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View Full Version : TR4/4A two questions- converting generator to alternator and breather cap query



Dash
03-03-2017, 07:16 PM
I'm gonna have to replace my generator and was looking at the alternator in a generator body that BPNW has (part# LRD100alt ) . It's negative ground, 45 amp output, and the claim is there's no mechanical alterations needed to install. Sounds like a nifty gadget. Has anyone sprung for one of these and have any advice as to why I should or shouldn't go this route ? Since I'm no electrical guru, other than some wire switching here and there, anything else I should be aware of?


Oh, so not to spam with a new post for a simple question..what's so special about the $40 oil filler breather caps from places like moss that a $10 one from a place like auto zone wouldn't do?

Geo Hahn
03-03-2017, 09:59 PM
No experience with the alternator dressed as a generator - but I think the price has come down from when these first showed up and only had 1 or 2 sources for them

The Moss $35 cap will be the correct color, have the original style dimples and (I think) the correct label. If none of that matters then yeah, you may be able to find a generic one(even chrome) for less.

Sarastro
03-03-2017, 11:29 PM
I also have no experience with that alternator, but I've been eyeing it, and I've tentatively decided to get one when I reach that point in my restoration. In general, I think that the generators used in LBCs are marginal. You can get by with them if you have a completely stock electrical system, but if you start adding electrical stuff you might well need more power. The BPNW alternator seems like an ideal solution.

I have assumed that, like modern alternators, it has a built-in regulator. If it depends on the stock regulator, which seems unlikely to me, I'd have second thoughts.

M_Pied_Lourd
03-04-2017, 01:11 AM
I have no first hand knowledge about the alternator dressed as a generator, but I do recall some folks on the UK forum having issues with them from the heat causing them to die prematurely.

Cheers
Tush

Geo Hahn
03-04-2017, 10:50 AM
...issues with them from the heat causing them to die prematurely...

Good point. I recall that when alternators were introduced on my other British car they went thru a series of changes to address heat issues as the alternator sat just forward of the exhaust manifold. Mostly these were differ styles of heat shields though some later models saw a complete relocation of the unit.

I expect the vulnerable components are the diodes. Because pulley fans (if I am thinking correctly) pull air through the unit from the rear, what else is back there makes a difference.

Dr_Mike
03-04-2017, 10:51 AM
I am making a similar conversion. But I question whether the original wiring, designed for 22 amps, is enough to handle 45 amps or whether I need to had heavier wire, and if so, how heavy?
I was unaware of this alternator and decided to use the Moss/Lucas kit.

Also, do we neer to put a shunt across the ammeter to stop it pegging?

trrdster2000
03-04-2017, 01:01 PM
Couple of things about the alternator conversion. The wiring in the back of the old voltage regulator can be changed and will let you keep things as original. Read up on how to do this. Your lights will be brighter and if you go with relays and ground strips to the frame, even better.
We did the GM one and only a small amount of grinding was required on one tab.
As far as the meter goes, unless your battery is way down, you will never see it charging to the full 45 amps.
It's been on a couple of years with no issues or smoke releases.

Wayne

DavidApp
03-04-2017, 01:21 PM
Several people have suggested if your battery is way down to charge it with a battery charger instead of letting the alternator do all the work. That way you do not get the high amp load going through the system.
I did get a 60 amp Ammeter that looks original as the ammeter that came with the car did not match the other instruments.

David

Sarastro
03-04-2017, 07:14 PM
The adequacy of the wiring depends on the load, not the generator. So, the existing wiring should be fine, with the possible exception of the wiring directly from the alternator. You might want to make that #10 or #12. It's really not all that critical. Of course, if you add more high-current equipment (like a high-power audio amplifier) you need to wire it appropriately.

