Ring lands lifting

[rocketracer380]

Took my 363 apart to find lifted ringlands on two pistons right at the intake valve relief what is this an indication of rich fuel mixture

[econo racer]

I have had that happen before on a SBC. It was my fault, I ran too much timing on 91 octane. Also it was about 11-1 compression.I did not catch mine as early as you did. I destroyed a lot of parts. Lesson learned

[rebelrouser]

I had a 340 mopar that looked just like that, I had a fuel pump fail on the big end, leaned out the engine. That was when I was young and dumb, I had an Holley 780 double pumper, and had one fuel pump for each bowl of the carb. The pump for the secondary bowl is what quit.

But it did run the quickest ET the engine ever turned. By the time I got back to the pits, it was smoking out the breathers pretty hard.

[hoodeng]

Detonation annealed.

[Geoff2]

Alum looks darker in the affected area. Metal thin because of the valve relief, got too hot & alum expanded...upwards.

[rocketracer380]

could this be too much fuel

[Mark O'Neal]

Lean...lean...lean

[Dave Koehler]

Was a bottle in play?

[F-BIRD'88]

Detonation piston and rings got too hot.
Top ring end butted. Lower the compression, use better gas.. Open top ring gap more.. Watch the spark timing.

[mag2555]

What cylinders did the failed two pistons come from,what intake manifold is being run, and also is the motor a standard firing order?

[Walter R. Malik]

Took my 363 apart to find lifted ringlands on two pistons right at the intake valve relief what is this an indication of rich fuel mixture

Excessive heat in that location is the usual culprit.
Now figure out what is causing that excessive heat; (usually lean or to much timing or detonation).

[Steve Haaf]

I always understood that was caused by detonation, too much timing, too lean or both.

[FloydODB]

Its somewhat of a heat issue. Detonation, preignition, lean, timing, octane. I did a 2bbl motor once about 12:1 on 110 octane with a comp 280b-6. Dynoed fine and only wanted 28° but would lift the ring land within a few laps. The srp nitride rings would butt and lift the land. After trying several things I put the cam in straight up instead of the 4° advanced and all was fine. I think it had more to do with getting the exhaust heat out more efficiently than anything. That was a ported factory headed 408 Windsor. Loved those nitride rings though, never scuffed the cylinders bad at all.

[Dan Timberlake]

Got some nice close up shots of the tops of the pistons, and the spark plugs?

[Mark O'Neal]

Look at the ends of your rings, where the dap is. if they are polished the rings were butting. They won't be polished.

When you lift the land adjacent to the intake pocket, you went lean.