Long alternator strap wanted

[Timleech]

As above, does anyone have a long alternator or starter strap sitting unused? I'm planning to fit a 7" dia alternator to a 4LW, and the straps I have are not long enough even with extended bolts. One for a 6" starter might do the job, at a pinch with an extended bolt. It might be possible to do it with two short straps and a connecting bolt, so anything offered might be useful.

I've asked Walsh's, they have nothing suitable.

Unfortunately the engine is not here at the moment to take precise measurements.

 

Thanks

Tim

[steamraiser2]

Tim,

 

We have had this problem in the past. To get over it we buy a stainless steel " Mikalor" hose clamp of similar diameter from a hydraulic hose supplier. Cut the clamp and bend to fit around the mounting pins , spotweld the tag ends and tighten with the clamp bolt. Cheap and cheerful and very effective.

[Timleech]

Tim,

 

We have had this problem in the past. To get over it we buy a stainless steel " Mikalor" hose clamp of similar diameter from a hydraulic hose supplier. Cut the clamp and bend to fit around the mounting pins , spotweld the tag ends and tighten with the clamp bolt. Cheap and cheerful and very effective.

 

Thanks for that. Do you know offhand the diameter of the mounting pins? They must be about 7/16" or 1/2", but there's no engine here at the moment that I can check it on, only an L2. I might have a guess at the length needed so that I can take something with me to the boat.

 

Tim

[Split Pin]

Tim

 

I can get you the measurments of the mounting points for the straps and the length of a 5" strap,

I am wondering how you are managing to fit a 7" alternator into the cradle. Let alone drive it

Always believed that the max is 6" on LW's

 

Steve

[Timleech]

Tim

 

I can get you the measurments of the mounting points for the straps and the length of a 5" strap,

I am wondering how you are managing to fit a 7" alternator into the cradle. Let alone drive it

Always believed that the max is 6" on LW's

 

Steve

Steve

Yes that would be appreciated.

 

Unfortunately I don't have the engine here to check, but my guess is that the cradles are actually made for 7" dia. An AC5, which I think is actually about 6.5" in strap mounted form, needs about 1/4" of packing. I have a spare AC5 but it's away at the menders at present so I can't check that either! Lots of guesswork, as the engine in question is over 150 miles away. I've got a dynamo packer from an LK which also looks like 7".

The starter cradles, at least on 4LW & bigger, are certainly for 6" dia. They might be for 5" on the 2s & 3s

 

Tim

[Chris Pink]

I've just been looking at an (empty) 6" diameter dynamo strap on an 4 LK. It's unlikely to be surplus but I could certainly measure it in whatever way you need.

 

an ancillary question; how does one source and fit an alternator in this position? What proportion of engine revs does it run at? How does the coupling work?

 

is there a manual diagram for this anywhere? (Even with a dynamo fitment)

 

would this fit?

 

http://www.ebay.co.uk/itm/Gardner-CAV-AC5-Y4-Alternator-Price-includes-VAT-/260482704557

[Timleech]

I've just been looking at an (empty) 6" diameter dynamo strap on an 4 LK. It's unlikely to be surplus but I could certainly measure it in whatever way you need.

 

an ancillary question; how does one source and fit an alternator in this position? What proportion of engine revs does it run at? How does the coupling work?

 

is there a manual diagram for this anywhere? (Even with a dynamo fitment)

 

would this fit?

 

http://www.ebay.co.uk/itm/Gardner-CAV-AC5-Y4-Alternator-Price-includes-VAT-/260482704557

 

The problem with alternators for the dynamo position on Gardners is that they tend not to turn fast enough. The drive is via the timing chain, and was originally designed for dynamos which were matched to the application.

It's possible to fit a smaller sprocket on the drive, to make it run a bit faster, but it's a lot of work unless you're dismantling the timing gear anyway. I've done this, with a 15t sprocket, because I had the engine completely stripped down anyway. There were several different sizes used over the years. I think the crankshaft sprocket is 30t, so 15t would give a 2:1 ratio. I think some dynamo sprockets were as much as 25t, giving 1.2:1, you would be on a hiding to nothing trying to run any sort of alternator with those!

The other aspect is having a low speed alternator. There was a special version of the AC5 made, especially for fitting to Gardners, the one in your ebay link may or may not be one of those (you would have to ask the vendor). I'm using one at the moment, but only getting about 15A into a low battery at reasonable engine speed. They're really only satisfactory for starter battery charging, but we had to leave in a hurry for the Pageant & I had no time to rig up the belt-driven job which is planned.

As a temporary measure until we get the boat home, I want to fit an AC7, like this ebay item, as I have one 'borrowed' from another (Kelvin) engine which is currently in bits. They can give up to 60A, depending on exact variant, and 40A at 1500 alternator rpm.

