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Ring gear and starter motor grinding noises
https://ausmini.com/forums/viewtopic.php?f=2&t=100426		 Page 1 of 1
Author:  rocky&bullwinkle [ Thu Oct 01, 2020 6:38 pm ]
Post subject:  Ring gear and starter motor grinding noises
G'day,
Just about ready to fire up Minnie after the motor rebuild and cranked it over for the first time (plugs out) to get oil pressure up. Everything brand new - new ring gear and new starter. Both items supplied by the same company and the supplier also fitted the ring gear onto the flywheel.

When I hit the starter button, the starter motor makes a horrible sound - a bit like the old 1954 Dodge truck did out on the farm. I turned the motor over by hand and I could hear and see that the starter motor was still engaged with the ring gear. The noise was a bit like grinding gears. I then pulled the starter motor off and the cog bit was fully engaged on the spline and wouldn't release back to the un engaged position without a gentle tap with a spanner. Once the cog is free it does spin up and down the shaft ok. The return spring seems a bit weak maybe. I've attached a picture of this.

To check if there was something wrong with the engine itself, I put in in 4th and rolled it back and forth - motor turned over and no noises from flywheel and ring gear. Stater motor was still out and plugs out.

I then put the starter motor back in and tried again. Same grinding noises. The starter motor does engage with the ring gear as the motor does turn over.

I'm trying to find out why it's making such a racket.

The motor is an 850, the new ring gear is part number 12G676 - 1/2 wide (>74) 107. The starter motor is a GXE4404 9 tooth. Is this the right combo?

I've removed the stater motor again and the cog is in the fully engaged position as previous and stuck there. There are some wear marks already on the starter motor cog although I've only cranked the engine over for perhaps 15 or 20 seconds all up. I've attached a picture to show the marks.

Any suggestions?
Author:  rocky&bullwinkle [ Thu Oct 01, 2020 7:31 pm ]
Post subject:  Re: Ring gear and starter motor matchup
A bit more info - I went out and counted the teeth on the ring gear and starter to make sure they're the right ones according to the invoices for parts. Seem ok.

Ring gear has 107 and starter has 9.
Author:  Karcraft [ Thu Oct 01, 2020 10:19 pm ]
Post subject:  Re: Ring gear and starter motor grinding noises
Ring gear on the right way ?
Author:  rocky&bullwinkle [ Fri Oct 02, 2020 8:10 am ]
Post subject:  Re: Ring gear and starter motor grinding noises
I would like to think so as a mini specialist did the job. I've attached a couple of pics as I don't know what it's supposed to be like.

Does this look right?
Author:  drmini in aust [ Fri Oct 02, 2020 8:14 am ]
Post subject:  Re: Ring gear and starter motor grinding noises
Yes it's the right way around.
Author:  rocky&bullwinkle [ Fri Oct 02, 2020 8:45 am ]
Post subject:  Re: Ring gear and starter motor grinding noises
Thanks Doc. I was starting to think the motor would need to come out again.

Any ideas on what's wrong?
Author:  rocky&bullwinkle [ Fri Oct 02, 2020 10:23 am ]
Post subject:  Re: Ring gear and starter motor grinding noises
Been trying to find out what's going on and have an update.

I rang the supplier of the starter and he said one of the checks I could do before sending the starter back to him was to power the starter out of the car to check the bendix was working ok. I did that and yes, the starter runs fine and the bendix slides in and out as it should. No rattling noises from the starter.

I've still got my old starter (it's well worn and auto elec suggested a new one instead of fixing it) but it still works. I bolted that in and the grinding noises have gone. There is a slight noise when the starter first engages but once it's spinning over, it sounds ok. The bendix on the old starter does disengage even though the motor hasn't fired. I checked this by moving the car while in gear. No rotation of the starter motor shaft.

I then re-fitted the new starter and the grinding noise is back. The bendix does not disengage and when I move the car while in gear, you can hear the grinding noises and see the end of the starter motor shaft turning. Therefore it's still engaged with the ring gear.

