Can I still use this camshaft? Rebuilding my first head.

[jc1000]

The scoring does barely catch my fingernail without a glove on. The lobes look great, so I would hate to waste it.

[TobyB]

As I said in the other post, if the journals look good,
get the high ridges off of it with a flat cutter (even a single cut file can do
it, if you work at it a while) then
gently polish it to a high finish (but not shiny, so it retains some oil)
just to get all the high spots down. Leave the grooves.
A machine shop can do this easily.

That's worked great for me. All you're trying to do is to keep it from galling
the journals by cutting the tops of the mountains off, and ignoring the valleys.

t

[reelizmpro]

I don't think mine were as bad but I had them polished down (as Toby described) and ran it without issue. The lobes looked great so I wasn't going to replace it over a journal.

[zaq123]

rebuilding...........................

why are you rebuilding it? I would actually "rebuild" and use new cam....otherwise what are you rebuilding and why are you taking it apart in the first place? That doesn't look good just so we are on the same page. Did you figure out why?

[jc1000]

why are you rebuilding it? I would actually "rebuild" and use new cam....otherwise what are you rebuilding and why are you taking it apart in the first place? That doesn't look good just so we are on the same page. Did you figure out why?

I was disassembling it so it could be honed, pressure tested, checked, and cleaned by the machine shop. When I disassembled it, I noticed the damage.

Why the new cam? Can I just have this one polished and run it with new rockers? I could also send this one to be reground I guess.

[TobyB]

A regrinder would polish that. The bearing surfaces don't get ground.

As to replacing everything in the engine because you're in there:
that's your call.
Zaq would do it once and throw a bunch of parts and money at it,
in hopes that guarantees he won't be back in. "Do it once, do it all".
Nothing wrong with that.

If you want to reuse a cam that looks fine, do it. You run a good chance of having
it work fine, as others of us have learned, too. You've had good advice to change the
galled rockers, polish the bearings, and you have a good chance of that working well
for another 50k+ miles.
Zaq might get a cam with bad metallurgy, and have his grenade in 5k.

Only one way to find out for sure with these things- try it and see!

t

[zaq123]

A regrinder would polish that. The bearing surfaces don't get ground.

As to replacing everything in the engine because you're in there:
that's your call.
Zaq would do it once and throw a bunch of parts and money at it,
in hopes that guarantees he won't be back in. "Do it once, do it all".
Nothing wrong with that.

If you want to reuse a cam that looks fine, do it. You run a good chance of having
it work fine, as others of us have learned, too. You've had good advice to change the
galled rockers, polish the bearings, and you have a good chance of that working well
for another 50k+ miles.
Zaq might get a cam with bad metallurgy, and have his grenade in 5k.

Only one way to find out for sure with these things- try it and see!

t

jeeezzz... thanks for good wishes :) I haven't heard of schrick cams go boom yet so let's keep it that way.
With that approach ....be careful changing the oil that is old/used but tested. Maybe you end up getting a bad batch with some aluminium oxide in it?



I've just been in many many situations (with my e30 too ) where I wished I'd do it right the first time. Will it work? Sure, I fixed leaking car window gasket with a bubble gum before as well. Would I use a
bubble gum if I have the windshield out? No.

Regrinder can grind anything you want. Will it fix the issue or make it better? No. Will it look pretty, sure.

1. On M20, rockers must be replaced together with the camshaft.

2. Don't have exact M20 numbers in front of me.....Average cam journal oil clearance is 0.0015-0.002. Scratches that one starts to feel with the finger nail: 0.001-.004 (on top of what was there per spec). By the time you grind that off to look nice, will that journal still be useful? Is it useful now?

Yes, everything is subjective to one's expectations/standards/specs. Do I throw in new parts just for a hack of it? No. Do I follow manufacture's specs? Yes. That cam is gone, Your rockers are gone.

Clean up high spots in the head bearing surface (gently), put new camshaft, new rockers and pray there are no metallurgy issues Seriously though, it's already a compromise in my book.

Does OEM Spec mean "a must" in your book or just a suggestion? If "a must" grab the micrometer and start measuring. If no and you want to know if it will run....sure it will run. Probably not as long as Japanese :)

[jc1000]

Thanks for the thoughtful replies, TobyB and zaq123 . I am sure learning a lot. I am leaning towards replacing rockers and camshaft - but man these things seem expensive!

zaq123 - honest question for you. What would you do in this situation? If the head casting, rockers, and camshaft all seem compromised, I guess the only option is to buy a completely new head? If that is the case, it seems that it would be worth running this one "into the ground" first anyway, since I already have it? (I would at least replace the rockers.) Any damage would be limited to the head, right? Or perhaps debris in the oil could cause damage elsewhere? Is that the main concern? It seems you are against this idea, but I just want to make sure I understand why.

