I have the 1964 4106 4 sp shft 8v71
I am not pleased with the two stroke/4sp man trans drive-train.
Do I sell it and upgrade to something newer that can handle towing a heavy load like a 32 ft boat or a 30ft trailer toy hauler, full, or can/should I update this drive-train to something more modern in the 4 stroke/auto trans category?.
What would you suggest either route ?
NAME?? -
The 4106 is the sports car of buses with it's original powertrain.
Would you tow a 30ft toy hauler behind a Porsche?
There aren't really any 4-stroke powertrains that fit the '06. You might find a S-50/VR-731 combo, but that's like searching for hen's teeth.
Time to start shopping for what you really want - a coach with either a Cummins, Cat or S-60 Detroit mated to an automatic.
FWIW & HTH. . .
;)
I'd be less concerned about power and more concern about if the structure of the coach is such that it can safely handle the load.
Depending on the maximum length laws of your state, you might have trouble with 30' plus trailers. The maximum length is usually 65 - 70 ft. total length hooked up. In my state, I can not legally tow my boat behind my 40'.
You could switch to an Allison automatic transmission. That will make it a lot more pleasant to drive but will not help you on the power side. If you want more power, I think it will much more cost effective to find another bus that will do what you want as is.
I love GM buses. But, one thing they aren't great for is towing other than pulling a toad with a tow bar. Definitely not any trailer with significant tongue weight. On GM's the engine and transmission are essentially hung from the rear firewall. If pulling a big boat or toy hauler is your interest, then I would look towards something with a frame that goes all the way to the rear like a Prevost or perhaps even look into getting a truck conversion.
A bus nut friend had a 4905. On I-75 between Atlanta and Chattanooga one night, they felt a throbbing, then lost power, then lost oil pressure and the engine shut down. It was towed to the Choo Choo garage in Chattanooga. They had changed the weight distribution of their trailer when they got a new truck. The increased tongue weight broke the engine cradle mounts. The engine/transmission/cradle sagged creating a bad angle for the drive shaft. The u-jounts broke at the axle end. the wildly swinging axle wiped out the oil filters and did other damage before it broke off and went sailing into the path of cars on the oil slicked freeway behind the bus. Lots of fun.
If you're going to be pulling a big trailer all the time, buy a truck conversion using a big rig front (like a Freightliner, Pete, KW, Volvo, etc) with at least a 12 liter engine and either an Allison of automated transmission. Then you'll have a full length chassis that's designed to pull weight. I know that Freightliner is designed to pull 110,000lbs.
I'm building a truck conversion from my '85 KW Aerodyne cabover (32ft box making it 40ft). The difference in serviceability is truly shocking-I'll never go back to another bus. Good Luck, TomC
Quote from: TomC on August 04, 2016, 08:14:29 AM
I'm building a truck conversion from my '85 KW Aerodyne cabover (32ft box making it 40ft). The difference in serviceability is truly shocking-I'll never go back to another bus. Good Luck, TomC
I don't doubt that it will be easier to service, but how is the ride comfort, and how long is the wheelbase?
There are currently plenty of options to safely tow with any GM coach..have only done it with this one for 16 years...rdw
The 4106 also has a very high first gear. No granny gears at all. We were told NOT TO STOP on a 6% grade at 9000 feet or we might smoke the clutch trying to get rolling again. Also I was told a clutch job on a 4106 was $very expensive$. 45 years ago.
But if you have a lot of money and want to improve, (ruin?) you cool stock 4106 GM highway coach, is it possible to find or build your own 8V92N 400 hp Detroit Diesel? Would that drop in? Full power use in 3rd and 4th gear still might be doable.
Also did not the neat cool 4106 have no practical way to install a working heavy duty trailer hitch assembly? There are no structurally strong point to mount it to? No real separate frame rails and such. Light hitches? Yes. Heavy hitches on a 4106?
Or ... you could find and buy about a 1985 Crown Supercoach 35 foot ex schoolie with the cool NTC 855 big cam Cummins engine running the infamous close ratio Fuller 10 speed Roadranger transmission. My old Crown had a gear for every occasion plus gears you normally would not need. Top speed was over 80 mph.
It easily started on a 12% grade in second gear at 25,000 pounds at 2000 feet. If your Crown has no rear trunk it would mean the big frame rails extend all the way to the rear bumper. Or if it does have a big trunk with the two big barn door it is still doable to extend the HD boxed 4130 frame rails to the rear bumper.
Just thinking outside the box. They also made Crowns with the Allision automatic. Up powering the Cummins has been done using cheap used factory parts. All the way to about 550 hp. The Crown will cool to about 450 hp continuous which equals about 100 mph. Yikes! Fast enough. Lenix speell chzk is fun. :)
What a salesman for Crown you would have been! They were built too solid, and that's what killed them. 30-40 years of service with no replacement needed dampens sales. They still look good, and a tandem axle model would be great for a conversion.
Can the over/under drive units be used on these things?? Used to be the go to for the older underpowered RV'S.Don't know if they are even made anymore .Haven't seen any advertising in a while.
Quote from: bigred on August 05, 2016, 05:48:41 AM
Can the over/under drive units be used on these things?? Used to be the go to for the older underpowered RV'S.Don't know if they are even made anymore .Haven't seen any advertising in a while.
They are still around (Gear Vendors, Inc., 1717 North Magnolia Avenue, El Cajon, CA 92020), but they are for light trucks and RV's with a gross load of 25,000 lbs. or less. They can be overdrive or underdrive.
Some outfit in Iowa made a 2 speed that installed between the transmission and the engine back in 80's I haven't seen those around in a while
8V-92 will not work with a V drive-the big vibration damper is in the way.
On my truck conversion, I have 8 air bag suspension in the back. I will add air bags to the front. And no, the ride is not as good, but I'm REALLY tired of working on my bus. Trucks are made to be worked on, and garages are not scared of trucks (especially mine with no electronics). Both my wife and I are looking forward to the day I get done with the truck and can move into the truck to use it. Good Luck, TomC
The bus world for converters is very small. A few years ago you could pick up a 80's Flex transit with the correct engine angle to fit a 4106. Most of those buses have been scrapped. Besides a 6V92TA, you. could get Cummins L10 V drive.
--Geoff I
Or you could lengthen your bus a couple feet and put in a T drive ;D look at my photo bucket link under my name and you will see how my bus has a heavy duty tow hitch installed
Have you ever weighed the rear axle?