Alternator Left or Right Handed ?

[Alan de Enfield]

I am looking at getting a spare / replacement / bigger alternator for the 55 amp I have.

 

It appears that Alternators can be right handed or left handed.

 

Is it "Right Handed" if it mounts on the Right Hand side of the engine, or is it "Left Handed" because the mountings are on the left hand side of the Alternator (to mount it onto the right hand side of the engine)

 

So what do I need (and any recommendtions as to size / make without having to mess about with Pulleys, twin belts etc - I just want a bolt on equivalent).

 

[Taslim]

Which side of the engine the alt is mounted on it will still turn in the same direction as the engine. The left hand / right hand bit will be due to mounting lugs as I have found out to my cost.

 

Others who know better than I will be on board soon enough and will put you right.

Edited February 23, 2014 by Taslim

[dmr]

On some (but not all) alternators you can slacken the bolts and rotate the end to change from left to right hand.

Replacement alternators is not straightforward. There are several physical styles so you will need to identify yours to get a bolt on replacement.

With a lot of searching you can find drawings of most alternators via Google

Some experts say you cam only go to about 70amps with a single belt, but with a good quality well adjusted belt 100 or even 110 might be ok, will depend to some extent on the "wrap" that you have. Is your engine speed/alternator pulley size such that you are working the alternator at a good speed? In the worse case if you are only just above the cut-in speed much of the time then a bigger alternator might actually produce LESS output. I realise I have not answered your question but hopefully may have given you a couple of things to think about. You could talk to somebody at Adverc but its a bit rude to get their advice then buy the suggested alternator on eBay!

 

...............Dave

[Timleech]

On some (but not all) alternators you can slacken the bolts and rotate the end to change from left to right hand.

 

...............Dave

 

Indeed you can , although it usually involves removing the screws rather than just slackening them.

More often than not, the adjuster limb of the front end frame has a tapped hole, for the clamping bolt, while that for the actual mounting has a through, clearance, hole for the mounting bolt. If you do make this mod., the threaded hole will need to be drilled out for the mounting bolt and the adjuster clamp will have to rely on a nut and bolt.

 

Tim

[Pete & Helen]

Found this on one of the alternator websites. It refers to Lucas alternators but should help identify Left and Right. http://www.ratsport.com/PBSCProduct.asp?ItmID=9667765&XMLOpt1=1&XMLOpt2=-1&RelatedPdtIDs=

 

Lucas alternators were produced in 2 versions - Left Hand Fitting and Right Hand Fitting

Right Hand Fitting (ie the attatchment bracket is on the right-hand of the alternator when you are looking at the front pulley wheel)eg Mini, MG Midget, Lotus Elan, Lotus Elite, Lotus Eclat, Triumph Spitfire, Triumph GT6, Jaguar XJ6 to 1981, Ford Crossflow, Jensen Healey, Morgan 4/4 etc

Left Hand Fitting (ie the attatchment bracket is on the left-hand of the alternator when you are looking at the front pulley wheel) eg Ford Pinto, Ford V6, Ford Escort Rs2000, Triumph TR7 etc

If you order the wrong hand then its very easy to convert a left-hand unit to a right hand unit and vice versa:

1) Loosen the 3 bolts that hold the casing on (the casing is just a cover, its not sprung - nothing will jump out)
2) Turn the body around (there are only 2 possible positions, left or right hand) while holding the plastic end cap (the plastic end cap must not rotate)
3) Retorque the casing bolts

[Alan de Enfield]

Thanks everyone - particularly P&H.

 

Now the next question - Is it 'worth' getting a 70 amp (A127) as opposed to the current 55 amp one ?

 

My understanding is that it would only be putting in the 'extra' 15 amps :

1) If running at optimum revs (3000 ?) &

2) for a short time (a few minutes) until the battery starts to become 'charged'.

 

I dont let the batteries get below 50% (12.2 v) and normally above 12.5v so I am starting from a reasonable state of charge.

[RLWP]

How many batteries do you have, and how do you use your boat?

 

Richard

[Alan de Enfield]

RLWP, on 23 Feb 2014 - 4:39 PM, said:

How many batteries do you have, and how do you use your boat?

