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Starter grinding noise caused by a broken housing.

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Re: ring gear closeup

Aloha Tom,

As the DrEntropy noted there are some dings on the ring gear teeth. I would guess the sparkling bits in some of the photos are flakes of cast iron from the broken nose piece. Abraded off as it rattle around in there. This also is probably what blunted the points on the ring gear. I concur with the Dr., the damaged shown is not fatal, but the rest should be checked to make sure some other sector is worse. A bad section of ring gear could tear up a replacement starter pinion.
 
Re: ring gear closeup

After looking at a high-res image I'm convinced the starter gear ratio is WRONG. Some of the teeth onna ring gear are impacted DEAD-CENTER by the Bendix gear: Like someone hit 'em with a center punch. Check the ring gear well for cracks or areas looking more worn than you show in the photos. If it's no worse the rest of the way around it, and you get the proper starter for the gear it'll be FINE!
 
Re: ring gear closeup

This is interesting - from the Moss TR2-4 catalog:

"The starter mounting shim, #549-430, is used to adjust the position of the starter pinion relative to the ring gear. With early starters, adding a shim brings the pinion further away from the ring gear, decreasing mesh. With late starters, adding a shim brings the pinion closer to the ring gear, increasing mesh. It seems that most cars were originally fitted with one shim which generally got lost or forgotten when the starter was replaced."

Moss separates early from late starter at TS50001.

Tomorrow I'll pull the plugs and do a 360 turn inspection of the flywheel to check all teeth and check if there are screws on the wheel.

I'm starting to wonder if the January 2006 flywheel replacement may have been with the *later* flywheel, but the starter was the *early* starter (or vice versa?). And thus, for just over a year the teeth have been merrily grinding away.

Tom
 
Re: ring gear closeup

<div class="ubbcode-block"><div class="ubbcode-header">Quote:]I'm starting to wonder if the January 2006 flywheel replacement may have been with the *later* flywheel, but the starter was the *early* starter (or vice versa?). And thus, for just over a year the teeth have been merrily grinding away. [/QUOTE]

Tom, you are probably correct on both counts. I'd also get several shims, "just in case."
 
Re: ring gear closeup

Tom, I have the original bullet nose starter from the race car out in the laboratory. The front bushing is gone, but the part that is broken on yours is good on mine. If you want to buy it, let me know.

Of course, you may want to go with a late starter even though it's not correct if you find that you have the late flywheel and want to keep it, and late tranny, as MGTF points out. It's easier to change starters than flywheels!
 
Re: ring gear closeup

Only problem with switching to a "late" starter is that, unless you also happen to have a later 3A or 4 type of gearbox, the starter won't fit inside the bellhousing unless you punch a hole on the backside to clear the Bendix. I seem to remember that this was actually written up in an old edition of the TSOA Handbook or maybe a TSOA Newsletter issue.
 
Re: ring gear closeup

Andrew Mace said:
Only problem with switching to a "late" starter is that, unless you also happen to have a later 3A or 4 type of gearbox, the starter won't fit inside the bellhousing unless you punch a hole on the backside to clear the Bendix. I seem to remember that this was actually written up in an old edition of the TSOA Handbook or maybe a TSOA Newsletter issue.
Click to expand...

That's why I wrote "and late tranny"!
 
Tom,
I'm a long way from my TR3A (TS44864LO) but your starter is the correct type. When the starter spins, the inertia of the pinion should make it jump forward into the ring gear. There is a lock-ring and cover at the end of the shaft that I can see in your photo. I wonder if it is supposed to keep the pinion from smacking the cast-iron shroud?

I don't know if repeated impacts from the pinion would be enough to crack it, but cast iron will sure break if you drop it. Would a too-thick washer at the commutator end move the shaft lock-ring and cover close enough to bind on the cast iron part when it's tightened down? Fit the broken piece back and see if it has clearance from the ring & cover.

I made one good early starter from two once, and one of them had a broken nose just like yours. I never thought about how it got that way though.

Jeff
Honolulu, HI
TR6 CF13816U
 
Here's what I've learned from the previous owner:

"Originally [about 3 years ago] it was too weak to throw the starter
gear far enough to the flywheel, and supposedly was part of the reason
for the [original] ring gear's demise. The starter was supposedly rebuilt but I
suspect they only turned it and put in new brushes. I started having
the same problems as before and they put in a new ring gear and then
welded some part of the starter mechanism so it wouldn't slip. It
worked great but I didn't like the fix. I know of no reason for the ring
gear wear-- no funny noises or clashing occurred that I could tell since
the last repair/replacement.

In retrospect I (and now you) might have been better off just replacing
the starter. Folks on the forum said the old ones were pretty sturdy
but I don't know if the "rebuild" or repair were ever right. "

I'm off to turn the flywheel the full 360 now. I am *really* glad the previous owner kept the maintenance records.



Tom
 
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