Difference between diesel and gas starter, starter rebuild tips?

[waterboy]

Howdy Folks,

Apparently I've been lurking here for somewhere over 14 hrs if the logger is true. I'm in the process of building up a 84 rabbit NA with an engine swap from an rusted out, but tight engined 81 NA Jetta. Thanks for all the energy and info put on here, you guys make this an awesome resource.

Seem to be having starter issues, the one that started the car a few times after the swap, died completely. Swapped in another well used starter from the replaced NA motor and it seemed to work for about a month till it started to be fail. Solenoid can be heard clacking but gives an intermittent rotation of starter motor, sometimes it does but most times now, it doesn't. Had battery load checked, twice, OK. Battery and ground contacts seem OK but cleaned just the same. I'm thinking solenoid now. Haven't done a voltage drop test from  battery to starter terminal though. Do folks use voltage drop to troubleshoot potential cable issues/failure?

 So decide I'll try a starter rebuild (clean up with solenoid replacement) . Used Burnitwithfire's post on the vortex  on starter upgrade repair

http://forums.vwvortex.com/showthread.php?2359900-DIY-Starter-Upgrade-Repair-troubleshooting-Replacement-(manual-tranny)
which has some great pics.

On my tear down of one of the starters (crappy one first, to get a feel for things) noted I don't have the plastic planetary reduction gears like he did and started thinking maybe I have a gas starter here, so started in on the second one which was the same as the first, no planetary just direct drive.  Also note I've only got 4 high strength magnets verse 6 in the rebuild post. He was doing a MK 2 and these were both out of MK 1's so perhaps this the difference? I would not of thought there would be that much of a difference between those two MK's.

 Any tips on keeping brushes in place for reassembly? I have picked up a new bushing as well and will replace.

Any input greatly appreciated!

[8v-of-fury]

MK1 diesel starters are direct drive, as well as MK1 gas starters. The diesel ones are much bigger though. Something like nearly double the power.

The MK2 started the gear reduction for our starters, if you have the means I recommend getting an mk2 diesel starter and using it. Much more turning power, much less power needed to turn it.

I have never had one of these starters apart, I guess i've been lucky . I have had other marine starters apart though, and used small wire to hold the brushes back while being slid over the shaft. The wire is then cut and extracted with pliers. Will this work in these starters?

[waterboy]

Thanks 8V, I'm heeding your advice,

I got impatient and didn't bother pulling the commutator out from under the brushes on the second starter, glad I didn't. I just threw the solenoid on and bolted the starter back together. Went well until, I came to getting the starter motor lead onto the solenoid.
Couldn't get the supplied nut onto the post on the new solenoid. The supplied nut fit on the old solenoids and the battery post.
The threads on the old studs mated perfectly to the new one.

The lead thread seemed odd so figured there was an irregularity and gave it a trim with the dremel to try to reshape (no tap and dies handy).

The whole time something just didn't seem right.

And it dawned on me. Why was there TWO starts on the stud?
 
This is amazing, the new solenoid's terminal to starter post has TWO threads! I had to get a fine point jiffy out to trace one ridge a few wraps to confirm my amazement. Same TPI as the old solenoids and battery terminal, but two threads! Disgusting! I wasted more time than I care to admit figuring this out. I don't think I've seen or been aware of a 2 start thread pattern used in automotive, especially in this application. I'm thinking this is just a gross level of incompetence in the jobber manufacturing process/ lack of quality control. By the way it came out of an Intermotor/SMP box sourced from Lordco, if someone might be walking the same path, maybe choose another.

So, I'll pull the solenoid off the one old starter and slap it onto the other for the short term. I've a 92 TD parts car about 4 hrs from here, so next time I'm by it, I'll pull its starter and plug it in.



 

[R.O.R-2.0]

gas starter is .7hp

diesel starter is 2.5hp

there is a HUGE difference.. 2.5x more power with the diesel unit.