Cam scoring, how much is too much?

[Joegreen02]

So I have this spare 885 head laying around that I purchased with some other parts. It's actually freshly rebuilt, New valves, springs, guides, seals, and seats. Stock cam and I have a set of the HD febi rockers and new rods to install. But I'm wondering about this scoring. The head currently on my car has a little scoring but probably half as bad as this one




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[Jaxx_]

If your finger nail catches it, it is "too much" by most standards. If the machine shop did new guides and seats, and let that pass... I would argue they thought it was fine. They could have machined the journals and put in a new surface.


Personally, I've run way worse on a street motor, and reamed valve guides with a hand drill. I think it will all depend on what you're trying to accomplish and what you're really looking to spend. As long as there are no "deposits," (peaks, not valleys) you should be OK. After all, scoring is just more room for oil, right? Many will disagree, and they're probably not wrong. What you will find in a text book and what people say will always be the 'right way,' but you can get away with a lot less.

[Joegreen02]

If your finger nail catches it, it is "too much" by most standards. If the machine shop did new guides and seats, and let that pass... I would argue they thought it was fine. They could have machined the journals and put in a new surface.


Personally, I've run way worse on a street motor, and reamed valve guides with a hand drill. I think it will all depend on what you're trying to accomplish and what you're really looking to spend. As long as there are no "deposits," (peaks, not valleys) you should be OK. After all, scoring is just more room for oil, right? Many will disagree, and they're probably not wrong. What you will find in a text book and what people say will always be the 'right way,' but you can get away with a lot less.

This was kind of my feeling on it too. Ran fine before I just tore it down to clean it up and I'm planning on running a little smaller cam in this one since I'm going to adding boost.


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[ForcedFirebird]

I would have it pressure tested. It appears to have a crack going from the cam journal down towards that spring closest to the camera. May be just the pic, but that's where 885 heads crack when they do.

Usually the cam journals are scored when a head gets warped. Many machine shops just mill them flat, but that doesn't fix the now non-aligned journals. As far as the scoring, I have seen far worse on good running 24v's, it's a judgement call IMO.

[Ceeker]

Sorry for reviving an old thread..but what amount of wear on the Cam mains are acceptable. as in mm or thous of a inch. I also received a head that looked newly machined. .
I know the cam runs on a thin layer of oil and there is no downward upward force unlike a crank or conn rod bearing. The cam does have scoring and I'll have my machinist
inspect it but I was wondering if it's salvageable?

Also the head journals have scoring as well..