Lost the motor?

Cougar281

Well-known member
Sep 11, 2006
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48
St Louis, MO
You can buy a USB borescope camera to attach to a computer for $25 or less. Very handy for lots of things. Make sure you buy one that has a head small enough to fit into the glow plug hole opening.
I'm not sure they make them that small. Even one small enough to fit through the injector nozzle hole is pushing it.

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Chevy1925

don't know sh!t about IFS
Staff member
Oct 21, 2009
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Phoenix Az
Compression check it. Cheap and easy to find out.

But yeah, like Corbin said, when you put all the compression into the lower end of the block, the pressure pushes the oil back up the oil return to the heads and out the pcv or as the oil squirter is injecting oil, back out the exhaust valve. Not to mention the amount of windage and aeration the pressure/air causes that will cavitate the pump.
 

danzick

playing with fire
Feb 20, 2014
447
1
18
Livingston, MT
Ah that makes sense. I bought a hf compression tester today. Truck is still on the trailer. Hopefully unload it tomorrow night. So what lesson is there to be learned here? Did it happen from high egts? Or from the 240 plus oil temps I was seeing pulling before I did the cooler? I don't want to do this again!
 

ZeroGravity58

Active member
Mar 23, 2008
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Maryland
Ah that makes sense. I bought a hf compression tester today. Truck is still on the trailer. Hopefully unload it tomorrow night. So what lesson is there to be learned here? Did it happen from high egts? Or from the 240 plus oil temps I was seeing pulling before I did the cooler? I don't want to do this again!
There is no lesson....we all pay to play. Age, mileage, power, it all plays a roll eventually. Lb7 pistons still crack just not as pron to it as lbz/lmm. Alot of us have seen stock trucks crack pistons and break cranks.
 

Chevy1925

don't know sh!t about IFS
Staff member
Oct 21, 2009
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Phoenix Az
I don't want to do this again!
put it back to 100% stock then, thats about your only chance. Otherwise, this is the game we play. built short block would be the only other way around it.

what size injectors do you have?
 

Chevy1925

don't know sh!t about IFS
Staff member
Oct 21, 2009
18,134
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Phoenix Az
that didnt help. stock means high pulse width and high timing. that means high cylinder pressures and heat when you beat on it before which may have started a crack or made a brittle area on the piston. then normal driving with little bit of spirited here and there finished it off. non-delipped pistons added to that issue.
 
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danzick

playing with fire
Feb 20, 2014
447
1
18
Livingston, MT
Gotcha. Well I'll probably be going with a set of mahle performance cast pistons. I think it's beyond a cracked piston. The amount of oil coming from the exhaust and the level of knock I was hearing makes me wonder if it totally crumbled.
 

juddski88

Freedom Diesel
Jul 1, 2008
4,417
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Chesterfield, Mass.
Fuel soaked creosote also appears oily. It honestly may not be as bad as you think, but sucks to have happen either way. It is never a fun day spending a lot of money to repair a vehicle.
 

ZeroGravity58

Active member
Mar 23, 2008
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Maryland
Time to pull it out. When you over revved it you could of had piston and valve contact and broke the head of a valve off. You will know when you pull it apart or pull the valve covers to see what the damage is.
 

Chevy1925

don't know sh!t about IFS
Staff member
Oct 21, 2009
18,134
399
83
Phoenix Az
Ouch!

yup, like zerogravity said. over-revving it floats the valves. you can either pop the keepers off doing that and drop a valve or if its bad enough, the piston hits the valve, bends the stem, breaks the head off and the valve head kills the piston, head, etc.

compression test aint worth it now lol
 

danzick

playing with fire
Feb 20, 2014
447
1
18
Livingston, MT
Yeah.... I just can't believe it overreved like that. I can't imagine kory messes with the factory limiter. Expensive mistake! Do you guys think I have a hole in the cylinder? Or the head is punctured?
 

2004LB7

Well-known member
Dec 15, 2010
3,388
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Norcal
if it is what we think it is then more then likely it's the piston. you may be able to get away with a new piston, cleaning up the head, new gaskets and hardware and you will be back in business

if it's the valve then you have a lot more to fix then just replacing a piston. probably a new head and piston minimum if you're lucky.
 

Ne-max

I like turtles
Nov 15, 2011
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Lincoln, Ne
A cracked piston wouldn't put coolant in the oil. A rod smacking the block will. If I was a betting man your long block is destroyed.
 

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