Stretchy belt demount and install QSB 5.9 440hp

[Phil Lack]

Having investigated ordering replacement belts as spares for my 2 QSB 5.9 440HP engines, I was surprised to see the single “stretchy” belt used to drive the raw water pump with no visible means of tension adjustment.

Reading up on these belts, I now need to buy a special tool to both demount and re-install these belts and it seems there are a number of types of tools available for the task.

Just wondering who may have also confronted this issue and what tool you used to (mainly) re-install a new belt onto these pulleys ? Also I am wondering if the main belt has to be loosened off in order to manually rotate the raw water pump drive pulley using a socket and wrench as many of the videos show when installing this type of belt.

All this is relevant in the context of swapping out the existing Sherwood raw water pumps for new SMX units as it definitely involves removing these belts. And can these used belts be re-used again as many YouTube videos suggest cutting off the old belts (although these are mainly automotive applications wiht belts on car engines).

regds,
Phil

Topic

[Phil Lack]

and still more of the message that was blocked:

I did also find a tool to mount/remove this belt and its a GearWrench tool #3681D. I haven’t used it yet but when my new SMX raw water pump arrives, I will try to take plenty of pics and post to this thread for others to see how it worked. If you Google “stretchy belt fitting tool” you will find plenty of different tools available including on Amazon.

I enjoy the collective wisdom on this site and its good to see some new members commenting on this subject. Having been into collecting and restoring classic 911 Porsches over many years, I know and appreciate Forums similar to this in sharing hard won knowledge. Kudos to Tony and his team for providing this Forum for us to learn from.

PS:
https://www.autodoc.co.uk/spares-search?keyword=4PK868 link to UK website showing 2 distinct price points on the 4PK868 stretch belt.

[Phil Lack]

Hi Steve,
to continue on, here is the rest of the message I was trying to post:

Your example does show 2 different length belts which would normally fit OK IF there was some adjustment for tension. I am keen to learn if your motor has any adjustment on either of the pulleys.

I have spent considerable time on Google researching these belts and have concluded that Cummins has probably had this length belt custom built to their specs and unique length (by Hutchinson in France) and whilst there are similar elastic belts close to the 868 mm length, there is no exact equivalent.

I did find a regular material “BANDO” 4PK 868 POLY V belt at US$ 4.82 ea but this is not a “stretchy” belt as Cummins (and Tony) specify. So I am keen to hear more about your experience and if indeed, a regular material belt has worked well in place of where a “stretchy” belt was specified.

[Phil Lack]

Hi Steve,
thanks for your input and photos. I note you have a QSB 5.9 230HP engine and I think this one does not use a “stretchy” belt, but you can correct me on this. A pic of my belt driving the raw water pump on my QSB 5.9 440 is posted below where you see there is no adjustment.

Your pic shows 2 belts with different part nos: 4PK844 and 4PK 850. This is a std method of identifying belts with the 4 signifying number of grooves and the other dimension being the length of the belt in millimeters. The belt also needs to be an elastic or stretchy construction which I believe they call an EDPM construction using particular materials and construction method which allows the belt to maintain its tension automatically. A pic of my Seaboard supplied “stretchy” belt for my engine is also below. It shows a 4PK868 part no. so its longer than yours and I doubt yrs would fit my engine.

Tony does make the point clearly in one of his tech tips that whilst you might find an equivalent length belt in a “normal” material and construction, it should not be used in this application, especially as trying to fit it , requires stretching the belt over the pulleys, which may indeed damage the belt or stretch it so it loses tension and drive.

[Phil Lack]

It seems a short message does get thru OK. I wonder is there a limit on the size of reply you can post ?
Might try again with a shorter response.

[Phil Lack]

I am trying to reply to this last post and keep getting blocked.
Any Admin out there that can help get me unblocked ?

[steve5]

Google this. Most hits will be European because they are BMW and Mercedes applications but it will get you started.
continental belt 4pk 850 (830) elast

[Gene Fuller]

“From some pics on this site, it seems Cummins did have a belt tension adjuster on this raw water pump in the past and I wonder why they went to this style of belt ?”

Traditional belts require an extra pulley and an adjuster mechanism. Water pumps are fixed, unlike alternators, so they cannot just be swung on a pivot to adjust the belt.

Ordinary belts also require more time to service properly.

Poorly adjusted belts can cause wear if too tight or can cause black dust all over the front of the engine if too loose.

Bottom line: cost and quality.

[Kraig Kirby]

Phil-

I did get mine direct from Cummins, it was made in France and was out of stock at the time of order. I tried finding a cross reference and couldn’t find anything. I’m a fan of OEM parts but when they are out of stock another option is welcomed.

Steve if you have a part number for the replacement you’ve found I’d love to get more info on that belt, I tried searching the number on it and came up empty.

