Nevada City Sparky
Jeeper
- Location
- Nevada City, CA
After 3000 miles on a new long block I have a blown engine. Here's what's been done to it, I'm trying to figure out why it blew, or find out if the machine shop is just hosing me:
89 Jeep Cherokee that's totally been rebuilt. Includes the following:
New Long Block from Machine shop
All new cooling system
All new sensors (except Hall in distributor)
Reconditioned Auto Tranny
New Fuel Injectors
Lots of other new stuff
Cleaned up wiring
The engine blew on a 500 mile trip when I was climbing a steep grade at approx. 65 MPH. At the top of the hill, as I coasted down the backside, I could hear rattling in the engine and pulled off immediately. Oil was pouring out of the airbox. This was after a break-in period of about 1000 miles of mild driving.
Machine Shop that did the work tore it down and says its a collapsed piston. I went and looked and sure enough, there's scuffing on the cylinder walls and some of the rings are looking funky. Bearings don't look too hot either with scuffing on them.
Machine shop says it was caused by detonation. Suggested computer or fuel injectors (even though they are new).
Neither of those sound plausable, since the engine was running good prior to that incident (you think you'd hear pinging or something).
Only other thing I can think of is that I'm running 32" tires with stock gears and the engine/tranny was hunting pretty hard for gears during the 65 MPH hill climb.
Engine has NEVER overheated since it was installed.
So, what could cause this to happen?
89 Jeep Cherokee that's totally been rebuilt. Includes the following:
New Long Block from Machine shop
All new cooling system
All new sensors (except Hall in distributor)
Reconditioned Auto Tranny
New Fuel Injectors
Lots of other new stuff
Cleaned up wiring
The engine blew on a 500 mile trip when I was climbing a steep grade at approx. 65 MPH. At the top of the hill, as I coasted down the backside, I could hear rattling in the engine and pulled off immediately. Oil was pouring out of the airbox. This was after a break-in period of about 1000 miles of mild driving.
Machine Shop that did the work tore it down and says its a collapsed piston. I went and looked and sure enough, there's scuffing on the cylinder walls and some of the rings are looking funky. Bearings don't look too hot either with scuffing on them.
Machine shop says it was caused by detonation. Suggested computer or fuel injectors (even though they are new).
Neither of those sound plausable, since the engine was running good prior to that incident (you think you'd hear pinging or something).
Only other thing I can think of is that I'm running 32" tires with stock gears and the engine/tranny was hunting pretty hard for gears during the 65 MPH hill climb.
Engine has NEVER overheated since it was installed.
So, what could cause this to happen?