 

I have arranged a couple of LKs with a modern alternator driven by a toothed belt from the dynamo drive, with a step up ratio on the belt, they have worked very well.

 

Tim

Edited August 10, 2012 by Timleech

[Chris Pink]

The problem with alternators for the dynamo position on Gardners is that they tend not to turn fast enough. The drive is via the timing chain, and was originally designed for dynamos which were matched to the application.

It's possible to fit a smaller sprocket on the drive, to make it run a bit faster, but it's a lot of work unless you're dismantling the timing gear anyway. I've done this, with a 15t sprocket, because I had the engine completely stripped down anyway. There were several different sizes used over the years. I think the crankshaft sprocket is 30t, so 15t would give a 2:1 ratio. I think some dynamo sprockets were as much as 25t, giving 1.2:1, you would be on a hiding to nothing trying to run any sort of alternator with those!

The other aspect is having a low speed alternator. There was a special version of the AC5 made, especially for fitting to Gardners, the one in your ebay link may or may not be one of those (you would have to ask the vendor). I'm using one at the moment, but only getting about 15A into a low battery at reasonable engine speed. They're really only satisfactory for starter battery charging, but we had to leave in a hurry for the Pageant & I had no time to rig up the belt-driven job which is planned.

As a temporary measure until we get the boat home, I want to fit an AC7, like this ebay item, as I have one 'borrowed' from another (Kelvin) engine which is currently in bits. They can give up to 60A, depending on exact variant, and 40A at 1500 alternator rpm.

 

I have arranged a couple of LKs with a modern alternator driven by a toothed belt from the dynamo drive, with a step up ratio on the belt, they have worked very well.

 

Tim

 

That all makes sense, thanks TIm. So an AC7 might do the job if the sprocket was changed?

 

Do you have any pictures of the belt drive?

[Split Pin]

Steve

Yes that would be appreciated.

 

Unfortunately I don't have the engine here to check, but my guess is that the cradles are actually made for 7" dia. An AC5, which I think is actually about 6.5" in strap mounted form, needs about 1/4" of packing. I have a spare AC5 but it's away at the menders at present so I can't check that either! Lots of guesswork, as the engine in question is over 150 miles away. I've got a dynamo packer from an LK which also looks like 7".

The starter cradles, at least on 4LW & bigger, are certainly for 6" dia. They might be for 5" on the 2s & 3s

 

Tim

 

Tim

Pm sent with details

Max dynamo/altenator dia is 6.5,on 3LW

Straps for starter are narrower than the dynamo mounting cradle

 

Steve

[Timleech]

That all makes sense, thanks TIm. So an AC7 might do the job if the sprocket was changed?

 

Do you have any pictures of the belt drive?

 

The change of sprocket isn't an option on the 4LK, because all the timing components including the chain are completely obsolete. Only applies to LW and, I suppose, LX.

Might be able to get a pic on Monday (customer's boat).

 

Tim

 

Tim

Pm sent with details

Max dynamo/altenator dia is 6.5,on 3LW

Straps for starter are narrower than the dynamo mounting cradle

 

Steve

 

Interesting, you've got me worried now as to whether my plan will work

Maybe the AC5 is only 6", I'll make some enquiries tomorrow.

 

Thanks

 

Tim

Edited August 10, 2012 by Timleech

[Timleech]

I've just been looking through the literature that I have. The old-style 2-part spare parts catalogue for the LK lists different dynamo sizes up to 6.5".

The equivalent LW book, on the other hand, dodges the issue and says that all spares requests in that department must be accompanied by engine number etc.

 

Tim

 

Edit - just found a reference in an L3B sales leaflet to '6 1/4" dia AC524 Alternator'. That's the CAV AC5 referred to earlier, so if that's 6.25" dia the cradle is probably indeed 6.5".

Oh well, back to the drawing board! Maybe I could set it up with a couple of UJ's

Edited August 10, 2012 by Timleech

[Split Pin]

I've just been looking through the literature that I have. The old-style 2-part spare parts catalogue for the LK lists different dynamo sizes up to 6.5".

The equivalent LW book, on the other hand, dodges the issue and says that all spares requests in that department must be accompanied by engine number etc.

 

Tim

 

Edit - just found a reference in an L3B sales leaflet to '6 1/4" dia AC524 Alternator'. That's the CAV AC5 referred to earlier, so if that's 6.25" dia the cradle is probably indeed 6.5".

Oh well, back to the drawing board! Maybe I could set it up with a couple of UJ's

 

Tim

 

In Instruction book 67 the cradle is listed as 6.5" for 2 & 3LW

7" for 4LW 5LW and 5LW20

8" for 6LW & 6LW20

So you may still be on track

Also says that irespective of size all altenators are driven by a 15 tooth sprocket giving a ratio of 1.8:1

 

Steve

[Timleech]

Tim

 

In Instruction book 67 the cradle is listed as 6.5" for 2 & 3LW

7" for 4LW 5LW and 5LW20

8" for 6LW & 6LW20

So you may still be on track

Also says that irespective of size all altenators are driven by a 15 tooth sprocket giving a ratio of 1.8:1

 

Steve

 

I hope you're right, but I suspect these things have changed over time.

