Piston Failure (I think)

HEEPJEEP

<--- Solid Axle "Leveled"
Mar 26, 2009
136
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NH
So, I started my truck at the end of the work day, driving normal, stopped at a red light, light turns green, pull onto interstate on ramp and get to about 65 MPH on the interstate and a guy next to me is honking and pointing. I look back and there's a cloud of smoke (white ish gray ish). Look down and I have oil pressure, there's gaurd rail and not much shoulder for the next 2 miles so I try to go a bit farther watching the oil pressure. I hit the hill and it starts to studder so I give up and shut it down at that point and pull over best I can. Pop hood, oil cap is missing and oil everywhere... I assume it's a piston, close hood, and call a tow truck...

This truck is an '06 LBZ, 101K miles, NEVER had a tune on the single charger, and has had what I would call a small tune on the twins. It hasn't ever been above 1100*F, and I think only that high maybe a few times for a very short burst. The truck has been hazing gray smoke at idle for a long time (probably since 50K miles). I assumed it was the nature of these trucks, but a few people have mentioned maybe I have a bad injector. Wish I had checked my balance rates...

Parked it for now till I can tear it down and afford to fix it...

My headgaskets have been blown for a while though... Is it remotely possible it blew to the push rod cavity??? I can always be hopeful and plan for the worst (piston). I just don't see how it could have melted a piston with such a small tune... This truck isn't very fast and wasn't built to be (yet), just wanted it for towing/hauling.

Oh well... Another LBZ eats it...
 

blk smoke lb7

<-----Lots of green $
Nov 8, 2010
5,694
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belvidere,ill
Sorry to hear that,if you need any lbz parts let me knoiw i have a 40k and an 80k lbz motors im parting out but if you get down there id use lb7 pistons,but if you need to get a daily driver back running and want stock for now let me know
 

HEEPJEEP

<--- Solid Axle "Leveled"
Mar 26, 2009
136
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NH
Thanks! I will let you know. I PMed a guy I sold my spare pistons too, and he has the left overs up for cheap, so going to give him a try. I would love to build another motor but trying to get my new shop up before winter... Was using that truck to haul materials... Back to rocking the 12V...
 
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RENODMAX

Dead Wrong
Mar 4, 2008
3,602
0
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Its easy to lose a piston no matter how large the tune if you have a faulty injector. Shouldve seen the torched pistons when I was building CR injectors.
 

HEEPJEEP

<--- Solid Axle "Leveled"
Mar 26, 2009
136
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39
NH
I have to assume it was an injector as it just never got run that hot... Ugh. I guess I will send them out and have them checked out...
 

RENODMAX

Dead Wrong
Mar 4, 2008
3,602
0
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I have to assume it was an injector as it just never got run that hot... Ugh. I guess I will send them out and have them checked out...

Are they stock or do they have extrude honed tips? Either way getting them flowed will show where they are at idle, wot, back flow etc
 

HEEPJEEP

<--- Solid Axle "Leveled"
Mar 26, 2009
136
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NH
Stock injectors. This motor is completely stock other than the twins and "race valve". Was bound to happen, but I figured with a much bigger tune...

Definitely having the injectors checked out, "cheap" insurance for a pricey motor.
 

HEEPJEEP

<--- Solid Axle "Leveled"
Mar 26, 2009
136
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39
NH
Started to dig into it. Unfortunately this land yacht doesn't fit in my garage so doing it in the yard... Repeat of last winter doing headgaskets and studs in the yard. Yay...

Really just want to call up SoCalDiesel...order up a long block, and sell mine off... Just would have to find that money. And honestly, it's just supposed to be a tow rig...
 

JoshH

Daggum farm truck
Staff member
Vendor/Sponsor
Feb 14, 2007
13,713
773
113
Texas!!!
Just an FYI, low EGTs don't necessarily mean cool piston temps. What it can mean is that more heat is being absorbed by the combustion chamber (piston, cylinder wall, head) and less is going out the exhaust.
 

HEEPJEEP

<--- Solid Axle "Leveled"
Mar 26, 2009
136
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39
NH
Hmmm. Well, I will know more once I get it all torn down. I will keep this thread updated and try to diagnose the cause...
 

DaveB

New member
Sep 6, 2009
409
0
0
Northeast Indiana
Just an FYI, low EGTs don't necessarily mean cool piston temps. What it can mean is that more heat is being absorbed by the combustion chamber (piston, cylinder wall, head) and less is going out the exhaust.

What do you do to make sure this doesn't happen?
 

sickdiesel

New member
Apr 22, 2010
1,019
0
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Just wonder what weight oil you were using?

Most lb.'s I know of popped on 5w-40 instead of running 15w-40