removed 50dn gear driven on 6v92

Brian R. · April 13, 2023, 03:39:52 PM

I removed this cam driven 50dn because it would not fit in tight engine compartment (MC-2), besides the warnings about their danger to your engine if they go. I intend to use the #3 position off the blower drive for a belt driven 50dn ( I have 2)(or an air cooled equivalent), as that is the setup I had on my 6v71.
Sort of dumb question time. What i'm looking at now, where the gear driven alternator was, is the 3" thick mount and a 3/4" spacer that houses the accessory drive. I need to remove them ( to make room for belts that will drive off the blower drive.) So I put a wrench on the big 1-5/8" nut that holds the sun gear (planetary gear?) to the cam. I put another wrench on the crank gear at front of engine to stop engine from turning. Then I put considerable wrench pressure on the sun gear nut. Then I stopped because the thought occured to me that the nut might have left hand threads. Not enough thread showing for me to tell so I better check. (My manual doesn't address this) Probably Rt. hand thread but maybe left ?
Also is holding the engine with wrench on the crank nut OK. It is a smaller nut and might unwind first. If I had the pan off I might block the crank, but don't want to dump the oil and do that if don't have to. I also have a big strap on the crank pully but it was slipping.
After I get this stuff off I see I will have to make a cover plate as none seem available.

Related issue is whether a blower accesory drive unit from a 6v71 will fit on a 6v92. My old one has a 3 belt pully and the bolt pattern and size look like it might fit. If that is a no go I guess I will be looking for one for the 6v92 if anyone can suggest a good place to find one. Thanks Gentlemen,...Cheers, Brian R.

luvrbus · April 13, 2023, 03:48:58 PM

The pulley will work and the cams are right handed thread ,did you remove the 2 allen head bolts holding the lock on the sun gear?.Just remove the 6 allen head 7/16 bolts and take the sun gear off and leave the rest. I never saw anything but a 1 in dia bolt on the end of the crankshaft and I have no idea what going on there.You have photos of the aluminum spacer and blower drive section on the spacer

Brian R. · April 13, 2023, 05:23:56 PM

I had to go take a look. The gear with the 1-5/8' nut holding it in place, is about 6-1/2" od, with teeth on the inside of the perimeter. It doesn't have any allen bolts on it, it only has 4 small drain holes for oil. I just found online a picture of an 8v71 with the same gear and it does have 2 smaller allen bolts and 6 larger allen bolts as you describe. My v92 is a mid eighties. Good to hear Rt hand threads so I will just use a longer bar, was being cautious. Yeah, my bad as the crank pulley has a 1-5/16 bolt (so probably a 1" bolt) , not a nut as I said. It is probably on there with more torque so ok to use to resist the big cam nut (?)
When I get the cam nut off and that gear out I need to get the 3" housing and the 3/4" spacer out of the way for room for the belts from the blower drive (which I don't have yet). I'd like to send you photos but my kid is at college, he could do it, I'm behind the times. Thanks...B.R.

Van · April 13, 2023, 05:25:34 PM

Brian R. · April 13, 2023, 05:35:20 PM

Great looking plate, that is exactly what I want to get down to. Did you use 3/16 or 1/4? ...is nice and thick.

Really like the cigar,...I grew up with them ( dad) King Edwards. I need more of those cigar boxes.
BTW...is this the same BB Coachworks with Gary Bennett?

luvrbus · April 13, 2023, 06:47:59 PM

Here is the only sun gear I ever saw on a 92 series

luvrbus · April 13, 2023, 07:12:02 PM

One problem you are going to have the blower drive will have 6 bolts and with the spacer you only have 4 and the large hole where the 50 d was removed there is not enough metal to drill the 2 bottom holes in the bell housing for the drive.

This is the way I did Kay's MCI I moved the power steering pump to the blower and used the pully setup where the power steering was mounted

Brian R. · April 14, 2023, 12:04:15 PM

Luvrbus,...that sun gear looks exactly like the one in the picture of an 8v71 that I found online. Mine has nothing except a very big nut
(1-5/8" socket fits it). My engine is a 6VF 114767----8067-7800.

I thought I was going to be able to just bolt on an accessory drive (like perhaps a #5133747- not sure if thats the right one) to the blower location (Like that blower drive pulley in your picture). The plate covering the blower drive location now has 6 bolts holding it. I won't have room to go under the compressor with belts to my P/S location as the clutch apparatus is in the way. Hmmm...

luvrbus · April 14, 2023, 12:34:32 PM

Never saw one like you describe

Quote from: Brian R. on April 14, 2023, 12:04:15 PM
Luvrbus,...that sun gear looks exactly like the one in the picture of an 8v71 that I found online. Mine has nothing except a very big nut
(1-5/8" socket fits it). My engine is a 6VF 114767----8067-7800.

I thought I was going to be able to just bolt on an accessory drive (like perhaps a #5133747- not sure if thats the right one) to the blower location (Like that blower drive pulley in your picture). The plate covering the blower drive location now has 6 bolts holding it. I won't have room to go under the compressor with belts to my P/S location as the clutch apparatus is in the way. Hmmm...

Your engine is 1984 transition engine when Detroit went from the Green to the Sliver engine,your engine does not have the upgraded camshaft for the gear driven alternator FWIW you have to have the 6 bolts inside the hub to check and set the lash and the true running circle of the drum with the alternator

Brian R. · April 16, 2023, 10:15:10 PM

I found out two things, and I think I got lucky. I thought I had to take off that big nut on the sun gear to remove the drive housing and the adapter plate. Finally found a Grease Monkey utube where he had taken the whole thing apart (good video- ball bearing worked loose and jammed the Alt. gear but in such a way as to push it away from the sun gear so no engine damage---BTW- it was the same kind of sun gear that I have, blank inside except for the big nut) Big nut can stay in place, housing and will come off just by working it off the studs. I found a MC-9 maintain manual online that helped my understanding too.
The other thing is that I don't have the figure 8 spacer, it is the other type which is independent of the blower drive, so I now know what you were saying about only 4 bolt holes for the blower drive. I've got the 6 so I should be good to go. I'm a little shamefaced about fixating on that big nut but I was without the proper literature. Thanks for taking the time to try to wise me up. Brian R.

luvrbus · April 17, 2023, 06:54:58 AM

You will need a longer blower drive for the 6v92,the later drives are splined through the drive ,and they made 2 spline counts if the blower drive is the less spline count than the later blower drive then you have another problem DD was always making upgrades on the drives to stop the blower drive failures

TomC · April 21, 2023, 10:02:38 PM

Don't you have a 2 belt pulley on the front left of the engine? On my 8V-92TA they powered the A/C compressor from that. Good Luck, TomC

Brian R. · April 23, 2023, 11:52:46 AM

Tom, I do have one there but it is half blocked by the bottom of the thermostat housing( unlike the 6v71) and by 4 or 5 fuel lines running back and forth to the primary and secondary fuel filters that are mounted on the rail down low on that side.
I took the rear accessory drive (from the blower position) off of the 6v71 and it seems to be a perfect match for the 6v92. It has the fiber/ composite slotted drive coupling ( which I think I read somewhere is designed to break first instead of damaging the blower) So I think I'm good to go. Still have to make a plate to cover the rear cam opening as in Van's photo.