Thread: mangled piston on a 454

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Hi, was boating the other day and the engine starting huffing smoke out of the one valve cover breather (engined stalled and I had to get towed). Figured it was a good time to take apart the motor and install my new 781 heads and weiand 177 blower. Anyhow, took the old heads off expecting to find a bad exhaust valve or something, and this is what I found (see pic).

Anyhow, question is, (see that I want to get back on the water ASAP), can I just put a new piston on the rod and reassemble (quick fix) for now, or won't that work? Should I take the crank out and have it checked/ fitted to new rods and pistons etc?

Just looking for quick fix now, and will probably stroke it to a 496 with forged parts this winter....

Thanks.

Turn the engine over (so the piston os deep) and take another pic for us. I see something in the cylinder wall that's not good and want to be sure my old age is not getting the better of me.

also if that is the head gasket still on there, remove it before anothe picture is taken. take one with the piston down in the cylinder as well up for us, it sure is a small mess you got going there.

most of the head gasket came off, but I'll try to scrap some more. Was going to wait until the motor is out of the boat to use my little high speed sander air tool with the scotch bright discs.... I'll crank the engine over and lower the piston down to bottom then take another pic. It almost looks as if I lost a valve seat or something, but the head on there is okay??? I'm wondering if the previous owner screwed me here a little since this motor never had the power it should have, and only recently starting huffing smoke... I wonder if the piston was coming apart but decided to go all the way....

Hard to tell in that pic, but something looks real bad in the cylinder wall right where the piston is missing the biggest piece. Like the others, can't tell if it is the gasket or the bore though.

Okay, series of pics that zoom in on the spot. There is a little roughness, tried to capure it. Will probably need rebore I guess...

To give you an avenue, your season is done until this thing comes out and is repaired with major surgery. The pistons don't have enough depth on the ring lands to survive blower pressure and decceleration reversion extremes. This will happen again with your current setup. I recommend a blower piston with deeper lands to prevent this from happening again on the repaired motor. I also noticed a tell-tale sign on top of the piston of a heli-coil. Is there a repaired thread up on the intake area or elsewhere a heli-coil can let go and enter the cylinder?

I didn't even run a blower on this motor yet, was going to but will change the pistons. Do I have to have the crank redone to install new pistons and rods? or can I just reuse the rods with new pistons.... trying to get back in the water fast.... but don't really want to break down again on the water. Sucks....

I realize the fact you haven't installed the blower yet. I was a bit premature in that area. I wanted to to know where you were at the present time and I apologize if I concluded a bad assumption there. Your cylinder wall is toast for all practical porpuses. I'm sorry, but nobody should run that block like that again. If you wish to re-use your rods and internals, just have them checked out. I would like to see you use as much as you can for rebuild. What about the heli-coil issue? I do not always see everything in the pics as I sometimes pressume.

I didn't see anything wrong with the heads, helicoil wise. Course the old owner said he had just given it a valve job... so maybe he knew about the issue.

Anyhow, you say the block is ruined, or can be reused after a bore out?

Oh, those marks I took pictures of are just barely there. I had to zoom in pretty close to photograph them. Can just barely feel if you know what I mean. I think a .060 over (496) might cover????? I'll have to wait until my machinist see's them I guess....

The boring will be dictated by how much has already been removed. Is it safe to say this block is already at .030?

the pistons say 00, so I don't think there is any bore done.

Give it to the shop and let them measure and check. Then your game plan can start forward.

unless I'm reading that wrong. I put .040 pistons in my SBC and they said 040 on them