My LS1 blew a hole in the number 7 piston and it did nearly the same thing but it blew the dipstick out of the tube and sprayed oil on the inside of the hood. I hope your problem isn't the same as mine.The truck shook, misfired, and smoked like a mosquito truck.

 

Also want to make sure all your steam vents are venting. It's my belief that most #7 problems are caused by blocked rear steam vents

 

There is a good possibility that this could be fix some what on the cheap. Pull the head and see if it damaged the cylinder wall. If there is no significant damage, which I have seen before, just cracks the ring and the rings no longer seal, you could pull the pan, pull that piston out, replace the piston and rings on just that cylinder, dingle ball hone the cylinder, button it up and good to go for a while! I have seen this done a few times.

 

dingle ball hone! you usually have to pay to see something like that! haha

 

hahahaha

 

guys I stripped down the driver side engine.. Took the driver side head off.

the head looks fine. I still believe I blew the rear main seal though I haven't done much under the truck yet.....


Melted number 7 piston.

piston 5 looks quite burnt or black or whatever on the top of the piston. much darker than the rest...

but yeah...piston 7.



The cylinder wall has some scratches...like you can feel them with your finger, no gouges or anything too deep.





heres my plan....

get an engine builder to either come out and look at the motor and determine if we can just hone cylinder 7. and put a new piston in.

and change the rings on all pistons and gap them for boost. And ARP head bolts which I already have, and LS7 gaskets.

basically find out what it will cost to get my existing shortblock rockin again with stock internals but better rings.

I will also order the vvt dod delete kit and a TR220 cam and upgraded springs from texas speed.

For real I want a bit of a choppy idle.



if I don't go that route. its either a 5.3 forged from schwanke motorsports or a 370 from TSP.


but the first option i'd like to go with. if the price is right.


Im all ears as far as what everyones opinions are on the melted piston.

 

Yeah, that piston got hot. I'd blame the tune and/or lack of fuel for it to run that lean.

 

Dear lord. How much timing were you running?

 

I wouldn't put that cam back in your truck... why not just have a boost cam spec'd that chops?

 

Tuner said 16 degrees and 11.6 AFR. That's what he said.

91 octane shell gasoline. 72LB injectors. Flex fuel pump. about 10 psi boost.

Unlikely the pump was sluggish as this truck is brand new and only has 9700 KM on it.

We didn't check fuel pressure.

This happened within 2 hours of final dyno tuning. on a Tuesday evening. cool temps outside, like 70F.


The Monday was the official dyno tune.

After the tune on Monday the truck went into limp mode. I forget what code it threw but it had something to do with manifold absolute pressure.

went back to tuner and he raised the limit on an air table? if the truck hit this limit it would go into limp mode.as if the ecm thought there was an air leak.


it hit this code every 15 minutes the next day. Tuesday. I would clear the code and get out of limp mode.

after work on Tuesday I went back to tuner and he further raised the limit on this air table. I still don't exactly know what this table is called.

he said that it was the quicker way to avoid hitting it, otherwise the longer way was to rescale the whole map.

again I don't know much about tuning but perhaps someone could chime in?