Isuzu Alternator Belts

[Rod_N]

Hi, my first post to this forum as a narrowboat owner for just a few months! I need the two alternator belts on my Isuzu 42 hp diesel engine. The belts can't really be seen as they are at the front of the engine under the stern decking so it will have to be done more or less by feel. Can anyone tell me whether it is a straightforward job or not? So often I find there are unexpected difficulties when doing a job for the first time, with a worst case scenario of ending up with a boat that no longer works! Also are any special tools needed?

[Flyboy]

Surely the stern decking is removable. Can you post a picture?

[RLWP]

Surely the stern decking is removable. Can you post a picture?

 

Welcome to the wonderful world of engine installations Not all boat fitters think about maintaining the engine

 

Richard

[Rod_N]

The stern decking is removable, but the opening created stops about a foot or so short of the front of the engine. So although I can get in to the engine compartment, I can't see round the front of the engine, where the belts are located.

[WotEver]

The stern decking is removable, but the opening created stops about a foot or so short of the front of the engine. So although I can get in to the engine compartment, I can't see round the front of the engine, where the belts are located.

 

What a ridiculous (lack of) design. You're sure no internal panels (steps?) can be removed to 'see' the front of the engine?

 

Hopefully someone will be along shortly who knows these engines and can answer your original query. Otherwise, it's mirrors and torches.

 

Tony

[Top cat]

On my Izuzu 42 which is fitted with a travel power unit and 2 alternators I need an allen key to remove the bolts holding one of the pulleys on so that I can get the belt past a sticky out bit of the engine casting. It's going to be a real b*****d of a job if you cant see what you are doing.

Its not just the boatfitters that don't consider maintenance its the engine marinisers too.

 

 

Top Cat

[Stilllearning]

If you can't see them but can get a small digital camera near to them, take a picture, then turn the engine over, by hand if possible, then take more, till you get images of both belts with the reference numbers visible. Then you will at least be able to go and get the right belts in advance of the job.

Yes, and be prepared to have to do some carpentry and redesigning of the bulkhead in front of the engine, for access to do the work. This is depressingly commonly necessary. Many engine and boat fitters should be made to live on the boats they fit out, just so they realize what idiots they are.

Having worked in a boatyard, I still have the scars on knuckles etc to remind me of the inaccessible places one has to be able to work in.

[The Bearwood Boster]

Hi we have the same engine with 2 70amp alternators. As other poster says you will need Alan key for one of bottom bracket bolts. Plus belts are different sizes plus you will need to remove outer one to get at the inner one if you see what I mean.

Edited August 6, 2016 by The Bearwood Boster

[Rod_N]

Thanks for all the replies so far. So far I have discovered (confimed above) that each alternator pivots about a bolt which requires a 6 mm allen key at the rear, where I can see it, and a 13 mm spanner on the head (where I can't see it). THere is also a nut and bolt which passes through a slider which holds the alternator in the chosen position. I've managed to loosen the left-hand alternator, but the right-hand one is done up so tight I haven't been able to loosen it, even with lots of WD40 applied! I'm going to try to get some sort of socket with a 6 mm hex end as my allen key is not long enough to apply sufficient leverage. Possibly a longer 13 mm spanner will help as well.

[WotEver]

Have you considered how much surgery would be required to your fitout to make a removable section to enable access for future maintenance? Would it be feasible?

 

Tony

[Rod_N]

Have you considered how much surgery would be required to your fitout to make a removable section to enable access for future maintenance? Would it be feasible?

 

Tony

Unfortunately it would mean cutting into a main bulkhead, so I don't think I will go for that! I've now managed to get the old belts off and order new ones. I can put my hands round the front and feel all the wheels and grooves, so I shouldnt have any problem putting the new belts on as long as they are not too tight.

[WotEver]

Let's hope you never have to maintain the water pump.

[Rod_N]

Let's hope you never have to maintain the water pump.

I think that would be a job where I would get a professional in!

