[Bazlow]

I finally broke down and got a set of rebuild heads for my 1990 F-150 and started working on the replacement this weekend. I have one question about the whole affair. That is, the components from the old heads, rods and rockers are highly carbonized. Probably 1/32" of hard black coating on everything. I got a can of Gunk cleaner and spend all day trading out parts from the driver side head to get it off. It takes 3-4 30 minutes soaks to get the parts clean. Granted it's an old engine with 160000 miles on it but is this normal?

I was blowing a lot of smoke out of the valve covers which I attributed to shot valves. Compression on all cylinders is still in the 140-160 range. And, I'm pretty religious about changing the oil out at regular intervals since I bought the truck. Was it the hot gasses blowing out of the valves that caused the heavy carbonization or is this normal for an engine this old?

A

[Steve83]

Yes, that's about right for an engine with that many miles, especially one that wasn't PERFECTLY maintained.



The smoke could have come from the valve guides, but it's just as likely to have come past the rings. And yes, that's what caused the oil to break down & carmelize all over everything. I recommend you fill it with 20W50 + a quart of good name-brand (I like BG & Berryman) engine flush to break up what's in the bottom end. Follow the instructions on the bottle TO THE LETTER or you could cause severe damage. It will involve several oil changes in quick succession, so have a case of oil & several filters on-hand.
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. . . '99 CV RIP