Cracked Piston solutions?
- Thread starter JDPlowboy
- Start date
i respectfully disagree, i have talked and worked with some well known builders as well. i dont speak from second hand info either. what ive posted is exactly what ive seen personally from throwing heavier pistons in an unbalanced, stock block. pull that engine down you threw the pistons in and post up some pics of the bearings, they wont look happy and clearances will be pretty open and as i stated before, its more weight/harmonics on a known crank issue.
if you dont care and dont mind the engine failing at some point to try this, its one thing but when you want it to last and dont want the put the money into an engine, thats a different story. Blake also aint no newb to it either, i dont doubt what hes seen as we talk about stuff/ideas all the time
Cause was on the other forum.. lol
I'm looking too.. I know I took pics of the pistons on my digital scales.
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I'm looking too.. I know I took pics of the pistons on my digital scales.
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all stock engines are blueprinted to an extent. you mean balanced. its stock, no added hp or rpm, and gm accounts for MOST of the weight in the crank counter weight and balancer/fly wheel. its the same reason you dont put an LBZ balancer on a LLY or vise versa and so on
Best thing to do IMO, if time and $ were available, would be to get a set of Motorsports cast pistons and have the pins lightened to make up some(hopefully all) of the weight difference.
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Found em...
4 grams diff on stock LLY vs Mahle [+.020" I think] with valve reliefs.
I was gonna say only 4g earlier but didn't wanta commit. Been told that 1.5g range is not uncommon within a set, so your only talking about 2.5g difference from stock. In a Duramax, that's like the least of your bottom end worries...
4 grams diff on stock LLY vs Mahle [+.020" I think] with valve reliefs.
I was gonna say only 4g earlier but didn't wanta commit. Been told that 1.5g range is not uncommon within a set, so your only talking about 2.5g difference from stock. In a Duramax, that's like the least of your bottom end worries...
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You are correct.. LML has more meat in it so should be heavier. Someone toss one on a digital scale for comparison and we will know for certain. The LML and Mahle look to be same dang piston from what I recall. Lot closer looking now than the old LLY's.
:hug:
guys.... an LML piston weights ~834 grams. that ~46 grams difference PER PISTON going off the weight Kid posted and ive seen race cast vary as much as 4 grams.
I'll have 8 on the table this afternoon. 6/8 were found cracked while I was doing hwadgaskets.
clean them well and weigh them without wrist pins or rings
found a post from Guy. also agrees with the weight i posted.
http://www.duramaxdiesels.com/forum/showpost.php?p=517109&postcount=25
Humm... Isn't the pin dia larger on the LML?
If so, that might just be a diff between years. We may be comparing apples to oranges. I would call Mahle and ask them. $1 says apples to apples it comes back to couple grams.
If so, that might just be a diff between years. We may be comparing apples to oranges. I would call Mahle and ask them. $1 says apples to apples it comes back to couple grams.
nope, difference is the width in the wrist pin head of the rod and wrist pin is shorter and lighter. Mahle uses the same pistons from 01-16 engines as they will still fit an LML rod just fine.
Then that 46g diff is gonna be a big deal.
Ok, tell the customer you need to buy a LLY so my math works out correctly. :roflmao:
Ok, tell the customer you need to buy a LLY so my math works out correctly. :roflmao:
You can take 50 grams from the pin without issue. It isn't hard to weight match those items. For a stock balance they are within 2 in/oz on balance. Performance balances are within .5 in/oz. people always refer to grams because of static weights when they match numbers. In the end anything over about 12 grams difference you will feel. The part you can't see though is the damage occurring to the bearings. Balancing is cheap. 250 to 350 depending on where and who is doing it. I got a set if Fingers pistons to within 34 grams on a previous balanced crank that had been done with Arias forged as the pistons. There is a noticeable difference in a balanced motor versus a stock item assembly.
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