So everything points towards the starter but has it has the right 9 teeth, what's causing the problem? To the untrained eye, the gears look the same on the bendix and the dimensions of the old and new starters look the same. To me, it seems as though the teeth on the starter don't match the ones on the ring gear. But if that's the case, wouldn't every starter in that batch have the same issue?
Author:  drmini in aust [ Fri Oct 02, 2020 1:08 pm ]
Post subject:  Re: Ring gear and starter motor grinding noises
rocky&bullwinkle wrote:
Thanks Doc. I was starting to think the motor would need to come out again.

Any ideas on what's wrong?


That pic of the starter concerns me, unless you've jammed the bendix in that position it should always come back against the spring end when free.

If it needs lube, I would use powdered graphite. Anything wet collects dirt and dust.
Author:  rocky&bullwinkle [ Fri Oct 02, 2020 7:18 pm ]
Post subject:  Re: Ring gear and starter motor grinding noises
Hey Doc - it worried me too. But after an afternoons work, I think we've identified the problem.

First up, I was less than impressed with the suppliers response to my problem so I decided to try and track the cause. I took the starter down to my local auto elec to get his advice. He told me to measure the gears on the bendix to make sure they were identical to the original one. Even though both cogs were 9 tooth, the problem appeared to be that the new starter cog was not engaging fully into the ring gear. He said that he could easily change the whole bendix bit (spline and cog bit) from the old starter onto the new motor part.

After careful measurement of the 2 cogs, the new cog is not only slightly larger than the old one but the shape of the teeth is different. Not noticeable at first but once you start looking at them closely and measured the dimensions, they were not the same. So he swapped over the bits onto the new motor.

I've just finished fitting it up and it works as it should. No grinding noises. I do have a bit of a 'clunk' when the starter disengages (motor is still not running) and I'll get the auto elec to check it out tomorrow. I now have a probably 57 year bendix on a new motor. :D

As for the bendix getting jammed in that position, if I recall the auto elec's comments correctly, the bendix was actually travelling past the end of the spline and the circlip? inside the bendix was getting hung up over the end of the spline. There's no way it would ever get back into its correct position without a knock.

So the washup of this was that the bendix drive gears on the brand new starter were dodgy. I think the fact that there is a new ring gear as well meant the two were never going to work together. Perhaps an old ring gear would have been ok.

Disappointing to buy new stuff and find out it's rubbish. Wouldn't be so bad if the price was in line with the quality.

Cheers, Rocky
Author:  Bill B [ Fri Oct 02, 2020 9:15 pm ]
Post subject:  Re: Ring gear and starter motor grinding noises
You've had your share of issues on this rebuild. But it's worse when new parts are substandard but you assume they will be OK.
I have been told the new starter motors for minis are made in India. In itself that shouldn't be a problem but clearly it is in this case.
I bought a reconditioned starter motor from my local auto electrician who had it sitting on a shelf for many years, waiting for a customer to turn up.
Worth keeping your old bits and finding someone to overhaul them.
Author:  rocky&bullwinkle [ Sat Oct 03, 2020 8:26 am ]
Post subject:  Re: Ring gear and starter motor grinding noises
Yes I have had a few challenges with sub standard new parts that have made life a bit more interesting while working on Minnie :D :D

I spent the majority of my working life in the commercial / industrial gas business where things just had to be right. I also believe in buying quality parts and doing the job properly.
What's been disappointing in this case (apart from the attitude of the supplier) is that the items were supplied by one of Australia's largest mini specialists. At the time I bought one, Karcraft were out of stock so I purchased elsewhere. You'd like to think that a company that only sells stuff for minis would ensure the parts are fit for purpose.

Interestingly, I see that MinisPlus now mention that their starter motors are quality UK made ones. Hard to see what the cog is like in the picture but the connection for the battery lead looks way more substantial than the one I have does. Looks like the original one.

Hopefully I can get the clunk sorted out today and then I'll connect the coil, put the plugs in and fire it up for the first time.
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