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Discussion Starter #1
Was getting leery of the performance on my truck's starter and I read on the ColoradoK5 forum that the 28MT geared reduction was a wonderful upgrade. The discussion on here was more mixed: http://www.dieselplace.com/forum/showthread.php?t=53403&highlight=28MT. So I thought that I'd add my own $.02 since I just installed a 28MT starter in my truck this weekend.

It rocks. :ro)

Turns over like a champ; alot faster than my old 27MT (which, admittedly, may have a solenoid issue--inconclusive test at Autozone since it popped the test stand's breaker when it went to check the solenoid after spooling up the motor?), but it turns over about as fast as my folks' fleet of 350 engined vans of the same vintage. Still need to glow the plugs on a cold startup, but after that it hardly needs them (outside temps in the 60s).

Somebody made the comment on the other thread that the geared reduction 28MT takes time to spool up and turns the same speed but with fewer amps...? There's no spooling up on it--the cranking is there when you turn the key--so I dont know where that came from. As far as amperage draw vs speed, electric motors all have a set of curves for that describe amp draw vs torque requirement, and torque output vs speed. The motor will find the balance point on those curves that gives the max speed while providing the torque to make that speed, and that's what drives the amperage draw. The fact that there's some gear reduction between the motor proper and the flywheel doesnt change this, and this says nothing of differences in efficiency at converting electrical energy to mechanical energy. The geared reduction starter will see less torque due to the reduction gears, so it can spin faster. While torque requirement through the gearing is proportional to the reduction ratio, the motor curves of torque/speed and torque/amperage are not, so the difference in performance between the same motor with/without gear reduction lies within those curves. But I'm sure that they've got different motors: I did find some references online for the 28MT having 2.9 kW (3.98 HP) of output, but couldnt find anything solid about the 27MT, although I do recall seeing something somewhere suggesting 2.5 HP (or was it kW?) for the 27MT awhile ago when I first started looking..?

It does need a different mounting bracket, which I picked up at the local Chevy dealer for $2.50 (which I never thought I'd get anything that cheap from a dealer before). The starter itself cost me $100 on eBay (Taiwanese aftermarket/at least its not made in China). I've also got (2) 1100 CCA batteries and the crossover cable is about 3/4" dia.
 

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Thats good that the starter is working out for ya.

The 27MT start varies quite widely in "health"

A healty 27MT starter works like a champ and starts the engine right off.

But, for the others, the ones with dragging brushes, bad solenoids, etc. etc. they still get the job done but with less that satisfactory results.

The advice that (I and others) gave in the thread that is referenced is of our own personal observation. I've had both the 28MT and 27MT on the same engines and could honestly say that the 27MT did a better job for me with my setup. My 6.5TD also had the 28MT starter on it and it never did or has started as well or as fast as my 6.2TD does in WARM weather.

In cold weather the 6.5 won every time, but that may be due to other things besides the starter (say computer advanced timing, etc. etc.).

Thanks for the review!

The only 28MT starter to own is the one made in Japan tho (original).
 

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Discussion Starter #3
I'll be taking the old 27MT apart to see what the problem was. High Sierra 2500 suggested on a different thread that I might have fouled up contacts on the solenoid that might be reducing the power to the starter.

So admittedly this isnt really a new vs new comparison. In case the new starter craps out, I'll have the old one (rebuilt/repaired as req) to put back in, and that might be the better comparison. Even if I like the sound of the new starter' cranking, I should find a tach somewhere to record the cranking speed while its still new. If I can get the cranking speed, I'll ammend it to this thread later.
 

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I had the same experience as chevydiesel. The geared starter just doesn't work for me. I don't know what the difference is that causes it to work for some and not others. In theory the geared one and the direct drive one should perform about the same.

I remember when my solenoid went out. It went out slowly, so it was hard to notice. It still cranked, but it took some time for it to gain speed while it was cranking. Once that was fixed the truck started in a fraction of a second. All you had to do was bump the key and the truck would start up. It was like ZERO crank time. Those days are gone now, though, what with my bad fuel injectors and a dead glow plug or two. Now it cranks through a couple of compression strokes before it starts... Still almost instant starts, but much slower than it used to be.

Even if I like the sound of the new starter' cranking, I should find a tach somewhere to record the cranking speed while its still new.
The way it used to be with my truck, you couldn't hear the starter before the truck started. It was so fast that all you heard was the starter drive engaging and then the truck was running. You would have had to unhook the power to the shutoff solenoid to get a cranking speed reading...
 
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I have a 1983 Winnebago on a P30 chassis with a 6.2L DD - which starter/solenoid should I buy the 27 or 28 MT?
Welcome to DieselPlace
I would lean towards the 28MT starter
(y)
 

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Ya cranking speed is king when it comes to Diesel engines
 
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