tinigunner11

iTrader: (1)

alright I bought my truck last august and I'm just now having the time to dig into it. I bought it with a blown headgasket, but when I got the head off I noticed something out of the ordinary. my #2 piston looked like this:


I know this is not normal. But what would cause this? Any help would be greatly appreciated. and sorry for the iphone quality pic.

scope103

Something hard was loose inside there. Sometimes it's the ground electrode from the plug, but those marks look a little big for that. I assume you have similar marks in the head, and you found nothing sitting in the cylinder when you removed the head (after a few seconds it could have pounded it into small enough pieces to escape through the exhaust valve).

The dents are bad but not a killer (though any mark on a piston can be a localizer for pre-detonation). What would make me replace the piston is the big chip out of the edge.

What does the cylinder wall look like? Since it is harder than the piston it may not have been "peened, " but if something got stock between the piston and cylinder wall it might be toast.

250000_yota

Tini-what did the head surface look like on that cylinder? Did it chip a valve or possibly break a plug on that cylinder?

tinigunner11

iTrader: (1)

I'm not sure what the head surface looked like for that cylider because my grandpa pulled the head and plained it with out me know as a surprise. But now that I look at the plugs is missing the metal part at the tip. Scope are you talking about the rectangle peice at 6o'clock on the piston? Unfortunately I can't go out and look at the truck till tomorrow because I'm in the process of moving and the truck is at the new house.

scope103

Yes, the part at 6 o'clock.

The missing ground electrode on the spark plug could be either a cause or effect. If there was something hammering around inside the cylinder, that could break off the electrode.

If your head was (planed? Probably surfaced.), that only affects the part that lays on the head gasket. You're interested in the combustion chamber exposed to the cylinder, and the valve heads. Surfacing doesn't touch them. The valves can be replaced (might have to be anyway; exhaust valves take a tremendous beating) but you need to see whether the valve seat is damaged.

dropzone

iTrader: (6)

Are you positive both valves were intact?

fierohink

I had a similar combustion chamber and piston top to that when the rings came apart on #2. Rotating the crank so that piston is at the bottom may reveal scoring from were the piston/ring came apart if it was like mine.

Engnbldr.com has all the parts you will need for a master rebuild. Mine ran about $1500 parts and labor for a full fresh; re-balanced, trued, and polished crank, trued main journals, honed cylinders, sleave for #2, tanked and decked block and head, oversized valves lapped and seated, rotating assembly installed, and new freeze plugs installed. I had them assemble the short block because it was cheaper than renting a ring compressor and doing it myself.

Spazzcdnm

iTrader: (1)

I dont think thats a chip taken out of the edge of the piston. I just got done rebuilding my 22re and the aftermarket pistons that Engnbldr supplied come with a little rectangle right there that is meant to face towards the front of the block. basically its there for alignment of the pistons. You can see a little of the one on piston #3 in the pic. It does look like the edges of it have been mashed a little bit, so I could see how it was confused for a chip. Regardless.. I would pick up a rebuild kit. I had damage on the head that looked like that when I took mine apart, but nothing on the piston oddly enough. I think its from a prior motor that the head had been on.. Had it shaved and right back on it went! Its been working like a champ. Love it.

arlindsay1992

iTrader: (8)

I had a piston look like that on my 88 22RE. I took it apart because of a head gasket leaking coolant. As far as I could tell the head gasket was original. The valves weren't chipped and the spark plugs were all fine. There was no scoring on the cylinder wall and the piston rings all looked fine. I put it back together and had no issues. I still don't know what caused it.

Inferno451

Spazz is right. On both his new pistons and my original pistons, there's a little rectangle at the 6 o clock position. It looks ugly, but it's probably ok to run.

tinigunner11

iTrader: (1)

Sorry I haven't updated the thread in a while. Thanks for everyone who posted. Unfortunately the valves were done when the head was resurfaced, so I didn't get a chance to see how they looked.


I've got a picture of the head surface but I'm using my iphone so I can't post it up until I get back to the house. It has very light chips in it. I would love to do a full rebuild but I need the truck up and running ASAP. I'm planning a full rebuild in the summer. Can I run it as is until then?