Direction Of Turn Of An Alternator's Pulley

This will not be a problem. The diode bridge built into the alternator will rectify the signal to the same orientation without a problem

Just curious, a larger alternator won't do or are you running separate equipment off it (like a winch, or lights,....)

Hi! the second alternator (12 V, 145 A/h) is intended to load a series of high amp batteries that operate separate equipment

Can you not mount the thing with another set of pulleys that would reverse the spin, although right now I am not seeing it, other than changing to having the belt run outside the pulley, not over it. Sort of like having the second alternator in place as a belt tensioner for the first one. I suspect this could cause all manner of issues, but maybe worth a shot.

I do know the electrons will not run backwards due to a backward spinning alternator.

hard to tell, have to take his word for lack of space.

I also evaluated such a scheme, but as it is a big alternator (145 Amps), im quite sure the belt will slip...

Older Lucas ACR and most Bosch alternators are 90° designs for universal fitment, with the correct cooling fan blade direction. Many years ago I had to run one reversed on a 2000cc Pinto engine in a reliant Scimitar, with it mounted on a cross beam in front of and above the engine, made a belt tensioner from a valve spring to cope with the movement of the engine, worked ok for several years.

That is one point you brought up I totally overlooked, the fan direction. Do you somehow take the fan off and reverse it? I don't see how to fix this problem at all, without having a special fan made or make one.

It all depends on the manufacturers method of assembly, taking the pulley off usually enables the fan to be removed, some can be flipped over, but not all, depends if they make replacements or if you can adapt one.

Flipping a fan over may change the efficiency, but it won't change the direction of airflow!

Leaving the fan alone would have it drawing heat out instead of pushing cool air in. No idea how much this would change overall cooling efficiency but if the alternator is not running at full load for very long periods of time it may not be a problem.

I checked that too, most alternator fans have angled blades, meaning they work only spinning in one direction. In this case, the blades are straight.

Straight blades I suppose indicates this will work as a centrifugal air pump either way.

How about a bi-directional alternator? Bi-directional alternator.

Option 2 looks like your best bet. Rotation is correct and you can install a longer alternator belt to run both alternators.

That is a toothed belt driving the first alternator. Can you not get a longer toothed belt and mount the two alternators close to each other?

On the "original" configuration there is a toothed belt as you say, (internal pulley of crankshaft, water pump, small alternator).

I fear that adding a second alternator (I may be wrong!) to the previous config would add too much stress on the water pump and small alternator, because cause the high HP draw from the new one.

Although that belt has notches to make it more flexible, I don't believe it is a 'toothed belt' (timing belt). A toothed belt must run on toothed pulleys, and no slippage is possible.

I'm pretty sure that belt is running on an ordinary V-pulley, which does allow slippage.

Right! the belt you saw is a normal "V" belt with tooths. I am evaluating to use a flat belt with teeth between the crankshaft and the large alternator.

I believe you are right, they grip better, but if the "life" is better or not I cannot say.....

I personally, as you apparently suggest, have never seen an alternator with a "proper" toothed belt, BUT, very sadly, VW did something really stupid with many versions of their TDI Diesel motors, they added the water pump onto the toothed belt that drives the Valve train!!!!

Countless VW Diesel engines have had to be rebuilt because the water pump has seized and stopped the valve train, with catastrophic results as valves meed fast moving Pistons.....

Here the repair costs around US$8,000 - US$10,000, or even scrapping the car completely.....

For some years now (I have had many VW Diesel cars over the years), I replace the water pump at the same time as I replace the belt, there are "kits" around that supply both!!

"Saving money" by retaining the old water pump is dangerous, but brings to light my favourite German saying (My translation!):- "HE SAVES MONEY, NO MATTER WHAT IT COSTS!!"

"...added the water pump onto the toothed belt that drives the Valve train!!!!"

Oh Really! I didn't know that! Both of our cars are the now-infamous Passat TDIs. I just looked, and I can't even see a water pump, nor a steering pump, if there is one. The alternator and the A/C pump are on the serpentine flat belt, and that's all I can see.

I'll definitely check more into that! Do you know at what mileage (OK, how do you say 'mileage' in kilometers?) the timing belt is normally replaced? The owner's manual doesn't seem to say.

It's well past 50 years since I changed out the engine in a car, and I'm sure as heck not going to do it now!

Firstly, I cannot say if they still do it, my 2.0l "Pumpe Düse" engine is 10 years old now.

Good modern engines have gone back to chain drive for the valves and I personally have never seen a chain driven water pump either....

