Joined "The Club"

[swinky]

Have faith! Haha

Negative ghost rider.

 

[OBS-Addiction97]

I got the motor apart today. Every piston had a hairline crack on it like this:

Any ideas on what caused that?

The cylinder walls looked good. You can still see cross hatches on them.

 

[psduser1]

Offhand, I'd say overfueling at lower rpms, lol.
Id have to say its related to the hole in the block. Your tuner needs to move the power up in rpms.

Where was your turbo really lighting?

 

[OBS-Addiction97]

About 2100-2300ish it lights up. I'll have to give Dyno proven a call

 

[Magnum PD]

Not having de-lipped bowls??

 

[psduser1]

About 2100-2300ish it lights up. I'll have to give Dyno proven a call

That doesn't sound terribly early. As magnum pointed out, std pistons, not delipped, maybe?

 

[97stoker350]

there is absolutly no point in putting a girdle in a forged block. needs line bored to accept a girdle and for that to happen the motor has to come apart. no billet rods no girdle. just saying. good luck to the OP been there it sucks lol

 

[m j]

same rod ad mine,

 

[Swaan]

Those cracks in the Pistons are from heat. High egts. Too much fuel and not enough air.

 

[OBS-Addiction97]

Those cracks in the Pistons are from heat. High egts. Too much fuel and not enough air.

Thank you sir. Could it be possible those have been there for a while? This thing used to get HOT before I had a ic with a D66/ 200/80s.

 

[ghohouston]

Thank you sir. Could it be possible those have been there for a while? This thing used to get HOT before I had a ic with a D66/ 200/80s.

What was your blowby like?

 

[Magnum PD]

Shoot.....trying to break in my new motor in and on sled pull setting, loaded trailer going up a mountain, my EGT gauge was buried.

But.... I built it to handle it.

Wasn't there long but the turbo said, "*** YOU"!!!!! And now I gotta mod up anothe turbo mount for the GT42

 

[OBS-Addiction97]

What was your blowby like?

For the last 7000 or so it's been "excessive". It wasn't blowing out my dipstick but when I took the oil Fill cap off it was a solid stream of vapor. It was burning about 2 quarts every 1000-1500 miles.

I Also have a ccv catch can, it had quite a bit of oil in there too.

 

[Charles]

Those piston cracks are nothing. The demise of my stock motor was from a cracked piston, but they were all much, much worse. Each piston had 2 or 3 huge cracks, min. #7 just happened to have two of them across from one another, directly inline with the wristpin. Cracked all the way down through the floor of the bowl.

Still drove fine fwiw...

I'm sure any truck that tows heavy and often with stock bowls probably has pistons all cracked up.

My pistons after machining the bowl exit smooth and coating them looked brand new after years of 600+ wheel and over 90lbs of boost at times. The stock bowl just has too sharp a point at the exit, creating a heatsink that gets superheated, and because of it's low mass to surface area ratio, it heats and cools rapidly. The constant expansion and contraction makes it eventually pop. Just like the tiny little ridge between the intake and exhaust valves in the head. Always cracked...

 

[OBS-Addiction97]

Shoot.....trying to break in my new motor in and on sled pull setting, loaded trailer going up a mountain, my EGT gauge was buried.

But.... I built it to handle it.

Wasn't there long but the turbo said, "*** YOU"!!!!! And now I gotta mod up anothe turbo mount for the GT42

What turbo did you have?

 

[Magnum PD]

HX55. Have you seen the rods yet? Did they bend?

Chuckles, HHHMMMMMM, I MEAN "CHARLES"!!!

Once the stock rod is bent from too much force, it just keeps on bending until it breaks off a cooling jet? Is that your theory?

 

[m j]

there should be a s467 rod breaker 'check in' thread.
I am now curious if the same rod gets broken on more then just OBS-addition's and mine.
it would also act as a pretty good sales tool for vendors that want to sell aftermarket rods when people contemplating the combo see how many rods fail

 

[Magnum PD]

That turbo increases the cylinder pressure too low in the RPMS vs higher more "forgiving" RPMS.

 

[swinky]

I think if you guys wanted to save rods you'd run smaller injectors and bigger turbos. That would take a lot of pressure off the tuner as well.

 

[m j]

IMO turbo doesnt make cylinder pressure, the fuel does that. turbo makes maybe 60# boost at full song