Alternator Belt Tension

[Peugeot 106]

I may have a small water pump leak. There is sometimes a small amount of coolant under the engine and I am investigating to see if it is coming from the weep holes. The belt is a POLY-V 4 ridge and I tighten it so that I can just twist it through 90 degrees on its longest run. I am going to take it off to see if there is any roughness when I turn the pump by hand. The manual is as shown below and I just wondered if my tightening method is good enough?

[BEngo]

A poly V belt should be positively tensioned by some sort of screw device and ideally the tension measured by the special tool, though if you have 3 or more hands  a tape measure and a spring balance (luggage weigher)  can do the job.

 

In the absence of the extra hands or a tool, I find an alternator belt can be tightened  to the point where it just does not squeal at tickover when the alternator is fully loaded charging a half discharged battery, say,.  You need to get the adjustment done quickly this way, as a squeaky belt is wearing more.

 

N

[magnetman]

I don't remember having a poly v belt when I had a LPW2. Maybe the bigger ones have them. Thinking about it the generator I once had which was a LPW3 might have had one of these belts which also ran the radiator fan from when it was a stationary engine. 

 

 

 

 

Is there a chance that the belt has been overtightened rather than the more obvious ?

[Peugeot 106]

22 minutes ago, magnetman said:

I don't remember having a poly v belt when I had a LPW2. Maybe the bigger ones have them. Thinking about it the generator I once had which was a LPW3 might have had one of these belts which also ran the radiator fan from when it was a stationary engine. 

 

 

 

 

Is there a chance that the belt has been overtightened rather than the more obvious ?

That’s why I’m asking. I am wondering if I’ve overtightened the belt

[jonathanA]

I think I just go for the no more than 1/2 inch deflection on the longest run and the 90 degree twist. That seems to be OK but if I get any squeal I put a little more tension on. So I'm not sure you've over tensioned, more likely the alternator bearings would suffer I'd think. 

[nicknorman]

From your description I’d say slightly over tightened. Twisting 90 degrees is a fair way to assess but only using moderate force. If you say “I can just twist it 90 degrees using maximum force” then that is too much. Put it another way, it needs to be just tight enough to avoid slippage, but not more. So back it off until it just squeals under max load at low rpm, then tighten slightly. Then note how much force is required to twist 90 degrees for future reference.

[Peugeot 106]

Thank you everyone. I may be slightly overtightening my belt. BEngo thank you I may try the luggage scale method I had thought of that before but access is of course difficult. Adjustment is coarse (a bolt in a slot with the windlass handle used for leverage) If I could find the proper spring pusher in the right force range I might go for it but I can’t find anything in the range 5-7.5 lbs. I’m not sure why it’s called a V belt as it’s flat with 4 ridges in it

[BEngo]

It reallly wants a better  tensioner than some sort of lever. 

O

It is not actually a V belt.  It is a poly-V belt, aka a multi rib belt.  Each of the ribs on a poly V belt matches the grooves on the pulley.  They work 9n smaller pulleys than V belts,  can transmit a lot more torque than a v belt or a wedge belt since there is more  area of contact for a given width and because  they are thinner they can easily be wound into the serpentine shapes needed to drive all the extra pumps and things on modern car  engines.  Should you ever need to buy a non OEM replacement they are specified by :

Number of ribs (4 in your case)

P

size of rib H,J,K,L or M.  J and K sizes are  popular in automotive work and their pitch is 2.34  or 3.56 mm respectively

Pitch length of the belt.

There may be a numerical code on the belt such as 6PJ1123.  6 ribs, J size, 1123mm long.

 

There is a lot of crap out there but Gates and Continental make good ones.

 

N

[jonathanA]

on the 4 cyl engine the oem/lister belts (751 17830) are 4PK 913.   As the pukka lister ones are circa £25 quid its worth shopping round for equivalents.  You can get some chinese shite for about a fiver, but the difference in quality is visible! that said I change them every 12 months so tend to try to find gates or something of decent quality if i can otherwise I just change the cheapos along with the oil. 

