Replacing a melted piston.
#1
Replacing a melted piston.
Hi y'all. I'm gonna need some help here if you guys don't mind. I have a 79 k20 350. I bought it in NM and it sounded like it was running on 6cyls. I replaced the distributor, cap, coil. Nothing helped. I Was on the highyway and it suddenly overheated. I got it home cuz the motor was acting like it was seized up. Put roughly 1.5 oz of marvel mystery oil in all the cylinders and let it sit for a week. It turned over by hand at the flywheel with a crowbar. So i bumped it with the starter. Coolant came out of the #5 cyl spark plug hole after 2 bumps. Turns out the starter was getting stuck in the engaged positon after 3 cranks. So forced it to free itself and bumped it until it turned over all 8cyls. #8 cyl had coolant come out the cyl also. I removed the heads, it had the original Steel head gaskets. The gaskets weren't physically "blown" per say. But the #5 piston was melted. I'm needing to get it up and running on the cheap, so we can have 2 running vehicles. Can i just replace the piston with a stock piston, rings & bearings, & new head gaskets?
#2
TECH Senior Member
iTrader: (2)
Is the cylinder wall okay and not scratched and marked up? No visible cracks?
Also that piston doesn't melted, it broke a ring land off and it did a little bouncing around in there.
But otherwise yeah you could just buy a new piston and slap it back together if you wanted too, 350's are like lego's.
Also that piston doesn't melted, it broke a ring land off and it did a little bouncing around in there.
But otherwise yeah you could just buy a new piston and slap it back together if you wanted too, 350's are like lego's.
#3
The walls are smooth for the most part. Just the top and the part of the cylinder where it " melted" had a build up of metal. It appears as though i could hone it out. The top of the cylinder had a 1" wide by 3/8" deep chunk of metal that came out by just lifting it up with my fingernail. But I'm still confused on why the #8 cylinder would have coolant in it?
#5
It has a 5.7 in it right now. I'm still not sure why there is coolant in the cylinders as the head gaskets weren't clearly "blown". I checked the heads and didn't see any visible cracks. But they are 624 heads. Going to get a set of 993 heads. Swapping for 2 old carbs.