Cracked Piston solutions?
- Thread starter JDPlowboy
- Start date
From the set of 16 Fingers just did for me before ceramic coating.
+0.20 Oval bowls, valve reliefs, -0.10 off the tops, and pins shaved down.
1293g with rings.
+0.20 Oval bowls, valve reliefs, -0.10 off the tops, and pins shaved down.
1293g with rings.
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I'm fixing a LML that rolled in here this week that has one piston skunked. It needs honed and hopefully can stay standard size bore
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Ya the guy was running backyard tuner tunes and the spray patten was across the entire piston.
So now when you buy new pistons from gm you get a unisex Piston now I guess.
Are those Lml stockers?
I'm currently having my LML (no tune, deleted, normal usage, 123,000mi) rebuilt due to a blown gasket. During the job, 5 pistons were found to have minor cracks, so they're being replaced with Mahle Motorsport delipped versions. (Mahle also supplies/makes the OEM pistons for GM). In the months I've been ordering parts, and educating myself on the build... the only time "rebalancing" has come up, is in cases where the crankshaft is being upgraded. I'm having the work done by a diesel tech at the GM dealership who's given me some great recommendations over the last month. He's not once mentioned the need to rebalance the engine at this point. For further reference, this truck was meticulously maintained, and not abused in any way. I've found that the reason delipped pistons are offered, is because the "lipped" versions were added (in 2011) to add heat/compression to the chamber, in order to aid in burning off pollutants. Unfortunately, this added stress doesn't seem to help pistons, as much as the environment.
I'm currently having my LML (no tune, deleted, normal usage, 123,000mi) rebuilt due to a blown gasket. During the job, 5 pistons were found to have minor cracks, so they're being replaced with Mahle Motorsport delipped versions. (Mahle also supplies/makes the OEM pistons for GM). In the months I've been ordering parts, and educating myself on the build... the only time "rebalancing" has come up, is in cases where the crankshaft is being upgraded. I'm having the work done by a diesel tech at the GM dealership who's given me some great recommendations over the last month. He's not once mentioned the need to rebalance the engine at this point. According to Mahle, their Motosport Delipped cast pistons weigh the same or less than OEM, and don't require being sent to a shop for balancing.
I don't think you can really mix and match lip pistons with delipped piston, unless they are the same weight maybe. There's some disagreements in exactly what pistons are in what trucks, so I think you would be wise to put 8 new ones in it. Lipped pistons have been around since 2004.
2001*. all dmax engines have bowls with a thin edge at the top to help with swirl
So whats the point of your post on a 6 year old thread?
you have not stated if the pistons you are putting in are Mahle OE or Race Cast, massive difference and one that will dictate longevity in your engine. Factory engines do not have a balanced rotating assembly but are balanced "in general" to an average weight of parts. when you change out parts to a non factory part, you could very well be outside of that tolerance and the rotating assembly should be balanced to keep that stock crank alive. All dmax trucks have "lipped" pistons from 2001 to today. your "delipped" pistons still have a lip but its much broader. the reason for it is for a better burn of the fuel, better mpg and a better running truck. instead, you are now hindering that. you also probably dont realize how much quench just changed because those pistons are proably .010 shorter and you state nothing about the machine work beign done.
Anyhow, your facts are incorrect and you need to do more research.
I never said I "mixed/matched" pistons. I replaced all of them with upgraded pistons. Only an idiot (IMO) would tear their engine down, and only replace 5 out of 8 pistons, with different type pistons. I'd think that was common sense.
FYI there's plenty of "idiots" that do exactly that. Sounds like you know what you're doing though and got all the common sense, so good luck.
Oh now I've tried it several times ya know... And failed every time.. LOL...
My experience with Duramax pistons, no matter who's name is on them, if ya bust one, the rest are guaranteed to follow. 1 bad piston will ruin the whole bunch...