 

Richard

 

1x 110 amp starter & 2 x 135 amp leisure batteries.

leisure & pleasure use, when out & about generally at least 4 or 5 hours per day engine running. If moored up and not cruising and battery drops to 12.2 volts then run engine for a 2 + hours.

 

100 watts Solar to leisure batteries

 

When in marina on 20 amp Victron charger / inverter

 

Edit to ad :

 

12v fridge on 24/7

TV - 26 watts couple of hours a day

LapTop 3 hours per day

LED lights

 

If using 900w Vaccum, 800w toaster, 900w oven or 900w Deep fat fryer thru the 1000w inverter will run engine for twice the time the appliance was used for

Edited February 23, 2014 by Alan de Enfield

[Eeyore]

The 70 amp is a direct replacement, however you may find (as I did) that the belt squeaks a lot unless as tight as a bow string. The 4PK section belt used on canal star engines just doesn't have enough wrap if yo use the original alternator pulley with the 70 amp alternator. You could of course use a larger alternator pulley to stop the squeak, but this reduces the alternator speed and output. You can probably guess that I'm suggesting that you stick with the cheap and plentiful 55 amp unit.

[Phil Ambrose]

Just a thought on running higher amp alternators, I replaced my 127 with a bolt for bolt,wire for wire replacement 90amp and got no slip or squeal. Google Driftgate2000 one man band and happy to talk.

Phil

[ditchcrawler]

I thought left and right referred to the rotation of the pulley and the correct cooling fan to cool the alternator effectively

[Alan de Enfield]

I thought left and right referred to the rotation of the pulley and the correct cooling fan to cool the alternator effectively

 

The pulley / fan will rotate the same direction whichever side of the engne it is.

 

The difference (try and imagine it) is that a left hand mounting alternator that has the fan / pulley at the front, will, if you swap it over to the other side will now have the pulley / fan facing to the rear of the engine if you keep the mounting bracket alongside the engine.

[RLWP]

1x 110 amp starter & 2 x 135 amp leisure batteries.

leisure & pleasure use, when out & about generally at least 4 or 5 hours per day engine running. If moored up and not cruising and battery drops to 12.2 volts then run engine for a 2 + hours.

 

100 watts Solar to leisure batteries

 

When in marina on 20 amp Victron charger / inverter

 

Edit to ad :

 

12v fridge on 24/7

TV - 26 watts couple of hours a day

LapTop 3 hours per day

LED lights

 

If using 900w Vaccum, 800w toaster, 900w oven or 900w Deep fat fryer thru the 1000w inverter will run engine for twice the time the appliance was used for

 

Apart from the 240v electrical fripperies, it sounds like your batteries have an easy life.

 

Richard

[OldGoat]

I thought left and right referred to the rotation of the pulley and the correct cooling fan to cool the alternator effectively

SO did I - and got ticked off for it...

 

methinks I should have stuck to my guns - as I've never seen an alternator with right and left bracket variations.

As it happens - and that's why I made a comment - because of my engine configuration, the only way to mount another alternator was to have it facing forwards, thus its rotation was changed and I bought a universal fan to cool it.

 

Ah well, one can but try.....

[ditchcrawler]

 

The pulley / fan will rotate the same direction whichever side of the engne it is.

 

The difference (try and imagine it) is that a left hand mounting alternator that has the fan / pulley at the front, will, if you swap it over to the other side will now have the pulley / fan facing to the rear of the engine if you keep the mounting bracket alongside the engine.

Some engines rotate in the other direction

[Alan de Enfield]

http://www.ebay.co.uk/itm/Lucas-A127-Marine-alternator-12v-volt-Isolated-Insulated-return-Lister-Sabre-/251439571820?pt=UK_CarsParts_Vehicles_BoatEquipment_Accessories_SM&hash=item3a8af7636c

 

12v, 90A Right hand fix (see photo). For left hand fix please message me and ask for item number 4032M.

17mm shaft diameter.