Kraig

[steve5]

Cummins replacement stretchy belt

You can buy these belts from auto parts stores for about $8.00 each. It’s an air conditioner belt for Mercedes. I have two years, and 7000 nautical miles on mine, on a QSB 5.9 230. At that price you can keep a couple spares. Haven’t needed a spare yet. Keep in mind, Cummins recommends replacement when ever the belt is removed for any service.

[Phil Lack]

Kraig,
did you buy the belts direct from Cummins as you mentioned the tool was included, or did you get them from Seaboard ?

I did buy one thru Seaboard a while back and its a Hutchinson brand and I believe its made in France. Cummins in Australia dont have any stock at present. I have been researching these Stretchy belts online and there are a few manufacturers but it seems you MUST get the exact length you need (868 mm in my case) and Gates or Dayco dont make one in that size. With zero adjustment, its critical to get the right one. From some pics on this site, it seems Cummins did have a belt tension adjuster on this raw water pump in the past and I wonder why they went to this style of belt ?

[Kraig Kirby]

Thank you for the follow-up, I just received my two new belts last week and saw the tool included however the instructions on how to use the tool are of terrible quality. I did notice they were made in France which led me to believe that is the reason for the delays in availability and also the cost. Best of luck in your journey!

Thank you,

Kraig

[Phil Lack]

Kraig,
I just called the local Cummins Australia Service Manager who advised that when you order the “stretchy” belt for the raw water pump drive, it comes complete with tools to assist in mounting and demounting the belt. He said these tools are NOT available separately but once you have the kit, you are OK for next time.

The main problem is the cost and I did buy a spare belt off Seaboards website at US$200 ea and was not happy to hear that Cummins out here want close to A$ 400 (US$296) for the belt kit (incl tools). I ws also advised that since this belt is made in France, COVID problems have caused many production delays and many items are hard to find (including these bets).

This may be the reason why Seaboards website shows many engine belts out of stock incl the one for my QSB 5.9. Having just ordered an SMX raw water pump I was hoping to add some other small parts to the shipment since its coming such a long way Downunder. Unfortunately we arent blessed with low cost and fast freight of parts like you guys are within the continental United States.

will keep checking on these belts to see when they get back into stock.

[Phil Lack]

So Tony,

thanks for posting this video where it appears you dont need a specific tool to demount or refit the stretchy belt. A lot of the research I did, albeit on automotive serpentine belts, showed a special tool needed so as not to damage the belt.

Of course the video shows the belt replacement in a workshop with plenty of available workspace and ease of standing in front of the engine to apply pressure to the belt. This is why I felt the special tool would be required when performing this task in the confines of a tight engine room, especially one like mine where I only have a max 4 ft headroom at the front of the engines and getting into a position to work on the belt requires some special yoga positions.

Do you or your mechanics still feel comfortable being able to do this in the boat ? Have you done this very often in boats and does any of the methodology shown in the video, vary at all ?

am just trying to picture myself doing this belt refit at sea and having mentally worked thru the process to ensure if he worst happens, its a straightforward job with the right tools at hand.
0
Kraig, sounds like you too are wanting to prepare yourself in case you are stranded. My 1000 nM trip will take me up along the east Australian coast from Melbourne, to Sydney then further north up to Brisbane in Queensland. I have done it plenty of times before, but in a sailboat which has a reasonable alternative propulsion system (sails) to augment the motor. I guess I am just still transitioning to power boats hence my desire to be prepared to any engine issues, especially involving raw water cooling.

[Tony Athens]

Stretchy Belt R&R

[Kraig Kirby]

Phil-

I’m doing the same, trying to be prepared and carrying spare belts however I won’t be covering 1000Nm anytime soon being in the Great Lakes! The installation video previously recorded makes it look very easy but it’s so short I don’t know that it is a true representation and I’m hesitant to try it without further information.

Kraig

[Phil Lack]

Still no reply from Brendan. seems he has fallen overboard…….

It seems both you and I still need some advice from someone experienced in removing and refitting this belt as to the best way to go about it. It worries me that should this belt fail, it leaves me without a functioning raw water pump so that engine gets shut down. Even then I need to either have a spare belt or try to find one in a coastal town and then still need that special tool to fit it.

I am just trying to be a good Boy Scout and “be prepared” as I have some serious offshore passage making of over 1000 Nm coming up soon and need to have appropriate spares on hand. Murphy will definitely ensure that if I dont have spares and the tool aboard, then a belt will break on this trip.

Any other Forum members have experience fitting this particular belt ?

[Phil Lack]

Hi Kraig, I too am still awaiting this video and even after emailing Brendan as per Tony’s suggestion, I have still heard or seen nothing.

Starting to lose faith in this Forum’s ability to provide answers to a reasonable question.

Lets see what happens if I resend the email to Brendan…….

[Kraig Kirby]

Looking for a video and any direction on the special tool recommended to replace the stretchy belt. It appears they are not in Cummins stock and almost impossible to find currently.

[Tony Athens]

Send my guy a note and ask him………….Burn his ears!

[email protected]

Obviously, I have no clout anymore in my shop..

[Phil Lack]

BUMP

[Author]

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