Serpentine belt for Cummins ISB w/o A/C Comp?

[Winemaker2]

I have a 2013 Newmar Ventana 3433 w a Cummins ISB 360 HP on FL chassis.
I have located info for Serpentine belt & tensioner and carry them as spares.
I have read of others wishing they had a shorter serpentine belt to bypass the chassis A/C compressor in case of a failure. That makes a lot of sense as a local shop was recently able to replace my belt & tensioner from below w/o major difficulty.
Can anyone provide part number / length / info for the shorter belt?

The OEM is a Cummins #5264021 (Dayco 5080910 Gates K080907) that is listed as 8 Rib 1.1" wide 91" length

Any help appreciated

[Old-Biscuit]

Have you called Cummins and Inquired?
(1-800-286-6467)

[Winemaker2]

Originally Posted by Old-Biscuit

Have you called Cummins and Inquired?
(1-800-286-6467)

I started w Newmar ( also had another MH specific question) but will progress if I don't get answers.
Just thought I might find someone here than has been down that road as it was here I read the suggestion and thought it was a good one.
Thnx for their #

[Skip426]

See if Freightliner can provide you with a belt routing diagram , like this one for an ISL , using the diagram you can determine if a shorter belt routing is possible , while still allowing the auto tensioner to maintain enough tension to rotate the rest of the items it should.

[dp7]

Originally Posted by Winemaker2

I have a 2013 Newmar Ventana 3433 w a Cummins ISB 360 HP on FL chassis.
I have located info for Serpentine belt & tensioner and carry them as spares.
I have read of others wishing they had a shorter serpentine belt to bypass the chassis A/C compressor in case of a failure. That makes a lot of sense as a local shop was recently able to replace my belt & tensioner from below w/o major difficulty.
Can anyone provide part number / length / info for the shorter belt?

The OEM is a Cummins #5264021 (Dayco 5080910 Gates K080907) that is listed as 8 Rib 1.1" wide 91" length

Any help appreciated

Glad you asked. I have the same question.

[Caymanedge]

So I just changed the belt on my MH with the exact same engine. Skipping the AC would help a little with the routing to the top side of the engine, but I'm not sure I'd spend all that time and then have to go back in and change it again.
Having a set of hands and eyes from the top is a huge help and it only takes 5-10 min to move the mattress and access the top of the engine. The eyes are very useful to make sure the belt is properly seated on each pulley. Without proper seating on every pulley it's almost impossible to get the tensioner loose enough to slide the last part of the belt in.
For what it's worth, I can slide under the passenger side next to the tailpipe, sit-up and do 90% of the install. The belt tensioner can be handled form the drivers rear underside.
I too carry a spare belt and an old working pulley.

[Winemaker2]

Originally Posted by Caymanedge

So I just changed the belt on my MH with the exact same engine. Skipping the AC would help a little with the routing to the top side of the engine, but I'm not sure I'd spend all that time and then have to go back in and change it again.

Having a set of hands and eyes from the top is a huge help and it only takes 5-10 min to move the mattress and access the top of the engine. The eyes are very useful to make sure the belt is properly seated on each pulley. Without proper seating on every pulley it's almost impossible to get the tensioner loose enough to slide the last part of the belt in.

For what it's worth, I can slide under the passenger side next to the tailpipe, sit-up and do 90% of the install. The belt tensioner can be handled form the drivers rear underside.

I too carry a spare belt and an old working pulley.

The purpose is not to simplify the install its to allow you to continue instead of being towed to a repair shop and possibly having to wait for a new A/C compressor. The temporary belt could be either DIY or by a mobile mechanic w/o need for a tow & delay. The shop / tech that replaced my belt & tensioner recently did it all from bottom access.
A/C can always be provided by gen & house A/C if necessary.
Am I not seeing something or is that photo of an engine w/o A/C? Looks like just an alternator as accy.

[Winemaker2]

As an update Cummins would only provide OEM belt info. I have reached out to both Newmar and FreightLiner and will update again with any addnl info received.

[Winemaker2]

Newmar - No help simply referred me to FLCC

Cummins - Little help as they would only provide the normal / OEM belt #

FLCC -
Provided the attached diagram with the following notes duplicated here for clarity:

This install dwg is from FK9285-ISB10
It may be possible to short-belt unit to bypass compressor using Cummins belt 3289952 & tensioner 3976834 # taken from AF4250 ISB07
Also may require Idler pulley 5259448 or 5259449 in place of A/C compressor

(not sure how another idler would be mounted??)

This doesn't look like a simple belt substitution like it may be on other engines / belt routing schemes.
If anyone has actually done this on a Cummins ISB and can confirm parts #s required it would be most welcome and appreciated.
Thanks

[Skip426]

Don, as your already aware the short belt set up ,possible on some set ups, may not be possible on your engine . I know it's not possible on my Cat with similar mounting ; A/C compressor below the alternator ;

A replacement idler , would have to mount in place of the A/C compressor, in order for the stock tensioner to do it's job.

I'll have a look to see if an 07 , ISB used a different tensioner arc than your 2013 and/or a different compressor mounting position.

[Skip426]

Caymanedge's photo of a no A/C 6.7 , shows the idler and mount ( yellow box ) that would be required to run with a slightly shorter belt ( A/C compressor pulley dia. being the difference ) if you were to consider the idler , bracket and shorter belt ; you might just as well carry a replacement compressor , with a replacement stock belt, install the compressor without the A/C lines and power to the clutch as the time involved would be the same . A/C could be charged later , after flushing the system .

[Unplanned Tourist]

Looks to me that a shorter belt to bypass the AC will hit the AC pully, so not likely that there's a quick fix if your AC compressor goes out.

[Winemaker2]

Skip426
Thank you for the pics and comments... that clarifies the FLCC comments and makes perfect sense. I agree there doesn't seem to be any practice point to trying to prep for a short belt set up. I recall looking up the compressor part # and if memory is correct it was only around $200 - $250.
At least I know that in a compressor failure situation a tow to a shop is likely.

[Unplanned Tourist]

If you are worried and have a lot of hours on your rig/AC compressor, why not just change it for your peace of mind?

Sort of like buying insurance.