Pull Power

[fraser8]

I have a Provost with a 8V71 and a 4 speed automatic, I would like to pull a trailer with my Classic ambulance on board. A 57 Chev (www.oldambulance.com) it weighs about 6,000lbs in total. The tandem trailer is rated at 12,000lbs and has electric brakes. I'm concerned about enough pull power and cooling problems. I would like to attend numerous emergency vehicle shows next year in Canada and the US. What do you think, should I stick to my Corvair???

[Stormcloud]

I doubt if a Corvair would pull your ambulance on a trailer

[Nick Badame Refrig/ACC]

Hi Fraser,

I'm sure your trailer weighs in somewhere between 3 and 4 thousand lbs. Add that to your ambulance and 10,000lbs is

going to be near your limit.  It can be done but, like you say, cooling problems may arise.

Another option you may have is Flat tow the ambulance. Is it stick?

A good tow bar set up, supplemental brakes, and with a shield to prevent damage from grease and stones may be a good solution.

Finding places to store a trailer at events and maneuvering a trailer to hook-up is going to be a pain in the neck anyway...

Good Luck
Nick-

[RJ]

I doubt if a Corvair would pull your ambulance on a trailer

Storm -

Hey, my '64 Corvan may not pull Fraser's trailer, but my '64 Giant Greenbrier will!   


Fraser -

Your Prevost will pull your trailer just fine, albeit with slower acceleration and hill-climbing.  Just make sure you shift the transmission manually and keep the revs in the 1800-1900 range on a partial throttle when pulling grades and you should be fine.  Remember, black smoke is unburned fuel, which can lead to overheating, so keep an eye on the exhaust as you climb.  Might want to read the following, near the end, for some time-tested tips:

http://www.busnut.com/bbs/messages/12262/16204.html?1167073154

Also, you might consider a Tuff-Tow unit, to take the majority of tongue weight off the rear of your coach, especially when you've got the vehicle inside the trailer.  Here's more info on this unit:

https://www.shogunindustries.com/cgi-bin/ws400CS.cgi?cart_id=1080503094815439&page=tufftowindex.html

I trust that you have a Jake brake to assist with your downhill braking??  If not, it's a VERY wise investment, especially if you're pulling a trailer that heavy.

Whatever you do, enjoy!!

FWIW & HTH. . .

[prevost82]

I would put a 8V92ta in it ... or at lest a 6V92ta. The other option would be a Cummins M11 with a 10 sp autoshift. With the 8V71 you'll have it near floored to maintain speed and will be doing 20 to 30 mph up the many grades in the west with that heavy trailer on the back. Prevost has a much heavier engine cradle compared to a MCI ... so I wouldn't worry about the a 12000 lb trailer.

I swapped out my 8V71 6 sp stick and put in a 8V92ta 6 sp stick (same tranny) ... took me 3 days and what a difference. With the 8V71, seated coach, empty, I came up the snowshed hill (8%) on the coquihalla @ 20 MPH ... with the 8V92ta with the coach converted and full of fuel and water, 38K lbs coach weight, towing a full size Chev diesel pickup, loaded with tools, 7000 lbs, I come up that hill at 50 MPH. With the side radiator in a Prevost, I've had no heating issues ever at high ambient temps, 95 degs F, on 6 to 8% long grades .... I used the same rad that was used for the 8V71.

And the last comment of Russ's about Jake's .... yes you will need them ... I wouldn't even attempt towing that much weight without Jake's in BC or in the west ... the grades are just to long. With the same combination, finished conversion towing the truck, going down the snowshed hill ... I will make 1 or 2 short brake app's doing about 55 MPH down the grade. 

Ron

[DrivingMissLazy]

First I think you should make sure there are good brakes on the trailer, then worry about Jake's on the coach.

Richard

[fraser8]

The Coach has Jake brakes and the trailer has 16" tandem wheels with heavy duty electric brakes. It was designed to carry 12,000lbs. I think the tow bar and aux. brake idea might be the best as I could unhook and drive it up the real steep grades like the Coque or the Salmo. I don't relish laying out big bucks for a new engine, the 8V71 only has 33,000 miles on it. The car with trailer combined weigh in at 8,450 lbs. I'll give it the tow test and see how it does, I agree that trying to park the trailer and coach at an event would be a problem, just unhooking the car would be a plus. Those extra wheels on the hitch look interesting, it's a novel idea. Thanks for the input

[TomC]

You could do what I did and have your 8V-71 turbo'ed with air to air intercooler.  I changed my injectors from 65 to 75 for an increase of power from 300 and 800lb/ft torque to 375hp and 1125lb/ft torque.  If you keep the same injectors, your power will increase to 325hp and 975lb/ft torque (about the same power as a 6V-92TA).  And the main thing is you'll maintain that power in high altitudes pulling the grades and not have any black smoke or have to keep your foot out of it to prevent black smoke.  Good Luck, TomC

[fraser8]

Tom, that sounds like a realistic fix, and it will update the power. I installed a Banks system on a 85 Ford diesel I once owned. I didn't have to check for cars on the horizon when I pulled on to the highway. The only thing I missed was the black smoked, it reminded me of an old war movie when the British navy laid a little smoke. I like simple and effective.

[ArtGill]

You may want to think about having your trailer RATED for under 10,000 pounds.  In North Carolina the HP guys have been cracking down on boat trailers and requiring, among other things, class A driver license to tow a trailer rated over 10,000 irregardless of the actual weight loaded.  And don't put any logo's on the side or they may want an CDL A.  North Carolina has reached the point that if you are going to a fishing tournament that it is a commercial boat and therefore you need a CDL to tow it.

If you purchase the trailer new you may be able to get the manufacturer to under rate the trailer with a new ID tag.

Art

[TomC]

In California, you're allowed to pull up to a 10,000lb pull trailer or a 15,000lb goose neck/fifth wheel trailer on a class C license.  Over that you need a class A non commercial license.  If you're pulling a trailer through New Mexico and your total rig weight is over 26,000lb, you better have at least a class A non commercial license, or the scales (RV's do get pulled through commercial scales at times) will make you drop the trailer and get a class A non commercial license before you can retrieve your trailers.  Good Luck, TomC

[fraser8]

I can easily change the trailer GVW to 10,000 lbs, and I have a Class 1 with air D/L, so I'm good in the license department. I'm still considering my tow options. I did a emergency services show today and had an opportunity to talk to a Diesel mechanic that works for a large truck dealership. I've known his parents for years and didn't know where their son worked. He's offered to assist me in any mechanical repairs I may have in the future. It seems he apprenticed on the DD's so things are looking good. I don't have any mechanical problems with the coach but you know the old saying if it's got the two T's it going to be trouble..... Thanks for all the input.