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TR2/3/3A Alternator Conversion TR3

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mgedit

mgedit

Jedi Knight
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Here are some notes I made to try to consolidate the advice given here over the years about making a switch to an alternator in a TR3. Still trying to sort out how to proceed. Some questions in bold placed within notes. Sorry if this information is well known, but thought it might help some others to share my notes. In final analysis, I'm trying to sort out what parts I need for conversion, and how to redo wiring to complete the conversion while adding a few more circuits. As usual, greatly appreciate your help. Cheers, Mike


  • Kits are available to do the swap (Triumph Rescue seems to be the common source for many other sellers) and come with all parts necessary for $175 plus $20 shipping (in US). Not sure what alternator is being used but it may well be the 10SI. Alternator with output between 45 and 60 amps should be sufficient.
  • Alternators in both positive and negative ground and with different size pulleys and outputs can be ordered from https://www.qualitypowerauto.com/item_574/12-Volt-Negative-or-Positive-Ground.htm or from https://alternatorparts.com/10si-all-in-one.html (the Delco 10SI model).
  • Delco (GM) 10SI alternator (Lester part no. 7127) is physically large. Other options are available such as Bosch or one for small Kubota tractor. Nippondenso (Lester part no. 14684 or 12184) may work. This is another possibility https://www.miparts.com/oem/13213
  • VTR wiring article on alternator conversion by Dan Masters seems no longer to be on VTR site. Anyone have a copy?
  • It is possible to gut the control box and use it to connect wires with the conversion. Conversion of control box retains a more original look. Some information here that might be same or very similar to what needed on TR3. Is this information same for TR3? (https://www.minimania.com/Changing_from_Dynamo_to_Alternator_721); or removing all together https://www.minimania.com/Alternator_Conversion_Instructions
  • Internal failures have been reported (by Randall) when using the old control box. For this reason switch to terminal block might be better. Wiring kit for 10SI alternator, as well as insulated terminal block, are available from https://www.madelectrical.com/catalog/alt-1.shtml, and https://www.madelectrical.com/catalog/cn-1.shtml
  • Although original generator pulley can be drilled out and used with alternator, it is better to get a smaller wide-belt pulley to turn the alternator more quickly and provide low-engine speed charging. Several sources on eBay for wide pulleys and alternators with wide pulleys.
  • Randall put a shunt (3.5" of 16 AWG wire) across the ammeter terminals to divert some of the current past the meter. With the right piece of wire, you can have the meter read approximately 1/2 the current (and thus not peg the needle at full charge).
  • Seems like good time to add some more fuses. Can something like this box be used to replace existing 2-fuse box? On second look, it seems like it is a way to break one input into six outputs, so this may be more what I need? If the second type is required, would be nice to find with screw connections. If these are not suitable, what is needed, how should it be wired, and what size spade fuses would be needed for horns (currently wired through a relay) and "rest of car" circuit? Just want to be able to add a couple of circuit for electric fan and for power outlet inside car, and have a couple potential left over just in case.
 
mgedit said:
Here are some notes I made to try to consolidate the advice given here over the years about making a switch to an alternator in a TR3. Still trying to sort out how to proceed. Some questions in bold placed within notes. Sorry if this information is well known, but thought it might help some others to share my notes. In final analysis, I'm trying to sort out what parts I need for conversion, and how to redo wiring to complete the conversion while adding a few more circuits. As usual, greatly appreciate your help. Cheers, Mike


