REFLECTOR: Continental Starter Adapters

[Brooke Wolf]

Does anybody have any experience with TCM starter adapters?  I have a TCM IO-550N engine with 145 hrs since major overhaul.  Suddenly, at about 130 hrs and an unknown number of starts I started getting a growling noise when I engaged the starter.  Initially the prop would not turn.  Upon reengagement, the prop would turn in a herky-jerky fashion but would start normally.  

My local AI thought it was a slipping clutch on the starter adapter.   After a couple of phone calls with my engine rebuilder and Niagra Air Parts, I determined the problem could be with either the starter or starter adapter.  I sent both to my engine rebuilder for analysis.  They said the starter was OK, but the adapter was out of specs.  They sent me a rebuilt one (partially under warranty).  I reinstalled both and, no change.  Still a herky-jerky prop movement.  Now, I'm thinking maybe it's the starter.  I talked to the engine rebuilder and he said they only did a cursory check on the starter and they weren't set up to do a in-depth analysis.  The starter was one that was rebuilt by Aerotech, a company that I have very little faith in.  I decided to send it off to Aircraft Systems, Inc, a company that impresses me with their craftsmanship and attention to detail.  They bench tested it and found that its current draw was  barely within limits on the high side.  They took it apart and found that the through bolts were grounding out to the field coil and there were some burn marks.  They replaced the field coil and brushes, (actually insulated the through bolts!) and sent it back to me.

The starter does turn better but I still have the herby-jerky prop indicating a slipping starter adapter clutch.  Now I am irritated!  I paid good money for a rebuilt adapter and they send me a bum one!  Well, my next step is to send the adapter to Niagra Air Parts.  To my knowledge, they are THE experts in TCM adapters.  I had a nice discussion with them on the phone this morning and we had just about decided to send the adapter to them for inspection and possible rebuild to the tune of $1200.  Just before we were about to hang up, the Aircraft Systems lady asked if I was using any oil additives.  I said yes, I was using Camguard.  She said "Thats the problem!"  It appears that cam guard is too good in reducing friction and as such will cause a slipping starter adapter clutch.  She said they have had multiple issues with this, and an oil change, without camguard, usually solves the problem.

So, my question is this Ya'll:  Has anybody else had issues like these?  What was your experience?  Any thoughts on camguard?  I guess one other piece of information I should add is that I use Exxon Elite 20-50 oil.

Sorry for the long post!

Brooke