It's a late 1930s basic engine, & if the AC5 is 6.25", judging by the spacer the cradle is likely to be about 6.5".

No doubt 15t sprockets were standard on later engines, but I took out a sprocket of about 20t & replaced it with 15t, I've seen them with more teeth than the one I took out. According to my instruction book, some special engines were fitted with 12t sprockets.

I'll check the size of an AC5 when I can.

 

Thanks

Tim

[Split Pin]

I hope you're right, but I suspect these things have changed over time.

It's a late 1930s basic engine, & if the AC5 is 6.25", judging by the spacer the cradle is likely to be about 6.5".

No doubt 15t sprockets were standard on later engines, but I took out a sprocket of about 20t & replaced it with 15t, I've seen them with more teeth than the one I took out. According to my instruction book, some special engines were fitted with 12t sprockets.

I'll check the size of an AC5 when I can.

 

Thanks

Tim

 

I have an older book (56.5) which was supplied wil an LX which says that the cradle is 6.5" on 4 LW's

So Gardners definatly changed the mounting size, no doubt to meet the requirements of PTO equipment.

So it would seem likely as its an early engine that it is 6.5"

There number of different sprocket sizes fitted seems to be endless, the one on my 3LW isnt even listed in the spares books of any age

Edited August 11, 2012 by Split Pin

[Timleech]

I have an older book (56.5) which was supplied wil an LX which says that the cradle is 6.5" on 4 LW's

So Gardners definatly changed the mounting size, no doubt to meet the requirements of PTO equipment.

So it would seem likely as its an early engine that it is 6.5"

There number of different sprocket sizes fitted seems to be endless, the one on my 3LW isnt even listed in the spares books of any age

 

It looks as though I might as well forget the plan to take the AC7 with me next time I go to the boat.

I might revisit the idea later, or maybe rig a belt driven AC7, they might be a bit quieter than the modern big alternators while working hard, if only because they don't need to turn so fast. That makes me wonder where the noise comes from in an alternator, is it just the belt drive or is caused by the electromagnetic stresses?

 

Thanks

 

Tim

[BEngo]

SNIP

 

That makes me wonder where the noise comes from in an alternator, is it just the belt drive or is caused by the electromagnetic stresses?

 

Thanks

 

Tim

 

 

The principal noise sources are the belt drive, any rolling element bearings (if fitted), the windage of the rotor and the fan (also if fitted).

 

N

[Timleech]

The principal noise sources are the belt drive, any rolling element bearings (if fitted), the windage of the rotor and the fan (also if fitted).

 

N

 

The modern high power alternators are significantly noisier when working hard (usually first start up), that's the bit I wonder about, it can only really be the belt drive or electromagnetic stresses.

 

Tim

[Timleech]

 

 

Do you have any pictures of the belt drive?

 

Not brilliant pics, because of the guards (sensibly) fitted by the owner:-

 

 

This shows the Lucas alternator on the side, driven from the dynamo drive coupling, along with a big Leece-Neville in front driven via a Polyvee belt from the crankshaft.

 

Here's a slightly better view of the belt drive:-

 

 

I spent a fair bit of time on the maths etc to get the right sizes of belts & pulleys, then machining pulleys to fit dynamo drive & crankshaft.

That particular arrangement (patents pending ) will only work on a rigidly mounted engine, of course.

 

HTH

Tim

Edited August 13, 2012 by Timleech

[Chris Pink]

Interesting

 

I'm a bit confused about the one on the front. I'll get a picture on Thursday. There's a water pump running on the crankshaft pulley which is 'buried' between two 'claws' that fold around it to form engine mounts.

 

The dynamo drive looks doable. Is that the largest pulley that would fit? And what was the maths involved?

 

Thanks Tim

[Timleech]

Interesting

 

I'm a bit confused about the one on the front. I'll get a picture on Thursday. There's a water pump running on the crankshaft pulley which is 'buried' between two 'claws' that fold around it to form engine mounts.

 

The dynamo drive looks doable. Is that the largest pulley that would fit? And what was the maths involved?

 

Thanks Tim

 

The large pulley was pretty much the largest that could be fitted.

The maths involved looking at possible ratios to give a good range of alternator speed, then working with a belt design manual to find an arrangement which would physically fit, give that ratio, and carry the power.

 

Incidentally, I was able to check my dynamo/alternator cradle over the weekend and it is for 6.5" dia. I do have a tentative plan for when it's closer to home.

 

Tim