And to be clear - it seems you are against regrinding, correct? As in, a reground head does not compare with a new one? I am seeing that I can have mine reground, but want to understand if that is "inferior" to a brand new one. I guess it would be, right?

Sorry for all the questions - this is all new to me! I greatly appreciate the help.

[ForcedFirebird]

New OEM cam is like $150. It's a wear item.

[zaq123]

Thanks for the thoughtful replies, TobyB and zaq123 . I am sure learning a lot. I am leaning towards replacing rockers and camshaft - but man these things seem expensive!

zaq123 - honest question for you. What would you do in this situation? If the head casting, rockers, and camshaft all seem compromised, I guess the only option is to buy a completely new head? If that is the case, it seems that it would be worth running this one "into the ground" first anyway, since I already have it? (I would at least replace the rockers.) Any damage would be limited to the head, right? Or perhaps debris in the oil could cause damage elsewhere? Is that the main concern? It seems you are against this idea, but I just want to make sure I understand why.

And to be clear - it seems you are against regrinding, correct? As in, a reground head does not compare with a new one? I am seeing that I can have mine reground, but want to understand if that is "inferior" to a brand new one. I guess it would be, right?

Sorry for all the questions - this is all new to me! I greatly appreciate the help.

1.new head would be nice but you won't find anything that is better than good used 885 head. Therefore if you head is not damaged or has an acceptable amount of wear, I'd use it. Damaged too bad, find good used one
2. The same goes for your rocker arm shafts, hopefully you didn't destroy your original ones when removing them. (some folks bang them out with the hammer which is not right way to do it)
3. As I stated, new cam and new rockers are the absolutely minimum for these old cars which at some point were $500 cars with very questionable maintenance history. It's typical to see Cam/valves/rockers on these in very bad condition due to the lack of proper lubrication.
4. The damage. I suspect its the oil pressure (or a lack of it) that messed up that journal (due to debris/clogged passages, oil level, worn intermediate shaft/its bearing, worn oil pump etc etc). Worth looking into it and address as needed.
5. Regrind is not new. I would not get a regrind unless I can't source a new one I need. When someone regrinds the cam, they regrind cam lobes. They do not regrind cam journals (unless someone build them up first which is sketchy) as it isn't like the crankshaft, you can't upsize bearings in the head to maintain the oil gap.
6. Are you keeping it stock? As FF said above, new Febi cam is $150. If you're doing something else - new Schtick cam is around $500. In the big scheme of engine building....$500 is a bucket of sand on the beach...as you probably already found out.

[jc1000]

1.new head would be nice but you won't find anything that is better than good used 885 head. Therefore if you head is not damaged or has an acceptable amount of wear, I'd use it. Damaged too bad, find good used one
2. The same goes for your rocker arm shafts, hopefully you didn't destroy your original ones when removing them. (some folks bang them out with the hammer which is not right way to do it)
3. As I stated, new cam and new rockers are the absolutely minimum for these old cars which at some point were $500 cars with very questionable maintenance history. It's typical to see Cam/valves/rockers on these in very bad condition due to the lack of proper lubrication.
4. The damage. I suspect its the oil pressure (or a lack of it) that messed up that journal (due to debris/clogged passages, oil level, worn intermediate shaft/its bearing, worn oil pump etc etc). Worth looking into it and address as needed.
5. Regrind is not new. I would not get a regrind unless I can't source a new one I need. When someone regrinds the cam, they regrind cam lobes. They do not regrind cam journals (unless someone build them up first which is sketchy) as it isn't like the crankshaft, you can't upsize bearings in the head to maintain the oil gap.
6. Are you keeping it stock? As FF said above, new Febi cam is $150. If you're doing something else - new Schtick cam is around $500. In the big scheme of engine building....$500 is a bucket of sand on the beach...as you probably already found out.

Thanks, zaq123 . I am putting the 885 head on an ETA (2.7) bottom end and turboing. Is there a cam you (or others) would suggest for that setup? And what is the best OEM replacement option (you mention Febi)?

[digger]

A stock cam is all you need