Direct vs. Gear Reduction Starter

[tgtaylor64]

What are the advantages/disadvantages of these two types of starters on a M1008 (both 24 VDC)? I know the brackets are different. Are they interchangable? Any problems?

 

[319]

I use a gear reduction on my 1028A1. Seems to spin faster with less draw. It's lighter than the direct drive. I bought mine from BD Electric.

 

[tgtaylor64]

Where did you get the correct starter bracket to hold it on the front?

 

[4x4 Forever]

http://www.steelsoldiers.com/cucv/57136-starter-bracket-gm-discontinued-once-stock-depleted.html

 

[Warthog]

Brackets are a dealer only item.

Some guys make thier own.

 

[Matt65]

My Rebuilt 27MT Direct Drive Starter spins MUCH faster than it did prior to the rebuild. The advantages of the 28MT are many. However, I find the 27 more than adequate when in good condition powered by healthy batteries. I run 2 Group 31 Interstate batteries.

 

[Hasdrubal]

My 27MT starter was also slow cranking until I rebuilt it myself. 7 years going strong and cranking over fast. I can see no reason to go to a gear reduction, all I hear is nightmare stories of them failing.

 

[Barrman]

The direct drive 27MT was American made. The reduction gear 28MT was originally from Korea and now China.

I have had two 27MT failures. The first time I had just gotten the truck and didn't know the glow plug card was not working right. I thought it was normal for 5-10 seconds of cranking for every start. I had it rebuilt with all Delco parts. I didn't tell the rebuilder to be sure and use a USA made solenoid. Almost a year to the day of the first rebuild. The Chinese made solenoid stuck on and burned it all up again.

When I put it on after the first rebuild, I also had fixed my glow plug problems by then. The truck never took more than 1-2 seconds at the longest to start. Hot or cold.

That was the M1009. It starts so fast, I don't think a higher rpm starter could make any difference.

The USAF Suburban I have with the 6.2 engine starts just as fast. It has a 12 volt 27MT. However, it also has the civilian glow plug system. Which sometimes works and sometimes doesn't. I never let it go more than 5 seconds. Because I limit the time it is trying, the starter just keeps on working every day.

I wrote all of the above to prove my point. If your 6.2 has a good fuel system, a clean fuel filter, a properly working glow plug system with all 8 plugs glowing and a good starter in it now. The truck should start up in less than 3 seconds hot, cold or warm. There is no need to switch to a redux drive.

GM had bungled the civilian glow plug system so badly when they first introduced the 6.2 that by 1988, 6 years into production, they were on the 3rd version of it. Lots of people just did what they do with a gas engine. Floor it and crank until if fires. Diesel starters can't handle that. Lots and lots of people did that and the starter got a bad reputation. When they changed over to the 6.5, they did the reduction drive starter swap too.

Now I am the first to agree that in theory a reduction drive starter is better than a direct drive. However, when you outsource the production to where something made 10K miles away with more parts and more machining needed is still cheaper than the old part. Something had to be given up. I think they gave up material quality and tolerance control.

That is my current view. I am a few months away from getting another M1009 running that will be reduction gear started. I will also be putting a 6.2 into my M715 and it could have a redux drive depending on where I find the starter for it. I will be sure and post up if my view changes.

 

[mkcoen]

I will also be putting a 6.2 into my M715 and it could have a redux drive depending on where I find the starter for it.

Trying to go all diesel or is the 396 just getting to pricey to fee?

 

[Warthog]

He blowed the 396 up!!!

Not really but it did hydro lock and he tried pull starting it and the final outcome wasn't pretty

 

[Barrman]

It was getting expensive to feed Mark. However, the window in the side of the oil pan made the decision for me.

Sorry I can't make the meeting tonight or the event this weekend. Scouts is keeping me very busy. I will be at Temple though.

I don't think I ever even crawled under the M1010 all those months it was here. What kind of starter did it have on it? I just know it started great.

 

[mkcoen]

I don't think I ever even crawled under the M1010 all those months it was here. What kind of starter did it have on it? I just know it started great.

One that worked every time I tried it. Beyond that I have no idea.

Sorry you can't make it this weekend. I will have the deuce along with the MKT at Temple this year.

 

[Dave Kay]

The direct drive 27MT was American made. The reduction gear 28MT was originally from Korea and now China.

I have had two 27MT failures. The first time I had just gotten the truck and didn't know the glow plug card was not working right. I thought it was normal for 5-10 seconds of cranking for every start. I had it rebuilt with all Delco parts. I didn't tell the rebuilder to be sure and use a USA made solenoid. Almost a year to the day of the first rebuild. The Chinese made solenoid stuck on and burned it all up again.

When I put it on after the first rebuild, I also had fixed my glow plug problems by then. The truck never took more than 1-2 seconds at the longest to start. Hot or cold.

That was the M1009. It starts so fast, I don't think a higher rpm starter could make any difference.

The USAF Suburban I have with the 6.2 engine starts just as fast. It has a 12 volt 27MT. However, it also has the civilian glow plug system. Which sometimes works and sometimes doesn't. I never let it go more than 5 seconds. Because I limit the time it is trying, the starter just keeps on working every day.

I wrote all of the above to prove my point. If your 6.2 has a good fuel system, a clean fuel filter, a properly working glow plug system with all 8 plugs glowing and a good starter in it now. The truck should start up in less than 3 seconds hot, cold or warm. There is no need to switch to a redux drive.

