gear drive vs direct drive starters

What is the advantage of gear drive? Does it put less strain on the starter bolts? Do they run faster? or require less amps?
I have seen no shim starters and starters that don't say one way or another. How can you tell if you need the shim or not?
I also read some people are afraid of the gear reduction starters because of shearing teeth off, possibly from the shim question. Is that a concern?


Thanks

simply put gear drive starters give you more torque. Thus allowing the engine to turn over easier when starting

A gear reduction starter allows for a higer speed motor operation for the starter which keeps the amps down delivering a steady torque to the drive gear. As far as maximum torque, an electric motor delivers its highest torque at low rpms. Obviously this is dependent on the number of windings and poles etc. As the motor's speed increases, torque peaks and drops to a steady level. Gear reduction starters allow for a quick rpm rise and steady operation. They also allow the starter to take advantage of the actual horse power the starter makes which is not available at low rpms. You may not believe it but a heavy duty dc starter motor can produce upwards of 10 horse power, maybe more, in a light truck with a gas engine. A diesel takes more to turn it over. Bigger 24 volt starters are much higher.

In your case, ultimately the amount of effort to start the truck is the same as it is simply making the truck's engine spin fast enough to start that is the goal of the starter motor whatever type it is. The amount of force applied to the teeth on the ring gear is the same, and most likely, as far as gear wear or breakage, the gear reduction starter will be less of an issue in the long run due to the more consistent speeds it runs at.

As far as shims go, you need to put the same shims back when you change a starter as it had to begin with. That being said, you also have to listen to the "lash" of the gears as the starter engages and when it releases.

If it is too tight the starter will growl as if it is laboring, and sometimes the drive will not release easily, or maybe not at all.

If the starter is loose, the teeth will wear prematurely. You will hear the drive sometimes drop out before the truck starts, or it will sound loose, or partially engaged with what I would call a "high pitch" as far as gear noise as the starter turns the engine over. When the lash is correct, you should barely hear the gears as far as noise goes and the noise should be more of the starter motor itself along with the engine as it proceeds to start.

I have been driving Chevys for 30 years and have only had to change the number of shims on a starter once from what it was when I took it apart. That is how well they machine the blocks and starters as far as accuracy.

Unless you have a strong inclination to think something is not right, put the shims back the way they were when you took it apart.

I have a direct drive in my M1009 daily driver. I had it replaced because it developed a dead spot and it was turning slow. The new one I put in spins the engine very fast, it is also direct drive, but it makes a high pitch gear noise type sound that I hadn't heard before, but there are no shims in there to take out. It hasn't given me any problems except the noise. People turn and look when they hear it turn over, it is very noticeable. I'm now worried that there is damage going on in there. I'm going to pull it and check it out, would it be recommended to try a shim?

Thanks

The TM's have the procedure on how to measure for the proper shim. Also search this forum as it has been covered.

I broke the nose on my starter yesterday, the engine seemed to kick when it broke only the second time it kicked in the time i have had it. I'm going to order a gear reduction starter and have the direct rebuilt for a spare. No shims and have already replaced the flexplate as it had broken bolts when I got it.

My mistake, the truck did indeed have a shim in there(changed starter over a year ago). I removed it, started the truck and it sounded much better, the high pitch noise is gone. This subject probably was covered before but I couldn't find very much. Thanks again!