Starters for grinding ring gears

Hey so it seems rather common for our idi's to develop the occasional starter/ring gear grind; I believe its due to the fact that our engines seem to stop in the same 3 positions and wear occurs mostly in those areas. Anyways, I put in a new clutch, flywheel and ring gear last year and its already starting to develop a grinding issue. Its drives me crazy I recall a post a long time ago related to a certain type of starter that engages slightly further/deeper and helped curb that grinding issue. Does anyone recall that or know what type of starter to use? Can a regular starter be ground down a but around the mounting flange to sit a little tighter with the bellhousing? I have a number of good starters around but they are just normal (direct drive) starters and I would like to experiment with one of them instead of buying a new one

When you say grind... Do you mean wear on starter teeth? Ring gear teeth? Abnormal noise on start?? Failure of the starter to engage the flywheel?

This is well known issue. My original direct drive wore the gear on the wheel so bad I would grind the starter nearly every time. I replaced the starter several times and finally installed a mitsubishi gear reduction to fix it.. for a little while. When the engine cavitated I had the gear "moved around on the heavy cast iron flexplate. That worked for a long time. Now I'm 9 years into the newer style stamped steel flexplate that requires the crank spacer and it has never ground once. If you have the 3 piece heavy cast iron flexplate you might try changing to the better thin stamped plate with the spacer. The bolt length and torque is still the same as the heavy wheel was.

I have an AMS SMF that I installed with me ZF. So, its all new. I would really rather not pull the flywheel off again to do any mods, but id be willing to do any starter mods.

When I had my flywheel surfaced the machine shop flipped the ring gear.

It's possibly to machine the end of the solenoid plunger to delay the terminals closing, but is somewhat of a trial and error thing. I had this problem show up last spring and was able to get past it by eventually taking about 1/8" off the plunger which also required shortening the spring slightly. I have a big lathe, so it's easy for me to take some off, probably be possible by hand but harder to do. I also now get a rattle occasionally from the pinion dragging a bit...

Interesting Thanks. I don't have a lathe but could take it in and have someone play with it, as much as I don't like others messing with it. But im still interested. How about grinding the flange down (where it mates with the bellhousing) a bit, so the starter gear will end up that much further onto the ring gear once engaged.

If you are thinking og grinding down the starter mount flange be careful. Best to get a clearance measurement before you remove any material. See what the distance is from the gear to the starter gear.

I wouldn't mess with the flange - this would more the entire starter in, which might cause interference between the starter nose housing and the ring gear. You'd also have trouble getting it square and even, and it's going to be permanent. Come to think of it, this would be more work, since the only way I can think to do it accurately enough would be to put the entire flange assembly in a mill and do it that way - if the surface isn't flat and square the starter woln't sit right and might cause more trouble.

Easy to replace the solenoid if you screw it up too....

I replaced my original oversized starter with a Mitsu style and noted it has a slightly larger gear on the starter and an additional tooth as well. It was from DB electric.

I was reluctant to use the replacement and double checked the application. Finally just tried it and no issues. Been years now.

They are both gear reduction but the original, Delco I believe, was way bigger. This might help your issues.


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Well maybe il try a mistsu style starter and see what happens. I just bought a 3G from DB electric and the price was great and quality seems up to par to.

Many of the original Delco direct drive pinions do not engage the ring gear completely, causing the eventual grinding at 4 spots on the ring gear. This is primarily because when activated, the solenoid/bendix throws the already spinning pinion at the ring gear, hoping the ramped teeth will help feed the pinion into the ring. On a gasser it probably works just fine, but the IDI has a higher torque need to overcome and as a result, the pinion teeth only grab about 1/8 inch of ring gear. Yikes.

My buddy fixed this problem by separating the two sequences. He installed a relay for the starter motor and a push button under the dash. After activating the ignition switch, which throws the bendix at the ring gear, you push the motor button and away it goes, with no grinding ever again! The beauty of this arrangement is that it makes your truck about impossible to steal or even start unless someone knows about the relay.

I would not try grinding or machining anything, it is likely just to ruin the starter and probably not fix your problem anyway.

When removing the ring gear, DO NOT flip it, just rotate it about 22 degrees. That will give the starter fresh new teeth to play with.

Wow that's an interesting mod! And it would be pretty simple to rig up AND, like you mentioned....its a great anti-theft device

You'd need a big honking relay though.... probably best bet would be another diesel starter solenoid, and maybe another relay to drive it. Would also need to be wired up with big heavy gauge wire... Not a bad idea though.

As I remember, the relay was about as big as a quart paint can. He hung it next to the Passenger side battery and cut the positive battery cable there. Installed two eyes, attached one end from the battery to the relay, the other from the relay to the starter, then ran a separate 14 gage wire for the push button.