Searching forums I'm not finding any hard facts about replacing camshafts besides recommending because timing can jump and bad fuel economy. Timing jumping would be a good reason to change, but... that doesn't happen unless the sprocket teeth are worn..?

What can I expect, or rather what's everyone's experience with worn cams. Seems fine running, before the rebuild

If you're looking for hard numbers: { MY CAM EXAUST measurements }
Journal Diameter service limit MIN: 1.0608 { 1.0600 }
Lobe lift .20442 to .2074" { .2055 }
runout: { can't measure. no gauge at the moment }
Oil clearance: Standard .0021" to .0040"{ .002" plastigauged }

 

Nevermind about the timing. Didn't think about firing the pistons. So, am I going to hear/see signs or is this something I should just leave unless "broke"?

 

So it's an S series DOHC. How many miles on it?
Are you rebuilding to address oil burning issues, did you burn a valve....?

Not quite sure I understood your statement about cam sprockets. You'd have to put a lot of wear on those, probably mostly by lack of oil, for that to happen, and the chiming chain is much more likely to fail first in any case on these engines.

The only time I've seen discussions about the DOHC cams are when people are considering performance enhancements. I can't really see the cams getting very far out of spec if the engine has been maintained properly.

If you are rebuilding, you should be replacing the timing chain, crank gear, cam sprockets, tensioner, chain guides, and anything else that comes in a standard timing kit for these cars. So if you're worried about the sprockets wearing, it should become a non-issue when you do the timing kit

So I would recommend not messing with it if it is not causing any issues or was not causing any issues

 

Exactly why are you doing this?

 

Yes, S series 320k miles. Though, I don't have history of the cams I've got. Bought a rebuilt head w/cams. Not reusing my cams as they are part of the core I am returning { worn, at least lobe lift is out of spec }. In any case, cracked head. Coolant issue, used strait distilled water. Overheated

And yes, sent block to machine shot and of course new chain kit. new pistons { oversized }, but re-using connecting rod {320k miles}

Appreciate the feedback. Still haven't got the car running again. Just worried for running out of spec cams. Again, normally would just replace but need to get back on the road, not waiting for new cams.

 

Sorry if i am being thick... Are you saying you want to temporarily put your out of spec cams and run them in the refreshed setup, while you wait for the cams That come with the head to show up?

Which would imply you have the machined block and the replacement head, but you do not have the replacement cams in hand. So you want to know about running your out of spec cams in the rebuilt setup until the new ones come?

I would think for break in purposes alone, you would want to have in there the cams that you plan to leave in the engine.

Ultimately, will it matter?

Someone else needs to address that as I do not have the experience to do so.

 

Not at all, my bad for not being more specific.
I certainly would replace with new, but I'm not waiting for new ones. It's such a pain to replace cams { unless I can attempt to pry the timing cover enough to remove the cam sprokets, while keeping tension on the chain and replacing the cams } so I am just running the worn out cams without replacing with new.

If a problem arises, I'll likely attempt to replace cams without taking the timing cover off. I think I can pull it off.

I posted this to let me know of any problems that I should be looking for. My goal is just to keep it running as long as possible. I'll take run the worn cams unless I find it needs replacing.

 

Why not just use the cams that came in the rebuilt heads? They're probably in better shape than your old ones.

 

I'm not a machinist, but it looks like your measured dimension of .2055 is well within the limits specified. You said the engine ran fine, does the cam show any damage otherwise?

 

Rube,

I don't think he can get his hands in them yet