Hi there,

Some background :
Blew my head gasket on the freeway, purchased a new head, cam, gaskets and all the other odds and ends just for the peace of mind. Got everything off and pulled the head off and saw that there is scraping in one of the cylinders, and what seems to be some surface rust in another. Three of the head bolts were also bone dry, and the end of threads were a little shorter than the others(3rd, 4th & 5th bolts from the left. One of these bolts appears to have left some powdery type substance (Pictures 3 and 4) where the threads are in the engine block.

Pictures

So the question is how should I proceed with fixing this? Is this block a lost cause?


Thanks

 

Toby -

Welcome to YotaTech. It's customary (useful) to list your year and engine; sometimes it matters and you might as well get into the habit (heck, add it to your "signature.")

The head bolts are "supposed" to be dry; most of the oil probably got on them as you were removing them. If you're at all worried replace the bolts; while not required by Toyota, they weren't writing the FSM for your age vehicle. Also, consider "chasing" the threads in the block. You can use a tap, but I've had great fun with a "thread restorer set," which you can borrow (no charge) from autozone http://www.autozone.com/loan-a-tools...d-restorer-set.

The rust might have gotten on the cylinder in a matter of the few days it took to get the head off; if it all comes off with a "ScotchBrite" (and you can't feel anything) I wouldn't worry about it.

The scraping, though, looks like a broken ring. If you can scrub off all the marking on the cylinder wall with a ScotchBrite, you may be able to get by with just replacing the rings. Otherwise, you'll need to re-bore the block. Either way, I don't see any way around removing the piston.

Good luck!

 

That is usually a sign of a ring breaking and getting smashed between the piston and cylinder wall. Always require a bore to fix it. Like scope says, if it wont scrub off or if you can feel it with your finger nail, it will need bored over.

It is rebuildable but I find it cheaper to just buy a rebuilt motor and you get a warranty. Been a while but I bought 2 motors from United Engine and they have been great. When you bore a motor over, you have to get new pistons and machine work adds up.
I have rebuilt numerous top end motors and one I did a complete rebuild from top to bottom failed on me. I had the head repaired and it is what failed. If it was me and it requires boring, I would look for a replacement motor.