Yours may have a chain......I don't believe they need replacing until they rattle, which should be far longer, an unlikely to be specified I feel....so I would guess you are lucky!!

But a VW mechanic should be able to tell you better than I can....

Its certainly a point to ponder if you are buying an older car with a VW engine. On mine it needs changing every 120,000 KMs.

I did finally find it in the service brochure: 130,000 miles. That's almost 210,000 km! In 2.5 years, I've only put 35,000 on mine, so it will be a while. We bought my wife's used; it already had 85,000 miles, and she drives more than I do, so hers will come first. I'm taking hers in for service tomorrow, so I'll definitely ask!

The reason is that you are simply not allowed to drive as fast as we are!!

Yes, in Deutschland, it is very critical to have all OEM scheduled PM's done on time, since at those speeds, one does wish to have an encounter of the third kind with some alien artifact left behind in the form of scattered parts and pieces strewn all over the Autobahn. You mess up the Autobahn, they tell on you to the Taliban.

LOL!!

I did check with the dealer yesterday, and they confirmed that the water pump is indeed powered by the timing belt (not chain) in the Passat, and that it is standard practice to replace the water pump at the same time as they replace the timing belt.

Interestingly, they said that was done at 120k mi, while my service manual says 130k mi. The earlier replacement is undoubtedly safer.

I did once have an engine blow (Ford Escort) due to a failed timing belt. That was before I started keeping computer records, so I don't know at what mileage it occurred. I think I recall something in the 90k mi range...

Some years ago here Ford had a lot of problems in that area.....especially on Diesel engines.

Today Ford has a lot of problems with its small diesel buses, ones that I drive, it seems they need expensive parts several times a year once the guarantee has run out.

Also, Ford started making its own injectors, they unscrew themselves, had it on two different buses this year already!!

I wish I could do what those injectors do...LOL.

LOL!!

Again, another reason for my favourite German saying, which I have mentioned before and only recently too here I believe:-

"He (Ford!), saves money no matter what it costs!"

That used to be the joke around here where I work, that our Production Superintendent would spend $100K, to save one dollar. Usually, it was saved by not spending that dollar on maintenance, or an item useful for diagnostics, even a cheap thermometer...

I was at my mechanic's shop a couple years ago and he had the entire front off of the VW Jetta he was working on. I thought he had to fix the core support, but instead he told me he had to take it all apart to get to the timing belt. Bumper + headlights, radiator, etc.

Honda's and Toyota's have the water pump under the timing belt cover. They run off the toothed timing belt. I haven't seen a water pump freeze and cause the timing belt to jump, but I guess it's possible.

Your VW may have the water pump under the timing belt cover also. Go to an auto parts store and ask to see a water pump for your vehicle. If it has a toothed pulley, you know it's driven by the timing belt.

Er spart Geld, egal was es kostet???? Never heard this saying!

It was my "battle cry" for many years when correcting computer system faults.

I had it as a poster, in the southern German regional accent, on the wall behind my office chair.....

IMHO - sort of stupid for VW to abandon their previous use of air-cooled engines, and to then turn around and rely on some flimsy belt for the valve timing. Why not gears internal, well oiled, or a timing chain?

VW and Porsche had to stop using air cooled motors, because of emissions control. I never owned an air cooled VW, but I heard they were easy and inexpensive to rebuild.

I did own a couple old air cooled Porsche cars. There's something special about the sound of those motors! I'd like to have an old 1960's 911 or 912, but they've become so expensive. And they weren't even that fast!

Air cooled motors have to be built with greater tolerances than liquid cooled motors, and because of that, tend generally to have a shorter life span.

Certain air cooled Porsche motors of yesteryear, would need a complete overhaul at around 100,000 Kms, a very expensive one!! You basically ended up with a new motor each time. The clever ones bought new and sold early to the mugs who thought they were getting a cheap car!!

Air cooled VW motors (on which Porsche partially based his cars many years ago!), were so badly designed that they did not have, even for the day, a proper oil filter, only a sieve!! Which did not improve the lifespan of the motor in the least!!

A car designer and engineer that used to work for Jaguar, UK., that I knew in the UK some years ago, as he helped a friend of mine design a new Kit Sports car, was telling me that all the manufacturers buy cars, on the quiet, from many other manufacturers, and strip them down for their "secrets, its normal business. His personal specialty was making a chassis properly "stiff" and saving weight while doing it....

He was telling me just how badly designed bodies of certain Porsches were made (and other makes!), with very "un-stiff" chassis.....the 928 of yesteryear was a well known example I remember.....it was not alone....