 

Someone on here told me it was worth cleaning any dust/gunge out of the pully grooves on the crankshaft/water pump/alternator so i do that from time to time and it seems to help belt life. 

[Peugeot 106]

1 hour ago, BEngo said:

It reallly wants a better  tensioner than some sort of lever. 

O

It is not actually a V belt.  It is a poly-V belt, aka a multi rib belt.  Each of the ribs on a poly V belt matches the grooves on the pulley.  They work 9n smaller pulleys than V belts,  can transmit a lot more torque than a v belt or a wedge belt since there is more  area of contact for a given width and because  they are thinner they can easily be wound into the serpentine shapes needed to drive all the extra pumps and things on modern car  engines.  Should you ever need to buy a non OEM replacement they are specified by :

Number of ribs (4 in your case)

P

size of rib H,J,K,L or M.  J and K sizes are  popular in automotive work and their pitch is 2.34  or 3.56 mm respectively

Pitch length of the belt.

There may be a numerical code on the belt such as 6PJ1123.  6 ribs, J size, 1123mm long.

 

There is a lot of crap out there but Gates and Continental make good ones.

 

N

The belts I have are I think Goodyear 845PK 333K 4 ridge I have a couple of spares as I did have some squealing a year or two ago. They weren’t £25 but around half that price as old stock. I’m not sure how I would alter the tensioning method without taking the engine out as I can only just reach the tensioning bolt as it is though it would be nice to have something more easily adjustable. It’s a bit trial and error with the windlass as a pry bar at the moment. I’d be happier if I could find a pusher that pushed in the range 5 x7.5 lbs as shown in the manual. I suppose I could “calibrate” my thumb against a spring balance. I’ve done this with spanner’s and torque wrenches in the past where access is poor.

i’m glad you’ve cleared up the v belt misnomer as it’s not like my old Morris 1000 fan belt which I could understand being caused a v belt. Multi Rib Belt is I think a more apt description

[Peugeot 106]

Reporting back. I rashly (late at night) bought from Amazon  a Gates Krikit 1 tension gauge armed with the my new found info from BEngo that what I’ve got  is called a “multi rib belt”.  The bumph says that it should read 10kg per rib. Since I have 4 ribs I expected around 40 Kg. It was in fact less around 20Kg. It twists 90degrees quite easily. I ran the engine for around 20 mins then took the belt off and inspected the pump for leaks at the weep holes. I turned it over by hand and there was no play or grittiness in it.

All seems to be fine and the belt despite being over a year old looks brand new so I reassembled it at the same tension. I ran it again and there is no squealing or slippage

 

i did have a few drops of coolant under the engine but haven’t seen them today so maybe they were spillage from previously topping up the coolant. Any expansion overflow gets directed into a milk bottle and o don’t think there are any other leaks. If I find my spring balance I will try with that

 

https://docs.rs-online.com/0707/0900766b8002ca6f.pdf
 

 

[blackrose]

On 01/02/2024 at 00:51, Peugeot 106 said:

That’s why I’m asking. I am wondering if I’ve overtightened the belt

 

So going back to your original post, can an overtightened belt lead to water pump leakage? How does that happen, through the pulley bearing and water pump seal being under too much tension on one side resulting in a gap on the other?

Edited February 4 by blackrose

[magnetman]

Good question. 

 

I assumed initially the OP was worried about not tightening the belt because  the sentence "The manual is as shown below and I just wondered if my tightening method is good enough?" seems to imply something not done up properly. 

 

It seems that overtightening could cause permanent damage but its slightly intriguing if it only leaks when overtightened then stops leaking when slacked off. 

 

 

[nicknorman]

I think it’s a case of the excessive side force wearing the bearing which allows a bit of play which wears the seal. Not really a reversible process.

