# Cummins B6 5.9



## daneinter (Jan 23, 2011)

Hi to all, I,m new on here and introduced myself yesterday re my Optare Metroliner self build.
I wondered if anyone had any experience of the Cummins B6 5.9 turbo. My model is fitted with the Allison auto box 4 speed.
It seems to run ok but two notes are that it seems to tick-over pretty high and on the road the shift change seems slowish. I'm not totally ignorant re these engines but wondered if my bus was low geared as an option? and if so whether an allison O/D box would slot in or perhaps a 6 speed? Finally wondered if a manual box like an eaton would fit. Cummins take alot of transmission options like eaton and zf in their trucks. I realise prop shafts might need altering and gearstick position could pose a problem but if anyone has any ideas.....
I am not unhappy too much with the present setup but realize that MPG will be an issue and its one of those projects for future thought....Anyone??? 
Much obliged
Regards
David


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## gromett (May 9, 2005)

I can't help you on the specifics. My Optare MetroRider has a Cummins Series B. I don't think it is a Turbo version though.
The Revs did feel a little high when driving but tick over is ok.
It is very low geared and appeared to change late but I was told this was due to it being a town bus not a long distance coach type vehicle. It is a fantastic starter however. I hadn't started it since last August and started it again just after the snow went and it literally started in half a second of turning over 

Karl


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## daneinter (Jan 23, 2011)

Thanks for your quick reply. Things yuou might be able to help me with are these items
What MPG do you achieve on average
Who is best insurer for this type of conversion. (I'm clean on convictions and claims with full no claims and an hgv license)
Much obliged to you
Rgds
david


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## gromett (May 9, 2005)

I used www.campton.co.uk with the SBMCC discount.
I think it was getting around 10mpg maybe a bit more.
Very hard to tell as I didn't do that many miles in it before deciding it was the wrong base vehicle for me going forward. My plans had changed somewhat.

Cheers
Karl


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## goldi (Feb 4, 2009)

Morning folks,

I had a seddon atinson when they first out with a cummins b6.

It had an eaton 9 speed gearbox with the first a crawl, would easily cruise at 70 mph if allowed. plated at 21 tonnes , the fuel consumption depended on how much weight was on. somewhere between 11 and 17 per gallon.
I reckon that the allison auto is tatally unsuitable for a motorhome.

Allisons tend to be fitted to buses and dustcarts which are constantly stopping and starting.


norm


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## brillopad (Mar 4, 2008)

Some piccys of these optare things would be nice so we know what they look like, thanks

Dennis


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## speedytincan (Dec 22, 2005)

*slot in or perhaps a 6 speed?*

Hi David, its the diff you need to change, in the gearbox you change springs that control the valves to give it a quicker change. Stu.


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## daneinter (Jan 23, 2011)

Thanks for your replies. can you please enlarge on the gearbox tweak and diff swap. Is it easy to tweak and which diff would be best.

I was pleasantly suprised at my insurance quote. Adrian Flux came in at £330 with £85 for full european breakdown. Quite a relief really. they stated that as long as it had a fixed bed and running water etc it would be classed as a motorhome and that will all be done by the weekend.

I think I will be quite happy to run it for this coming summer with the MPG being 10-15. My current car / caravan setup only produces 20mpg so its not too much of a pill to swallow considering what a lovely setup this optare will give. (Pics follow) They are a solid outfit with plenty of space for 2 + dog.


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## daneinter (Jan 23, 2011)

Picture of my optare as requested/


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## gmberryman (Nov 21, 2009)

As mentioned above it's the differential that you need to change its not a big job but you would need a lift and a little bit of knowledge, there should be a tab on the diff stating the final drive ratio as with the box and engine the axle would be found on many different makes but you will need to know what ratio you've got before you start to look for a replacement.


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## daneinter (Jan 23, 2011)

My friend who is a cummins HGV expert has come up with a few interesting solutions to my ratio problems.on my allinson 4 speed auto coupled to cummins 6 cyl B6 I would appreciate any comments.
1) Increase size of drive wheels
Fit a 2 stage (speed)axle (I have air supply) they are cheap as not popular anymore)
Change auto fluid. He states most change probs are down to this as after some years auto fluid seems to sludge into a brown mess
Any comments?


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