[2bdeLrrp69]

Hello Again,
After reading all of the negatives on this Forum about the VT555 Cummins I am wondering how long mine may stay together.  I am a worrier, and I am good at it!

She runs fine now except for a little smoke but after being stored for so long it probably should.  My question is this,  If I ever have to REPOWER which engine would be the closest to fit and be suitable for the Coach?  1974 Newell 35', currently with Allison 4 Speed.

Thank You

Alfred Nesbitt

[MrE]

@Retro has repowered 2 70's Newells with Cummins 8.3s and Allison 6 speed transmissions and been quite happy.
https://newellgurus.com/showthread.php?t...ht=repower

[Jack Houpe]

I would love to have the time to retrofit a older classic with a Duramax, these older coaches being shorter and less weight offer a lot of different conversion ideas.

[Guy]

I would love to hear from a GURU who has completed a repower on their Newell. Hope someone can chime in with results, and pictures ?

[2bdeLrrp69]

Do you think a Duramax would be an easy replacement?

[Jack Houpe]

I had a 5500 topkick truck with the Duramax that pulled a 50' enclosed car trailer with 2 cars and lots of other goodies with no issue what so ever and cruised down the highway at speed limit. The Duramax is found in pre DEF trucks and parts are everywhere in the country if it breaks down, foot print is small so you have that going for you. I know nothing about the 555 but what I have read and seems they have a weak crank. Duramax offers a lot of piece of mind.

[MrE]

I haven't looked at the dimensions, but physically it's probably an easy replacement. The Duramax is an electronic engine meaning you'll have to get a compatible electronic transmission to communicate with the Duramax ECU. I don't believe the Duramax uses the J1939 CANbus protocol that Class 8 trucks and Newell use, so Silver Leaf and Blue Fire probably won't work to replace your analog gauges. You would be able to use Torque Pro, a $5 Android app with a $20 BlueTooth adapter and an ODBII port that would have to be wired in.

[Jack Houpe]

You know another choice would be the straight 6 Cummins that has mechanical injection, they make a racket but are outstanding engines.

[HoosierDaddy]

I had a 1978 35' with the 555. It would go as fast as I wanted on the flat but struggled in the hills and had a great mellow V8 rumble. If I remember correctly it had 180,000 miles on it when I sold it to the historian of the RV/MH hall of fame museum in Elkhart, Indiana. He stopped in to my house a couple years later on his way back from Florida in the Newell.
I too had contingency plans in place after hearing others speak of its weaknesses. When I considered the size and configuration of the engine compartment and rear radiator placement, final gear ratio etc I was leaning toward a V8 diesel. That lead me to look at the Duramax or the IH "Powerstroke" engines that Ford used in their trucks. I really like the Cummins B series engines but I'm not sure if one would fit without moving the radiator as they are an inline 6.

[Little]

I worked for Cummins during the '555 era'. All of my experience was with farm tractors,Versatile 555 4 wheel drive tractors. The engines had a high failure rate from various issues, however most managed to get to 4000 hr. I bought one of these with a seized engine (crank) and put a mechanical 8.3 in its place. Since there was room to move the rads ahead 5" there were no real fitment issues. The transmission failed about 2 yr later and I sold the tractor to another fellow who had a bad engine.
In our shop we have changed out 2 2003 Hummer H2's 6 litre gas engines to DuraMax 6.6. We used the LBZ engines and complete power trains from GMC 3500 trucks (2007) I had a GM mechanic blend the wiring harness and all gauges etc work great. After some fine tuning these are great vehicles which wife uses a a daily driver and we tow them behind our Wanderlodge.
The single most difficult part of the swap was the wiring harness. MrE has experience with wiring these older Newells.
If you are satisfied with the performance I would do an oil analysis and see what it says, maybe roll in some rod/main bearings and go. Good luck.