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MG Midget and Sprite Technical Starter Motor vs Ring Gear BBS discussion at MG-Cars.net
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MG Midget and Sprite Technical - Starter Motor vs Ring Gear
| Hello Folks: It seems that when I turn the ignition key to the “start” position, the starter engages and off we go…but when I release the key and it returns to the “run” position – you can hear a metallic crunch noise which is most likely the pinion spinning it’s way out of the ring gear. The return movement seems to generating some noise. Almost as if I turned the key a second time when the engine is running... My question is: does this sound like a tired & worn ignition switch whereby the key “slowly” returns to the “run” position which is re-energizing the starter motor OR is it more likely that the pinion drive gear is simply hanging up on its return trip back into the starter motor and the now fast spinning ring gear is battling with the starter drive? Plan "A" - I am contemplating a spritz of the ignition key internals with some graphite lube of some type since I really don’t want to remove the plastic steering cover surround with those mysterious Phillips screws that I can never see. Plan “B” might be a replacement with a new hi-torque starter motor – but those units seem to be rising in price lately. Anyone have any luck with the more modern starters? Also, is the long term downside further damage to the ring gear? Can I defer any solution for a while – possibly until the end of the summer driving season? I did a ring gear replacement on my previous midget way back in the 1980s and it was NOT a lot of fun... Any suggestions would be appreciated… Thanks Mike P. Buffalo, NY |
| Mike Pelone |
| I wouldn't bother with plan A because the electrics are either on or off. There shouldn't be any "slow" disengagement. I don't think it's an electrical problem but a mechanical one. You may have a weak spring in the Bendix gear which causes your slow disengaging and therefore making the unwanted noise. Or it may just be dirty. You could try pulling the starter and cleaning the Bendix mechanism. It should move freely when you "engage" it by hand and let it go. If it is a bit slow, clean it but don't oil it. Oil collects grit and other nasties which would make the problem come back. If you want you could put the graphite lube there but I wouldn't. And yes, if you let it go for too long, you will have to replace the ring gear and the Bendix gear also. I'm sure you'll get some more better educated opinions soon. |
| Martin Washington |
| As Martin says, it doesn't sound like the switch. |
| Dave O'Neill 2 |
| Martin & Dave - thanks for the suggestions... I have previously searched the BBS archives and have found several posts about cleaning the bendix BUT don't lubricate it suggestions... By chance, my accelerator cable also broke last week - so I will be able to pull the starter since the vehicle is going nowhere for a few more days... Any thoughts on those hi-torque replacement starters? The car has always been an easy start with the choke - so I don't see the need to spin the cylinders any faster with a $200 starter... Mike |
| Mike Pelone |
| I don't know about high torque starters since I use the standard but as far as the throttle cable goes, I'd go to my local bicycle shop and get a brake cable and housing and make my own. Cost should be about the same as from Moss but without the shipping. You can cut it to any length you need, the housing is Teflon coated has on the inside (the Moss one is coated with a polymer (polyoxymethylene)) and the brake cable has two different ends (one of which you normally cut off) which gives you a choice as to which end works best for your car. And it's cheaper than an "original" one. Plus being a brake cable, you know that it is going to be strong. I did that to my Frogeye about 10 years ago and haven't had any problems. |
| Martin Washington |
| Mike Try setting up a test light on your starter solenoid on the small terminal that excites the solenoid By doing this you will be able to check if the ign. switch is operating properly or giving an extra little spike/feed Also, Martin's idea of the p/bike brake cable is a goer I've had one on our Lotus from way back past where I can remember - also trouble free The Shimano Durace cable is a better/finer cable than the normal Shimano and would be a good choice willy |
| William Revit |
| Mike, Have you checked the two starter mounting bolts? It may simply be that they have worked a bit loose, so that when the starter disengages from the ring gear it kicks the starter out of alignment and makes the extra graunch noise. |
| Guy W |