[Peugeot 106]

Apologies to everyone if this seemed like a false alarm. I have done quite a lot of work on my engine. Main oilseals, head gasket etc. including taking the engine out. I would describe myself as a keen amateur. Before attempting anything I like to get as much information as I can. I’ve seen plenty of damage done by gung-ho mechanics including so called marine engineers. I am aware that a little knowledge can be dangerous and lead to expensive mistakes. I’ve even dropped a head nut down the plug hole after reassembling a Ford Escort side valve engine.  In my youth I’ve sat looking at plenty of stripped/snapped bolts wishing I’d taken things more slowly. As I’ve got older and wiser  I’m aware of just how little “feel” I have got for tightening things and where I can I rely on torque wrenches etc 

This forum is great for hand holding and thank you all. Hopefully I’ve learned a bit more

[Tony Brooks]

Be aware that in the very early stages of water pump seal failure, they are notoriously unreliable. They sometimes leak only while running, only while stationary, or when they think they will. So, if you think the leak has gone, keep an eye on it for a while.

[Peugeot 106]

1 hour ago, Tony Brooks said:

Be aware that in the very early stages of water pump seal failure, they are notoriously unreliable. They sometimes leak only while running, only while stationary, or when they think they will. So, if you think the leak has gone, keep an eye on it for a while.

This will make a change. I got used to spotting an oil splodge after running but having sorted that will now have to look for a coolant splodge! When turned by hand without belt the pump turns very smoothly without a trace of play but maybe I shouldn’t count my chickens!

[BEngo]

Bog roll or white kitchen towel are often handy when checking for leaks of all types.  Just place a piece to intercept any possible weeps, seeps or drips.  You can normally get it closer to a possible source than tracing the route of a damp patch which has appeared under the engine.

 

N

[Tony Brooks]

43 minutes ago, BEngo said:

Bog roll or white kitchen towel are often handy when checking for leaks of all types.  Just place a piece to intercept any possible weeps, seeps or drips.  You can normally get it closer to a possible source than tracing the route of a damp patch which has appeared under the engine.

 

N

 

Whilst I agree with the sentiment, I am not sure that it is a good idea to publish that on a forum where we have no idea about members' competence, especially for the engine water pump. Too much chance of an idiot wrapping their fingers in a running drive belt.

 

Only try it with a stationary engine.

[Peugeot 106]

1 hour ago, BEngo said:

Bog roll or white kitchen towel are often handy when checking for leaks of all types.  Just place a piece to intercept any possible weeps, seeps or drips.  You can normally get it closer to a possible source than tracing the route of a damp patch which has appeared under the engine.

 

N

I have a roll of blue tissue that I have used to find leaks. I have wiped everything clean and then tied wadges to the engine with string and tape before running it with some success. I’ve tried fluorescent dyes as well but they are not brilliant. I had a pesky oil leak for ages!

 

20 minutes ago, Tony Brooks said:

 

Whilst I agree with the sentiment, I am not sure that it is a good idea to publish that on a forum where we have no idea about members' competence, especially for the engine water pump. Too much chance of an idiot wrapping their fingers in a running drive belt.

 

Only try it with a stationary engine.

I would like to assure you Tony that I am a very careful idiot. My fingers, hair clothing or any other parts will be no where near a running drive belt. I worked with a young lad who got his shirt caught in a tractor PTO shaft. He survived but it did not end well. Another contemporary started a Fordson Major whilst standing in front of it and it pinned him to the wall before someone came to help. Luckily it was on smooth wet concrete. Still  his ribs were crushed and he was hospitalised for several months. 
In my youth  (50 years ago) I was a Roughneck on Semi Submersible Exploration Rigs in the North Sea. Ocean Rover, Pentagon 86, Atlantic 11. There were 4 of us Roughnecks and hardly a two week spell went without one of us being injured. It made me very wary of rotating machinery. 

[Tony Brooks]

7 minutes ago, Peugeot 106 said:

I have a roll of blue tissue that I have used to find leaks. I have wiped everything clean and then tied wadges to the engine with string and tape before running it with some success. I’ve tried fluorescent dyes as well but they are not brilliant. I had a pesky oil leak for ages!

