Re: Questions about engine detonation....
jan9898 said:
I just have a hard time beleiving that this motor that had all these extra beefy good parts, could be shot already from some low octane gas and detonation. We never heard any knocking or pinging in this engine.
Well... believe it, now you have first hand proof of it. Im not saying you had detonation, but it certainly will destroy even the best, most expensive of parts.
You more than likely will not hear it knock, especially if it's high speed detonation.
aloysis said:
2) detonation doesn't break valves
Sure it does. Especially if the detonation is causing temps to rise, but your not holding it at wot. If your on and off the throttle, causing temps to go up and down... valves get brittle awefully fast.
Jan... any chance you can post pictures of your damage? I'd like to see the piston, the clyinder walls, the underside of the head (valve area and combustion chamber) and the spark plug.
If you had detonation, it will show up. Discoloring of 1 side of the piston or combustion chamber vs the other side (it's the exhaust side your looking for). Is the plug just broken or does it look like it melted? Color of the insulator?
How's the valve seat look, is it beat into the head? Where the heads new or used? Valves new or used. Where the valves fitted to the guides by a competent machinist or mechanic?
It's impossible to say without seeing the engine. You could have had detonation or pre-ignition. Especially if you ran the engine with a known carb problem.
You may have had a defective valve from the get to. Improper assembly and fitting. The engine may have injested something, a nut or bolt, especially if ran it without the flame arrester off. I've seen screws that come out of throttle blades on carbs because somebody thought it was a good idea to grind the peen over to pull the shafts and they throw the screws back in... they fall out that way.
Lot's of variables on this. Where'd you get the motor? Why no warranty? Long block or short block? Who put it together, installed it, test ran it?