Blown Engine. But What Happened

[mitragorz]

I blew the motor in my '88 K2500 plow truck. The engine had been low on power for a few days, but was particularly bad the hour or so before it kicked the bucket.

I was on my way to a client when the motor died. I was able to restart it, but with it had a very loud knock. It ran for a few minutes and died again.

I drained the battery trying to restart it. I called up the wife to come give me a jump. I figured the motor was toast, but I was hoping I could at least limp it the mile and a half home. Got it running, made it about halfway before it started smoking and died again. Tried to restart it, but got a loud bang and a small fire at the bottom of the engine.

Anyway, we pulled the motor out today (got a nice used 305 for $350) and the oil pan had a hole in the side. Would I have been able to throw a rod through the SIDE of the pan? If not, what would have broken through? This is the driver's side of the engine.

You must be registered for see images attach

 

[michael hurd]

Yes, that is typical of a connecting rod cap exiting the block at the weakest point. Hard to say exactly what caused that.

I had something similar happen in a 3.8L V6, back about 2 decades. A connecting rod broke, after knocking for a few days, then broke the engine camshaft in two, and the camshaft pushed the plug in the rear of the engine block, and lodged in the engine flexplate. To pull the engine, we had to leave the torque converter on the engine, unable to remove the bolts.

 

[mitragorz]

Yes, that is typical of a connecting rod cap exiting the block at the weakest point. Hard to say exactly what caused that.

Great, thanks. I wasn't sure since 1) I've never blown an engine, and 2) it was the side of the pan.

I'm hoping to finish the swap tomorrow and have the old girl back up and running.

 

[90halfton]

Tired plowtruck motor in a 30 year old truck? I wouldn't overanalyze it too much. It was its time.

 

[mitragorz]

Tired plowtruck motor in a 30 year old truck? I wouldn't overanalyze it too much. It was its time.

Oh yeah, this old girl owes me nothing. She was a Hurricane Sandy flood truck, but I didn't figure that out until I got her home, started tearing into her, and found mud everywhere, including under the vinyl floor mat.

I knew months ago that the motor was on it's way out. The truck got a new tranny last year, so it'll be nice to get a "fresh" engine in there. She's still a money-maker.

 

[Ironhead]

Hoping you'll pull the pan, and maybe the heads, and let us know what happened...

 

[drewcrew]

I blew the motor in my '88 K2500 plow truck. The engine had been low on power for a few days, but was particularly bad the hour or so before it kicked the bucket.

I was on my way to a client when the motor died. I was able to restart it, but with it had a very loud knock. It ran for a few minutes and died again.

I drained the battery trying to restart it. I called up the wife to come give me a jump. I figured the motor was toast, but I was hoping I could at least limp it the mile and a half home. Got it running, made it about halfway before it started smoking and died again. Tried to restart it, but got a loud bang and a small fire at the bottom of the engine.

Anyway, we pulled the motor out today (got a nice used 305 for $350) and the oil pan had a hole in the side. Would I have been able to throw a rod through the SIDE of the pan? If not, what would have broken through? This is the driver's side of the engine.

You must be registered for see images attach

Give it a proper burial. After being in a plow truck it's earned it.

 

[Justin S]

I blew up a tbi 350 once. Had started slightly knocking, so I drove it to the junkyard where I had bought it a month before so they could hear it so they'd give me a free replacement. By the time I was halfway home, it was lacking power and was sounding like someone put rocks in a dryer. Finally made it to my road so I just went WOT and got up to about 50mph and it blew, left a huge trail of oil and smoke for the last few hundred feet as I coasted in my driveway . Never pulled the pan off to see what carnage was inside, because the oil pan had been pushed out so far that it covered some of the pan bolts. When I pulled the engine out, I also found this.

You must be registered for see images attach

 

[mitragorz]

It'll be about a week before I have the time to dig into the block, but I'll be sure to report back.