As for the ammeter--you probably will see less motion that with the old, generator system, because an alternator will balance the charging and system currents much better. When I added an alternator to my Bugeye Sprite, I hardly ever saw the ammeter needle move. It was that good. The only way you might get a high current is when you have a flat battery (say, you had to jump-start the car) and then the needle might pin. I'd just let it do that; it won't break anything. The internals of the ammeter are just a chunk of brass, and 45A won't fry that.

steveg
03-05-2017, 12:25 AM
I'm gonna have to replace my generator and was looking at the alternator in a generator body that BPNW has (part# LRD100alt ) . It's negative ground, 45 amp output, and the claim is there's no mechanical alterations needed to install. Sounds like a nifty gadget. Has anyone sprung for one of these and have any advice as to why I should or shouldn't go this route ? Since I'm no electrical guru, other than some wire switching here and there, anything else I should be aware of?


Oh, so not to spam with a new post for a simple question..what's so special about the $40 oil filler breather caps from places like moss that a $10 one from a place like auto zone wouldn't do?

These are probably Dynamator alternators, also sold (maybe made by) AccuSpark in England. I have 3 Austin-Healey friends who have installed them. One died after a few miles - evidently the voltage regulator allowed it to charge at full voltage for 20 miles of freeway driving and it cooked some of the stator windings. The Dynamator guy in Canada sent my friend a new one without any complaints. A guy on the Healey AutoX newsgroup in Germany said his supplier ordered 10 of these and 3 or 4 were DOA. I believe the voltage regulators may be poor quality.

They use a very common Bosch voltage regulator ($15 approx). I'm planning on using one of these but plan on having it tested before use to make sure the regulator is OK. This is the bad one with the fried stator windings. I'm contemplating having the stator rewound so I'll be into it for around $125 since my friend gave me the bad one for free.
PS - they use the stock pulley and fan from your generator. Some are available in positive ground.

If you buy one of these from BPNW, you might ask if they test them before shipping.

47496

dklawson
03-05-2017, 11:02 AM
These are probably Dynamator alternators,

It appears the Dynator and Dynalite products are different (see the MGA Guru link below).

"Dynalite" appears to be a generic term now. When I first saw these products almost 10 years ago, I thought Dynalite was a proprietary, copyrighted name. At that time the only source I found was the U.K. firm Racemettel and Moss Europe was a distributor while Moss U.S. was not. That made them very expensive to buy.
https://www.racemettleltd.co.uk/dynalite.html

Some performance information on the Dynalite and Dynator can be found on Barney Gaylord's MGA Guru website.
https://mgaguru.com/mgtech/electric/ac210.htm

Hopefully the reliability of these products has improved since I last considered them.

ghawk16
03-05-2017, 01:07 PM
I was looking at one of these for my conversion even tho I'm sure my generator is in good shape. Can always switch to LED bulbs to keep amperage down as well. But if I do go with one of these I may check with BPNW to see if they have indeed tested these as Steve recommends above. They sell like hot cakes it seems so if there are more failures out there I would assume BPNW would know.

Sarastro
03-05-2017, 02:33 PM
Bummer about the reliability. I'm still a fan of alternators, though, and one way or another, I'll put one on my TR.

Dash
03-05-2017, 03:50 PM
Really good feedback on the alternator conversion, Thanks fellas, just what I needed to know. I have to do somethin with my generator cause even though it isn't back on the car yet just spinning the pulley by hand I can tell it's toast...sounds like a rusty squeaky door. I really want to go with the alternator but now I'm armed with some hard core questions to drill the vendor about.

TexasKnucklehead
03-05-2017, 05:48 PM
Well, I wouldn't have too many bad thoughts about the noises coming from a hand turned generator. If the brushes are tight, as they should be, they will drag and make a little noise (especially when rotated in reverse). If the rear bushing is dry, it can squeak, but it requires regular oiling. I've not had good luck with generators and installed an alternator after toasting 4 generators in under 20,000 miles in my TR3. -I had the "up-rated" /increased capacity TR4 style generator.

