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bad news for my 3800

mac507

mac507

New member
It has been a rough week for my car.
On a quick side note ... i am running a stock pulley and the only mods i have are a K&N CAI and a 3" catted DP. I installed a boost guage with the same mods and it said i was running 13 psi at 5,500 rpm ... i know crazy.
After i installed the gauge i checked for vac leaks and i was clean.

Here is the worst of it. I was driving around and got on it pretty good. The car did not upshift but stayed at about 5,500 rpm. at the next light it ran so rough and almost stalled out .... then my SES light went on.. then started to blink which made me chuckle because that could only mean really bad news. On the way home i stopped and ran the code at the local shop. Missfire cylinder 3. I drove it home (2 miles) and pulled the plug. The plug was jammed into itself (no gap). I am assuming that i blew the motor :(
What do people do at this point? In have the knowledge to rebuild the bottom end. or should i just replace the engine altogether. My father who is a master mechanic thinks it s connecting rod. Also where can i buy a bottom end rebuild kit?
Does this happen often when people are running too much boost? (BTW i did not touch the pulley... its stock) Let me know your opinion.
 


L67/36/32/26 are a dime a dozen, they can be had for cheap like sub 500.00.

I would just do a L32 bottom end swap and call it a day
 
Sounds like you chipped a piston. I did that about 9 months ago and still am running the same motor with no problems.

Just drop in a motor from the JY, these motors are pretty stout as they are.
 
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You broke a piece of the top piston ring land off, aka chiped piston, not a term I use because it;s not really a "chip" but more of a "chunk" of aluminum off the top of the piston (directly above top piston ring). First of, 13psi on a stock engine is twice as much as it should have, why do you have that much on a stock pulley? There has to be a problem somewhere.
What happens is the sudden rise in combustion temperature from detonation causes the top piston ring not to be able to transfer the heat to the cyclinder wall fast enough and the ring expands to the point to where it locks together and pulls the top part of the piston off at TDC when the piston starts back down, that is what flattend your spark plug.
It would be a good idea while your rebuilding the motor to open the top ring gap a min. of .010-.015 for saftey.
 
QUICKSILVER462 said:
You broke a piece of the top piston ring land off, aka chiped piston, not a term I use because it;s not really a "chip" but more of a "chunk" of aluminum off the top of the piston (directly above top piston ring). First of, 13psi on a stock engine is twice as much as it should have, why do you have that much on a stock pulley? There has to be a problem somewhere.
What happens is the sudden rise in combustion temperature from detonation causes the top piston ring not to be able to transfer the heat to the cyclinder wall fast enough and the ring expands to the point to where it locks together and pulls the top part of the piston off at TDC when the piston starts back down, that is what flattend your spark plug.
It would be a good idea while your rebuilding the motor to open the top ring gap a min. of .010-.015 for saftey.
Click to expand...

Boost is a measurement of restriction. Id venture to say his cats clogged. Run a stock bottom end, Id recommend a l26 or l36
 
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thanks i appreciate your input ill keep you guys posted. We will be pulling it apart this weekend to take a look
 
Yea, I bet somthing is clogged. It might be a good idea to check your cat. converter even though it is only a year old, somthing may have cause it to melt down inside.
Like they said above, boost is a measure of the amount of restirction in the system, and if your reading of 13psi is correct, on a stock pulley, than somthing is horribly amis.
 
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