Hill climbing

[Len Silva]

Just returned from a fun trip in our motorhome. Weighs about 30k, 300 Cummins, 6 speed Allison etc.
We visited a campground near Asheville, NC (Mama Gerties, great place) with a very steep approach. From a dead stop I couldn't quite make 1500 rpm or get out of 1st gear.
One of the hosts told of a Prevost that had to unhook their toad to make the climb.

So, the question; in a stock 4104 or 4106 in good condition, would this be a problem?  Is there any hill you couldn't make from a dead stop halfway up?

I don't mind going slow but not being able to make it at all would be embarassing to say the least.

I never had my 4104 out of the flats so I don't know what to expect.

Len

[RJ]

Len -

Not without frying the clutch.  Need a stump-puller first for those situations, which ain't gonna happen with a GMC.

San Francisco, as we all know, has lots of hills.

You don't see stick-shift charter buses going up (or down!) them - they skirt the steep stuff.

Even the auto-equipped avoid them - including Muni, the city's transit system.

OTOH, I have seen 10-speed RoadRanger equipped Crown & Gillig skoolies walk right up these hills, fully loaded.  Maxed out in first gear at 3 mph, naturally.

FWIW & HTH. . .

[Len Silva]

In addition to the question above, how about a 4106 with a stock 318 and either a VS-2 or V-730?

Len

[Dallas]

Len,
Mine's not a 4104, but it is a 4103, lighter and fewer accessories. Standard 4 speed spicer and 6-71 with N65 injectors.

We were at Warriors Path State Park in NE Tn a few years ago to meet with George Lowry in his 4106.

As you pull in around the bend of the entrance there is a short hill that has to be 6 or 7% grade. I had to slip the clutch all the way up just to make it. If I had been at a dead stop, I never would have been able to do it at all.

These old coaches were built to run, not to climb and it really hurts them to be asked to do it.

Georges 4106 you ask?? Well, he had a little bit of modification to his..... Powered by a Cummins VT903 turned up plus a propane injection system. Transmission was a V730 and highway gears. He walked up the hill and accelerated all the way.

Too bad he sold the bus, but it's still tooling around from what I hear.

Dallas

[WEC4104]

I have the stock 4104 setup (6-71 & 4 speed Spicer) and have tackled some pretty steep inclines.  While I wouldn't want to race anyone to the top, the ol' girl has never given me cause to wonder if I would make it.  I attribute this to the gearing ratio in 1st & 2nd, certainly not the torque and HP of the 6-71.

The most extreme case would be to have to start from a dead stop on a major grade, and I've done this.  Not the most clutch-friendly situation to face, but still doable.  Fortunately, with the 4104's gear ratio you do not have to be moving forward all that fast and still be able to release the clutch fully without lugging at too low an RPM.  Once past 1200 RPM, I've never had any problem getting to the redline in first gear, even on some pretty incredible inclines.  It is really unusual for me not to be able to at least grab 2nd while climbing any hill of sustained length.  --- and most of these experiences were before my engine rebuild.

As long as there isn't traffic tied up behind me, doing a slow climb up an extended hill in the 4104 is something I find interesting in a twisted sort of way. There is just something about crawling up the side of a REALLY steep mountain at 15-25 mph with the redlined 6-71 just screamin' away in the back.  After a mile or more of this, you get to the top and you feel like you've accomplished something. The bus gets an "Atta girl!" from me, and I get an extended smile on my face.  I guess it's just a busnut thing.       

[Barn Owl]

I have a stock 318 with the V730 and I have no problems no matter how steep the hill. If you could see my driveway, you would completely understand. 7/10ths of a mile long and straight up a cliff. It's as close to four wheeling as you can get in a bus. If it were not for the auto, 35' length, and low height of the 4106, I would not have it sitting in front of my house.

[jjrbus]

79MCI5C with a 6V71 4 speed auto. I'm really concerned that I am going to get a ticket for loitering on a long hill!!!

[Utahclaimjumper]

Barn Owl, no such thing as a STOCK 318, a 318 is a modified 8V71 usually up from a 270.>>>Dan. (318 with VS2-8 and propane mixing)

[Ncbob]

Len!  You devil....you were only 70 miles from me, not too far from Kyle and Uncle Ned either.  Sure would have liked to seize the moment to meet you.

Let's try it next time.....

NCbob

[John Z]

~This got to be longer than i thought, so i apologize up front the rambling.~
I bought my stock 6-71 and 4 speed spicer equipped 4104 last Oct. I drove it home about 350 miles. I could not wait to use it, so the second weekend with it, i was heading out to a state park in Minnesota. I had never been to this particular park so was being guided by my navigator as to where to turn off the highway.

