Regular Mahle pistons are garbage.
Thanks, The more of a consensus the easier it is to pick, and as the below states there is a difference in the quality of pistons made by Mahle.
The Coated skirts is standard on the LBZ and up when they changed piston manufactures.
The Duramax pistons are directional I believe because of the oil squirt location and possibly pin offset. You have right bank and left bank pistons.
Thanks, I thought it was just Mahle that coated them.
Here are Mahle Replacement OE type pistons so you can see the difference in the markings.
Great link, and with the info in the description, I learned that even the rods have an offset. Thanks
Mahle does make a race cast piston that is stronger than the stock LBZ/LMM and debatable if they are stronger than a stock new LB7/LLY piston thats been delipped.
Thanks, this thread was made so there could be a debate and we can hear from different people's known experiences to help me and others looking for the same answer.
I think the OE manufacturer for LBZ/LMM pistons was a company called Dong Yang or something like that.
Most likely. I had read an article that GM switched to a South Korean piston manufacture for the LBZ/LMM pistons manufacturing.
www.dypiston.co.kr
Thanks guys, it is scary when the South Koreans are involved. I used to do building maintainess and in the early 80s American steel mills where shutting down the price for American steel skyrocketed and the building construction contractors where sourcing their plumbing pipe from South Korea, the steel had many impurities and turned out to be thinner than they were spec'd at. By the 90's we were replacing the pipe almost weekly and a few high rises I worked at just got fed up with it and replaced the whole 57 stories worth of cooling stack! Needless to say I cringe when I hear the South Koreans are involved!
01-05 LB7/LLY was for sure manufactured by Mahle.
Thanks
That's what I assumed, but since I've never compared them side by side, I didn't want to say for sure one way or the other. For all I know, GM changed to a different manufacturer for OE replacement LB7/LLY pistons after going with someone else for the LBZ pistons. All I know (from what I have been told by trustworthy, reliable sources) is that the pistons GM/Isuzu used to originally build the LB7 and LLY from 01-05 were manufactured by Mahle, and they changed to a different manufacturer starting with the 06 model year (including the 06 LLY).
GM did the same thing on the LS motors. The early ones were manufactured by Mahle and later they switched to a different manufacture when they started coating the skirts then they switched to a floating pin rod. I have pictures of them some where. comparing the underside of the castings and the OE marks on them.
The machinist I used filled me in that they were separate from the OEM and the Aftermarket Replacement pistons.
I am always curious to learn the back story on things.
Thanks guys, I like backstories as they sometimes give us a reason why things happen, as my story a few lines above I wouldn't be surprised if the South Koreans made the pistons slightly under specs like the pipe I encountered. If it wasn't clear it wasn't just one building it was all the buildings built during that era with the Korean pipe.
I think I mentioned it in another thread, but the new go-to piston, according to Jeremy Wagler himself, is the Mahle aftermarket stock replacement for a LML. Part number 224-3935. Their delipped piston package starts as them now. Wagler along with myself have had almost every set of motorsports cast pistons crack in any level of application. So he went looking for a solution and that's where they ended up. I'm putting one together now with those pistons, so time will tell.
This is what I am looking to hear, with direct information!
I know im just one guy on the internet but I've put numerous duramax together, for all power levels and applications. The race cast have failed in enough of them that i won't use them again. Then I talk to Jeremy wagler and he says the same thing. So seems like we are out of options except what he now recommends.
I talked to fingers about a set of race cast(non oval) I had fail after 60k miles of towing, 400hp truck with tuning from a reputable tuner. He kinda insuated that the hot shot type app is probably worse on them than high hp competition use.(oil temp) But I've had 2 engines break a race cast in competition use. Both compounds, enough fuel & air for 4 digits. Time slips prove it too. One is Buchanan on here.
There are 2 engines I can think of that have race cast still surviving, and they are both oval bowls. I have no doubt ovals are stronger, but bottom line in my simple mind says they are made of the same material.
Thanks again!
Kind a sad to hear, my buddy's LML cracked a race cast at 60k. His truck pretty much never went anywhere without a trailer, had twins, and was with around 425-450hp. Even had big injectors for most of it's life until the fuel system shit. Nothing for additional oil cooling though.
I've been using my built motor LB7 in my sig for towing it's a twinned truck, race cast, 100 over inj, ect . I have additional oil cooling though with a big air/oil cooler. Starting to get nervous after the above one and now hearing about others though. I might think about changing my pistons after 50k if it makes it that far, It's had hard use with towing, and some occasional spirited driving. Motor is studded everywhere so really the only cost would be gaskets/pistons and my time.
Thanks, the extra info on your buddy's setup gives a clearer picture of the load/situation.
DHD is a similar story but they tend to run the LB7/LLY piston from Mahle which is 224-3451WR/224-3452WR in whatever overbore needed.
Thanks Bdsankey, I like to hear what the reputable shops are running, it means they have a good experience with the particular part.
The number of engines NOT having failures far outweighs the ones that do. Personally I am going to be running coated race casts, big oil cooling like you (along with 11+ piston cooling nozzles), 100%, 12mm, compounds etc. I am not worried. I think a lot of it is luck and tuning related more than anything but that is 100% a theory.
What hp is your goal? I think it is higher than my goal. Do you have a thread started somewhere on your engine build?
Forgot to mention my pistons are top coated to, not sure with what though. They were a satin silver color, Industrial did the coating. I am running LML squirters and oil pump to but so was my buddies truck since it was a LML. I left the factory LB7 oil cooler because I didn't want to put anymore heat load into the cooling system, wanted most of the oil cooling separated since these trucks need all the additional cooling they can get. I'm limited by my cooling system anyways, have to slow it down over the big passes to keep coolant temps down. I think my buddies problem was the 15+LML's have such a better cooling setup he would just set the cruise for 80+ and let it eat over the big passes thinking all is well with a built motor. No oil temp monitoring so who knows how bad it was.
Thanks for the extra info on your setup! Parts noted!
I question the efficacy of delipping these pistons, personally, when the correct injector and timing is being used. I'd much rather have more complete combustion with the eddy created by the lip utilizing the correct flow and spray angle of the injector, than building the engine knowing I'm reducing the combustion efficiency even a few percent.
I can answer this from my research so far the reason for delipping is to remove stress risers, it makes the piston stronger.
