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08-03-2003, 06:44 PM
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put yer pistons on backkerds!
okay another post of bull-lischious bull sheetosis; as usual, whilst sitting 'pon the crapper readin me hot rod or phr, i came across this article (sppput!) about buildin yer sbc adding 5hp by puttin yer pistons on the rods backerds! spozed to be dyno proven, anybody else agree with this? i think he means that the rods go on the crank as per usual, (as they would have to) and the dots are pointing twards the rear of the engiine. check??? dont speculate, just let me know if you've tried it and it works/dont work. tata
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08-03-2003, 06:54 PM
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I`ve tried it, couldn`t tell any difference, EXCEPT the pistons rattled a little and they are prone to break as a result.
The wrist pin is off center enough to keep the piston pushed against the outside wall of the cylinder,Thats why one side always has more wear than the other side. The theory is less friction by turning them around. Very impractical on a street engine.
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08-03-2003, 06:57 PM
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okay, so is this motor still running?? i wouldnt expect to feel 5 hp anyway. why do you think they would be more prone to crack?
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08-03-2003, 07:53 PM
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It's an old dirt trackers trick, only works with stock type ofset pin flattop pistons, yes it works, gives better rod angularity and is very noisy when cold.
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08-03-2003, 08:15 PM
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Bob is correct, this is a well known trick amoungst dirt trackers. Not much good in todays environment though.
Vince
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08-03-2003, 08:16 PM
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It`s called piston slap. The piston shakes (rattles in the cylinder)
Like running a piston thats to small or worn out. The skirts break off.
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08-03-2003, 08:29 PM
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Often, I see racers run pistons backwards as well as offset boring to improve on the leverage of TDC centerline. With the piston being 20" or more of offset, then boring a cylinder offset by as much as 20" will give around 40" total offset of centerline in relation to the crank TDC. Anymore than that and you get into making blocks too thin on the thrust side and you end up ballooning the walls. But it does make for substaincial power gains when a cam is ground to hold the valves later into the power stroke. A filled block will see the most benifit.
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