Seized up twice but still runs smoothly?

[extramile]

Re: Seized up twice but still runs smoothly?

Motor mounts seem tight.

I still have the question of "If the cylinder is scored or piston ring is damaged from overheating, can it still be running smoothly like it is or would it run very rough?"

 

[F_R]

Re: Seized up twice but still runs smoothly?

Well it should run rough if it has a overheat/damaged cylinder. The word is "should". But to what extent? Anything from barely noticable to won't run at all.

However, I consider it a moot point, because you said the paint is not scorched. You also say the compression checks out evenly.

That is not to say that something else could not have caused scoring, like maybe it swallowed a screw or something. Again, if that were the case, it would affect the compresion readings. Who knows?

 

[Paul Moir]

Re: Seized up twice but still runs smoothly?

I wonder if the motor was somehow ingesting water to the point of hydro-locking? Although an overheat would account for it, that would also explain the clean plugs. But for the life of me, I cannot see how you would get that much water into the engine and have it feeding all three cylinders. Did you try revolving the flywheel backwards when it was locked?
Still, despite the lack of scorched paint, I personally think an overheat is the most likely cause given all the evidence. An engine will sound fine on muffs even with severe internal damage so that doesn't really prove anything.

Which spark plugs are you running?

 

[h_lankford]

Re: Seized up twice but still runs smoothly?

or are the white plugs a result of using Avgas? ? ? ? Doubt it, water seems more likely.


I still wanna know about the use of "oil and lead in the gas"

what kind of oil?

what kind and what source of lead?

what gas? octane? pump or other source?

Sorry guys, I know this might be a wild goose chase, but so far we still do not have a definitive answer for what's going on here, although I'd vote for Paul . Harvey

 

[h_lankford]

Re: Seized up twice but still runs smoothly?

ok, more questions, on hydro-locking.

bear with me.

if you were running at WOT and the gas tank pickup sucked up 100% water and killed the engine, could the amount of water ingested through the carbs and reed plates be enough to hydrolock the pistons? steam clean the plugs? all of them ? and then drain out slowly around the rings into the crankcase and then allow restart? of course, restart should not be possible is all that's in the tank is water, unless it was refilled.

gotta run this thing under load, not just on muffs, and see what happens.