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bedford mj speed problems


nuttycircusman

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hi all-my names matthew and im 22 i love classic military trucks-i am a ringmaster in the circus. (just a quick introduction) :-D

 

i own a ex military bedford mj 4x4.

i bought it from david crouch a very helpful and knoledgable man in june 2009.

the bedford only had 8000 miles on it it is a left hand drive and was in excellent condition.

 

it came with a radio and office body on it. and i have since converted the box for a workshop/costume storage unit.

the 4x4 is second to none on our muddy fields coming in very handy.

 

however i do have one quiet big problem with it. which im hoping someone can help me with.

 

heres the problem

 

it is a 1986 truck with a 330 turbo engine in it with 4 speed gearbox like most others.

 

anyway i use the truck to pull my mobile home it is 32ft long and ways about 4 ton.

the bedford goes very well upto 5omph on a flat road with it, however when it gets to any kind of hill the bedford just dies, im often doing 15 miles per hour with it and down to second or first gear.

i used to pull this caravan with a 2.5 ltr turbo renault 5 ton van and that used to fly with it.

 

i have been told by several people that the bedford should be able to go faster than that uphill. i mean im not wanting or expecting it to fly uphill but a little faster would be great.

 

THE BEDFORD ALSO DIES ON THE HILLS ON ITS OWN. WHEN IT IS NOT TOWING

 

i am getting full throttle out of it and the clutch is fine. as i say the truck only had 8000 miles when i got it and it now has just over 10 thousand.

 

 

so please guys does anybody know what could be wrong with it.?

 

any help would be very very much appreciated.

 

thankyou in advance matthew

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Hi matt.

Just one other thing too check is the o ring in the fuel filter housing, when you changed the filter was the rubber seal seated in the housing correctly. I had this problem getting the seal to seat properly on a bedford

just recently it kept on twisting. (just something to check ). hope this is of some help.

 

Clive

............................

protruckservices.com

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Hello mate.

 

I also own a Bedford MJ. I have to say that my truck is also slow up the hills. On a flat it will do 50 MAX, 40 is the comfortable cruising speed. Mine is fitted with an Electronic Radar Repair Workshop with all the kit still fitted. The all up weight must be around 8.5tonnes. The BHP of a Bedford MJ 330 is 108bhp. My truck has only done 2,500 miles so the engine isn't even run in yet. I've changed the fuel filter, the air filter is new (the truck had a two yearly service and inspection at ABRO two months before release - this included the fitment of a new transfer box, front wheel bearings/hub seals/brake shoes/new fuel tank etc, etc

 

With my truck, it will slow down to 2nd gear (speedo not working properly so can't say what actual speed is) on a steep hill. When in 2nd gear it manages OK and eccelerates very well, but seems to be too low geared as the revs increase pretty quick, but to change into 3rd gear will kill it, so you have to stay in 2nd until the climb is finished. I used to drive them in the Army and can't really remember what they were like, but the ones I drove were GS versions without a very heavy box body on the back. I have been behind other Bedfords and these also were slow up the hills.

 

I don't tow a trailer and it's one of the things that has put on hold my requirment for a living van.

 

Has this just happened with the truck or has it always been like that? The turbo on mine doesn't make any noise whatsoever, even under heavy load, and I find this somewhat strange. I know the turbos fitted to the MJ were either low pressure or meduim pressure units. I'm betting mine is fitted with the low pressure version. As I'm a truck driver for a living I have driven enough trucks to realise that the turbo can make a BIG difference to the trucks ability to hold speed uphill. Personally I think the problem I have with mine (and it looks like you also have the same problem) is to do with the turbo pressure being too low. When you look at the size of the intake turbine, it's huge. This would be like blowing into a dustbin, just no increase in pressure at all under load. The exhaust side is roughly the same size. I'm actually going to look into the possibility of fitting a different turbo, but the problem you then have with a higher pressure turbo is the stress on the engine that it wasn't designed for.

 

If it was a poorly fitting fuel filter seal you would have air getting in, or diesel getting out all of the time and not just when you go uphill. This would lead to problems starting as there would be air in the system (I had this trouble with a 106 diesel. The fuel line was pinched under the seat rail and had a pinhole in that was letting in air. It ran like a dog and the fuel pump was constantly bleeding the air out - all because of a pinhole)

 

I don't think it's the fuel pump either.

 

There are enough members on here with Bedford MJ's, so come on guys, what is your truck like up the hills? I don't think there is a problem with yours as both of ours seem to suffer the same problem, unless of course both of ours seem to be suffering from the same problem??? (If that makes sense:sweat:)

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thank you all members for your help-ill have to keep playing with it and trying different things.

just i have a friend who has a funfair and he tells me and i have seen the pics of him using a bedford mj non turbo ith a generator on the back to pull a fairground arcade and also a 35ft living wagon.

he said it still used to climb hills ok.

