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Well, after getting the head out and having the machine shop jet clean it, the valve specialist discovered hairline cracks leading from the plug hole to just under the exhaust valve seat on both #2 and #3 cylinders. Cylinder #3 crack is more a subtle fracture than #2, but still evident.

I had originally taken it in for what I thought was a stretched valve in #2 (couldn’t get valve adjustment) it actually was a recessed seat. It was mushroomed at the contact of the valve seat allowing the valve to seat further into the head. The lead indicator on the head had melted showing overheating at some point in the cars history. The second owner of the vehicle had replaced the water pump and had done a valve job at some import car shop in San Francisco back in 2000 or so. It’s hard to follow the previous owner’s names and their maintenance records on the poor car. I think I’m number five. The head had been resurfaced which was indicated by the linier scratches on the surface. That water pump problem may have had something to do with the head problem originally. I don’t know. No real logs from the POs. All I have to go by is the invoice and service billings he had received.

Here’s an interesting antidote:
When I looked the car over for purchase, I had immediately notice that the car was only running on 3 cylinders. When I remarked to the seller about that he replied “that’s the way it always sounded”.
“WHAT!”
“You mean to say that’s a normal sound to you??” I shot back.
“Yeah, that’s the way it has always run.” He said.
“OK”, I said. “Does that shaking engine look alright to you?”
“Oh, it probably just needs some engine mounts.” He said.
“Oh, alright…” I held back.
“Do you mind if I pull off the plug wires to isolate the possibly bad cylinder?”, says I.
“Sure, go ahead”, says he.
After finding the bad one I asked him is he agrees that there was something going wrong with number 2. He laughs “Yeah, I guess so!”.

Now, before you shake your head and think this fellow was playing stupid with me, I have to say that I truly believe that he thought that WAS in fact, the way it was supposed to sound. Also, I believe he had actually bought it that condition from the previous owner. And he had driven it that way during his ownership of the vehicle.
The cylinders in 1,3 & 4 all seemed to have the normal signs of combustion by-products from use. But number 2 looked brand new.

The PO also chimed in with “It may sound kinda rough, but when you get her up and running she sure is peppy!”
Indeed.
When I test drove it still had lots of punch in the upper-end.

I got what I thought was a good deal on the car. At the time, at least.

So, the head is in the shop, almost completed now with new valves and seats on the exhaust side and those potential problem cracks.
Is there anything to really worry about? From what I’ve read thus far, it seems somewhat common to have some hairline cracks at the area between the plugs and the exhaust. Is it so?
 

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1966-2013
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<-- cracks in the head are never good or even remotely normal.

Mabe you'll get lucky and someone can weld them up then refinish the chamber, but I would be looking for a new head otherwise.



Someone else may say different, but it's nothing I'd ever pass off as 'ok to run with'.
 

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Cracks in the head between the spark plug hole and exhaust valve are not desirable, but are not uncommon either. A good machine shop that knows aluminum should be able to weld up and refinish the shape. May not be economical compared to finding a good used head that doesn't need such work, but it's done all the time.

Andrew
 

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As long as the head is aluminum, welding up cracks is not a problem. If new heads are readily available, check the price on a new head before you commit to welding the old one. Make sure the cost of welding the old head does not exceed the price or come close to the price of a new one.
 
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