Piece of a Piston

[loudnslow]

Doing a cam swap and dropped the pan to get the timing cover off.
In the pan I found ~1" piece of the #3 piston. It's the very bottom "ear" of it. The engine runs fine.

Any idea how this could have happened? Any reason to worry about it?

 

[Russell]

That'll cause some balance issues, I'd definitely be replacing that piston and checking all the bearings in the bottom end.

 

[4X4HIGH]

That is part of the piston "skirt" which keeps the piston squared in the bore. You really need to replace that piston with another one of the same brand (to keep the balance as close as possible). Sure the engine will still run with it broken (and it's probably been broken for a long time) but eventually it will lead to catastropic failure and usually at the worst inoppurtune time.

 

[4xcrazy]

yeah, i found the same thing when i tore mine apart several months back, thing about it is, it had been in there for quite some time, as it was pretty well stuck to the bottom of the pan.... hmmm...

 

[fmstruck]

I'm not saying at all that it doesn't need to be fixed. It's obviously broken and that's never good, but I bet that piston is still longer, even with the skirt broken, than my pistons were in my long rod 496. It would have run forever if you didn't know it was broken. Now that you know, it probably won't make it out of the driveway. At least that's how my luck runs.

In the '70s, Dad had a '66 442 that he drag raced in stock trim every weekend at the local strip (80 miles away) for I think 2 years. It used a quart of oil to get there, one to race and one to get home. When he pulled it apart 7 out of 8 pistons had broken skirts. On one piston, one skirt was completely gone and the other cracked. Once again had he known it was that badly wounded, he would have ventilated it the first time down the track.

 

[manchildau65]

what's the cost of replacing one piston compared to an entire block? you're gonna have a top end gasket set invested plus a new piston... that's like $150 max, right?

 

[ChrisPerry]

What condition is the rest of the motor in? I know you said it runs fine, but doing a cam swap and adding some performance stuff will put more stress on all the internals. If its got low millage 30-50 thousand easy miles, I'd say swap the piston and go. If you run it hard, as we all do, then I'd say get a rebuild kit from Summit etc. For between $250-$300 you can get the kit and $150 for the block prep. $500 or $600 is worth the peace of mind IMO.
Now, if your really low on funds, I say leave it stock and hope for the best.

 

[loudnslow]

It's got 120k and I've had it for about 1k miles. Judging from the condition of the truck it had a fairly easy life, but not very well maintained at least by the owner before me.
Doing the valve springs I've found that a couple of the valves were leaking too much air, especially #3 intake.

This motor can use a complete rebuild, but the compression is still 135-150, so it's not so bad yet.
I'm just going to let it ride and start putting a replacement motor together.
Thanks guys.

 

[Dabba]

...but eventually it will lead to catastropic failure and usually at the worst inoppurtune time.

Always seems to happen