BMC 1.5 Drive Belt - Help, I've chopped mine in half!

[ionayes]

Hey boaters,

 

I need help identifying what my drive belt is called so I can buy a new one. At least, I think it's called a drive belt. Maybe an alternator belt? 

 

It's got 3 ribs and a small wide groove on one side and is smooth on the other. I have attached photos, if anyone knows please could you have a look and tell me what it's called?

 

I'd love to know where I can get a cheap new one too, if possible. 

 

Thanks ever so much.

 

All the best,

 

Iona

[Tony Brooks]

That is not a normal 1.5 or 1.8 belt because they sue a normal V belt. Changing the engine pulley to suit that belt is no small job, as is the water pump pulley.  If the engine pulleys are correct for that belt, then I think it has been modified to drive a much larger alternator.

 

your best bit is to take the broken belt to an engineering supplier to get it matched up. Let's have your rough location and someone may be able to give you a location.

 

Photo of the pulleys, please.

[ionayes]

3 minutes ago, Tony Brooks said:

That is not a normal 1.5 or 1.8 belt because they sue a normal V belt. Changing the engine pulley to suit that belt is no small job, as is the water pump pulley.  If the engine pulleys are correct for that belt, then I think it has been modified to drive a much larger alternator.

 

your best bit is to take the broken belt to an engineering supplier to get it matched up. Let's have your rough location and someone may be able to give you a location.

 

Photo of the pulleys, please.

 

Thank you,  it seems nothing about this boat is normal!

 

I've attached the only picture I can find as I'm away, but I'm heading home tomorrow so I'll add to it then. (I currently have no spill rail, please ignore my glove covers!)

 

That's great advice, I'm near Reading on the Kennet and Avon if anyone has recommendations.

 

[Tony Brooks]

Sorry, that is no good, we need to see the grooves in all three pulleys. From what I can see, it looks as if that might be the wrong belt for the engine, but can't be certain unless we get better photos.

 

I know you did not ask, but where is the injector leak off pipe? If this is an inland boat, it might be a BSS fail.

[ionayes]

11 minutes ago, Tony Brooks said:

Sorry, that is no good, we need to see the grooves in all three pulleys. From what I can see, it looks as if that might be the wrong belt for the engine, but can't be certain unless we get better photos.

 

I know you did not ask, but where is the injector leak off pipe? If this is an inland boat, it might be a BSS fail.

Ok, no problem .

 

Thanks again, I will post another picture later today or tomorrow once I’m home. 

 

I’m not sure about the position of the pipe either, I’ll take a few pictures. 
 

all the best  

[Tony Brooks]

PS, that alternator does not need the sort of belt you showed. I suspect someone misunderstood advice to get a cogged or notched belt and bought a ribbed belt. Then just fitted it without looking and thinking about the implications.

 

It is just a drive belt, fan belt (although you have no fan), or alternator belt. Any motor factors/car parts shop should stock them, but they will need to know the length. If the pulley photos show no ribs in the pulleys then just this once I would buy from a marine supplier who knows the engine like Calcutt boats or ASAP Supplies.

1 minute ago, ionayes said:

’m not sure about the position of the pipe either, I’ll take a few pictures. 

 

That is why I asked - it is not there.

[pete.i]

Maybe the glove fingers are a futile attempt of containing the injector leakoff diesel. Looking at the small part of the drive pulley that can be seen, and it really isn't very clear, but looks like it might be a grooved pulley rather than a V pulley. If it is then the alternator pulley would have to be a grooved pulley as well and that isn't normal on what looks like a Lucas alternator.

Edited July 2, 2023 by pete.i

[David Mack]

Looks like you should have a standard V belt, although better photos of the pulleys would confirm. But if that polyvee belt is the right length it will help with sourcing a replacement. Is there any writing on the back of the belt?

1 minute ago, pete.i said:

Maybe the glove fingers are a futile attempt of containing the injector leakoff diesel.

Or maybe someone has put them on when the leak off pipe was removed to stop dirt getting in.

Edited July 2, 2023 by David Mack

[bizzard]

6 minutes ago, pete.i said:

Maybe the glove fingers are a futile attempt of containing the injector leakoff diesel. Looking at the small part of the drive pulley that can be seen, and it really isn't very clear, but looks like it might be a grooved pulley rather than a V pulley. If it is then the alternator pulley would have to be a grooved pulley as well and that isn't normal on what looks like a Lucas A127 alternator.

