89 S10 2.5L 5 Speed, hole in #2 Piston

[lesterl]

89 S10 2.5L 5 Speed, hole in #2 Piston, Picked up the truck a few months ago and tore into it finding a hole in #2 piston, looks like it was melted thru as there is some slag on cylinder wall (a little, should hone off). I do have a second motor that is currently in the truck and has the same hole in #2 piston, Radiator is clear, I flushed it and flowed good, #1 cylinder piston was showing signs of being scorched (black deposits that wouldnt come off, brushed #3/#4 with some light weight oil and the cabon came off. Cat didnt look plugged up. Truck is 2hrs away currently at my grandfathers house (has shop). Truck has 60k on it and 1st motor, other is a junkyard motor and appears to have had a rough life. Any Ideas?

[trailwart]

i had a 91 vin code E with the #2 piston all jacked up. not sure what caused it to go? truck had about 220K miles on it and quit on the highway 1 day, opened hood and the exhaust manifold was glowing red. got it towed home and tried to start it and it fired right up, but ran like chit. tore it down andthe piston looked (2stroke dirt bike piston that failed from detonation on the exhoust side). the head looked great, didnt hit a valve or nothin.

[lesterl]

did you fix it and did it stay fixed?

[trailwart]

my truck wasnt worth fixin, would og needed machine work on the cylinders +new pistons. plus the truck had 220K miles on it. i should of done a v8 swap in it thou, but i sold it.

[lesterl]

Yeah, my uncle offered to get me a 4.3l and Automatic for it, but it wouldnt be much better on gas than my Fullsize I just got rid of. My uncle is GM mech, and Grandfather is retired there, we have the tools available, and the block looks excellent (no wear). Oh well will wait and see. Not positive on the Cat though.

[trailwart]

i had someone tell me it was caused by my cat. funny thing is i had mine removed, so i knew that isnt what caused mine to go.

[s10-den]

thats strange.Both motors come out of this truck ?With both having holes in #2?

[lesterl]

Yup, I suspect it overheated, as it MELTED a hole in #2 and #1 looks scorched, #3/#4 are ok, Rings were froze in piston both motors. Dont want to spend alota $$$ rebuilding to have happen again, will look at over memorial weekend, will ck head and all, radiator flowed, wonder if water pump is good?

[s10-den]

Sounds like it leaned out,but, dont understand why only on #2 and not the others.Like NOS,when you get it to lean, it will literally burn the piston slam in half.Had that happen befor,but there was some"slag" on all of the pistons.Thats strange.Has to be fuel related im thinking.But could have overheated too

[lesterl]

The #1 piston was scorched and there was some carbon on #3/#4 cleand last 2 up good, rings were froze in piston groves #1#2 didnt look at 3/4 yet, looked like the oil got real sludgy in the rings, but the piston would have had to gotten hot enough for the aluminum to melt, dunno, will try to tear into it over the week end (hopefully) it is 2 hrs away (I do minor things up here) major stuff happens at my grandfathers garage.