The Stovebolt Site Forums The Shop Area Engine Shop Starter grind with new starter

I'm in the process of replacing the 6-volt starter and am having a grinding issue I'm hoping someone can help me out with. The old starter was getting worse at not engaging at all. As in no sound or action out of the starter. Replaced it with a rebuilt and it engaged and cranked the engine on the first 2 attempts. Been sitting a while so not unusual for the engine to actually start. Attempts 3-5 just caused grinding with starter and ring gear. Ideas?

Dennis

Not sure if that helps, but on my 41 I have to floor the starter really fast - otherwise it grinds.
I recon it starts spinning before it is in the right position - so hammering it in really helps. Not a long term solution though.

Maybe the point where ist starts spinning can be adjusted. Haven't looked into it yet, but it is on my bucket list.

Frank

It didn't grind before but I suppose the linkage could be wrong for this starter. Is there a procedure to adjust it?

Dennis

I don't see any adjustments if your starter looks like the picture (1941 Shop Manual).
http://chevy.oldcarmanualproject.com/shop/1941/41csm272.htm
You may have linkage wear issues.
Poor meshing can cause damage to your flywheel ring gear (time-consuming and costly repair).

Since it was grinding before the new starter was installed, I agree with bouymaker, your linkage may be warn. Another possibility is your flywheel. Drop the clutch inspection cover and check out the teeth. Hopefully it the former than the later. Good Luck!

Yep, I'll drop the inspection cover and take a look. It did NOT grind with the old starter. Well, let's say very seldom did it grind.

Dennis

Do you still have the old starter? Make sure the you have the right number of teeth on the starter gear.

Disconnect a battery cable, drop the flywheel cover, and observe how the starter gear engages the flywheel when a helper pushes the start pedal. The most common cause of grinding is worn pivot points in the linkage that allows the armature to begin spinning before the starter gear engages the flywheel. It's also possible you've gotten a 12 volt starter instead of the 6V you need. Both starters have the same number of gear teeth, but the diameter and pitch is different due to a different number of flywheel teeth. A 12V starter has a smaller diameter shaft, and the pinion gear turns slightly as it engages the flywheel. A 6V starter has a bigger shaft, and the pinion gear moves straight to engage the flywheel.
Jerry

Right # of teeth. Same diameter shaft as my old starter, around .558" according to my $10 caliper. Pinion goes straight, no rotation. Bench testing with ohm meter between battery lug and case shows it does not connect until the pinion gear is fully extended (within 1/16" maybe).
After removing the inspection cover I can see it fully engage MOST of the time. Sometimes it does not engage and grinds. Try again and it may engage or grind. This has me baffled since my bench test would say it would not engage. Lunch break!

Dennis

I suspect that you have a defective starter drive. We used to change them routinely, instead of swapping the whole starter, but we also did a lot of in-house starter rebuilding. Did you source the rebuilt unit from a local supplier, or one online? If it's not too big a hassle, you might want to return the starter and try another one. If not, places like Rock Auto still have replacement drive units available, I believe. Good luck!
Jerry

Got it from Classic Parts of America. I tested again with key off. Engaged 20 times in a row. Key on, grind of 3rd but OK for another 19 until grind. At this point I marked the flywheel at about 5 1/2" from where the pinion engages. Rotated the flywheel so I could see the teeth that the pinion was trying to engage. Yep, worn some. Maybe if I dressed the a bit I'd be OK? Would this be as likely as bad starter drive?

Dennis

Possibly a worn flywheel ring. Can be flipped over but requires pulling the transmission,clutch, bellhousing and flywheel. Maybe someone has a better solution.

A flywheel will stop in one of three positions most of the time- - - -when one of three pairs of cylinders reach the compression stroke as it coasts to a stop. You will usually find three areas of more wear equally spaced around the flywheel. The fix is to either replace the ring gear, flip it over so the unworn side of the teeth face the starter, or just find a better condition flywheel. All those fixes involve removing the trans and flywheel, but it's a lot better to fix things right the first time. Good luck!
Jerry

So if you position it right at where it is worn and it grinds there every time, I think you would have your answer.

I think you are right. What I don't understand is how does the starter start turning before the pinion is extended into the ring gear. Bench testing showed no electrical contact until the button is almost fully depressed at which time the pinion is fully extended. I'll look at that more tomorrow and this time restrict the pinion from fully extending.

Dennis

Not sure if that would work, but looking at that drawing - I think notching out the part of the lever, that pushes at the "button" would make it start spinning a bit later.
Also taking any slack out of the linkage by fabricating some bushings would sure help.

Both should be an rather easy fix.

There's some pretty complex geometry involved in making the foot start system work properly. A tiny bit of wear or slack at several pivot points, plus a little wear on the flywheel ring gear can combine to cause the problem at hand here. There's no quick fix, and no way to adjust anything. Tackle the whole problem one step at a time instead of looking for the "easy" button! The engineers did a lot to solve the grinding problem by making the 12 volt starter drive rotate slightly as the starter gear engages the flywheel, but there's no way to make that happen on a 6V setup. If the pinion jams against a flywheel tooth instead of engaging smoothly, and there's enough slack in the linkage to let the motor start spinning- - - - -GRIND!
Jerry

Modifying anything can make the situation worse. Rebuilding or restoring back to original is the best solution.

The teeth of the ring gear and drive gear may not be in perfect initial alignment as the starter is engaged (neither are synchronized with each other). In the picture I see a slight taper and rounding for the drive gear. If the drive gear is also spring loaded, it should move into mesh when the teeth are aligned as the starter motor just begins to move. The original design would be to make the meshing happen as quickly as possible creating less wear. If the teeth meshing does not happen quickly, the torque motor will spin-up to maximum speed (whine sound) and the unmeshed drive gear will be spinning too fast to engage.

If the foot start linkage is worn, it could cause the motor to start before teeth meshing. Not good.

One wear point that's not visible is the pivot of the bellcrank in the starter nose cone that engages the drive gear into the flywheel. An oval-worn hole in the lever and/or a worn pivot pin will let the linkage push the switch button before the pinion engages the flywheel teeth. That pivot can't be inspected without dismantling the starter. The Y-shaped yoke that moves the starter drive can also wear and create just enough slack to cause a grind.
Jerry

Looks like the starter is OK. Discounting the possibility HR mentions about the oval-worn lever. I will assume that isn't the case and my issues are 1) worn ring gear and 2) accumulation of variance at the linkage pivot points. I did do another bench test today to determine how the starter starts spinning before the pinion is fully extended. I put a close pin on the shaft and could fully depress the level. Guessing there must be a spring in there instead of being solidly mounted as I assumed.
Appreciate the schooling guys. I see some replacement ring gears so I will get one to have on hand should it get worse or when I have tranny or clutch issues.

Thanks for playing.

Dennis