 

I would like to assure you Tony that I am a very careful idiot. My fingers, hair clothing or any other parts will be no where near a running drive belt. I worked with a young lad who got his shirt caught in a tractor PTO shaft. He survived but it did not end well. Another contemporary started a Fordson Major whilst standing in front of it and it pinned him to the wall before someone came to help. Luckily it was on smooth wet concrete. Still  his ribs were crushed and he was hospitalised for several months. 
In my youth  (50 years ago) I was a Roughneck on Semi Submersible Exploration Rigs in the North Sea. Ocean Rover, Pentagon 86, Atlantic 11. There were 4 of us Roughnecks and hardly a two week spell went without one of us being injured. It made me very wary of rotating machinery. 

 

That was not addressed to you personally, it was intended as a general warning. You know what might happen, and so do I and BEngo. Having seen the state of a stupid student's finger, who thought it would be a good idea to totally ignore all the earning about keeping one's fingers, hair and clothing well away from running bets etc. I would not wish that on anyone.

[Alan de Enfield]

9 minutes ago, Tony Brooks said:

Having seen the state of a stupid student's finger, who thought it would be a good idea to totally ignore all the earning about keeping one's fingers, hair and clothing well away from running bets etc.

 

Many many years ago, when I was at night school doing my HNC in electrical engineering a fellow student was working away in the machine shop on a lathe, for some reason he was holding a piece of emery cloth onto a rotating 'bit of metal' using the tip of his little finger - no idea how it happened but something 'grabbed' and his little finger was pulled completely off, he calmly bent down, picked it up, & walked down the Workshop to the Tutor and said "my finger has come off" and promptly fainted.

[magnetman]

I've had loads of silly situations where I should have died or been badly injured. 

 

One of them was when my mother found me in the hay barn with a rusty can of paraffin trying to light a match but the matches were damp. I was about 8 we had a big house with  outbuildings. 

 

sinking a dinghy with 5 teenagers (I was 15) on it with no lifejackets in the middle of the Thames ended well. I saved a kids life. Another of the kids couldn't swim and was saved by a bloke who swam across from the pub opposite (Boaters Inn Kingston on Thames) and got her ashore. It was a crazy evening I almost lost the dinghy but luckily it turned upside down and retained an air pocket (no flotation and an outboard) so it was not lost. I was dead relieved. 

 

Loads of others but there seems to be a survival gene for some reason. 

 

I expect a lot of people have had near misses. 

 

 

 

 

Edited February 4 by magnetman

[Peugeot 106]

We had some proper hard bastards. One was a Derrickman. One day he hadn’t seen an errant  drill pipe and I pushed him out of the way probably saving his life. His only thanks was “ the devil looks after his own” The pipe caught me in the shoulder and I was black and blue  next day and sent back to Aberdeen. A month later we were running casing in the middle of a cold, dark, windy wet night for the well. The same Derrickman was in a temporary ramshackle lift that ran up the derrick on

an RSJ. (The casing was too short to use the monkey board). He left his hand outside the cage and ALL his fingers were chopped off. He climbed out of the cage and 60 feet down the outside of the derrick lattice. We searched everywhere for his fingers and even had a chilled poly bag to put them in while we waited for the rescue helicopter. We never saw him or his fingers again

Best of all I got to work the Derrick in his abscence but I didn’t keep the promotion probably due to not being a hard enough bastard. You can’t be a scaredicat in that job!

 

1 hour ago, Tony Brooks said:

 

That was not addressed to you personally, it was intended as a general warning. You know what might happen, and so do I and BEngo. Having seen the state of a stupid student's finger, who thought it would be a good idea to totally ignore all the earning about keeping one's fingers, hair and clothing well away from running bets etc. I would not wish that on anyone.

No harm in reminding us. Familiarity can breed contempt