WhatWASit?

[Jim Yergin]

Can anyone identify what this used to be?

Hint, it used to reside here in my engine.

I finally got a chance to pull the engine and drop the pan. The first picture is of the remains of piston #3 that I found in the pan.

Jim Yergin

[Tony Cipponeri]

Hey Jim, I think you have an extra hole in the cylinder wall also. I hope that wasn't your only motor. Tony C

[John Reddie]

OUCH!!

What caused that to happen Jim?

John R

[RobertKB]

OMIGOD! Definitely not reusable!!

[Flatie46]

That's a compression bypass hole. I guess it could be sleeved but would probably be better all around to find anthor block.

[JIPJOBXX]

I would say lots of money to be spent!

[Joe Flanagan]

I guess "detonation" is the appropriate term.

[RobertKB]

I guess "detonation" is the appropriate term.

To paraphrase Crocodile Dundee, "That's not detonation.......that's DETONATION!!!"

[Don Coatney]

Jim;

Parts find as expected. Reason?

[Joe Flanagan]

This is a forensic case. You need one of those specialists who come in after mechanical or structural failures and attempt to figure out what happened.

[hkestes41]

Little too much boost from the blower combined with too big a shot of Nitrous would be my guess.

[martybose]

Little too much boost from the blower combined with too big a shot of Nitrous would be my guess.

Or maybe a missed shift at 9000 RPM!

Marty

[Plymouthy Adams]

my first question would be the state of piston prior..was not this engine recently overhauled? and if so was the pistons new or were they used...and if used could someone gotten a bit aggressive in decoking the piston ring lands and especially the oiler lands and cut a bit too deep..

outside of total instant disenigration .there should have been some indicator something was amiss..

[Jim Yergin]

The pistons were surplus NOS from Vintage Power Wagons. Had 3,000 miles since the overhaul and installation. Thinking back, I remember hearing an occasional slight banging sound that I thought was the exhaust pipe hitting the frame. Obviously I was wrong.

Jim Yergin

[Plymouthy Adams]

then I would ASSUME and we all know what that means, that you may very well have had a wristpin sieze due to a number of problems that could be from poor lube, improper reaming etc.

[norrism1]

Hmm, I wonder if the rod bearing spun and starved the wrist pin of oil?

[martybose]

Hmm, I wonder if the rod bearing spun and starved the wrist pin of oil?

There isn't a passage from the rod bearing to the wrist pin; the wrist pin is lubricated by splashed oil through the hole you can see in the first picture in the thread.

Marty

[norrism1]

There isn't a passage from the rod bearing to the wrist pin; the wrist pin is lubricated by splashed oil through the hole you can see in the first picture in the thread.

Marty

Yep! Definetly had a brain fart there>

[Jim Yergin]

Last night I removed the valves and the camshaft. Discovered four damaged tappets. They were missing pieces around their rims. The camshaft looks OK. Also, the valve guide for the broken valve was damaged. Some nasty stuff was going on in that engine. Next step is to remove the pistons and crank and see what condition they are in.

Jim Yergin

[Joe Flanagan]

My first thought was that pieces of the shattered piston were thrown up into the cam/tappet area and caused that damage but then there is no clear passage from the crankcase up into that area, is there?

[Niel Hoback]

Maybe broken piston pieces got trapped between the valve face and the head, That would cause a bent or broken valve which would damage the guide, maybe transfer enough force to cracka tappet? At any rate, ouch!

[martybose]

My first thought was that pieces of the shattered piston were thrown up into the cam/tappet area and caused that damage but then there is no clear passage from the crankcase up into that area, is there?

If all of that shrapnel was recovered from the oil pan, it definitely could have reached the cam when the piston came apart. Don't forget that the cam area is open to the oil pan for drainage, and clearly the crank was still turning as the piston was coming apart, so it could have thrown piston bits up into the cam area.

Marty

[Don Coatney]

Jim;

What did the rod bearing look like? Had it seized?

[Jim Yergin]

Jim;

What did the rod bearing look like? Had it seized?

Don,

Funny you should ask. Last night I removed the pistons and the crank. The rod bearing on the destroyed piston had not seized but it was destroyed. It also damaged the journal on the crank. All the other bearing inserts showed sign of wear from the "shrapnel" but, to my eye, the other journals on the crank looked OK. Will have to get it to the machinist for his opinion and advice.

Jim Yergin

[Joe Flanagan]

Jim, I'm wondering: with the rod caps tightened down and the bearing inserts clamped into place around the journal and protected, how could the pieces of the destroyed piston get between the inserts and the journal? I'm just curious as to how this stuff happens. I know that with the forces at work in an engine some pretty strange things can take place. Just go back and look at that picture of the hydraulically locked piston that Don C. posted.