| Mike, I fitted a Powerlite starter to my newly built replacement 1360 motor. www.powerlite-units.com It is very effective in turning over a tight, high compression engine, especially straight after the build, whilst I was guessing at fueling and ignition settings along with building up oil pressure (which topped out at full scale on the gauge). It would continue to churn the motor over briskly, for quite long bursts, with no wilting. It didn't flatten the quite old battery either, so I think the lower power consumption claims are probably justified. Buying the starter was influenced by the existing unit being tired. It would regularly refuse to engage with the ring gear. That was partly down to worn bendix and ring gear teeth though. The new build included a new MED flywheel, so I didn't want to run old starter teeth on it. The powerlite was quite expensive, but I bought it at a show and got a discount. It was a direct replacement for the standard unit. The nose orientation is adjustable, so it will fit R/H and L/H layouts at different angles. There is a an on-board relay, so it is possible to remove the existing solenoid and wire direct from the key to the starter. I've left the existing solenoid in situ for the moment. Its a handy point for distributing power to other circuits. The starter is supplied configured to just accept the existing high current supply cable. On balance I think I made a good choice for my shiney new engine. I expect further benefits in cold weather. If I had a starter problem on an existing standard-ish engine, it's probably overkill. I think I'd just remove the starter and give it a clean as suggested, with new brushes and bendix if required. Sorry for the wordy response, and bear in mind I'm not as expert as most on here. Regards, Mark |
| M Crossley |
| O.K. - here is an update... Just removed the distributor and starter to get access to the two mounting bolts... Removed and cleaned up the starter and used kerosene to clean off the drive portion of the unit. Nice and shiney - BUT, when I use my fingers to spin the pinion drive up and down, it seems that the return spring is barely able to slide the pinion drive back into the neutral or "rest" position. And when I invert the unit, the return spring can't over come gravity at all and the pinion and barrel returns only part way. The "restraining" spring - item 16 in the attached photo - seems v-e-r-y weak and Moss USA only offers the complete pinion & barrel assembly for about $40 or so. My question is: has anyone had their starter apart lately? Is the restraining spring supped to "snap" the pinion & barrel back quickly? Is it likely that the original spring is partially broken? The hi-torque starter replacement option is starting to look better & better... PS: there are 9 teeth on the pinion drive Any thoughts or advice appreciated Mike P. Buffalo, NY  |
| Mike Pelone |
| Mike. FWIW.... My understanding is that the spring is there to assist the bendix gear to initially disengage from the ring gear.Basically to "flick" it loose as the the load comes off it. I think the idea is that once disengaged the sudden deceleration of the starter motor causes the bendix gear to whizz back to it's rest position under the rotary inertia of the gear itself. In other words the spring shouldn't need to do much work - as the starter comes to a stop the bendix gear "wants" to keep going and the only place it can go is back along the coarse thread to it's rest position. My suggestion is that you thoroughly clean and degrease the mechanism and lubricate it but NOT with oil of any sort. I would try PTFE spray lube or dry graphite. Oil will stick cack onto the screw like the dust from the clutch for example and eventually cause it to stick again. No doubt someone wiser than me will be along directly, but for now that's the approach I would take. BTW Martin is spot-on about the throttle cable. Get yourself a teflon lined kit and make your own. I like the Venhill kit. It's 100x better than the original and cheaper besides. I've learned this the hard way! |
| RS Hughes |
| RS Hughes: I let the unit dry out for a few hours in the garage - and did another "test spin" with my hand. There appears to be very little "flick back" than before. I also chucked the starter in my garage vise - then clipped my battery charger terminals to the starter body (negative) and put the positive clamp to the back terminal - and promptly blew the breaker on the charger unit. Very strange - I was expecting the bendix to spin up then retreat to the "rest" position. Bottom Line? I have more doubts about the starter unit than before I took it out.. USA supplier on the East Coast has hi-torque units available for less than $200 including free shipping. I am going to think about that option for another day or so...the Summer driving season out this way is short and not tolerant of parts and repair issues... Mike |
| Mike Pelone |
| Hey Mike. Sorry to hear you popped the breaker. Actually no - I'm not sorry. The breaker did it's job and hopefully saved your charger. Can you repeat the test using a battery and jumper cables? Your charger, unless it's a monstrous great big bugger, is unlikely to be capable of spinning up even an unloaded starter. The current demand is pretty high. But a good battery should be able to supply it ok. I have a used-but-good spare starter here that I was given for free. It's for a 1500 - I have no idea if it would fit your car. You might have an A series for all I know and I don't know off the top of my head if it's compatible. However if you need it you can have it for the cost of shipping, but I don't know what that would be. Hopefully less than $200 tho! You could very well be right to suspect the spring but I just tried the one in The Shed by hand and it's not very strong, although I know it works. With luck someone clever will be along soon. Anybody........? |
