<VV> Serious Problem with Otto Parts TB-20 Camshaft (link to pictures enclosed)

[Rick & Janet Norris]

Joe,
Years ago on an engine I built I had the same problem. I installed a 
complete Racer Brown cam and kit in my 140 rebuild. I did all the break in 
procedures including using GM EOS and assembly lube. In less than 500 miles 
I made a cam lobe look like a bearing journal! Doo doo occurs as they say. 
Mfg. defect? Who knows. I replaced the cam and last I knew it was still 
running. However all those metal particles that were once a cam lobe were 
dispersed through out the engine, with most of them embedded in the main and 
rod bearings. As well as I recall all the crank needed was a re-polishing.

Rick Norris
First President CORSA 1971
Email rickjanet@charter.net
Web Site http://webpages.charter.net/corvairalley
V8 Vairs Web Site http://www.v8vairs.com


> Hi Gang,
>> Roughly 8-10 years ago, I rebuilt the engine in my 64 Spyder.  I ordered 
>> all
> of the rebuild parts from Clarks... Including (for the sake of this
> particular discussion) all new lifters, valve springs, new camshaft, 
> thrust
> washer, cam gear (and not particularly applicable to this discussion)
> pistons, rings, gaskets, etc.
> > A year or so after the rebuild (roughly) with perhaps 5,000 miles on the
> engine, I noticed a vibration in the engine... At a specific RPM.  I 
> polled
> this group on the possible causes, but never tracked down the issue...
> > That is until a few weeks ago.
> > Upon tearing down the engine... And looking at the camshaft.
> > The clark's supplied camshaft has one entire lobe completely worn down 
> > to NO
> LIFT.
> > Somehow... A single camshaft lobe was completely worn to nothing.
> Inspection of the intake valve for this lobe shows that the valve, valve
> spring, and all associated parts are working perfectly.  There is nothing
> wrong with the head either... Cylinder is perfect.  EVERYTHING is 
> absolutely
> perfect... Except for this one lobe on the camshaft.  I broke in  the
> camshaft properly and adjusted the lifters cold before I installed the
> engine (and then did only minor adjustments after that).
> > Here's a link to some pictures:
>> http://www.flatfendertj.com/clarks/clarks.html
> > I ordered a new camshaft from Clarks (and new gear, thrust washer, 
> > lifters,
> etc) and have received the new parts and am in the process of rebuilding 
> the
> engine.  Now that the engine rebuild is almost complete, I'd like to 
> resolve
> this camshaft issue.
> > Here's the question for the group:
> > Is there anything I could have done to cause this problem?  Has anyone 
> > seen
> anything like this?  The ONLY thing I can think of is that somehow this 
> lobe
> didn't get hardened properly... But I don't know if this is even possible
> given how camshafts are made.
>> I have contacted Clark's and they have been kind enough to consider 
>> giving
> me a credit for the new cam and cam gear that I purchased to replace this
> defective one (I need to send it back to Clark's for them to take a look
> at).
> > I'd be very interested in everyone's thoughts... And by the way... I'm
> pretty pleased that Clark's is being very stand-up about taking care of 
> this
> issue for me.
>> Kind Regards,
> > Joe West