Cracked Piston thread

NathannialD

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correct, there is no steel insert in the top ring land. so there is a compromise: either run a keystone ring and let it wear the ring land, or run a soft ring that will wear and cause a loss of compression.

either option will result in needing to tear the motor down to replace these parts. life expectancy depends on use but typically on the duramax its about 25k miles. most will check compression periodically and when it starts falling off its know that the motor needs a refresh.
 

NathannialD

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Wish I would have known. Any idea on pricing for a set with standard length rods?

pricing would be a bit more than 6.0 forged ($2600) the ideal part of the forged is you can get them in any compression ratio with or w/o valve reliefs. meaning you could run a huge cam w/ .150" valve reliefs and still have 17/1 cr if thats what you wanted.
 

Jbenso127

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Currently dealing with what i believe is a cracked piston as well. Was running HD 300 with elite 71mm, no gate, when it happened. Blew my glow plug harness out on back 2 cylinders. Now has a lotttt of blow by, a light knock/tap and white/blueish haze out of exhaust.

Is that the symptoms for one?
 

powerstrokin15

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Currently dealing with what i believe is a cracked piston as well. Was running HD 300 with elite 71mm, no gate, when it happened. Blew my glow plug harness out on back 2 cylinders. Now has a lotttt of blow by, a light knock/tap and white/blueish haze out of exhaust.

Is that the symptoms for one?

yup. see if you can pull any contribution balance codes... and don't run the truck.


Sent looking at my blown up 6.4
 

weekendwarriorfsw32

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Well I guess I will chime in my 2 cents.
I blew piston #8 pulling a grade with about 19k in tow was between 1,100 to 1,300 when I heard a pop and then a hiss, thought it was just another intercooler boot going but the noise I heard was boost going though the piston into the crankcase of my block that blew out glow plug harness # 6 and that oil coated the truck and toy hauler :flipa:
Tore it down and found a chunk and crack out of #8
-4FF9-401B-8BEB-7C511C192514-4827-000001F44C1AB33A.jpg

I am torn between high EGT's cause fatigue over time because I have seen 1,600 down the track in a big tune or a cracked injector tip putting all the fuel and heat on one side of the piston as you can see by the black mark on the crack. For whats it's worth I was running the KEM 210 Tow tune when it blew and that is the tune that I always towed in. I have another truck in the shop right now with under 50,000 miles that I just did studs on 10,000 ago and he had no cracks or anything and now has a cracked #8 piston. He sled pulls his truck and races it HARD. He runs H&S Hot Damn tune and KEM 345, it blew getting on the freeway easy in the KEM tune he says.
-92C8-4756-8F0C-C89ED570E46B-2103-00000178F3CD16C0.jpg

I am Installing a set of Hallers coated International coated pistons into his truck as well. My theory is that there is so much of an unsupported lip and the heat and cylinder pressure being high is to much and stress crack come about and they only get worse from there or in my cause and injector tip was broken putting to much heat on one side of the piston, I could be way off but that's my theory on it.

I was also concerned about the international pistons dropping the compression to much for cold weather starting but I talked to Dustin about and he sent me a cold weather vid and it took my doubts out of my mind. Last week I was up in the snow and the weather was very cold like in the -10's most of the time so I filmed a start up vid of it at -9 and it started just as it would at 60 degrees out side with just a split second of injector knock then it goes away.
http://www.youtube.com/watch?v=XW8V24Ngriw&feature=youtu.be
 

DMDP

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Reading through all this makes me nervous. Not so much for my truck, cause I have no problem fixing it if something were to happen. But my fathers truck which is his work truck and he would ****ed if something happened.

I know they fail in stock trucks too. But outta people on here who have had one crack, how many were just runnin an egr block off vs some sort of waste gate? I haven't deleted my egr cause I don't like the thought of it not having a wastegate and can't afford a wastegated kit right now
 
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I'm doing a dmax right now with the forged pistons. The piston manufacturer that I use is claiming with their new harder alloy forgings that they have a much longer service life. Close to what the stock ones deliver. They have a dmax now that is at 60k on these pistons with no compression lost as of the last compression tests.

Will they go 200k? I bet not, but if your running enough power to warrant the forged pistons it may be worth the lower service life. If you get a 75-100k on a set of pistons that don't crack then I'd say its worth it. If you wanna run 200k go with IH and hope they don't crack.

It all depends on how much power and longevity you want. You can't have 900rwhp and have a 6.4 that lasts 200k, hell they barely last that long if you don't put more power to them!
 

DMDP

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I really dont think the wastegate has anything to do with them cracking or not cracking.

I'm sure running no gate isn't helpin. But yeah, just thinking out loud. Seeing that it doesn't matter how its run, stock or race tuned, they re cracking no matter what.

just don't wanna believe its a bad designed piston when I already have one money pit truck LOL
 

duddy

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Are the pistons cracking on trucks that are worked more often? IOW, Are the trucks that are pulling trailer every day or the trucks that are street toys/Daily drivers having the issues? I may have just missed the answer earlier in the thread and just not understood it.
 

Jbenso127

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yup. see if you can pull any contribution balance codes... and don't run it

I had it put on a ford computer to check for contribution codes and some other things and everything was in check. I've continued to drive to truck because it is my work truck and funds haven't permitted the chance to have it fixed correctly. I was working in Wyoming when it happened a drove it home to Florida and have put around 4k miles on it with no real issues. Glow plug harness has not come blown back out, the knock has stayed the same and goes away from time to time. Only thing is the blowby and haze has gotten slightly worse, and it uses a very small amount of oil. Maybe a quart every few fill ups.

I really dont think the wastegate has anything to do with them cracking or not cracking.

The only reason I mentioned the wastegate, is I figured temperature, combined with cylinder pressure/back pressure, may play a roll in the failure of the piston.. Just a thought though, so please don't crucify me if I am incorrect. Lol. :poke:
 

NathannialD

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I wouldn't worry about the hd pistons causing cold start problems, they don't even drop a full point. On my first built motor I dropped to 15/1 (about 2.5 points less than stock) and it started just fine, not exactly apples to apples just trying to say they will be just fine.
 

Wemoy1

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wow there are alot of important messages about the pistons in these trucks. so basicly a completely stock truck is about the best way to keep these engines to keep from cracking pistons
 

Dzchey21

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wow there are alot of important messages about the pistons in these trucks. so basicly a completely stock truck is about the best way to keep these engines to keep from cracking pistons

Nope not the case either ,.I've seen a handful at stock levels too... Think heat and regen...
 

Wemoy1

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oh ok and it sucks dot is starting to check these trucks around my house for the cans so removing it is going to get harder without completely gutting the can.
 

Dzchey21

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Im sure increased cylinder pressure doesn't help matters but heat...cool...heat...cool...heat....cool... Just isn't good on them.
 
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