Hey all, I drove out into nowhere a few weekends ago on the premise of purchasing a running take-out 4AC for cheap(to swap into the tercel). I showed up to find a nice big hole in the side of the block.. lame. not wanting to have a wasted day; I decided to take the head since it was aluminum. Pulled the head and found completely collapsed cylinder walls underneath. neat.
So I got the head into the parts cleaner the last few days and can now see it has valve seat inserts. 1 or 2 of them look really nice but the rest of them have buildup and/or corrosion on them. So the question is; should I just scrap this thing or is it worth/possible to rebuild it. Would anyone on here be interested in it? think eBay would move it?
Otherwise I think aluminum is ~.60/lb
pictures are from best looking to worst.
looks like it sat with water inside it, which is likely if the water jacket was breached. It can be salvaged but it needs the exhaust valve seats recut. I would take it to an automotive machine shop, hopefully you have a good one nearby, and have them check the wear on the valve guides, and regrind the valve seats, install new exhaust valves, valve stem seals, and assembly it for you. Than it will be worth using. Might also have it boiled out to get any rust deposites out of the water jacket.
The intake valves if not damaged can be reground if necessary and reused. Be careful to inspect the head, valves and everything around the cylinder that blew, sometimes just as the rod is letting lose the piston will slam against the head pretty hard. this could damage the valves, head, etc on that cylinder. So look for impact marks on the head where the piston would strike it. It dose not mean the head is not usable, it just means you need to check for cracks if it was struck, and possibly resurface it to remove the impact marks.
I want to clarify here, my concern is that the hardened-steel(maybe stellite?) valve-seat cannot be machined. Have you ever seen that done? I will call my machine shop but it just logically didn't add up in my mind. If rust is pitting the valve seat, I don't know how much material can be taken off, if any.
But I don't have experience with inserts. hence my question.
thanks petros
It can be reground, quite a lot can be take off. Typically the seat cutting machine is a shaped grinding stone mounted on a mandrel that goes in the valve guide, it will take off the pitting and recenter the seat to the valve guide. what I see there looks like it can be reground. If badly burned or pitted it can also be replaced, I have seen it done many times, but if you do that make sure the shop really knows what they are doing. check the cost first as well, if it needs that much work it might be cheaper to find another one without the problems in a wrecking yard. It is not like these are so rare you have to rebuild it at any cost.
