Projects 283 broken piston

Let me start off by saying I am a new member to this forum, I have read many threads here over the years and I'm happy to join the HAMB community.

Ok so I bought a 283 from a local guy and it's been sitting in my garage for about 2 years. I decided to tear it down and inspect it before putting it into my z. Here is what I found, no sludge to speak of, I pulled off one head and everything looked good except piston #8 was installed backwards. Pulled the other head and #5 was destroyed broken ring land and detonation? I'm not sure. Also why is this piston broken and all the others in good shape

 

Looks like something was on top of the piston instead of where it should have been.

 

Got a picture of the head from that cylinder?

 

Definitely impact marks from something foreign inside the combustion chamber. Dropped in from a failed lifter? Screw?

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That could really help!

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That is impressive

 

Yes......as others have said......there are some marks showing that there was debris on top of the piston. The big question is whether it was "outside" debris or simply pieces of piston and/or broken ring pieces floating around because of whatever started the distraction in the first place......detonation......trying to compress fuel coolant that had leaked into the combustion chamber etc. If stuff came in thru valves, there will sometimes be witness marks on the back side of the intake valve.
Bigger question......how do cylinders look ?......scoring......cracked ......how is cylinder head surface ?

 

Here's the head

 

And the cylinder

 

looks like both to me.
Debris and possible detonation issues.
Kind looks like the piston had a detonation issue then cleared up some how and was ran a while with debris in that cyl.

 

Tunnel -

Check the valve seats in that chamber, as something small was bouncing around in there.
Not positive of what was the cause the missing ring land, but, if it was small enough and shaped right, it could have been.

What's the cylinder wall look like?

I hope you didn't pay a whole lot for the engine..!
Rebuild time.

Mike

P.s. - Looks like we were typing at the same time. Kinda hard to really tell what the cylinder wall looks like. It "appears" to be alright, but...

 

Once I get the valves out I will do further inspection. I paid $120 for engine

 

The cylinders actually look pretty good in person

 

good that you checked it before putting in a project - if not done yet, might as well pull the pan to look for metal

 

For sure something was in there.
Might have been the the first piece of piston that broke off then completely destroyed it one chunk at time like dominos.

 

Can you post a picture of the oil pan? As said before...How metallic is the oil?

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You're showing 1 and 3

 

I remembered incorrectly when I wrote the original post it is cyl#3 like you said. I already drained oil and cleaned pan no metal bits, I'll cut open filter later tonight after kids go to bed.

 

It looks almost as if someone got the heads redone, and didn't want to fix the messed up piston? Strange.

 

With # 8 being backwards, and what looks to be standard bore pistons, I'd bet on an overhaul gone wrong. Cast ring in the top groove broken on install. Likely slipped out of the compressor, hung on top of the bore and got driven home anyway. It ate the ring land and the little bitty piece pinged the chamber, valves and piston crown until they went out the exhaust.

Wouldn't be the first time it happened.

 

I'm not sure about the "redone" maybe pulled and cleaned up and stuck back together with the bad pistons to unload the car.
It for sure started with the detonation. That usually means a lean condition in the cylinder or a lot of carbon build up that glows like charcoal when it gets hot and causes the detonation.
It isn't unusual for a foreign object piece to bounce out of the cylinder and follow the runners to another cylinder and damage that one though. That is usually the missing screw, nut or washer that manages that though.
That the head is marked but not indented with the same marks across it and those marks match the indents in the piston I'd say that it was chunks of the piston bouncing around.
This is what a piston looks like when a piece of metal decides to go down the carb.

You can see some of the matching marks from that pin or screw here. Cad 500 in my 71 GMC.
I've seen damaged from detonation pistons on cylinders on companion runners on the intake that were caused by a vacuum leak on that pair of runners. That usually damages 4 pistons though. Usually the engine has a vacuum leak on one side of the intake and the owner decides to pull a trailer or heavy load and a long grade and steady pull kills it.

Still that little engine looks like a good builder. You need to check the taper to see if it needs to be bored and have the heads checked out along with the other steps but the core price for a rebuilder wasn't horrific.

 

I'm with KenC. But where is that top ring? I surmise that top ring did a lot of damage to that piston when it spit pieces out. Like to see that cyl wall better. That ring should have done some damage to that wall. If that cyl wall is good you need to buy a lottery ticket. LOL. Lippy

 

I found part of the broken ring in the groove of the piston. I'm guessing the rest went out the exhaust? The cylinder actually looks good to me except for very slight ring ridge. I will try to get some better pics of cylinder. From what I've seen so far it looks to have been rebuilt not too long before the piston let go. It has new looking cam, rod and main bearings a new timing chain. It does have a .040 overbore with what I have identified as Silvolite cast pistons.

 

It was evidently together long enough to put a ridge in the cyls. Unless someone rebuilt it and the new rings hit the ridge they neglected to remove therefore causing the condition we are seeing. Lippy

 

After a wipe down I noticed one scratch on the outside of the bore. On first pic it's to the left of center right above where BDC would be. I cant even catch a fingernail on it.

 

Damn!....

 

Sounds like that explains the better part of all seen here so far

 

Likely a broken land from the piston installation. Good news is the cylinder wall looks ok.