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3.903 mahle pistons

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Old 12-10-2006, 05:27 PM
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Default 3.903 mahle pistons

i've looked at the sponsors on here,and a few other places on the web.but i can't find a mahle piston for a 3.903 bore, stock.945 wrist pin diameter and the stock 6.098 rod length.does anybody stock these,or are they a special order item...or can you even get them?
Old 12-10-2006, 06:55 PM
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Seems like those tend to be made in a 3.908 bore so thats what I ended up going with which is fine as long as you don't have a 97-98 block.
Old 12-10-2006, 06:59 PM
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Originally Posted by pist0lpete
Seems like those tend to be made in a 3.908 bore so thats what I ended up going with which is fine as long as you don't have a 97-98 block.
look at my sig,lol.
Old 12-10-2006, 10:11 PM
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Oh damn my bad man haha. Ya I would give one of the sponsors a call and ask them what they have in stock. You may check ebay I think some company was selling mahle pistons and forged rods for like 800 or something like that. I bought my pistons from texas speed and have been pleased with their service but there are many good choices as to who to deal with.
Old 12-11-2006, 01:00 AM
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Wouldn't really worry about the pistons size, the correct sized rings are more important.
Old 12-11-2006, 05:24 AM
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Summit sells them with a .927 pin size but the ship date is 1/12/07. That doesn't help much if you need them now.
Old 12-11-2006, 07:29 AM
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Check with Lingenfelter
Old 12-11-2006, 01:28 PM
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Originally Posted by Fraser@speedinc
Wouldn't really worry about the pistons size, the correct sized rings are more important.
so are you saying it's ok to have a little more piston to bore clearance that what GM specs out,as long as the ring gaps are good?
Old 12-11-2006, 01:34 PM
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Originally Posted by LS1MCSS
Summit sells them with a .927 pin size but the ship date is 1/12/07. That doesn't help much if you need them now.
no,don't need them now.i'm either going to go with a 370ci next year or just rebuild/buy a 347 shortblock.just trying to get an idea of the costs and options i want to go with..i want to keep my stock rods either way..
Old 12-11-2006, 01:35 PM
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Mine are a 3.905.Check TSP they had a few it seems like
Old 12-11-2006, 01:46 PM
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Originally Posted by SuperZ
Mine are a 3.905.Check TSP they had a few it seems like
are you still running the stock rods?and thanks for the info,but i checked their web site already...
Old 12-11-2006, 05:15 PM
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I had my '00 block machined and all it required was a light hone, so it can still use the stock piston size. Even trying to get forged pistons in the stock bore size is turning out to be a major PIA! The block had about 20K miles on it, so it did not have a lot of mileage and cleaned up nicely. It seems the most common size is 3.905 which is getting close to the limit for a '98 block. Good luck, Ken.
Old 12-11-2006, 05:42 PM
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Originally Posted by LS1MCSS
Summit sells them with a .927 pin size but the ship date is 1/12/07. That doesn't help much if you need them now.
6.125 rod length. If it's for 6.098 rod it should be .945. At least that's what my mahle book tells me...
Old 12-11-2006, 06:01 PM
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I recently bought a set of Mahle 3.903 pistons for 6.125" rods with a -9cc dish and valve reliefs. I got them from Thunder Racing, and it took about 5 business days to get them drop shipped to me by Mahle.

Too bad Mahle forgot to send me the wire locks!!!
Old 12-11-2006, 07:44 PM
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Originally Posted by PICNIC_GEORGE
6.125 rod length. If it's for 6.098 rod it should be .945. At least that's what my mahle book tells me...
Correct, that's not just Mahles though. All stock 6.098 rods use .945 pins, 6.125 rods use traditional .927 pins. I just recently picked up a pair of forged 3.905 Diamonds with 2cc valve reliefs.
Here's the thread:
https://ls1tech.com/forums/generation-iii-internal-engine/620345-putting-forged-pistons-only.html

Originally Posted by the.erinyes
I had my '00 block machined and all it required was a light hone, so it can still use the stock piston size. Even trying to get forged pistons in the stock bore size is turning out to be a major PIA! The block had about 20K miles on it, so it did not have a lot of mileage and cleaned up nicely. It seems the most common size is 3.905 which is getting close to the limit for a '98 block. Good luck, Ken.
Can you clarify this a little, it's some what contradictary, thanks. Were they easy to put in or not?

Originally Posted by Fraser@speedinc
Wouldn't really worry about the pistons size, the correct sized rings are more important.
Can you elaborate on this somewhat. So using a 3.905 file to fit ring would you just gap it slightly more to make the ring smaller? What sort of gapping would you recommend for a large nitrous application, like a 225 shot on my forged diamonds and rod bolts only?
Old 12-11-2006, 10:05 PM
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Originally Posted by Beaflag VonRathburg
Can you elaborate on this somewhat. So using a 3.905 file to fit ring would you just gap it slightly more to make the ring smaller? What sort of gapping would you recommend for a large nitrous application, like a 225 shot on my forged diamonds and rod bolts only?
You wouldn't want to make the ring gap smaller for nitrous, figure the added cylinder pressure > compression > heat. The rings will expand more.

So while you maybe at .016" ring end gap stock, you may want to be closer to .020" with heavy nitrous.

Many of the piston companies specify for top ring .004" per inch diameter ring gap.

3.903 inches bore x 0.004 = 0.015612 inches ring end gap

add between .002 - .004 for nitrous.

Last edited by Fraser@speedinc; 12-12-2006 at 12:48 AM.
Old 12-12-2006, 03:20 AM
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Originally Posted by Fraser@speedinc
You wouldn't want to make the ring gap smaller for nitrous, figure the added cylinder pressure > compression > heat. The rings will expand more.

So while you maybe at .016" ring end gap stock, you may want to be closer to .020" with heavy nitrous.

Many of the piston companies specify for top ring .004" per inch diameter ring gap.

3.903 inches bore x 0.004 = 0.015612 inches ring end gap

add between .002 - .004 for nitrous.
can you elaborate further about your comment about piston size?do you run a different piston/wall clearance than most?



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