Look like condoms to me. He's been to the barbers, anything for the weekend sir.

Edited July 2, 2023 by bizzard

[pete.i]

8 minutes ago, David Mack said:

 

Or maybe someone has put them on when the leak off pipe was removed to stop dirt getting in.

Okay a futile attempt at keeping dirt out.

[MtB]

"BMC 1.5 Drive Belt - Help, I've chopped mine in half!"

 

I'm imagining from your photos you mean the drive belt has severed width-wise in the centre making in effect, two half-width drive belts. Is that right? 

 

If so, I's say it is a racing certainty your engine pulleys need an ordinary vee belt rather than the polyvee in your photos. They come in several widths (you'll probably need an "A": width) and a massive choice of lengths in 1/2" increments, and it usually takes a couple of purchases to discover the exact right length in my experience. Bearing factors such as "Bearing Boys" keep stock of wrap some rope around the three pulleys to get the rough length then order that one on ebay or amazon. If your first one fits, great but you'll probably find it is a couple of inches too short or too long, in which case order another one a better length.

 

https://www.bearingboys.co.uk/V-Belts--3290-c

 

As a shot in the dark this is probably close-ish to what you need:

https://www.ebay.co.uk/itm/295529031797?

[koukouvagia]

Or you could get a link belt.  These are very good and you can adjust the length as required.  A bit pricey, though.

 

[StephenA]

According to some scribbled notes we have our BMC 1.5 has a Motaquip VFB 230

[Tony Brooks]

27 minutes ago, MtB said:

"BMC 1.5 Drive Belt - Help, I've chopped mine in half!"

 

I'm imagining from your photos you mean the drive belt has severed width-wise in the centre making in effect, two half-width drive belts. Is that right?

 

With that and the photos, I could not work out what she meant by chopping it in half, unless she is holding the two cut ends together for the photos. The last one suggests she might be.

 

I think that you are right about needing a V belt, but someone else has said they think they can see grooves in the pulley, so I await tomorrow's photos to be sure. I did plat with the photo to try to get a better view of the pulley, but to no avail.

1 minute ago, StephenA said:

According to some scribbled notes we have our BMC 1.5 has a Motaquip VFB 230

 

Thanks, that should give a good starting point from motor factors/Halfords once we know about the pulleys.

[ionayes]

Thank you so much to everyone! 
 

here is a photo of the pulleys.

 

yes, they are glove fingers covering the nuts that hold the spill rail in place. I’ve had to take it off to braise the rail back together and so I’ve covered it just to make sure nothing gets into the fuel line.

 

[Tracy D'arth]

That is a nice conversion to a poly V belt.  You need a 4 rib poly V belt. The alternator needs the blocked groove cleaning out.

As to what section of belt see   https://duckduckgo.com/?q=poly+v+belt+size+chart&atb=v314-1&iax=images&ia=images&iai=http%3A%2F%2Fwww.practicalmachinist.com%2Fvb%2Fattachments%2Ff25%2F187006d1482720272-poly-v-belt-sb9-micro-v-belts.jpg

Its most likely to be J section.

 

Take the old belt to a bearing shop or engineers merchant, let them match it up. That assumes it was the right size to start with.

 

Buy 2, then you have a spare, and note down all the numbers on the back of the belt for future reference.

Edited July 2, 2023 by Tracy D'arth

[Tony Brooks]

Right, then your belt looks like i is the right one apart from the fact it seems to have lost one of the ribs - no idea what that is unless it was incorrectly fitted or was running out of line.

 

Check the remaining ribs on the old belt fit into the grooves on all three pulleys because the engine pulley looks a bit as if the grooves are smaller. I think that the alternator pulley may not match the other two groove width wise.

 

If they drop straight into the grooves, then you can use the old belt to measure the length for the new one. I think that you will need to get that one matched up with the old one. A bearing supplier, engineer's supplies, or a motor factors (garage supplier) are more likely to do that than Halfords & Co.

 

Good luck

Just now, Tracy D'arth said:

That is a nice conversion to a poly V belt.  You need a 4 rib poly V belt. The alternator needs the blocked groove cleaning out.

As to what section of belt see   https://duckduckgo.com/?q=poly+v+belt+size+chart&atb=v314-1&iax=images&ia=images&iai=http%3A%2F%2Fwww.practicalmachinist.com%2Fvb%2Fattachments%2Ff25%2F187006d1482720272-poly-v-belt-sb9-micro-v-belts.jpg

 

Take the old belt to a bearing shop or engineers merchant, let them match it up. That assumes it was the right size to start with.