The road into the park dropped down very sharply as soon as i turned off, and my immediate thought was "OHMYGOD i hope i don't have to stop here on the way out!" After getting out and stretching our legs and finding out there were no sites available, it was time to leave. I had never been on any hills with the bus, so i was worried to say the least.

I left it in first and had it wound up pretty good as we started to climb out. I was silently praying "please God, don't let there be any traffic on the highway when i get up there." Well, just to prove that God has a sense of humor, of course there were all kinds of cars on the highway. But He did grant me the help of letting me be the first vehicle at the stop sign! I stuck as much of the front of the bus out into the shoulder of the road, put in the clutch and stopped!

My mind was racing trying to figure out what to do to get this seemingly-impossibly huge vehicle moving again. I had read about the relatively frail clutch on the parlor coaches when combined with the tall gearing. I looked into my mirror and see that a SUV towing a boat has pulled up behind me - Great i thought, just what i needed. I thought about holding the bus with the emergency brake but there really was not enough time to work out all the details and get comfortable with that idea.

So the traffic clears enough and i am thinking about the DTS and not using the throttle for fear of toasting the clutch on my first trip out! I let the clutch out until i can feel it load up against the brakes, release the brakes and release the clutch some more... and it dies! CRAP!!! I look over at my navigator, and there is sheer panic on her face. My body temperature seems to have instantly risen at least 15 degrees, and my stomach is doing flips. Huge beads of sweat are forming on my forehead. I stab the brakes to hold the bus and hit the starter button. The DD fires right up with a bit of black smoke, and i notice the SUV is now franticly trying to back his boat down the hill - "smart man" i think to myself.

I have only a few seconds to decide what to do next before my next opportunity to pull out passes. I really don't have 1500.00 to spend on putting in a new clutch. I sure am not going to give up and just sit here for a while as i try to figure this out. It always amazes me how fast the mind can process all these different bits of info - really amazing! I decide to just let the clutch out enough to where i can feel it start to grab. I move my foot from the brake to the throttle and poke it half way down, while just dumping the clutch (still was scared of toasting it by trying to slip it).

My poor old 4104 had of course started to slightly roll backward and i thought this can't be good. It shuddered a few times when the clutch started to grab. The clutch slowed the engine down - way down. I honestly thought it was going to die again. I look in the mirror and the SUV had managed to get himself about 15 - 20 feet of space before reaching the vehicle behind him. Black smoke is pouring out as dear old Tubby starts moving forward. I have no idea of what the rpm's were at that time, as i am too busy praying, and watching the traffic coming downhill on the highway from my left. They really did have plenty of time and room to slow down some as we started creeping out onto the highway. I bet i could have counted the rpm's, it was barely running. Just when I expected the DD to quit again, the grade changed enough to let Tubby roll a bit more. I got control of my leg enough to let up on the throttle a lot as we started to swing out onto the highway! Tubby made it! I realized i had been holding my breath as i took a deep gulp of air! I could have cried tears of joy!

Those old GMs are strong, over engineered, and extremely well built. But the parlor coaches were not meant to start out on hills. Their thing was to back out of the depot and jump on the highway and run down the road to the next depot. And the bus companies had already figured out that it was not a smart idea to build depots on a hill!

I would appreciate any hill starting tips from the old heads on the board. This turned out to be quite a bonding experience, but i promised Tubby that i would do my best to avoid every putting him into a situation like that again.

[Len Silva]

John,
That reminds me of an incident some years ago.  It was in my yard and not all that steep.  I had stopped for something and when I started forward again, the coach rolled backwards.  I gave it a little fuel and let out the clutch and it started going even faster in reverse.  My brain said the clutch is gone, give it more fuel and get up the hill.

It went even faster in reverse and my wife was screaming about something.  I looked in the mirror and huge clouds of white smoke were pouring out of the intakes.

TMALSS, I had stalled out and it and restarted backwards.

After the panic subsided, I checked it out and everything was OK.  Got it restarted and up the drive with no problem.  A DTS on a steep incline can be hell on the nerves.

Len

[Barn Owl]

Utahclaimjumper,

Yea, I was responding to Len using his words when he said "how about a 4106 with a stock 318 and either a VS-2 or V-730?"

I have #70 injectors, I only know what I have read others say, those injectors will make it a 318, right?

[Utahclaimjumper]

Barn owl, No, a 318 has been "A" timed and N65 or larger injectors.>>>Dan

[Barn Owl]

How would I know if mine is "A" timed?

[Utahclaimjumper]

There is a method discribed in the manual as going thru a injector hole to check piston position to cam relationship. I know mine is "A" timed cause I did it during a trans change.(trans needs to be removed to get at cam timing gears)>>>Dan