I took a piston out of the block and it mic'd out at 4.458,I thought 502's were 4.466 standard. was I told wrong?
If so what size do I have??
The guy who pulled my motors said they were new pistons and they look new.
Only markings on the pistons are SRP 75f ???
I need to get a ring set, even if these look good...
johnny
Thread: what size of piston do I have?
Results 1 to 9 of 9
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11-24-2009 05:22 PM
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11-24-2009 06:28 PM
12524293 is the GM part # for the ring set ( individual, not 8)
for a std bore 502
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- Join Date
- Oct 2008
- Location
- St. Petersburg, FL
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- 3,965
11-24-2009 07:32 PMThe standard GM 502 bore is 4.466"
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11-24-2009 08:56 PM
42JOHNNY
The standard bore size for the newer GM 502 is 4.466”, some previous Gen blocks delivered @ 4.468”. If (big if) you have the SRP OEM replacement pistons for the 502 they would be part # 281916. The .002” over on the SRP pistons would accommodate the hone, while keeping the piston to bore in spec. The P/W on the SRP line is significantly tighter than a 2618 alloy (JE) piston.
Bore Size: 4.470
Oversize: 0.002
Dome Volume: 1cc
Weight: 665
The ring set is as follows;
JE Pistons Part#: J100S8-4470-5
Description: 1/16-1/16-3/16 4.475 4.475 MOLY TOP/CAST 2ND/3PC STD OIL
Ideally you would validate both the bore & piston size prior to ordering the ring set.
Bob
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11-25-2009 12:17 AM
Will do and thanks again.
I was told when I bought the boat, the new owner wanted the motors pulled and rebuilt even though they had little hours on them, then he had it and lost a bearing where it sat for years before I bought it.
He did not know what was wrong with the motor as it had good oil pressure and ran fine, just something was not right so he parked it.
that is when I took it out to launch and found this out to, something was not right. So we pulled the motor, and found a spun bearing. But the pistons/bores looked good. so, now the bottom end is fine and now need to work on the other parts, I have not got into the other motor yet to see if all is the same with it though.
johnny
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11-25-2009 11:18 AM