Community Forums

scenicruiser · 01-12-2012, 06:58 AM

Hi guys first time here. I am rebuilding a 1954 GMC Scenicruiser and am weighing my engine options. I am replacing the complete drive train, radiator, tranny, engine, wiring, the whole works. I have read several threads on different power packages but would like some more advice. The bus weighs 29,000 lbs according to the original spec sheet and has room to fit just about any engine I want. I currently have (but not installed yet) a 2000 Cummins ISL 370hp package but after reading some posts am concerned that may not be powerful enough for the Colorado Rockies that I live in. I am looking to tow a vehicle and while I am not looking to race- I would like to do the project with no power regrets. Thoughts?
Thanks
Jon

Oldkarphart · 01-12-2012, 07:21 AM

If it were me, iI'd keep it all GMC and install a Duramax and Allison Trans. Find a late model wreck and get the eng, trans, and wiring harness......It'd be a "Neat Conversion"!!!!

Mike Canter · 01-12-2012, 07:23 AM

You should be looking for an engine prior to the EGR installation. So something in the early 2000's between 2000-2003. Also do you need a side mounted radiator or a rear mounted radiator because that makes a difference if the motor has a fan drive on it or not. A Cummins L-10 or an ISM-500 would be ideal

scenicruiser · 01-12-2012, 07:59 AM

I have been looking at the Cummins ISM but I'm still debating if its worth the money or time to "upgrade" to it over the ISL. I also have been looking at the DD13. Do you think there is that big enough performance difference from the ISL to the ISM to switch?

Thanks

scenicruiser · 01-12-2012, 08:00 AM

side mounted radiator

Mike Canter · 01-12-2012, 08:33 AM

That ISM is just a great engine. It is considered to be a million mile motor class like the Detroit Series 60 and the CAT C-15. Whole different class in motors. The big thing is you do not want an engine with that EGR system on it. There are some big motorhome junkyards where you can buy motors. The advantage of a MH motor is it has way less miles on it than a 18 wheeler motor. Remember with this big motors you have to have a Allison 4000 transmission and not the 3000.

scenicruiser · 01-12-2012, 09:25 AM

I know where I can get a complete ISM. Do you feel the difference between the ISL and the ISM would be that big? I know the ISM has an additional 300 lbs of torque.....

Mike Canter · 01-12-2012, 09:40 AM

For one thing a ISM-500 requires the Allison 4000 transmission and I don't believe the ISL does. The ISM is a lot heavier motor than the ISL.

An ISL would be a good engine also if you can get one back far enough not to have all the EGR system on it. If I remember correctly in late 2003 Cummins changed to a High-Pressure Common Rail system for emissions and a varible geometry turbo which kicked up the performance. Even the emission version is a great engine but stay away from the 2005-2006 ISL engines because they had a bad piston/wrist pin problem. They refused to fix them and detuned them instead.

See here:
http://www.irv2.com/forums/f123/cumm...call-5834.html

Sepisllib · 01-15-2012, 06:00 PM

Quote:

Originally Posted by scenicruiser

Hi guys first time here. I am rebuilding a 1954 GMC Scenicruiser and am weighing my engine options. I am replacing the complete drive train, radiator, tranny, engine, wiring, the whole works. I have read several threads on different power packages but would like some more advice. The bus weighs 29,000 lbs according to the original spec sheet and has room to fit just about any engine I want. I currently have (but not installed yet) a 2000 Cummins ISL 370hp package but after reading some posts am concerned that may not be powerful enough for the Colorado Rockies that I live in. I am looking to tow a vehicle and while I am not looking to race- I would like to do the project with no power regrets. Thoughts?
Thanks
Jon

You trying to burst my bubble?

Here all this time I thought my 370 Cummins powering my 2001 Monaco Dynasty running around in the 30,000's and towing a toad was great.

Haven't been too much in the Rockies, but have been all over the east, WV, VA, and points from there - not once did I feel my coach was under powered. On top of that - my average fuel mileage (in total since purchase) is right at 9.2 mpg

Wow!

Maybe I need to take her in to the Cummins boys and have them pump up the power a bit.

PS - really, if you put in the 370 you will be tickled pink, and if you might opt for a larger unit the tickle will be be just a little bit better - but not that much really.

But - it's your coach, you do what YOU want.

God Bless

Bill