chrysler 2.5 head crack

The car is a 1994 acclaim, 2.5 litre original engine, with about 150km. I've decided to rebuild the engine because of increasing oil consumption, reduced power and gas mileage, and a coolant leak to cylinder # 1.

The exhaust valve guides all seemed to have slipped down into the cylinder by as much as 0.3 inches. Is this cause by engine overheating? Can the valve guides be pressed back into position? Is there something I should do to prevent this problem on the rebuilt engine?

Also, I've noticed there is a small crack between the exhaust valve seat and the intake valve seat of each cylinder. Should I weld these cracks, replace the heads, or leave them as is?

Any advice would be appreciated.

David

Reply to
nawks
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Find a local competent machine shop that does a lot of automotive heads and get there opinion. They will be able to tell you what is possible and what is not. Many salvage yards also carry lines of rebuilt heads from a major rebuilder. price both out and see which is the most economical way to go.

Bob

Reply to
Bob Urz

"nawks" wrote

You've compared the valve guide position to ones in a new head? I don't recall the 2.5's having much of a problem with dropping valve guides.

If you have a machine shop look at them, you will probably get a variety of answers. Pretty much every 2.2 or 2.5 engine I have ever had apart, has those cracks between the valve seats. I've been told that it's fairly normal, and in most cases doesn't pose a problem. Eventually, if the crack gets too large, sometimes the seat will become loose in the cylinder head and the seat will drop out of the head. This usually results in the rocker arm being thrown out from between the cam and valve.

Ian

Reply to
shiden_Kai

I rebuilt the same engine before. Take the head to a competent shop and have it examined. If your car was overheating, there is a good chance the head is warped. You can buy a replacement head from Autozone etc. or fish one out at a junkyard.

Reply to
Rajsircar

Those are good reasons to do that.

Are you quite sure? That would be extremely unusual for this engine.

Valve guides need to be replaced or at least reconditioned during the overhaul.

...on virtually every 2.2/2.5 cylinder head, yes. They are officially (and really!) a nonproblem. They're unsightly, but that's all they are. On rare occasions, you'll see one of these cracks that goes clear through and into a water jacket, but that's really rare. Recondition the head and don't worry about it.

No.

DS

Reply to
Daniel J. Stern

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