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sorry guys i also forgot to say that a friend of mine has a older bedford mj with a non turbo 330 in it and he put a fith wheel coupling on the back and pulled a artic living wagon weighing approx 8/9 ton trailer.????

 

i must say they are wonderful trucks and it im very very happy with it, just need to sort it out re the speed.:-D

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What does the Brake horse power per ton work out for each of the two scenarios you describe? BHP per ton is the most significant factor that affects how fast you can get up a hill.

 

Just guessing at some figures if an MJ weighs 5 tons and has a 98 hp engine and is towing a 4 ton caravan this works out as 98 horse power for 9 tons or 10.88 horsepwer per ton.

 

If a Rennault (Master?) weighs 2 tons and has 76 horsepower and tows a four ton caravan, this works out as 76 horsepower for 6 tons or 12.66 horsepower per ton.

 

Ie the Renault has about 16% more power available per ton than the Bedford, so yes if I have made sensible guesses as to power and weight, then it will be noticibly quicker up hills.

Edited by antarmike
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Later versions of the Renault have an output of 150 horse power, The figure would be something like weight of van 2.5 tons + 4 ton caravan .

 

150 horsepower for 6.5 tons equates to 23.1 horsepower per ton .

 

This is over double the power to weight ratio of the Bedford MJ towing the same caravan, so on these figures the MJ will be much slower, (possibly only half the speed up hills.)

 

based on these figures you MJ is probably doing the best it can and has no actual problem, you are just working at a much lower BHP per ton than you are used to.

Edited by antarmike
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Not sure if this is of any use as it refers to the MK, ie multifuel non-turbo, but the MVEE data book for cargo version gives a Gross Power to Weight ratio of 8.36 kW/t

 

To compare this with a Land Rover Series 3 109", that has GPW ratio of 22kW/t

I thought thta the figure quoted for the horsepower of an MJ seemed low. 98 BHP is probably non turbo figure.

If you take 1 BHP to be 746 watts, then 8.36kW/t equates to 11.206 BHP per tonne which is roughly what I guessed, so potentially a 2.5litre Turbo Renault could have twice the BHP per ton when pulling 4 tons, hence it will be significantly faster up a hill than an MK.

 

Until I know an authoritive output for the MJ I can't say much more, but to have a higher BHP/ton than the 150 BHP Ranault towing 4 tons (grossing 6.5 tons) an MJ (towing 4 tons and grossing 9 tons) would need to be 208 BHP. and that seems unlikely!

Edited by antarmike
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Until I know an authoritive output for the MJ I can't say much more, but to have a higher BHP/ton than the 150 BHP Ranault towing 4 tons (grossing 6.5 tons) an MJ (towing 4 tons and grossing 9 tons) would need to be 208 BHP. and that seems unlikely!

 

About 100bhp out!

 

Bedford 6 cylinder in line diesel unit of 5.40 litres (330 in^3) capacity. It is direct injection turbo-charged with a compression ratio of 16.1 producing 80 kW (108 Bhp). The engine is water cooled and pressurized at 0.44 -.0.53 bar (61⁄4 - 73/4 lbf/in^2).

 

I think you may be asking a bit much of the old girl...

 

Stone

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Stone is correct in that the 330 has an output of 108bhp. But remember this is probably for a new engine. Every engine will vary considerably. I've driven artics that are rated at, say, 460bhp, but every truck will pull differently. An engine will work better if it's been pulling maximum weight since new. I've driven trucks that were used on very light work. Once you need to use it for heavy work they die up hill, where as the same make and engine size of a truck that's been used on maximum weight all it's life will go far better. Don't know why this is though?

 

 

The MJ's are very under powered in my opinion. A Reo is (I think) 8 litres and 140bhp for equivalent total weight. The bigger Ural 4320 has a monster 10.8ltr V8 diesel producing 240bhp, plenty of engine for the size of the truck.

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Hi, I run a Bedford RL fitted with a normally aspirated 330. The all up weight with its retro fitted box body is 5.5 tonnes, probably slightly heavier when returning from Beltring with that years new purchases !! As a yardstick, it grinds down to around 15 mph in 3rd up those Bastard great hills out of Paddock Wood on the A20. When I got it the engine was a recon so hardly run in & it was even more gutless but with use it seems to have bedded in & performs much better now. On any incline I run it down to 20mph in top & then hit 3rd which you can push down to about 12mph. in most cases you've got over the top before the need for second arrises! Only on the steepest hills have I had to resort to second, but when you do, you could get out & run faster ! Also I have on occasion A framed my 2A landy on the back, hardly noticeable on the flat but get to a hill & its 2nd & 10mph again. In conclusion, the 330 is a good old plodder but no rocket ship & what you are experiencing doesn't surprise me, given that bloody great trailer! Welcome to 1960's Bedford world ! Be patient young man, it'll get you there, just not very quickly, all the best, Basil.

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