L20B broken rings

[kelowg]

motor blew two pistons(too lean, broke ring lands). but pulled motor apart and found all four top rings broken. question is besides driving the piss out of the old girl, what would cause this? or more to the point, most likely thing.

[datzenmike]

Over heating and/or insufficient ring end gap. The pistons don't expand much with heat but the rings sure do. If the end gap is to small to allow for expansion the ends will meet and there is no where to go and they will break. If the motor is overheated this will do the same thing.

 

Gas absorbs heat as it evaporates and cools internal engine parts like spark plugs, valves and the piston tops. Running lean will cause the motor to run hotter overall or cause localized hot spots..

[I'm BLUE]

both issues can score the shit out of your cylinder walls as well :hmm:

[datzenmike]

I've slit my fingers many times handling used rings. They can be razor edged besides being brittle hard.

[kelowg]

cyl walls untouched. does run hot in 105f weather about 220-230f and i know ring gaps were more than spec(was in a hurry assembling everything. likely well get new rad when funds allow.

[kelowg]

anyone know where to modesto i can get wrist pins pressed out and into new pistons?

[I'm BLUE]

what does "I know ring gaps were more than spec" mean ?

hurry in assembly ?

 

Maybe you require chrome moly rings(if available lol)

I'm not sure your setup.

 

time to re-jet :lol:

 

Just about any machine shop will press piston pins in-out for you.

[I'm BLUE]

I've slit my fingers many times handling used rings. They can be razor edged besides being brittle hard.

 

:blink: holy crap

obviously I haven't tinkered with shit as near as much as you lol

[kelowg]

gapped bigger than fsm recommend gap

[datzenmike]

cyl walls untouched. does run hot in 105f weather about 220-230f and i know ring gaps were more than spec(was in a hurry assembling everything. likely well get new rad when funds allow.

 

It should never be run that hot.

[DAT510]

My L20B stays at a steady 180F in 100 degree weather. rebuilt radiator and a 50/50 mix.