  • Kits are available to do the swap (Triumph Rescue seems to be the common source for many other sellers) and come with all parts necessary for $175 plus $20 shipping (in US). Not sure what alternator is being used but it may well be the 10SI. Alternator with output between 45 and 60 amps should be sufficient.
  • Alternators in both positive and negative ground and with different size pulleys and outputs can be ordered from https://www.qualitypowerauto.com/item_574/12-Volt-Negative-or-Positive-Ground.htm or from https://alternatorparts.com/10si-all-in-one.html (the Delco 10SI model).
  • Delco (GM) 10SI alternator (Lester part no. 7127) is physically large. Other options are available such as Bosch or one for small Kubota tractor. Nippondenso (Lester part no. 14684 or 12184) may work. This is another possibility https://www.miparts.com/oem/13213
  • VTR wiring article on alternator conversion by Dan Masters seems no longer to be on VTR site. Anyone have a copy?
  • It is possible to gut the control box and use it to connect wires with the conversion. Conversion of control box retains a more original look. Some information here that might be same or very similar to what needed on TR3. Is this information same for TR3? (https://www.minimania.com/Changing_from_Dynamo_to_Alternator_721); or removing all together https://www.minimania.com/Alternator_Conversion_Instructions
  • Internal failures have been reported (by Randall) when using the old control box. For this reason switch to terminal block might be better. Wiring kit for 10SI alternator, as well as insulated terminal block, are available from https://www.madelectrical.com/catalog/alt-1.shtml, and https://www.madelectrical.com/catalog/cn-1.shtml
  • Although original generator pulley can be drilled out and used with alternator, it is better to get a smaller wide-belt pulley to turn the alternator more quickly and provide low-engine speed charging. Several sources on eBay for wide pulleys and alternators with wide pulleys.
  • Randall put a shunt (3.5" of 16 AWG wire) across the ammeter terminals to divert some of the current past the meter. With the right piece of wire, you can have the meter read approximately 1/2 the current (and thus not peg the needle at full charge).
  • Seems like good time to add some more fuses. Can something like this box be used to replace existing 2-fuse box? On second look, it seems like it is a way to break one input into six outputs, so this may be more what I need? If the second type is required, would be nice to find with screw connections. If these are not suitable, what is needed, how should it be wired, and what size spade fuses would be needed for horns (currently wired through a relay) and "rest of car" circuit? Just want to be able to add a couple of circuit for electric fan and for power outlet inside car, and have a couple potential left over just in case.
Click to expand...


I used the Kubota($70 on ebay 40A)and the moss fan eliminator kit,thin belt,which matched the stock Kubota pulley.
Since I had no control box anyway I used a vintage bakelite Lucas SF4 Four fuse box with screw terminals for bare wire ends and a nice cover that looks similar to the original regulator.These where used on Morgans,Cobras etc.
I also used a volt meter that looks similar rather than overload or shunt the amp gauge. This made wiring easier,but probably not for most folks.
Have Fun
Tom
 
I installed a GM alternator in my TR3. I feel that it is much to large to fit properly in a TR3. I wish I had used the Kubota or some other alternator that has a much smaller form factor.
Regards,
Bob
 
It's not required to 'gut' the original control box or even open the lid. Just disconnect the ground wires (and tie them together) and remove the old lead from the 'F' terminal to the generator. The old lead from the 'D' terminal can be used to connect to the warning light output on the alternator (assuming it has one).

With no ground, neither relay will pull in. That leaves A connected to A1 through a short length of heavy wire (wound around the regulator relay), and D connected to F. But since F won't be connected to anything, the connection to D doesn't matter.

I ran that setup for some 10 years and roughly 100,000 miles. But if you want to be sure, you can add a jumper underneath between the A and A1 terminals.

Also, someone reported a few months back that the terminal block is no longer available from MAD electrical (even though it's still on the web site). Check with them obviously, but don't make too many plans around it before you do.

Rather than replacing the original fuse box, I added one. The SF4 that Tom mentioned is more period correct (and I may switch in the future), but I used a more common (as in on my shelf) 7FJ as used on the TR6.

Whether you want to break one input into multiple outputs or not depends on what you are connecting. One to many is fine if all your new circuits are hot all the time. But if you want some things to be controlled by the ignition switch, then that's probably a separate input. Ditto the headlight switch. With the 7FJ and SF4, you can just daisy-chain as many inputs as you like, or not.

I also used some circuit breakers, mounted under the dash where no one but me will ever see them; plus a couple of in-line fuses.
 
I did a moss alternator conversion earlier this year, including a narrow belt and dampner pulley conversion.
the instructions were pretty straight forward, also I think moss has a tech video (talking hands) on the conversion.
the only thing I didn't like about the Moss alt. was the external alternator fan. It never really felt secure on the shaft.
however it's been 6 months & hasn't given me trouble. & the external alt. fan does tend to move a fair amount of air in the exhaust manifold neighborhood.

i wired in a main post & fuse boxes ( from Jegs), along with some relays I got from MAD.
have had no trouble

here is a couple of blog entries, fwiw:

https://www.britishcarforum.com/bcf...acement-sleeve-for-Moss-dampener-crank-pulley

https://www.britishcarforum.com/bcf/entry.php?115-22-Rear-suspension&goto=prev
 
Thanks to you all for your replies. Yes, Randall, that looks like the article from VTR.

Cheers, Mike
 
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