GM had bungled the civilian glow plug system so badly when they first introduced the 6.2 that by 1988, 6 years into production, they were on the 3rd version of it. Lots of people just did what they do with a gas engine. Floor it and crank until if fires. Diesel starters can't handle that. Lots and lots of people did that and the starter got a bad reputation. When they changed over to the 6.5, they did the reduction drive starter swap too.

Now I am the first to agree that in theory a reduction drive starter is better than a direct drive. However, when you outsource the production to where something made 10K miles away with more parts and more machining needed is still cheaper than the old part. Something had to be given up. I think they gave up material quality and tolerance control.

That is my current view. I am a few months away from getting another M1009 running that will be reduction gear started. I will also be putting a 6.2 into my M715 and it could have a redux drive depending on where I find the starter for it. I will be sure and post up if my view changes.

I am currently in starter replacement mode for M1008 and this thread sounds like good info hashing I want to get in on--- Agreed--- the 28MT seems a better design no doubt but try to get one that is NOT either made or re-manned in China--- junk just I won't buy if I can help it--- good luck on that one!

Problem is after searching the web for a few weeks it seems that your best chance is to happen on a 28MT either new or re-manned by Delco Remy or AC Delco and take your chances waiting it out--- score!

Otherwise, you can collect and rebuild the 27MT's and hope your electrical/mechanical skills will see your through. I've only pulled my 27 just last week and am already dreading the re-install antics I can only imagine right now. Which makes me start to think about 24 to 12 volt conversion doesn't sound like such a bad idea anymore... thoughts?

BTW; nobody will bench-test my 27 because they claim that the part number that needs to be entered into machine to test--- is obsolete--- anybody heard that one from their local shops? (sheesh!!!)

 

[Barrman]

I am glad you brought this thread back up.

I needed to update my opinion of the redux 28MT. I have been using it just about daily while moving the RED M1009 project around to work on it. That thing sure does spin the engine fast. It also seems to be nicer to the batteries. We started the truck up for several weeks with no working alternators.

However, it just sounds more violent which is just an opinion thing. I won't know for another year or so if it means anything mechanical.

Since you can still buy the mount bracket for the redux, they are all over the place for sale and they do turn the engine faster. I would suggest you go ahead and get one with a warranty if possible, get the bracket and put your direct drive in a box as a spare.

 

[Keith_J]

The 28MT starters are easier to install since they are half the weight. Oddly enough, gear reduction starters were introduced in the military MEP 002/003A generators around the same time with the same benefits.

Sure, sounds like magic to have half the starter work better but remember, we are dealing with the limitations of the pinion and ring gear reduction. You could go with the 12/24 volt analogy but my 12 volt VW TDI uses a reduction starter.

 

[dependable]

My experience has been that the original 27MT starters work great and last a while, but when they fail, I use the 28MT gear reduction. The 'rebuilt' 27MTs often have a short life span. Have been running several 6.2s for years, and the same is true for the 12V civy units. The 27MT 'rebuilds' are not worth installing. If you come across some OEM 27MTs, or are good at rebuilding them yourself, that would be a different story. Keith is right in that the gear reductions are easeyer to install.

 

[Hasdrubal]

"The 'rebuilt' 27MTs often have a short life span."
Why is that? I would be interested to know. Rebuilt my 27MT myself with a $40 rebuild kit 6 years ago. Still cranks fast, no problems. As for being easier to install..maybe you guys need to get fit. I've heard nothing but nightmare failure stories within 2 years from people who have switched to the 28MT.

 

[SouthernSteel]

I didnt have a choice when i bought my gear reduction i was in a bad postion.When i bought my m1008 it wasnt in the best shape.The gear reduction is a great starter its been on my red m1008 for about 2 years with no problems.I bought another one to go on my army one if the original fails.I bought my gear reductions from a small mom and pops business in wilmington nc called Coastal rebuilders those guys have been awesome.My army m1008 still has the orginal starter as long as it works im gonna leave it.But i have back up if needed. I was told the parts for the original starters were getting hard to find and expensive.

 

[dependable]

"The 'rebuilt' 27MTs often have a short life span."
Why is that? I would be interested to know.

Cheep components. shoddy work? If I has some good components, I might rebuild too. For a while I was taking rebuilt starters back to parts store repeatedly, getting 'new ones' still in warranty. On multiple trucks, that gets old fast. This was also the experience of an other guy I know who runs 6.2s in his work fleet. You can still find good gear reduction starters as well as the cheep ones. Have had pretty good luck with both, although the cheep solenoids fail sometimes, they are only $40.

I always keep at least one 12v and one 24v spare on the shelf. When your crew is waiting around on the clock while you to fix their truck, you go the quickest route. These days, I have the luxury of spare trucks too, but it was not always that way.

Remember to replace the starter bolts along with starter. When they fail and you are trying to install a Helicoil, you will wish you did.

 

[hodgeb]

Am I going to see much of a difference between a 24V direct drive and a 24V gear reduction? I've heard it said annecdotally by one person that the DD is going to actually spin faster than either 12 or 24V gear reduction, but I can't make sense of that. As I'm understanding, 24V DD out, 24V reduction in, and it should result in faster cranking regardless.