Diesel Engine Conversion to Frying Oil

[Oonrahnjay]

not the good one

    Sorry, it's hard to take a photo of a dark engine in a dark place, but is this one of the good ones???

[TomC]

No actually it is the worst one. That electronically controlled fuel injection pump is what gave Cummins so much problems. When it goes out (and it will) just get a new one or factory rebuilt. They are trouble some.
The inline mechanical fuel injection pump or now common rail electronic fuel injection pump are the best. Sorry to give you bad news. Good Luck, TomC

[Oonrahnjay]

No actually it is the worst one. That electronically controlled fuel injection pump is what gave Cummins so much problems. When it goes out (and it will) just get a new one or factory rebuilt. They are trouble some.
The inline mechanical fuel injection pump or now common rail electronic fuel injection pump are the best. Sorry to give you bad news. Good Luck, TomC 

     Better to know it now.  Thanks,  BH

[jackhanow]

Been wanting to reply. But had to move to my winter haven. Got busy when I got here. In my experience, most of the trouble was when they changed the fuel in 08 ish. I would go ahead and put it in because although pricey, it's not a super big job to change the pump on that motor and that was the main issue. You can also buy full kits with injectors and pump and transfer pump. If it's not gonna be easy to get to the front do it before installing. Btw I believe you need a throttle pedal sensor for that motor. Not sure how this one was set up.

[Oonrahnjay]

Been wanting to reply. But had to move to my winter haven. Got busy when I got here. In my experience, most of the trouble was when they changed the fuel in 08 ish. I would go ahead and put it in because although pricey, it's not a super big job to change the pump on that motor and that was the main issue. You can also buy full kits with injectors and pump and transfer pump. If it's not gonna be easy to get to the front do it before installing. Btw I believe you need a throttle pedal sensor for that motor. Not sure how this one was set up.   

    Yeah the Gillig was running well when it was put up for auction.  The mechanic who is helping me with the engine swap was in charge of the maintenance of the bus before it was sold off (US Govt would not support the financing on a 30-foot bus so Transit Authority had to sell it off and replace it with a 40-footer, also, the turbo was fried and that knocked the price down way far) says that the bus had about 350K on it when sold.  Rear end and transmission replaced within the previous year (although I'm changing the rear end from 5.29 to 4.63).  My mechanic says that the engine had never needed to be touched -- he says that they always used Lucas fuel treatment in their buses.

    I'm too far down the road to go back.  If I have to replace the pump, injectors, etc., then that's just the way it is.  I was never foolish enough to hope that this was going to be an inexpensive hobby.  The original engine in my bus sat in a "bustle type" engine compartment; since the Cummins is a bit longer and the radiator bigger, I'm going to have to build a new engine cover- the plan is to have a hinged cover, unlatch the cover and lift it up and the entire engine above the oil pan gasket level is exposed.  So at least it will be reasonably easy to access the engine for work.

    The TPS is on a plate with the brake cylinder.  The brake cylinder on my bus was working OK but the one off the Gillig is newer and more compact so I'm going to move the entire assembly.  I've already stripped the Gillig wiring from the pedal to the main connector to the engine ECM so it's ready to go in.

    Some things about this swap are easy, some are devilishly difficult but all in all, it's going well.  Thanks for your comments and assistance.

[jackhanow]

I saw an older bus, not sure what make it was, a gmc maybe, but they put a series 50 in and just built a box around it and just moved the bumper plate back about 8 inches. The box swung open for access and I must say, the bus was a little rough on the outside and the box blended in like it belonged there and the engine job was well done. Makes me want to do that to my mc5.

[Oonrahnjay]

I saw an older bus, not sure what make it was, a gmc maybe, but they put a series 50 in and just built a box around it and just moved the bumper plate back about 8 inches. The box swung open for access and I must say, the bus was a little rough on the outside and the box blended in like it belonged there and the engine job was well done. Makes me want to do that to my mc5. 

     Like I said - a separate engine compartment.  The new one will be similar but a little longer.

[jackhanow]

I too have pondered the double decker idea. I bought this 102 because it was handy and I couldn't beat the price for what I got. My next one will be something I can do some real mods to and set up better for me. This one I bought so I could go back to full timing it right away. My 5 is also a great unit but wasn't working well with my plan unless I could take more time and money to Frankenstein it. It's getting harder to find any good 71/92 mechanics and I'm not that experienced either. I just study and pull some thing out of a hat, kinda like an educated guess. Anyway they have a neoplan listed on one of the converter sites and can really see a good use for the luggage SHED.

[TomC]

Bruce-reducing the rear end ratio from 5.29 to 4.63 will only lower the rpm of the engine at 60mph by 330rpm-not worth the work and cost. What transmission do you have? What engine do you have? Tire size? What speed do you want to cruise at?  Let me know-I'll give you another opinion on your gear ratio. Good Luck, TomC

[Oonrahnjay]

Bruce-reducing the rear end ratio from 5.29 to 4.63 will only lower the rpm of the engine at 60mph by 330rpm-not worth the work and cost. What transmission do you have? What engine do you have? Tire size? What speed do you want to cruise at?  Let me know-I'll give you another opinion on your gear ratio. Good Luck, TomC 

      Thanks, Tom.  The problem was that the last rebuilder on the transmission installed the output bearing without seating it in the bore and the entire shaft started to float axially.  It cooked the bearing and the pinion gear and the wear pattern on the ring gear was all over the place.  So, it has to have new rear-end gears.  I ran the number through the calculator and it gives 61 Mpg for 1700 Rpm with the 6th speed enabled on the Allison B500.  The Cummins is flexible enough to give a little more speed if I need it but I figure the 60-65 Mph cruising range is good -- that big brick will be pushing a lot of air over about 60 and no matter what the gearing is, it's going to be slurping the fuel.  Besides, I'm an old retired guy who drives slow anyway.

(Engine Cummins 8.3 ISC photo above
Allison B500
Tires 275/70-22.5*

*Those tires are a God-send -- the bus was originally built with a height of about 13-8" with 11R22.5 tires; going to the 275/70's brings it right down to 13-6" -- the legal height east of the Rockies)

[eagle19952]

are you sure that you can get 6th gear unlocked ?

[Oonrahnjay]

are you sure that you can get 6th gear unlocked ?  

     Yeah,   inside job!

[eagle19952]

     Yeah,   inside job!

double 

[Oonrahnjay]

Bruce-reducing the rear end ratio from 5.29 to 4.63 will only lower the rpm of the engine at 60mph by 330rpm-not worth the work and cost. What transmission do you have? What engine do you have? Tire size? What speed do you want to cruise at?  Let me know-I'll give you another opinion on your gear ratio. Good Luck, TomC   

    Tom, I used an on-line calculator (just eyeballing it looks like it works right).  I didn't so much look at the Rpm as the speeds.  At "best fuel economy cruising Rpm", it will do 52 Mph with the 5.29 and 60.6 with the 4.59 diff gears; since 60 Mph is my target cruise speed, the 4.59:1 should work well.  But, as I said, it isn't an issue since the diff had to be rebuilt anyway.

[TomC]

275/70R-22.5=547rpm. 4.59 x 547 x .65 = 1631rpm @ 60mph. This is good for the ISC. If you need to climb a hill, drop to 5th that would turn 1883rpm @ 60. Good Luck, TomC