 

Buy 2, then you have a spare, and note down all the numbers on the back of the belt for future reference.

 

Now you mention groove cleaning, the dirty grooves on the alternator and water pump seem to match, but the engine pulley has the dirty groove on the other side.

[Tracy D'arth]

1 hour ago, Tony Brooks said:

Right, then your belt looks like i is the right one apart from the fact it seems to have lost one of the ribs - no idea what that is unless it was incorrectly fitted or was running out of line.

 

Check the remaining ribs on the old belt fit into the grooves on all three pulleys because the engine pulley looks a bit as if the grooves are smaller. I think that the alternator pulley may not match the other two groove width wise.

 

If they drop straight into the grooves, then you can use the old belt to measure the length for the new one. I think that you will need to get that one matched up with the old one. A bearing supplier, engineer's supplies, or a motor factors (garage supplier) are more likely to do that than Halfords & Co.

 

Good luck

 

Now you mention groove cleaning, the dirty grooves on the alternator and water pump seem to match, but the engine pulley has the dirty groove on the other side.

Yes, I noticed that and that it was a 3 rib belt. Could have been fitted cacked  or maybe the pulleys are not in line.

The alternator seems to have a complete circle of belt fabric in the groove.  No wonder the belt gave up.

[Tony Brooks]

8 minutes ago, Tracy D'arth said:

Yes, I noticed that and that it was a 3 rib belt. Could have been fitted cacked  or maybe the pulleys are not in line.

The alternator seems to have a complete circle of belt fabric in the groove.  No wonder the belt gave up.

 

I think it looks like a four rib belt, with the lower rib (in the first photo) missing. I think that you can see the shadow of its root. Why it is like that is anybodies guess, but what with the dirty pulley grooves, very odd. The outer edges are badly frayed and distorted as well. I can't recall seeing a ribbed belt do that before, which is why I suspect alignment or one unmatched pulley.

 

Also, the back of the crankshaft pulley looks domed, unless it is the rubber bush extruding backwards, and it looks as if the torsional damper body has been machined to provide the grooves. How they got rid of the V belt groove, I don't know. Maybe the base engine was something special, with a much larger alternator.

Edited July 2, 2023 by Tony Brooks

[StephenA]

37 minutes ago, Tony Brooks said:

 

I think it looks like a four rib belt, with the lower rib (in the first photo) missing. I think that you can see the shadow of its root. Why it is like that is anybodies guess, but what with the dirty pulley grooves, very odd. The outer edges are badly frayed and distorted as well. I can't recall seeing a ribbed belt do that before, which is why I suspect alignment or one unmatched pulley.

 

Also, the back of the crankshaft pulley looks domed, unless it is the rubber bush extruding backwards, and it looks as if the torsional damper body has been machined to provide the grooves. How they got rid of the V belt groove, I don't know. Maybe the base engine was something special, with a much larger alternator.

 

My V60 D5 shredded a belt when the A/C pump started to randomly stick - I ended up with a belt with shredded edges which looked quite similar to that.

 

The alternator mounting to the water pump looks different too - but it looks very similar to this one which is another polyV adaption.

 

 

 

Edited July 2, 2023 by StephenA

[Tracy D'arth]

I would love to know where those poly V water pump pulleys come from.

[StephenA]

5 minutes ago, Tracy D'arth said:

I would love to know where those poly V water pump pulleys come from.

 

And who machines the crank pulley....

[sueanddaren]

Our old boat with a BMC 1.5 had a very similar modification, that used a 4PK1052 belt, but until you offer up a new belt to the pulleys it is very difficult to tell. 

[Tony Brooks]

Just now, sueanddaren said:

Our old boat with a BMC 1.5 had a very similar modification, that used a 4PK1052 belt, but until you offer up a new belt to the pulleys it is very difficult to tell. 

 

Thanks, that part number should help the OP

 

Any idea where the modification came from?

[sueanddaren]

2 hours ago, Tony Brooks said:

 

Thanks, that part number should help the OP

 

Any idea where the modification came from?

Wish I did, we had that boat for 14 years, contacted all the previous owners even spoke to the guy that actually built her, but never found out about the pulleys or many other odd things. The engine however was marinerised by  Oxford Marine but never found any info on them.