| RS Hughes |
| R.S. Hughes: Good point about my battery charger effort! Right now, the vehicle's battery is fully charged. After dinner, I will find my longest set of jumper cables and give it a go. I just want to get a bird's eye view of the pinion drive "action" and see how well the spring moves the pinion drive back to it's "rest" position, if at all... Also, I appreciate the offer of the used starter - over here, the eBay site has a very limited number of used items in very dubious condition. Plus, I am somewhat leery of purchasing a "remanufactured" unit for more than $125 bucks or more... The replacement $50 drive pinion subassembly from Moss USA might now be a good plan "B" - I just need to fabricate a mini spring compressor with some flat metal stock and a few bolts. I was hoping this would not turn in a "project"... More on the jumper cable test this evening Mike |
| Mike Pelone |
| AFAIK the spring is more to keep the pinion in position, rather than get it there. When the engine fires and the starter is released, the flywheel turning should 'fire' the pinion back down the shaft. |
| Dave O'Neill 2 |
| Good luck Mate. The spring only needs to move the bendix gear half an inch or so. After that Isaac Newton is your friend! The offer is good if you need it. Have a good dinner - I did! BR; Rod |
| RS Hughes |
| Dave O'Niell - I hope didn't step on your toes. My point was that I doubted that Mike's spring was the root of his trouble. I liked Guy's post about the mounting bolts :-) I've been there.... There was a recent thread about this problem but there was no "closeout" post about how it was resolved. Please gentlemen it would be great in general if people posted resolutions as readily as questions. That would be a huge bump in the learning curve. Just a thought...... Night night. Rod. |
| RS Hughes |
| O.K. - just back from another "field test" using my heavy duty jumper cables. Unit spins nicely and sounds good...however, when mounted in the bench vise which is in the same horizontal plane as it would be when bolted to the engine back plate - the drive gear moved back about 1/4 to 1/2 inch when jumper cables were removed. The drive gear never returned to what I have called the "rest" position. Should it go all the way back with a noticeable "snap" - sure seems to react as if the return spring is either weak or broken. If I was a piece of metal - I know I would not want to be that close to any ring gear... Also, it would seem to me that if the total length of travel from the ring gear to the opposite end of the shaft is about 3 inches - that the drive gear should move all of the way back. After all, the fly wheel ring gear is spinning very fast and I would assume that the drive pinion was designed to move all the way and hide out until the ignition key makes the starter wake up and get to work again... The unit is clean, dry and NOT lubricated. I am wondering if $200 is a reasonable price to pay for replacing a 43 year old Lucas unit with a hi-torque starter... Mike P. |
| Mike Pelone |
| Hmmm... That's interesting Mike. AFAIK the pinion gear ought to return to it's off-duty position in a fairly lively manner, but also AFAIK it's not the job of the spring to make that happen. Or not entirely anyway. When the starter is powered up it's the inertia of the assembly that causes it to fly out to the end of the shaft and engage the ring gear and I thought it was similarly the inertia of the assembly that should cause it to retreat. When the starter is de-energised it should decelerate very sharply and there should be considerable stored energy to move the pinion back where it came from. Which leads me to wonder if the assembly is as free to move as it should be. Have you tried a good dose of lube? If you have any PTFE lube I'd give it a go. It's what I use most of the time (in preference to WD40 for example) because it doesn't leave any sticky residues. (Although WD40 is still unbeatable for removing sticky labels and the mess they leave behind, but I digress...). When I get the chance later on today I'll repeat your jumper cable experiment on my spare starter, in the name of science. I'll let you know what happens. BTW I personally think $200 all in for the hi-torque starter is reasonable and $40 for the new bendix gear assembly is also not bad IMO. Never a dull moment, eh! |
| RS Hughes |
| Hi again Mike. I tried the jumper cable test just now on my spare starter. The bendix gear assembly doesn't snap back to it's rest position, but it returns fairly quickly all the way as the motor decelerates. However, like yours there wasn't inertial energy to return it when I "flipped" it into the working position by hand. Everything looked clean and shiny, but I gave it a skoosh with PTFE spray anyway. After that it did return all the way when flipped by hand, so I repeated the jumper cable trick and it returned a little quicker, but still without a snap. Here's my motor - is it the same as yours? |
| RS Hughes |
This time with the photo. I had a digital interface problem. (Finger trouble haha)!
