Starter grinding noise caused by a broken housing.

[NutmegCT]

Just removed the noisy starter (see previous thread). Thank you Brosky for stopping by and making a diagnosis!

Take a look at what I pulled out:

Starter pieces removed.


The grinding noise was probably caused by the broken housing getting caught between the ring gear and the pinion gear.

Question: is there a possibility the starter doesn't match the engine? Would this have caused the break of the pinion shaft bearing end?

Pics and info are on the link. If the starter is correct I'd like to get it fixed (or replaced). But the ring gear looks pretty new for a 50 y/o engine. Is there a way to tell from the engine number and starter number if the match is correct?

How to tell what starter I should get - if the ring gear and starter don't "match" then undue pressure on the housing may have caused the break.

What to do ... what to do?

Tom

 

[DrEntropy]

Can't really tell about that ring gear, but it kinda looks decidedly UN-new. Very possibly a mis-match t'wixt ring gear and starter gear. To break the housing in the manner it has done would take a great deal of force. It appears the Bendix gear was riding too shallow on the ring and has "self-machined" the ring's teeth down to a point where it was only partially engaging... Can you get a better photo of the ring gear posted?

 

[NutmegCT]

Just added a slightly better pic of the ring gear.

T.

 

[Tinster]

Your ring gear looks a whole lot better
than my 69TR does.

Chalk mark the ring gear, pull your plugs and slowly
rotate the ring gear by using the fan blades. Inspect
all 360 degrees for damage, broken or missing teeth.

Try to post a close-up of the teeth after you inspect
for obvious damage. You might have "machined" off
some of the tips or edges.

d

 

[Twosheds]

Like the Doc says, hard to tell if the ring gear is correct from that photo.

My old TR3 racecar TS22312 had the old style "bullet-nose" starter like yours. When I tried to buy a gear reduction starter from Ted Schumacher, Ted would not sell me one until I looked at the ring gear to see if it was held onto the flywheel by screws or not. This is because some PO might have swapped the flywheel for the late style, causing a starter/ring gear mismatch. I found no screws, so Ted sold me the gear reduction starter that replaces the early starter.

So look at the ring gear with a flashlight and mirror whilst rotating the engine.

No screws = early

Screws = late.

Also look for abnormal or excessive wear.

And I'm writing this before Gin & Tonic time, so I'm pretty sure about the screws/no screws. But someone correct me in case I have it backwards.

Lycoming O-320s had the same problem, by the way!

 

[Twosheds]

Just added a slightly better pic of the ring gear.

T.

Looks chewed up to me.

It's G&T time!

 

[DrEntropy]

Still ~looks~ like the ramps have been knobbled down to a degree the starter gear would not engage but rather "ride" on the tops of the teeth. That'd snap the housing and bugger the starter motor.

 

[NutmegCT]

Ring gear - just found in the previous owner's maintenance records that in January 2006 the ring gear was replaced, the starter repaired, and the clutch release bearing replaced.

T.

 

[Brosky]

I can't tell from the angle, but it looks to me as though all of the teeth are beveled in in the same amount and I don't see a whole lot of metal in the bottom of the bell housing.

But, could the PO have removed all of the metal shavings prior to installing a possible incorrect starter?

Tom, have you called the PO to ask about this replacement?

It was my pleasure to stop by. Once I heard the noise, I knew that the drive was crashing and the starter had to come out. I'm just not sure if the wear is excessive on the teeth and I will defer to those with TR3 experience on that matter.

 

[MGTF1250Dave]

Aloha Tom,

The Bomb shell or Bullet type starter has the bendix engage the ring gear from the engine side. The later type starter has the bendix engage from the gearbox side. The later style starter (also used in the TR4) requires a different bell housing to accommodate the longer bendix. From the photos of your ring gear I would say you have the correct type starter. Tinster made a good suggestion to rotate the engine and examine the entire ring gear. From what I saw in the photos it looks good to me, but you are only looking at a small section. The bigger question is what fractured the cast iron nose piece. It may have been dropped in the past and a small crack over time resulted in it breaking off. These type starters have rubber filled sleeve assembly that separates the motor shaft from the pinion. In theory, this is to that up the shock on engagement between the motor/starter pinion and ring gear. I had the rubber fail on my starter most likely due to age. I would think that yours would have failed before cracking cast iron. In any case I'm sure the starter can be rebuilt as long as parts can be found.

 

[martx-5]

My experience with broken noses on starters is usually the result of a backfire while cranking.

The pics of that ring gear aren't very encouraging. The front of the teeth look flattened out, when there should be a chamfer there. The bullet nose TR3 starter engages fron the front, rather then the rear of the post TS50,000 cars.

 

[DrEntropy]

Ring gear teeth should have a machined ramp on 'em and come to a definite point. Those (tho I again say: hard to "see" in the photo)seem to have been blunted kinda badly. I hope it's just a bad angle in the shots.

 

[DrEntropy]

I dragged the photo into PhotoShop but the resolution is too coarse to really get a good vidi of the teeth... A mirror held to reflect the other edge of the teeth could be of some benefit.

 

[Brosky]

I may have to try to stop again on Thursday when I'm in CT.

Harry, where are you???

 

[DrEntropy]

You do have a point about the LACK of "sparkly stuff" in the bell-housing, Paul. I'm hopin' it's just a wonky catchlight off the teeth causin' me to mis-read the photos.

 

[NutmegCT]

ring gear closeup

ring gear teeth closeup

ring gear teeth closeup 1600:1200

Taken at 1600:1200, but website may be reducing it.

T.

 

[DrEntropy]

Re: ring gear closeup

MUCH improved!!! I can see some "funnies" at the peak of the teeth but NOTHING to run screaming from. WHEW!!! Looks completely servicable on that section, Tom.

Do the chalk mark and rotate it thru 360° and eyeball it all the way 'round. If it looks the same as the section you photo'd, the starter gear ratio is gonna be the suspect in this mystery case.

 

[NutmegCT]

Re: ring gear closeup

I'll rotate the wheel tomorrow after my dental appointment ...

This advice is priceless guys - thank you very much! If the wheel is decent and I know whether there are screws or not, I guess the next step is to figure out which starter I need.

Tom

 

[DrEntropy]

Re: ring gear closeup

Prezactly. Once that's discerned I suspect your starter problem will be a memory.

 

[Brosky]

Re: ring gear closeup

Doctor & Tom, I think that the amount of metal in the housing is now from the starter drive gear chewing it's case apart. But there seems to be a small amount of wear on the flywheel teeth, probably caused by all of the broken parts in there.

Tom, as Dale & the good Doctor have suggested, mark the FW with chalk and do a 360 inspection, looking closely at the teeth AND the ring gear itself, to insure that there are no cracks in the actual ring. You will then determine how it is attached as well.

Good luck...