I personally have never been a Porsche fan, probably because I knew too much.....there are plenty of better sports cars around....though I am not particularly a sports car fan!

Depending upon the power output of the alternators, that is almost guaranteed to have "slip" when driving high electrical loads.

It needs a doubling of the belts to be even halfway safe....

The deep cycle battery bank this new alternator will feed should be always loaded from shore power, or a Kohler genset I also have on board; therefore I expect not having very high electrical loads. Nevertheless, I´ll see what happens... if there is belt slippage, I will go for double belts or flat toothed belts.

It seems to me the best place to mount it is opposite to the water pump,using a bracket similar to the water pump,and adding another pulley to the front of the crankshaft.

There are plenty of stackable, multi-belt pulleys around,and you may find one in a scrap yard that fits your purpose.

An adjustment bracket, or two,(or struts),could be secured to one or more of the timing cover bolts.

I suggest a triangle configuration with two struts from a common point of the alternator to two bolt holes on the timing cover.

The bottom hole of the alternator should be bolted solid to the bracket clevis.

One of the struts would have a slot for adjustment.

Simple fix.

Right, I finally went that direction! I found a 8mm x 25mm flatbar and made a clevis out of it, which I welded to the left half-craddle of the engine. Finished some minutes ago priming it with epoxi paint. Tomorrow I will place the alternator in position and look for the best position for welding the adjustment bracket. Everything went smooth so far -even a little fire on a corner below the engine (didn´t notice a little pool of Diesel down there) that got lit up by some welding sparks.... I always have a fire extinguisher at hand, but fortunately did not need to use it (preventing a big mess). I will post some pictures tomorrow and next week after buying the new belts and having them in place.

Thank you!

As Andy stated,there will be a lot of torque required under heavy load.

I suggest using a Poly V belt,and increase the "wrap" around the pulley as much as possible by strategic location of the alternator with respect to the drive pulley.

http://www.poly-v-belts.com/

It appears that you have plenty of room to add an idler if necessary to accomplish

this,using the timing cover bolt holes.

Then shorten the top braces as much as possible to give the belt more wrap.

A minimum of 50% wrap if you can get it.The more wrap,the less tension required to deliver the same torque without slippage.

Increase the length of the mounting bolts by the thickness of your brackets to ensure full thread up into the holes.

Good luck.

Whenever I am working in a closed area with a welder,I always use a wet towel below

my work to help catch the rogue sparks.

Good ventilation is also essential to prevent accumulation of vapors.

You were very blessed.

Liquid diesel and fumes down below,sparky up above=

Recipe for disaster.

Good luck,and be careful!

yeap! completely right! Yesterday I had the chance to learn to be more careful.... today I isolated the surroundings of my working area with some scrap metal sheets from a boat nearby. The wet towel is a god idea and far more practical than the sheets I used!

That looks like a standard Delco 22SI type alternator of which I use them on our farm tractors.

They are bidirectional.

And as others said, at full load, they do require two belts.

What is the original stock alternator rated for? If it's substantially smaller I would put the bigger alternator in its place.

You are right! But this is a Chinese copy of those. Before buying I asked a bit around and was told there are plenty of them installed in passenger transport boats (Bus-Boats) which are real workhorses 14/7. So far (some are up to 6 years old) they have had no problem. No need to say that these alternators cost a 50% less than the "real ones". The original (engine) alternator is rated 40 Amp. I tried to put the new one in place of the latter, but there is a fuel filter in the way, so I placed it below. Thanks for your input!

I would have just tossed the old 40 amp unit out and moved the fuel filter to a new location.

Me too... but I have been working such a long time on this boat and have made so many changes that I arrived to the "least effort" moment on the things I work on.

I want to get it back into the water ASAP, sail a bit around, have some fun and start all over again after having enjoyed the break!

Can you fabricate a small bracket to allow the two pivit bolts of the two altomernatorsto be almost next to each other, with an additional adjustment bracket running between the adjustment bolt of the first to the adjustment bolt for the second. But use a spacer to allow the second pully to align with the accessory water pump pully?

I effect hanging the second alt from the first.

Dear Mr.r&ddoc.,

There is alternator or generator known as ROSENBERG GENERATOR, and this will develop DC power irrespective of direction of rotation. If you need AC power, use an Inverter.

The speciality of the Rosenberg Generator, is its pole will be large when compared to other type of generators.

Residual Magntism will remain and builds up the voltage while starting.

For example, about 3 decades back) Railway Coaches are fitted with this type of generators since it has to charge Batteries also. But to-day's scenario, AC power at 120 Volts are used and for battery charging inverter and convertor combination is used.