 |
| RS Hughes |
| RS Hughes: Thanks for the parallel field test results... Yes, your unit appears to be the "clone" of the one on my work bench. I realize this is a sample size of TWO - but it seems like your review of the bendix drive movement is similar to mine. Later today, I will find some PTFE spray (or equivalent) and see how much the return sliding motion is improved. However, the underlying issue is still the age of the stater and general condition of the brushes and other internals, etc. Unfortunately, I don't have X-Ray vision, so I will have to make a best guess later in the week - I really don't want to put that stater back in, only to take it out in another few months... I find it more (and more...) difficult to get under the car and work on my back as the years (and miles) roll by.. Mike P. Buffalo, NY |
| Mike Pelone |
| Reference my Ashley track car. The bendix on my hi torque starter parted company from the shaft and then left the bell housing at high speed! A couple of race preparation companies I contacted said they had also experienced problems with hi torque units so they reverted to a standard starter and treated them as a consumable item during the winter engine refresh process. On this basis, I fitted a new Bosch [made in India] unit when the new gearbox was fitted. It has been fine starting the 120bhp 1380cc engine even when hot. HTH |
| Doug Plumb |
| Doug: Was your reference to the Bosch unit (foreign made) in your comment above based on the original Lucas "style" with the elongated shaft or to the more modern gear reduction starter design which is more compact (and lighter weight) unit? I have found and Old School rebuilder in my city that will give me an assessment of my current 43 year old starter. My preference is keep the car original with the 9 teeth drive gear versus a "generic" gear reduction design. Mike |
| Mike Pelone |
| Mike, The unit I referred to is a Lucas OEM type. On looking closer at the label, I now think the importer is a Bosch company, not the manufacturer [but possibly made to a Bosch specification].  |
| Doug Plumb |
A photo showing the damage caused by the flying bendix
 |
| Doug Plumb |
Good Grief - that would take nasty bite out of anyone standing close by... I just completed another "flush" of the drive pinion assembly with brake cleaner followed by a large(r) dose of dry lubricant. The return movement is now very smooth and the drive gear drops all the way back to the "rest" position. I also noticed that the two machine bolts that connect the front and rear aluminum covers were loose and took about a full turn to tighten up. I doubt that would have created much of an elliptical orbit of the starter shaft. There is definitely some minor play in the starter motor shaft after all these years - but nothing that really scares me at this point. I was very surprised to see the improvement after using the dry lubricant product. Later tonight, I am going to try and get the starter back in, then install the distributor tomorrow. Hopefully, no change in ignition timing. Your story about the failure of your gear reduction starter made me re-think how reliable modern light weight starters may (or may not...) be. Mike |
| Mike Pelone |
| Hello Mike, Even money says that, when you get it back on, you will find that you have fixed it. Charley |
| C R Huff |
| That would be my bet too Charley :-) Good luck Mike! Now - about that throttle cable........ Haha |
| RS Hughes |
| An added comment on the return spring. It really is there to get the gear started on its trip back to its normal resting position (as mentioned above). If it were any stronger the gear would have a hard time engaging. Good to hear that it's all working smoothly. |
| Martin Washington |
| Thanks for the endorsement Martin. It's only a light spring for the reason you say. Mike I think you're onto something with the slack machine screws allowing elliptical motion. It wouldn't happen under load, but as the load comes off the gear (especially it the gear doesn't disengage fast enough) any elliptical freedom (and it wouldn't take much) in the gear's orbit could very easily be the cause of the symptom you described in your first post. I can see in my mind's eye the decelerating gear bouncing back and forth along part of an ellipse against the accelerating ring gear. Good catch! I agree the worldwide sample of two motors is statistically unsound. Not good science! I trust all is well now and you can take the Midget out and wring it's neck, as the Maker intended :-) |
| RS Hughes |
| Just a short note to close out this thread. Dry lube spray DID make a big change in the sliding friction issue and expedited the return action of the drive pinion gear back to the neutral position. It remains to be seen how long the dry lube spray will do its job. The protection provided by the bell housing should also help. Bottom Line? No metallic “grinding” noise heard. Also, I did spritz the ignition switch in the steering column. The key action also seems smoother – but that could just be me. The ongoing issue with owning these cars is the relentless March of Time. The car is old, most owners are old(er) and maintenance is further complicated by the long term trend of poor quality parts, etc. Sounds bleak I know – but when I get into that car, put the top down and drive helter skelter down the back roads of Upstate New York, it all seems worthwhile… Thanks for the encouragement and insights into the solution... Mike “On The Road Again”... |
| Mike Pelone |
This thread was discussed between 27/05/2015 and 02/06/2015
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