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Piston pin heights.

2K views 6 replies 4 participants last post by  Hippie 
#1 ·
How accurate are the advertised pin heights among the various piston manufacturers? I know the old TRW's were usually right on the gnat's behind but not so the Speed-Pro TRW replacements of the same PN. I bought Speed Pro "TRW" forged pistons a few years ago, the catalog said pin height was 1.560, they measured 1.540. I would expect that of cast rebuilder pistons but not a supposedly "High Performance" part. Can you believe ANY of them and if so WHO? Thanks.
 
#2 ·
Hippie said:
How accurate are the advertised pin heights among the various piston manufacturers? I know the old TRW's were usually right on the gnat's behind but not so the Speed-Pro TRW replacements of the same PN. I bought Speed Pro "TRW" forged pistons a few years ago, the catalog said pin height was 1.560, they measured 1.540. I would expect that of cast rebuilder pistons but not a supposedly "High Performance" part. Can you believe ANY of them and if so WHO? Thanks.
"In God we trust, all others are audited" is a sign at my tax guys office. For an engine builder this means parts are what they measure, not what the printed or virtual literature says they "are".

However, giving Speed-Pro the benefit of the doubt, those pistons might be meant for a 6 inch rod.

Bogie
 
#3 ·
oldbogie said:
However, giving Speed-Pro the benefit of the doubt, those pistons might be meant for a 6 inch rod.

Bogie
How would that make any difference, they are just short by .020" From the published spec?? They won't come out right for any common factory SBC stroke crank with any common off the shelf rod length, only a totally custom piece.

It's just BS that you can't look up actual spec's, even from the people that manufacture and sell the parts.
 
#4 ·
pistons

All the top quality pistons are spot on. Speed pro is not exactly top quality anymore IMO. I have a set of Speed Pro big chevy pistons brand new in the box and one is .015" under on the OD. There are no more on the shelf and there not filling back orders.

So if you buy a quality piston they will be correct.


Keith
 
#6 ·
pistons

Hippie said:
I share your opinion. I miss TRW.... :(

Yea, Speed Pro has had like 5 owners in 5 years, or something like that. The only thing I use from them anymore is there rings. I love there SS50 oil ring. I am told when the stock of them is gone ,expect junk.

Keith
 
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