DHAYANANDHAN.S

Ok... stationary engine... so you don't need the A/C compressor or the powered steering pump, yes? Could you not replace either one of the aforementioned with your larger alternator?

Another option would be to change the pulley driven off the crank shaft with a pulley with more belt slots, make a bracket for the new alternator on the engine stand with tension slides and fix it that way, correct way round.

When in the British Army, REME we had landrovers that had larger alternators in addition to the standard one to power the radio pack, and they were fitted to the engine using extra brackets, extra belts and a non standard drive pulley.
I see no need to reverse your alternator.
A photo would help!

Hi Brich!, the pictures are posted under # 17. As described, there is a double drive pulley at the crankshaft, and no AC nor power steering. The "stationary motor" is actually the starboard engine of a trawling boat

you may want to think about replacing the double pulley with a triple and mounting the extra alternator to the side of the engine, but one the engine, hence my post and link to a web site selling brackets etc.
They also can advise too!

Trawling boat, and you wanted to put this extra alternator on the deck (or nearly so) beneath this engine. I would not. Obvious reasons when storm comes up and trawler is taking on water, you lose that power.

From the place where I wanted to place the alternator first (beneath the engine) there are still 20 inches to the deepest part of the bilge. Should the boat take enough water to flood it, my boat and me would be in a really s..tty situation Now it is placed 15 inches higher. Tomorrow I´ll borrow a lathe to adapt the centers of new pulleys to the holes in the crankshaft and waterpump. Will post some pics as soon as assembled,

photo of high power alternator for a long wheel base Land rover FFR.. (fitted for Radio)

LINK to web site

This is likely not feasible, but I'll throw it in the mix anyway. I've seen a couple of Doodle Bug tractors that utilized 2 belts driven by the same pulley but driving 2 different accessories. The inside belt ran in the bottom of the pulley groove; I couldn't tell if it was running on the bottom of the groove. The outside belt was the normal configuration with the Vee belt running in the same pulley groove, but the width kept it to the outside of the groove. I think I have a photo of this buried somewhere.

On some alternators there is a bolt into the end of the alternator shaft that holds the pulley on. You will want to be sure that if this is the case with your alternator, that the pulley wont unscrew itself.

Some alternators also have cooling fans built as par of the unit. Cooling air will also depend on direction of rotation of the cooling fan.

You are right! If the alternator turns in the opposite direction, the nut that holds the pulley may unscrew itself. In the "normal" position (as placed now) the more it turns, the more tighten it gets

You can buy left hand threaded bolts and even thread cutting equipment, or simply get it reversed by a machine shop.

Or add a couple of tiny locking grub screws, and check it regularly.....

Looks good to me.

If the belt slips,you could consider going to a larger cross section V-Belt,like a "B" size belt and corresponding pulleys.

The "B" size belts can handle much more torque than the typical "A" size belt,which are generally referred to as FHP--fractional horsepower belts.

Explore this link for more information on belt sizes:

http://engineersedge.com/xbelt_size.htm

If the only purpose of the alternator is to keep the batteries charged,I do not foresee the alternator requiring full output,so the standard belt should be good.

Thumbs Up from me!

Good Luck!

Thanks for your input and also for the great info in the link!

The 600 Amps battery bank served by this alternator should be always charged, as it will get electricity from the shore, and also from a 10KVA Kohler genset; therefore I do not expect it to slip.... but you never know!

You are welcome.

I like the way you made the curved adjustment bracket.Looks very professional.

Plenty of adjustment to use a variety of length belts,making a replacement easier to find in a pinch.

The 145 amp alternator will only require about 4 horsepower to turn at full output,so

there should be no problems with the belt, since it will seldom be at max output,but

always carry a spare(Murphy's Law).

Looks good mechanically! And neat too!!

Well done and many thanks for the update.

I would be very happy with my work if I had done it myself! (if that makes sense!!)

Looks like your hard work is going to pay off!

Get those sluggards to dredge the harbor and get that supply scow off the scotch.

Lol!

Looks good! I wish you years of enjoyment from your new boat.

Thank you!

Wow, very professional looking results. Both of the pulleys used with the high output alternator have a full half of the pulley in contact with the belt. As mentioned, nice adjustment range. If the pulley alignment is good, it appears better than some of the automobiles that I have had to deal with.

Better than good, I'd give it an excellent.

Thanks a lot for your comment! (I worked hard on it) It took some time and a lot of trial and error to find this pulley / belt configuration. In some days I´ll know if it works! Letya know!