thoughts

[john miffco]

makes more sense with more info
and not guessing,,,,,,,,
could tell cyl was replaced but not how long ago

when rebuilt the sleeve was improper installed
thats why it blew the 1st gasket
then blew the 2nd gasket
the sleeve was installed to low or sunk the 1st time motor was ran
so why it was low when you replaced gasket

gasket surface must be flat across all cyls,,,,,,,,,,,
learning experience not to run motor again if find a blown gasket and see mating surface not flat or sunk

to have properly installed the sleeve in the block
1 would have welded the top of cyl to get rid of the lower corroded area
of allunimum
2 then after installing sleeve milled the top deck flat across all cyls
to have a true plane
and make sure gasket would seal

gotta replace sleeve again or find another block with less corrosion
for a better starting point
for longevity
john

[850cc racer]

okay thansk john, was going to have sleeve removed and check block then replace sleeve & piston and have decked so it is a flat area again.

once i have it pulled down ill post some more pics!

thanks

[Sam La Banco]

I think John is right about the water.

The SST 60 motor will burn a head gasket in a heart beat if things are not 100%, we change them after a few races all the time.

[Tim Kurcz]

The attached image shows #1 damage caused by simple fuel starvation. Sad to say I've seen this many times. Though you may have a cooling issue, be sure to thoroughly check your fuel delivery system. The top carb is the last to get fuel. It will get you every time. Good luck!

Tim

[john miffco]

that pic of a piston you show is NOT the same melt
as the piston this thread is about
look at the 2,,,,,,,,,,compare,,,,,,,,,,,

what i described in detail earlier in this thread

a piston melt from a blown gasket,,,
looks like the 1 in this thread,,,,,dark grey/black burned with smooth edges
from exhaust blowing in the water cavity creating a steam pocket around the cyl,,,which causes the heat to start the burn
the reason for blackened and smoothing on the burn is from the water sucking in on intake stroke,,,,,,,,

same as throwing water on a hot frying pan,,,it sizzles and burns leaving residue,,,,,,,,,,

the piston you show was burned from lack of fuel
from everything DRY,,,,,,,,,clean melted areas,,,,,,,more jaggy
no residue/goo burned into piston,,,,,,,,,,,,,,,,

if it was from lack of water or way too much timing
there would still have oil residue on the rod,bearings,inside cyl under piston

the 3 ways to burn a piston,,,,,,,

[Tim Kurcz]

If it were my engine, it wouldn't get reassembled until every system was checked including clocking of the ignition system.

[850cc racer]

Hi Tim, the whole thing will certainly be checked!

Hey John: When i got the boat on the trailer and took spark plugs out there was no water/residue on number 1 spark plug?

maybe Fast Fred might see this hopefully: something ive found over here x3 looks like this one has had a boom at sometime!