Starter Ring Gear Question

[aboard_epsilon]

As you can see in this picture

the starter ring gear of my car is worn

compare the teeth in the top of the picture to the lower.

now ..i don't feel like doing the job .......and im hoping that i can put it off for a while ..maybe next year ..or 6000 miles.

every now and again the starter whizzes around (turns fast) and does not engage .......problem is sorted by slamming the car door.......been doing this for two years ......the problem does not seem to be getting worse .



well the flywheel is getting worse .......but its a horrendous job ..drive shafts gearbox out ..right pain..
the question is .......

i have a plentyfull supply of what is called "dry moly paste"

not any old stuff ...this stuff is £180 for 700ml...rocal ...i got it real cheap though.

why its called dry ..i dont know because its a wet feeling paste.

anyway .......will putting this stuff liberally on the ring gear..sort of just gently wiping with a paint brush ..sort of thing ..will it help to give me a bit more time..helping it engage without spinning .......i will file the teeth ..take away any burrs first ..

the flywheel stops in the same place's ..thats half the problem..hense the wear accelerates in those places

[MotorradMike]

Looks to me as though the starter isn't getting it's pinion gear all the way out before it starts spinning.
If that's the case and you get it working properly, you might be OK for a good long while.
If the ring gear is also part of the clutch, you need to be careful about putting lube in there.

[MrSleepy]

Once you've cleaned up the ring...is there any room to move the solenoid main contacts back slightly...so you get a delayed drive after engagement.
We used to have a kubota powered ride on mower that did the same and I cured it by adding spacers into the solenoid.

Rob

[aboard_epsilon]

I'm not going to plaster the stuff on .......and by its very nature centrifugal action spins any crap off it..towards the edges .

i have taken the starter motor apart .,..cleaned and lubed the bearings front and rear .

all the best.markj

[aboard_epsilon]

Once you've cleaned up the ring...is there any room to move the solenoid main contacts back slightly...so you get a delayed drive after engagement.
We used to have a kubota powered ride on mower that did the same and I cured it by adding spacers into the solenoid.

Rob

don't know

i will take the starter apart again ..and have a look.

i want to put some of this dry moly on the spiral Bendix thingy ..

here's a picture from five years ago ..when i took it apart ..

[duckman]

The high lead helix on the starter shaft needs to be clean and dry if its not the Bendix won't spin out and engage the ring gear, and it will spin and destroy the teeth on the ring gear. There are different types of starters some use a solenoid to drive the Bendix out before starting the starter motor, others just use the inertia of the Bendix to spin it out when the motor starts to spin.

[Void]

There are two things going on here (in reverse order):

The real determination of how long you can get by is whether and when the problem will aggravate itself to the point where you are stranded. The "whether" is a done deal. It will get worse and it won't fix itself.

So the problem is "when?" Almost as sure as the sun rises it will happen at the most inconvenient time imaginable.

1. The ring gear is obviously worn. Some significant fraction of the time a car engine crankshaft stops rotating at the same position. That position is likely where the damaged part lines up with the starter motor pinion. The reason for this is the pinion engagement to the ring gear has been a problem for a while and created the worn spot on the flywheel over time. Once the pinion "catches" (engages) with the flywheel it is driven by the torque in to further engagement. If it doesn't engage right away it acts like a milling cutter and buzzes off the teeth of the ring in that area.

2. I suspect the starter, specifically the Bendix, is the real culprit in that it caused the problem to begin with. Unfortunately a relatively inexpensive part (especially labor wise) causes a much more expensive part to fail.

The least expensive way to just get by for now would be to fix what is wrong with the starter. You are going to have to fix it anyway because even if you were to replace the ring gear and used your existing starter it could cause the problem all over again. All it takes is a few buzzes with faulty starter engagement to remove enough metal and make your new ring gear look pretty much like the one you have now.

My advice is to fix both now.
If you can't afford the cost in dollars or anguish of fixing both now then at least fix the starter now. If everything else is mechanically and electrically perfect on the starter then the just replace the sticking Bendix. Also if you are going to use your existing starter be sure to check the bushing in the nose of the starter housing and the shaft diameter for excessive wear and clearance.

-DU-

[aboard_epsilon]

I CANT SEE ANYTHING WRONG WITH THE STARTER ..
As far as i can make out ..it only has to fail to engage once ..then it causes burrs ..and its downhill from there on.

anyway will have another look at it today ..

all the best.markj

[strokersix]

You can drive the ring gear off the flywheel and turn it around for a low buck solution. It's an interference fit.

Agree that the starter mechanicals need to be in good shape or new ring gear teeth won't last long.

Of course, by the time you get that far into it you may decide put some new parts in......

[MrSleepy]

There is no Bendix on Marks starter (of the true Helical drive type).

It uses a solenoid to lever/pull the sprag clutch forward into mesh.
When pulled forward enough..contacts on the back of the solenoid allow current through to the armature.

The wear pattern on the pinion will tell how far the pinion is being levered forward by the solenoid (and wether its going far enough).

Rob