've been told I have 18:1 Pistons now. Serial #SDP04546. All liner protrusions are close to .0045. I'm considering counter boring and shimming to .005. Appreciate any help.
There is a shop in Ohio that can make your 18:1 pistons 16:1 without just cutting material off the crown, they match them to the 16:1 by machining the bowl to make them identical.
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post #6 of 9 (permalink) Old 02-10-2017, 11:25 AM
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Originally Posted by Pete379X View Post
I have a Cat SDP that keeps blowing head gaskets. VVAs are off so the stock high compression pistons are too much. Does anybody know what the Cat part numbers are for the correct low compression pistons? Should I be looking for 15.2:1 or 16:1? I've been told I have 18:1 Pistons now. Serial #SDP04546. All liner protrusions are close to .0045. I'm considering counter boring and shimming to .005. Appreciate any help.
10R-7172 cylinder packs are 16.0:1 for industrial C15 Acert engines. These are expensive and hard to get at times from Cat
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post #7 of 9 (permalink) Old 02-11-2017, 02:49 PM
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There is a shop here in PA, that does that also, but it doesn't seem to work on pistons that have been used. It seems to harden the steel, making it very difficult to machine.
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post #8 of 9 (permalink) Old 02-25-2017, 04:34 AM
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Maybe this is a stupid question, but what benefits would one gain by dropping the compression ratio? Other than less risk of blown head gasket?
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post #9 of 9 (permalink) Old 02-26-2017, 11:30 PM
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I am told, that they run better.
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