O-470-L COntinental starter adapter slipping

C170Driver · Post by **C170Driver** » Fri Aug 06, 2004 1:29 am

OK - so maybe you tuned in to see what crazy 170 owner has a monster O-470 cobbled on the prow. Not so. Just a lowly former 170 owner/driver who lost his mind and is now wrestling with a 180.

But before you go off in a huff - I know this crowd to be the best when it comes to sharing years of painfuly and duly acquired experience!

The starter adapter in the O-470-L suddenly started slipping when it hit a compression stroke (about 1/2 blade through) on the second flight following the first oil change. I can easily get it started by bumping the starter a few times in a row (release the button when it lets go, tap it again and it advances a few more inches - maybe through TDC - then lets go, tap it again and it swings through and starts) but am concerned about making metal in there!

Engine has 13 hours SMOH with Titan cylinders. Every start before the oil change and the first one after were all positive starts with NO slipping. Adapter was rebuilt at OH and I have the old shaft and spring in a box in the garage.

Have been using Phillips X/C 20-50 (AD oil) as specified by ECI, except that at the oil change I added one quart of Chevron AD20-50 - which is also a mineral base AD oil (no semi-synthetics, sez ECI) - because I didn't have enough X/C around to make full. Both Phillips and Chevron folks say shuldn't be an issue (I was thinking the additives were arguing.)

No concesus so far. Have most guys saying "Aw, they all do that, no worries if you don't keep the starter engaged and let it spin once it lets go." Am I being paranoid? Rebuilder sez he is sending the "new style" adapter, but admonishes that with the new adapter it is a no-no to turn the prop backwards for fear of hosing the tighter adapter.

Any thoughts?????

Post by **GAHorn** » Fri Aug 06, 2004 1:50 pm

If the starter adaptor is slipping on an angle-adaptor with those few hours on it....make a warranty claim as you've just done. It only gets worse as time goes on, and that spring will keep slipping and shearing metal bits into your sump.
If the starter adaptor has wound up tight and won't let go,....you don't want to turn ANY of the backwards...all for the same reason...you'll further damage the adaptor. In such case,...again it's time to exchange the adaptor. If the adaptor isn't wound up tight, then turning it backwards won't hurt it.
A primary cause of such damage is a backfire/backrun during a start due to advanced timing. (Shower of sparks systems may not ground the non-firing mag (or failed impulse coupler) and prematurely fire sending the prop backwards....definitely putting the adaptor into harms way because it's already wound up tight.)

spiro · Post by **spiro** » Fri Aug 06, 2004 11:07 pm

Hi Pat, sorta followed this on the 180 list. Sounds like a typical failing starter adapter. Who rebuilt it? They really rebuild it or just install new shaft & spring? You running a perm magnet (Lamar) starter? - they'll tear up the adapter. Best bet, call Niagara Air Parts, (800) 565-4268 - they're the starter adapter experts.

- paul

C170Driver · Post by **C170Driver** » Fri Aug 06, 2004 11:56 pm

As always, you guys come through with sage advice. The new adapter arrived today. By most reports - kind of a pain that may require at least loosening the mount for clearance at the firewall - but we'll see.

It's a skytec starter, one of the light ones. Don't know if that is the same difference.Thanks, Again! I'll report back how it all turns out.

spiro · Post by **spiro** » Sat Aug 07, 2004 10:39 am

SkyTec is a permanent magnet motor. Problem is they don't freewheel when deenergized, and the starter adapter needs the starter to rotate backwards a few turns to unwind the spring and disengage. Niagara says *don't* use perm magnet starter motors.

I thought SkyTec stopped selling starters for big Continentals for this very reason. They've redesigned one that solves the problem but keep delaying the intro date - last I saw they were promisng Fall '04.

Unless something's changed with this "new style" adapter you may still want to call Niagara and SkyTec and make sure you're not going to repeat this adventure. Maybe even call the TCM rep - I think they're installing Lamars on factory remans now, so maybe there's a solution I'm unaware of. Then you can report back and tell us how dated my info is <g>.

- paul

C170Driver · Post by **C170Driver** » Wed Aug 11, 2004 5:23 am

Paul - you are right on. After talking to Niagra yesterday, I called SkyTec and low and behold - they don't list the C12ST1 any longer, only the C12ST3 which free-wheels allowing the spring to unwind. Shipping now but trouble meeting demand due to parts, but promised this week if supplier comes through.

Talk started out about how they usually charge $150 for the swap but seeing how we have less than 200 hours on this how about we just swap. Not a bad deal, though smacks slightly of hush-swapping. Biggest pain is the fact that the engine has to come off the mount to gain clearance for changing out the adapter. All that beautiful wring and control routing to be un-and-re-done. Ugh.

spiro · Post by **spiro** » Wed Aug 11, 2004 10:38 am

good deal! Got a free upgrade to a starter that won't eat your new adapter.

Post by **GAHorn** » Wed Aug 11, 2004 4:52 pm

spiro wrote:good deal! Got a free upgrade to a starter that won't eat your new adapter.

Or to put it another way: The manufacturer normally charges extra for products than don't inherently damage your engine...("Oh! You mean you don't care for metal grindings in your oil? That costs extra!")..but didn't charge you for correcting defective workmanship they normally charge others.

C170Driver · Post by **C170Driver** » Wed Aug 11, 2004 9:20 pm

I was going to wait to make that observation until the new unit was in hand!

C170Driver · Post by **C170Driver** » Fri Aug 20, 2004 12:43 am

Starter adapter is swapped out - actualy was fairly painless. We quickly elected to pull the four bolts from the firewall and disconnect various hoses and wires in order to move the engine away from the firewall. I am convinced this saved us hours, in the end.

With the engine on the hoist a few extra inches from the firewall - we were able to leave some stuff connected, and still reach in to argue the adapter off of the accessory case to which it was stuck with ample gasket gookumpucky.

Once off - we see that the collar that contains the spring was sticking out of the adapter what looked like more than it should - about an inch and a third; but still clear of the gear teeth on the end of the shaft that mesh with the crank gear. The new-style one we installed does not have the collar - so could not compare how it should look. No apparent damage or bright metal.

All else looked good (including the roller-bearing inside the case that carries the end of the shaft) so scraped off the old gasket and replaced same and adapter. UPS sez the new style starter is in town for delivery tomorrow.

Big diff. in adapters - old one you can spin the shaft that drives the crank either way with ease; new one you can only rotate the shaft one direction with any ease - very hard going in reverse.