Telma Photos

[boogiethecat]

Some photos of the Telma and installing it, the new tranny and clutch
in my Crown
The new (from a junkyard) Meritor "RH"23160 rear end (high pinion option) turned out to be a whomping big unit... they move the pinion up 6 inches from normal and then use two big helical gears inside to transmit the drive down to the ring and pinion, which are on the other side from normal so that rotation becomes the same as a normal rear end. The result is that the pinion housing is GIANT- I had no idea the thing would be this big... ended up that my driveshaft had to
be cut fully 10 inches, and now the "tube" is only 2" long!!  It made it, barely, and now the driveshaft is almost straight... not more than a
degree or so at most, which is perfect.  Without the high pinion option, it would have ended up at about 10 degrees which would have been
quite bad!

[Brian Diehl]

Thanks for the photos.  Sure looks like a big job, but you should have a great stopping coach after it is all together!

[Lee Bradley]

Looks great but a word of caution on the driveline alignment; u-joints need 2 or 3 degrees of movement to keep the rollers rolling. The rollers will be beaten flat if they don't roll.

[TomC]

I saw the rear end at Don's when I picked up my bus.  What struck me was that you could have used a Mack rear end-I believe most are high entry also.  With the power you have, you could have gone with a 21,000lb rear end and eliminated about 350lb-but of course nothing wrong with going big-it'll probably never break.  Hopefully the short driveshaft won't be a problem.  On rear engined Freightliner motorhome chassis, some will come in with blown out driveshafts-but they have air suspension.  With your spring suspension, you'll hopefully not get that kind of axle travel.  Will be curious as to the performance you get!  And I thought my turbo project was big!  Good Luck, TomC

[Barn Owl]

I love the photos, I wish more posters would document and share like that.

What is that thing and how does it work?

[boogiethecat]

Hi Guys,
WEll let's see...
Barn Owl, it's an electromagnetic retarder... in a nutshell a non friction electromagnetic brake that turns stopping energy into hot air.
It's about 3 times (or more) as powerful as Jakes, does 90% of the bus's braking, and is the most amazing safety device I've ever driven.
Coming down grades you're in more than full control, period.  Once you drive one, you'll never go back...

Tom, Yeah I could have probably picked a different rear, but that one was available and it fit everything which was a big plus.  Some of the weight between it and the Telma is made up by the fact that the new tranny is almost 500 pounds less than the old one...
Because the driveshaft is almost straight, the only thing that will happen over bumps is it gets longer, and there's LOTS of spline room.

Lee, I gotcha on that one.  The saving factor is that the engine and pumpkin are offset quite a bit in the horizontal plane, so even though the driveline is fairly straight in the up/down vector, it's got 2-3 degrees in the left/right vector due to the aforementioned alignment of the engine.  So I'm ok...

Brian, thanks for the comments.  Yes, I'm sure I'll never have another 'ars clencher' on a grade again.  It was fun removing the Jakes and knowing that what was in store for the bus was many times better!!!!

I'll post more on it all in a couple of weeks when I get the engine running better (bad injectors still)...

[belfert]

This thread reminds me I never heard back on a couple of salvage Dina coaches.  I called to see if they had Telma retarders in them as that was a factory option.  A swap from a Dina should be reasonably straight forward as I own a Dina.

Brian Elfert

[Barn Owl]

Couple of questions:

1.   Can one of those be put on a GM?
2.   Where do you find them?
3.   How much should one expect to spend on one?

Another question not related to those above. How did you manage to get so many photos uploaded into one posting? I really like the quality. They don't have the size attached at the bottom. Why is that?

[Buffalo SpaceShip]

Go, Gary, go! What a post. Very nice.

To answer Laryn's question, if you host the images on your own domains(s), they can simply be embedded into the code. It's the pic attachments through the BBS that have the limitations.

And do a search on here sometime for "Telma" for more of Gary's observations about this amazing safety device.

Brian Brown

[belfert]

The other big plus about a Telma is that it can be used any place that engine brakes are prohibited as it is not an engine brake and makes no noise.

Brian Elfert

[TomC]

As to installing on a GMC with V-drive or a transit with V-drive, according to what I found out you cannot install it.  The rear axle will not facilitate it, there is no where to mount it on the rear of the transmission and the drive shaft is too short usually.  Unlike having spring suspension, most all V-drives have air suspension that requires lots of axle travel, so a short drive shaft just wouldn't work.  Besides, most V-drive buses do not have a frame, so mounting 500lb of retarder would be next to impossible.  So for now, the only retarder for V-drivers will be a Jake brake.  You can have a hydraulic retarder on a electronic V731, but hydraulic transmission retarders are not good for long down grades, they heat up the transmission to much.  But in contrast, Jakes on a down hill keep the engine warmed up so it doesn't cool down to much so when you reapply the gas on the flat, you won't get white smoke.
As to Jakes on 8V-71's, I've had one installed before I picked up my bus.  As it was installed, the performance when coming down the north bound I-5 Grapevine (6% grade for 5 miles) with my car in tow, I would have to tickle the brakes about 5 or 6 times to bring it back down to speed.  After Don Fairchild adjusted it, now I have to switch it back and forth between high and low (2 heads or 1 head) and never touch the brakes.  Properly adjusted, they work very well.  When I had my truck with a 8V-92, grossing 80,000lb coming down the Grapevine was a no brake touch also at 35 mph, revving at 2100rpm.  Plus, they sound great!  Good Luck, TomC

[Barn Owl]

Tom,

I didn't know you could adjust the Jake Brake. How is it done?

Laryn

[TomC]

Barn Owl- adjustment on the Jake brake is just a clearance gap adjustment. Most mechanics adjust them very conservatively to assure that their sloppy work won't affect engine reliability (improperly adjusted Jakes can cause the exhaust valve to hit the piston causing major engine damage if not failure).  Don Fairchild has been working on 2 stroke Detroits for over 30 years. From experimenting at Delaney and Ahlf in Bakersfield (they were the premier Detroit Diesel  experimental engine shop during the hay day of the 2 stroke engine use) they discovered the tightness they could safely adjust the Jakes to without engine damage-which is tighter than the factory suggests.  The more air you pass through the system the more braking power you can get.  Adjustments can make a 100hp difference in braking power.  Good Luck, TomC

[DrivingMissLazy]

As I recall the Jake manual advises to adjust valve clearance to 0.59 or 0.63 depending on the actual head on the engine. I also believe that this adjustment is to be made with the engine up to temperature. 
Whatever, I changed mine to 0.55 and it was really unbelievable the difference it made in amount of actual braking I got.
I actually found out by accident that this would help. One morning, immediately after starting out, I needed to slow down and when I turned my Jake's on, the braking action was very drastic. A little later on, when I again needed to use them, the braking action was significantly less dramatic. I therefore concluded that with the cold engine the valve clearance was more than it was with a hot engine so the next time I had a chance, I experimented and reduced the clearance by 0.04 inches. I realize I was taking somewhat of a chance by reducing the clearance, but over time and many thousands of miles I realized that I was not damaging the engine.
Richard

[TomC]

I believe .55" is what Don used.  Good Luck, TomC