Now I have one of those tiny Kubota 30A alternators. It's been installed for about 4,000 miles without a problem -longer than I managed to have any of my generators last. I used the original pulley, with some red lock-tight. I fabricated a spacer to replace the stock pedestal bolt. I also drilled/re-tapped the tensioning bolt for non-metric threads and used a grade 8 bolt with a back-up/locking nut on the other side. I tried to offset the rapid charging at initial start-up by wiring as the attached picture shows -at the control box. You should notice a small white wire added to the fused side of the green fuse that runs to the alternator "switched/sense" terminal. Also the small-Y/G is tied to the small-Y for the dash idiot light. Y and NU are on the A box terminal, while NW is on the A1 box terminal taking advantage of the internal resistance to somewhat limit initial charging. Box terminals F and D are open, and G isn't required, but doesn't matter since the box is only there for looks. My Ammeter never pegs, my lights are never dim and my battery remains charged.

If you decide to use LED headlights, you may get brighter lights that draw less power. I have off-the-shelf halogen bulbs that use less power than the original bulbs. They may be brighter than original, but not as bright as modern cars. I don't see that adding relays to my headlights are worth the effort. I do have a new wiring harness, and know that 50 year old wires will not conduct as well as new. I do not see my headlights dim when the TR3 is at idle, as I did with the generator.

If I were to do it all over again, I think I'd first paint the Alternator Black, so it didn't look as obviously non-original.

TR3driver
03-09-2017, 08:00 PM
Purely FWIW, I "rolled my own" conversion using a 45 amp unit originally from a Suzuki Swift. It does look like an alternator, of course, but it fits perfectly and with no modifications to the engine.

https://i258.photobucket.com/albums/hh260/TR3driver/TS13571L/th_DSCF0001_2.jpg (https://s258.photobucket.com/user/TR3driver/media/TS13571L/DSCF0001_2.jpg.html)

I did modify a control box (not the original one), but the mods aren't visible.

https://i258.photobucket.com/albums/hh260/TR3driver/TS13571L/th_DSCF0004_2.jpg (https://s258.photobucket.com/user/TR3driver/media/TS13571L/DSCF0004_2.jpg.html)

Here's a shot showing how it mates to the original generator bracket.
https://i258.photobucket.com/albums/hh260/TR3driver/TS13571L/th_DSCF0019_1024.jpg (https://s258.photobucket.com/user/TR3driver/media/TS13571L/DSCF0019_1024.jpg.html)

I previously ran a 60 amp Ford alternator (on a previous TR3A) for close to 30 years and never had any problem with the original wiring harness. But I did use heavier wire from the alternator to control box area, and tied my added loads (120 watt headlights, electric radiator fan, high power stereo) directly into that wire so that current to run them only ran through the original harness when the engine wasn't running fast enough for the alternator to keep up.

In both cases, the ammeter would peg every time I started the car (especially in cooler weather). So I added a shunt across the ammeter, to make it read (roughly) 60 amps full scale instead of 30. Here's a shot of the previous TR3A (as it was being parted out after the wreck)
https://i258.photobucket.com/albums/hh260/TR3driver/TS39781LO/th_Ammetershunt1.jpg (https://s258.photobucket.com/user/TR3driver/media/TS39781LO/Ammetershunt1.jpg.html)

Mink
03-10-2017, 06:56 PM
I'm running a Delco (GM) 12si alternator in my TR4. Dirt cheap and reliable.

Gerald_Gordon
03-12-2017, 11:00 AM
As for the ammeter--you probably will see less motion that with the old, generator system, because an alternator will balance the charging and system currents much better. When I added an alternator to my Bugeye Sprite, I hardly ever saw the ammeter needle move. It was that good. The only way you might get a high current is when you have a flat battery (say, you had to jump-start the car) and then the needle might pin. I'd just let it do that; it won't break anything. The internals of the ammeter are just a chunk of brass, and 45A won't fry that.
Push-starting my TR4 with a flat battery and a 60-ampere Ford alternator did fry the ammeter, which is now at West Valley Instrument Specialists being converted to 60 amperes with a corresponding face.