[Rod_N]

Yesterday I obtained the new alternator belts from a nearby chandlery, and successfully managed to change the belts! I needed a good torch to see what I was doing. For reference, the belts are SPA-882 for the left-hand belt (driving the water pump and left-hand alternator), and the right-hand belt is an SPA-975. These are not Isuzu belts, but as I understand that Isuzu no longer make these engines, Isuzu belts may be hard to source. To change them, I had to sit astride the engine and lean well forward, until I could feel the pully wheels and the ends of the nuts which attach the alternators. Fortunately it was not too difficult to get the new belts on, and I ran the engine without problems for several minutes after fitting the belts and tightening everything up.

 

On reflection, I would definitely change the belts myself again if required! Thanks again for the suggestions and comments posted here.

[RLWP]

To change them, I had to sit astride the engine and lean well forward, until I could feel the pully wheels and the ends of the nuts which attach the alternators.

 

Fun isn't it - working on installed boat engines. I was thinking this only yesterday while putting a pin through a clevis using only my left hand to pull the parts together against a spring, align the holes I couldn't see and push the pin in. Fortunately, I could see the job with one eye this time

 

Good work Rob, and thanks for reporting how you got on

 

Richard

[Flyboy]

Yesterday I obtained the new alternator belts from a nearby chandlery, and successfully managed to change the belts! I needed a good torch to see what I was doing. For reference, the belts are SPA-882 for the left-hand belt (driving the water pump and left-hand alternator), and the right-hand belt is an SPA-975. These are not Isuzu belts, but as I understand that Isuzu no longer make these engines, Isuzu belts may be hard to source. To change them, I had to sit astride the engine and lean well forward, until I could feel the pully wheels and the ends of the nuts which attach the alternators. Fortunately it was not too difficult to get the new belts on, and I ran the engine without problems for several minutes after fitting the belts and tightening everything up.

 

On reflection, I would definitely change the belts myself again if required! Thanks again for the suggestions and comments posted here.

Available from Ebay post free from this supplier. I would imagine a lot cheaper than a chandlery.

 

http://www.ebay.co.uk/itm/SPA-Section-13mmx10mm-Wedge-Belts-SPA732-SPA1420-FREE-DELIVERY-/322197479995?var=&hash=item4b0477623b:m:mYwelvKQ7LVp95xK19JmXMA

[Top cat]

Rod glad it went well.

 

T C

[nebulae]

The belts fitted by HMI are as you have found out standard belts available from engineering suppliers. Although HMI ltd,based at Babcock Airport no longer exists.the basic 4L.42 engine is made by Isuzu for many applications such as generators,pumps etc. As I understand it,HM Plant are UK importers of Hitachi excavators,which use Isuzu engines. They set up HMI as a division to build the various small engine conversions,including Isuzu Marine. The only parts which might be problematic are those made by HMI(such as bellhousings engine mounts and water cooled manifolds.)

[nebulae]

Just Googled and 4L.42 still listed on Isuzu website as available for industrial use. Parts available from Engines Plus Ltd, in Quedgley.These are the same people who worked for HMI (Mainly ex Lister,I understand)

[Fender151]

On 11/08/2016 at 10:13, Rod_N said:

Yesterday I obtained the new alternator belts from a nearby chandlery, and successfully managed to change the belts! I needed a good torch to see what I was doing. For reference, the belts are SPA-882 for the left-hand belt (driving the water pump and left-hand alternator), and the right-hand belt is an SPA-975. These are not Isuzu belts, but as I understand that Isuzu no longer make these engines, Isuzu belts may be hard to source. To change them, I had to sit astride the engine and lean well forward, until I could feel the pully wheels and the ends of the nuts which attach the alternators. Fortunately it was not too difficult to get the new belts on, and I ran the engine without problems for several minutes after fitting the belts and tightening everything up.

 

On reflection, I would definitely change the belts myself again if required! Thanks again for the suggestions and comments posted here.

Hi Rod, can i pick your brains please, i want to change the alternator belts on my Isuzu 42, the right hand belt, which charges my leisure batteries  looks straight forward, the left alternator, that charges the engine battery, looks tricky. As I believe there is not enough clearance between the engine casing and the front pulley wheel to get old belt off and new one on.  ONJ my setup I have four bolts holding the front pulley wheel on, which i can access, but wondering if i will need to use a puller to get the front and rear pulleies separated and not sure I have the clearance from the bulk head for a puller.

Was this your experience.

Cheers