Re-Ground Cams

Re-Ground Cams

Does anyone have any experience with re-ground cams in a Lycoming O-320? Are the a viable alternative to new? Do they last?

Seems like a band aid for replacing the cam.

Thanks

Vin

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Re: Re-Ground Cams

I have discussed the refinishing of a crankshaft, which is acceptable during an overhaul, so I would imagine it wouldn't be a problem for a cam as long as it still meets minimum specifications and there are no other defects/flaws.  Wouldn't the hydraulic lifters accomodate small diminsional changes? 

I would not consider machining an item as a "band aid."  The maching process would eliminate the defect.  (As long the above caveats are met.)

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Re: Re-Ground Cams

I should withdraw a part of my last remark.  Grinding should not be confused with machining as I did.  I think you should get an opinion from a overhaul shop, manufacturer, or review a shop manual for the the engine to see if it is allowed by the manufacturer as an approved repair.

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Re: Re-Ground Cams

Several years ago, when I had my O-470 overhauled, then engine shop called me and told me that my camshaft was in remarkably good shape.  I was told that it's pretty much SOP to replace them at OVH, but they suggested that I have mine "regound".  They said it should last as long as it did the first time around.
I was left with the impression that "regrinding" would be dependant on what shape the camshaft is in.
I would imagine that a flat lobe of some serious pitting would be a deciding factor.
I felt comfortable with the regrind.

Michael

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Re: Re-Ground Cams

Regrinding cams is an approved and accepted method of restoreing a cam up to new condition again.
they will only remove about .010 in the process. That isnt enough to affect the opening of the valve or to go through the heat treated surface of the cam.rc ia

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Re: Re-Ground Cams

  I personally would never ever consider putting a re-ground camshaft in an overhauled engine
Why would a person skimp and save bucks when the engine performance will suffer it will never turn full RPM  and risk ruining
an expensive overhaul due to camshaft wear, those camshafts
are surface hardened after final grinding in the manafacturing
process and when they are re ground they may or may not go through that surface hardening.
I mean its like playing russian roulette with that new engine!
  I personally have been told by quality engine rebuilders that they won't use a re- ground cam and lifter bodies because of the likely hood of premature failure!
  I also know of two engines that were overhauled with re-ground cams that just will not turn the rated RPM no matter what.
                     thats my 2 cents worth

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Re: Re-Ground Cams

Andrew

These have been my concerns all along and the reason I wanted to canvas a number of people that have any experience with this issue. The local engine builder here says the excat same thing about re-grinds, and says they may be good for 1000 hours but...

Unfortunately, I have run into several "reputable" shops that put reground cams and lifters into their products. I am glad that my mechanic suggested that I look closely at the engine overhaul yellow tags to see what was done to the cam. This is how I found out how many regrinds were out there.

We did not buy the plane we were looking at for numerous other reasons but this was a factor.

Thanks to all for your input and please keep your experiences coming since I would like to get a feel for how this process holds up in the long run.

Thanks

Vin

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Re: Re-Ground Cams

Cams are not heat treated after final grind.  They are heat treated and THEN final grinding takes place.  As stated above, not much is removed during a regrind.   A PROPER regrind is as good as new in my book.

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