Awful noise when starting

[TCipolla]

I know there was a thread a while back about squeaking noises when starting the engine. I've been having this noise for a while now and have just dealt with it, until I started having trouble starting it up. I referenced what some suggested in the old thread, and I ended up replacing the starter shaft, coupler, all starter shaft bearings, clutch bell bearing, and put a new clutch on. Well, after all that, she still sounds like she's going to explode on startup. I pulled the glow plug out and ran my starter on it and it was smooth as silk, but when I replaced the plug, the noise was back. I'm at a loss. It's late so I haven't actually put fuel through it to start it, I was just dry motoring. Any suggestions?

[Phillips0417]

Ahh, the good 'ol Raptor squeal. Typically this is caused by the one way bearing in your clutch. I would replace the clutch or bearing if you have the capability and like to be hands on. Replacing the entire clutch would minimize downtime. I think that's definitely where your problem lies though. I've experienced this many, many times.

[TCipolla]

Well, I probably should have just gone the easy route and only replaced the clutch, but I went all out and replaced the starter shaft too. Got everything replaced, took her to the field and got about 2 minutes of flight and heard the most awful noise. She started to lose power (engine running fine) so I autoed her in. Found the main gear with no teeth on it. Chewed all to hell. Ordered the gear, disassembled everything again and now I find my pinion gear to be bent. How that happened I have no idea. UGH.

[djaypro]

Pinion bent You might want to check your fan nut Sometimes they back off. Could be putting stress on your clutch.

[TCipolla]

I'll check that too. Pinion wasn't bent, just worn out. Put the new pinion in the clutch bell assembly and it's smooth as silk. Where the support bearing sat was worn on the pinion allowing some slop.