Alternator rpm

[bizzard]

I was going to swap the pully on the alt to a 5-8rib so the belt had a flat running area on the fly. But wanted to check what you guys thought about running the alt off the fly ill then match the alt pully to the correct size so if a 2" pully (same as on now) is ok ill just get a 2" ect ect.

 

I see your point on amp meter.

I don't think you can get multi rib pulleys to fit an ACR alternator which have a different size shaft than the A127. The shaft and pulley on a ACR has key way slots and keys.

[cereal tiller]

The one thing that has not been mentioned is belt wrap on the small pulley. As the drive pulley gets bigger this gets smaller. Too small and the belt will slip and squeal.

 

As an example, my A 127 70A is on the limit with a 6 rib poly v belt. The drive pulley is 12 in and the alt pulley about 2.5 in.

A ploy v belt will drive better and run more happily on the rim of the flywheel compared to an ordinary A or Z section v belt.

 

N

Have managed to get 240 hours out of a 4 rib Polyvee wrapped around a 10 Inch smooth Flywheel

 

It drives a 70 AMP. A127 Type Alternator

 

The belt was changed at service time,did not actually fail ,it just started to look fed up.

 

CT

[bizzard]

Just spoken to the chap who's boat I fitted a new alternator to. The wrong one that Calcutt boats sent to him instead of a correct hand 70amp A127 IS an Lucas Prestolite ACR 45amp. It is for sale at a discount if you need one.

[Jrtm]

I don't think you can get multi rib pulleys to fit an ACR alternator which have a different size shaft than the A127. The shaft and pulley on a ACR has key way slots and keys.

Not a problem ill just stick a steel or brass round block on the lathe and make one if i cant buy one. Just cost alot more than buying one off the shelf.

 

If it cant be done easly then it will have to stay as it is its just not very practical or safe due to the clearences of the pully on the fly ill take some pics today and post on here then we know exactly which alt it is and the spaces i have to work on.

[Sir Nibble]

Acr alternators were never more than 45A but if that is enough I can easily get you that at tick over with a modified alternator.

[Jrtm]

My alt is a dra1691 looks like a 1L old mini alternator + few others

 

29 amp

 

Ive also looked at my current flywheel i have a few options

Its got a bolted on extra big pully 12"

Its got an original dynamo / alt drive pully thats a big cast unit with 4 bolts thats also a flywheel nuts cover

Or there is the flywheel

The alt bracket is bolted onto the exhaust side of the engine by the looks clearly designed for a big dynamo type alternator but would be fairly easy to mod to move the alte brackts or even make a bolt / bar to go threw it to alow me to move the alternator back to use the stock cast alt pully.

Space between the big fly pully and the alternator pully to the fuel tank is 1 inch you can just get your hand sideways bewteen the pullys and tank but its tight. Pics to follow.

[Jrtm]

Pics

[bizzard]

In pic 3 the rear alternator mounting bolt needs a spacer as will not be tight and will put stress on the two front ones. In fact there looks like a crack on the front mounting lug of the alternator. If it is it'll be caused by that rear one.

[ditchcrawler]

In pic 3 the rear alternator mounting bolt needs a spacer as will not be tight and will put stress on the two front ones. In fact there looks like a crack on the front mounting lug of the alternator. If it is it'll be caused by that rear one.

Doesn't the back one normally float on a slide and the front one nips it up. Be gentle with me, working from memory.

[Jrtm]

Most cars have 1 with a moving ring inside to take up slack and 2 1 top and 1 bottom that bolt direct.

 

I havent even looked if im honest ive not got as far as the alt wiring yet or how its mounted

There are no cracks i can see lots of dirt or oil but no cracks

[bizzard]

Doesn't the back one normally float on a slide and the front one nips it up. Be gentle with me, working from memory.

Yes, a sliding interference fit split hollow dowel. It looks like its got one, but its barely long enough to bridge that gap, will need a spacer as well I think.

Edited November 24, 2016 by bizzard

[Tony Brooks]

I would also suggest that for greater reliability you take the large female blade off the cable, strip the cable back a couple of inches, fit 2 new blades and insulate the two lengths of bare wire. This will save you putting 45 amps through just one 9mm blade. I have seen too may loose and burned so in my view a bit of a bodge is worth it.

 

On most cars one of the pair of 9m blades charged the battery while the other fed the car's electrical system. I thought "typical Lucas, using the alternator as a junction box" but then realised it actually reduced the current through the blades. .

 

 

[Jrtm]

 

 

I would also suggest that for greater reliability you take the large female blade off the cable, strip the cable back a couple of inches, fit 2 new blades and insulate the two lengths of bare wire. This will save you putting 45 amps through just one 9mm blade. I have seen too may loose and burned so in my view a bit of a bodge is worth it.

 

On most cars one of the pair of 9m blades charged the battery while the other fed the car's electrical system. I thought "typical Lucas, using the alternator as a junction box" but then realised it actually reduced the current through the blades. .

 

 

Yes you would normally run 2 cables but as its only 29amps and i dont have any electrical system to run only a battery this is why there is only one (not that i have put this part of the system together) everything you see is how i got it. But its all having new wires put in with a new fues box and switches in the engine room as before the switches and fuses were just in open air.

My dilemma as not the alternator or its wiring its what drives the alternator thats my concern as my engine has to be lifted so anything i cant to change pully wise needs to be done first

[Split Pin]

Acr alternators were never more than 45A but if that is enough I can easily get you that at tick over with a modified alternator.

I have a Lucas publication from about 1990 that list the ACR range from 15ACR - 28A up to 25ACR - 65A.

Never came across anything above the 22ACR - 45A though.

I had an 18ACR with an Adverc controller fitted for about 25 years, worked well except that the front bearing life was poor.

 

The 3/8 in (9mm) blade is rated by Lucas at 35A maximum so anything bigger needs to use both blades

 

Steve

Edited November 25, 2016 by Split Pin

[Sir Nibble]

You are quite right, I remember the horrible things on jags and range rovers and the like. Somehow I always conflate acr in my mind with the 15, 16, 17, 18 in those same casings. A 70A A127 with stator reconfigured from delta to star (effectively a 24V stator) will give 45A from about 1000 rpm shaft speed and fit right in.