used cam shaft blemishes- will a engineers polish it
used cam shaft blemishes- will a engineers polish it
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Discussion

steveo3002

Original Poster:

11,085 posts

198 months

Monday 3rd July 2017
quotequote all
ive picked up a slightly hard to find used cam at a fair price , its got a couple of tiny blemishes on it id rather werent there

is this something engineering shops will polish out ? any ideas what it might cost me

tapkaJohnD

2,000 posts

228 months

Tuesday 4th July 2017
quotequote all
Are these small patches of corrosion that you can feeel with the finger tip?
In which case very fine Wet&Dry (1500 grit), wetted with WD40, polish them off yourself.
May leave slight staining in the surface, but if the finger tip can't feel it, that's OK.
This study found that the fingertip can feel half a thou of imperfection: https://www.sciencedaily.com/releases/2013/09/1309...

If they are damage/wear, is this on the cam lobes? In which case, yes, they can be ground back to restore the surface. Then the valve gaps adjusted as usual
Ground cam bearings would need thicker bearing shells, if they are available.

Anywhere else on the shaft, doesn't matter.
John

Steve_D

13,801 posts

282 months

Thursday 6th July 2017
quotequote all
just to expand on Johns answer if I may.
Wet and dry as said but being most critical on the tips of the cam lobes and the cam bearing surfaces. All other surfaces (sides and back of cam lobes included) you will want to clean up but do not matter if they fail the finger tip test.

Steve

steveo3002

Original Poster:

11,085 posts

198 months

Thursday 6th July 2017
quotequote all
one small pit is right on the peak of the lobe...id imagine theyre hard to have any effect with wet n dry ?

stevesingo

5,024 posts

246 months

Thursday 6th July 2017
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Pictures might help!

GreenV8S

30,999 posts

308 months

Thursday 6th July 2017
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I wouldn't worry about a few small pits - just make sure it isn't proud anywhere.

E-bmw

12,417 posts

176 months

Thursday 6th July 2017
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As above your cam followers will be fairly wide & not just in contact with one single point on the cam, so unless the pits are across a wide band on the cam lobes I am sure you will be fine.