This one shows it best :

http://www.ebay.co.uk/itm/Lucas-A127-70-amp-Alternator-Right-Hand-Fix-with-Fan-Pulley-Bolt-on-Terminals-/221330613300?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item3388552434

 

And more examples

 

 

http://www.ebay.co.uk/itm/NEW-A127-70-AMP-LUCAS-ALTERNATOR-ROVER-PERKINS-MARINE-TRACTOR-LEFT-HAND-FIT-/291075001936?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item43c56c0e50

 

http://www.ebay.co.uk/itm/RIGHT-HAND-LUCAS-A127-3-PIN-ALTERNATOR-100-056-/191063001612?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item2c7c3e0a0c

Some engines rotate in the other direction

 

Irrespective of which way the engine rotates, the alternaor will rotate in the same direction whichever side of the engine is mounted.

It may rotate the 'wrong way' for a particular engine, but it will still rotate the 'wrong way' if you change engine sides.

 

This seller of marine alternators expalins the mouting system with pictures :

 

http://www.ebay.co.uk/itm/Lucas-A127-70-amp-Alternator-Right-Hand-Fix-with-Fan-Pulley-Bolt-on-Terminals-/221330613300?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item3388552434

[ditchcrawler]

Irrespective of which way the engine rotates, the alternaor will rotate in the same direction whichever side of the engine is mounted.

It may rotate the 'wrong way' for a particular engine, but it will still rotate the 'wrong way' if you change engine sides.

 

This seller of marine alternators expalins the mouting system with pictures :

 

http://www.ebay.co.uk/itm/Lucas-A127-70-amp-Alternator-Right-Hand-Fix-with-Fan-Pulley-Bolt-on-Terminals-/221330613300?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item3388552434

I am fully aware of that, its quite obvious, But if the OP's alternator rotates left handed then he needs to replace it with a left handed one, not a right handed one regardless of where he mounts it or it will overheat and have a short life. I do not consider an ebay seller to be the definitive answer.

[Timleech]

Re the hand of rotation rather than hand of mounting:-

 

The vast majority of alternators are happy to work in either rotation, though there are exceptions.

It's the fan which might be directional, if the blades do not follow radial lines. That said, 'wrong' rotation fans will still shift air (in the same direction), I've known of alternators running for years with the 'wrong' fan without failure. Not a good idea to do it if the alternator is working hard for long periods, as many boat alternators are nowadays.

 

Tim

[Alan de Enfield]

 

I thought left and right referred to the rotation of the pulley and the correct cooling fan to cool the alternator effectively

 

 

 

Some engines rotate in the other direction

 

 

I was originally answering your statement that left & right handed referred to the rotation and not the mounting brackets.

 

You then stated that some engines rotate in the oher direction - to which I replied that for the discussionwe were having regarding the mounting brackets this was irrelevant as the alternator would rotate the same way which ever side it was on.

 

 

The OP (thats me) original question was regarding the mounting brackets orientation not the direction of rotation - although as you have now reminded me I will of course take it into account.

 

 

 

 

[bluebug73]

I had an old ac delco unit but it failed it was left hand. 3 alternators later from ebay (recon) lucas type non worked they were faulty on the bench. I borrowed a fellow boaters alternator which I knew worked to test the wiring which was fine. I ended up buying a marine left hand cost about 200 but no trouble so far . Hope it helped been there.

[nb Innisfree]

If alt is run backwards the thread on the fan nut needs to be considered, though a directional fan in reverse may possibly move enough air to cool alt sufficiently, the nut could unscrew!

[Timleech]

If alt is run backwards the thread on the fan nut needs to be considered, though a directional fan in reverse may possibly move enough air to cool alt sufficiently, the nut could unscrew!

 

That is true with those alternators which don't have a key for the pulley, the answer lies in a bottle of Loctite.

 

Tim

[nb Innisfree]

 

That is true with those alternators which don't have a key for the pulley, the answer lies in a bottle of Loctite.

 

Tim

Wot, the whole bottle?....

[Timleech]

Wot, the whole bottle?....

 

No, the answer lies IN the bottle

 

 

Tim

[Bod]

http://www.qxcomponents.co.uk/tech.pdf

 

Have a look at this site, tells all with pictures.

Scroll down to page 4.

 

Bod

Edited February 24, 2014 by Bod