Smells Like Teen Spirit: Conversion of 1999 Thomas MVP

[Tango]

Depending on which model Allison you have, reprogramming to pick up 6th gear can make a huge difference. The two top gears are both OD. On mine (as I recollect), 5th is about .75 and 6th is .63. That's a pretty big jump that can equate to lower RPM's or more MPH as well as improved MPG at highway speed. Any way you slice it...sweet!

If you want to nail down just exactly how much difference, you can plug your numbers into any online gear/rpm/wheel size calculator...

like this one...
http://www.csgnetwork.com/multirpmcalc.html

Handy little tool.

[Docsgsxr]

Originally Posted by porkchopsandwiches

I contacted a dude on Reddit who works on these. He sent me a PDF of the manual.

Think I could get you to email me it??? PLEEEEAAASE!!!!!!!

[sdwarf36]

Make sure you get all the oil out of the cylinder before you put the injectors back. Even if it means cranking over the engine with a towel over the top.

[porkchopsandwiches]

Originally Posted by Docsgsxr

Did you pick up a manual for the motor? How do you know the torque secs? If you did, how much was it, and where did you get it?

I need to do an injector swap on mine too. Figured while I am in there...........
-Doc

I contacted a dude on Reddit who works on these. He sent me a PDF of the manual.[/quote]


Think I could get you to email me it??? PLEEEEAAASE!!!!!!! [/quote]

Its only for the procedure I did, I don't have the whole manual. Don't do this repair unless you have to...and it is only injector SEALS not the whole injector. Replacing all injectors would be like $2500 in parts. I can send you them if you want, PM me your email.

Originally Posted by Tango

Depending on which model Allison you have, reprogramming to pick up 6th gear can make a huge difference. The two top gears are both OD. On mine (as I recollect), 5th is about .75 and 6th is .63. That's a pretty big jump that can equate to lower RPM's or more MPH as well as improved MPG at highway speed. Any way you slice it...sweet!

If you want to nail down just exactly how much difference, you can plug your numbers into any online gear/rpm/wheel size calculator...

like this one...
http://www.csgnetwork.com/multirpmcalc.html

Handy little tool.

Thanks, I have calculated that before. I forget the numbers but if I remember right it was something like a 400-500 rpm drop in RPM at 65 mph if 6th was enabled. This motor makes peak torque at 1400 so spinning at 2400 (at the rev limiter) is doing nothing but excessive wear and wasting fuel.

Originally Posted by sdwarf36

Make sure you get all the oil out of the cylinder before you put the injectors back. Even if it means cranking over the engine with a towel over the top.

Thanks, I got a suction gun I am going to use. I also will rotate the crank over slowly with a wrench with the injectors reinstalled in hopes that any pooled oil would get pushed past the rings. Though the way the pistons are shaped its more likely to be trapped in there. In any case, it will probably run like crap for the first few minutes, due to the oil in the cylinders, air being pumped out of injectors oil passages and fuel passages, and installing new oil / fuel filters. Probably will take a lot of cranking to get it to fire even after priming the fuel rail.

[Diesel Dan]

Originally Posted by porkchopsandwiches

Thanks, I got a suction gun I am going to use. I also will rotate the crank over slowly with a wrench with the injectors reinstalled in hopes that any pooled oil would get pushed past the rings. Though the way the pistons are shaped its more likely to be trapped in there. In any case, it will probably run like crap for the first few minutes, due to the oil in the cylinders, air being pumped out of injectors oil passages and fuel passages, and installing new oil / fuel filters. Probably will take a lot of cranking to get it to fire even after priming the fuel rail.

I've not followed this conversation is great detail, but oil in the cylinders may cause "runaway diesel", which is not so much running poorly, but running out of control at high RPMs. A scary and possibly destructive situation for the engine. In your case, I suppose there is only a limited quantity of oil, so the runaway situation would hopefully only last for a relatively short time, but still... yikes!

[porkchopsandwiches]

Originally Posted by Diesel Dan

I've not followed this conversation is great detail, but oil in the cylinders may cause "runaway diesel", which is not so much running poorly, but running out of control at high RPMs. A scary and possibly destructive situation for the engine. In your case, I suppose there is only a limited quantity of oil, so the runaway situation would hopefully only last for a relatively short time, but still... yikes!

Yeah it could. There isn't really another way to do it though, since the injectors are hydraulic and are direct to the cylinder. So when you pop them out they spill a ton of oil into the cyl because they are full of it, and the passages are exposed when you pop them out. The goal is to just try and get as much out as possible, that way you don't have enough to hydro lock it or cause it to run away.

[porkchopsandwiches]

Good news, everyone!



Turns out I CAN get 6th gear enabled in my bus. According to my calculations, right now in 5th I hit the rev limiter at 66 mph (2400 rpm). With 6th enabled, I will be at about 2000 rpm at 66, and will have a new theoretical top speed of 77 mph (I will never test this). I just have to take it to an allison tech and give them this, and they will take care of it.

If anyone has this same trans (MD3000 or 3060) and wants info on how to do this, PM me.

[Docsgsxr]

PM sent!

[porkchopsandwiches]

Yessir. I already have a car that sucks down fuel at 3600 rpm on the highway ('87 3-series) I don't need another

Tomorrow morning I'm going to take all 6 injectors to a local diesel shop to get them cleaned and tested. I'm doing this because none of the oil-to-fuel passage O rings look terribly bad or obviously broken to cause the leak , so I want to make sure none of them are leaking internally. I'd be pissed if I put it back together and had the same problems. Also they are a bit carbon heavy on the tips, and I can't safely clean those myself. Hopefully with this, the valve adjustment and 6th gear enabled, I can break 11 mpg

Originally Posted by Docsgsxr

PM sent!

Email sent

[M1031]

WOW Porkchop!

Congrats on the letter!!!! Once my bus goes to auction, I'll be asking how you did that if you don't mind! Katy ISD won't let me drive over 50 mph with my bus . I'm sure I'll have some questions for you once I get my baby.

M1031