TR4/4A TR4 alternator install

[joejoecat]

I'm going to convert my TR4 to an alternator,a Delco 10si 64amp to be exact. I plan on keeping the wide belt so I have a wide pulley for the 10si. Can anyone who has done this alert me to any physical modifications that have to be done.I have a universal bracket that is adjustable that I plan on mounting the alternator on. The diameter of the alternator looks a lot bigger than dia of the generator and looks like this may pose some problems. Thanks

 

[TR4nut]

The only mod I had to do was cut approximately 1/2" off the lower mounting boss of the alternator - otherwise it sticks too far forward to get good belt alignment. Maybe you won't have to do that with a universal bracket but my guess is its still an issue.

 

[TR3driver]

On my TR3A, I had to use a belt that was effectively slightly longer than the stock belt. Still difficult to change the belt, because the alternator would not go as close to the engine as the generator would, but the belt change made it possible without having to completely undo the alternator mounts.

I also notched both the alternator housing, and the mounting bracket slightly, so it could get just a bit closer. But that was with a Ford alternator, not a 10Si.

None of which may be necessary if your new wide pulley is smaller diameter than the original generator pulley.

 

[joejoecat]

Thanks guys ,gave me some things to consider.

 

[Rrbbeerrttoo]

Today I am doing exactly the same on my TR4a, converting to a Gm 10si alternator . And I have some problems still to solved, ignoring ssliding fan belts behind the radiator and the rack and pinion mechanism.
Sorry folks, this will be a long explanation , especially with the new longer belt required:
1. I am reusing all original wide pulleys, including the generator pulley. Had a machine shop bored this pulley and mounted on the alternator.
2. Alternator installation was simple , it only required cutting off the alt. bos, as someone else had suggested; it then lined up perfectly with the other pulleys after placing spacer between the upper adjustable alt. arm and the engine block. So far I used all original parts except for the spacer..and alt., of course!
3. Now for the belt lenght problem. The only belt I found so far is a bit too long( Gates, TR24400 ), sold by Grainger and advertized as 3/4 in x 40-3/4 in, OC. and 20 x 970 mm, IC. The next shorter belt available from Gates is much too short.
4. Now I run out of belt adjustment ( alt. almost contacts the front fender ) when I set belt deflection for 3/4in., which may be a bit loose. Unfortunately at this setting the belt ( not the alt. pulley ) rubs slightly against the tube crossmember in front of the engine.
5. At idle speed the belt is causing no problem even with the small rub, but whaT can happen if the belt elongates with age..or does it?
6. I now need a shorter belt but I have failed to find the correct belt lenght to make use of the new adjustment available.

My next attempt is to unmount the alt, twist it, engage on a new shorter belt and attempt to remount the alt.
Any ideas will be appreciated

 

[TR4nut]

I think I've used Gates TR28386 which is 39 1/8" - is that too short for you? It may be tough to install but it was workable for me.

ps. welcome to the forum by the way.

 

[TR3driver]

Have you tried a Gates TR28386 ? Yes, the belt will get shorter as it wears, and will wear quickly if it is not tight enough.

Another alternative would be to source a smaller diameter pulley. The generator pulley diameter is really too large for optimum performance from an alternator anyway.

Personally, I intend to solve the problem by using a "mini" alternator for my next conversion. Here's a shot from "Mad Marx" of a Suzuki Swift alternator on his TR4 race car.

 

[TR3driver]

BTW, the TR28386 is nominally 7/8" wide rather than 3/4", so it will ride just a bit higher in the pulleys, making it effectively slightly shorter. If that is too short for you, a TR28390 would be the next step longer (effective length 39-5/8), and then the TR28400 at 40-5/8 (but still 7/8" width, so effectively slightly shorter than your TR24400).

PS, I've had trouble in the past with a 3/4" nominal belt bottoming in the crank pulley, after it gets a bit worn.

 

[Rrbbeerrttoo]

Thanks ,

You guys are good and very helpfull. You have loaded me with questions, and quickly. I thank you. I will investigate all your comments. However the other facts I can pass on may add clarification to my problem!:

0. Effective lenght is difficult to use as a guide. What is neede is the inner circunference dimension , that is the dimension that slides over the flange of the last pulley, the small alternator pulley. This IC must be about 37.5".

1. My original cogged belt is now too short. It is a Flennor (German) and looks brand new although very old. It is stamped 20 x 900Li for Inside Circ. Outside circ. measures 39 in. plus a bit. It is 5/8 thick. The 20 mm translates to 0.787, almost 3/4 in, using 25.4 conversion to mm; the 7/8 translates to . 0.875, agree, it is quite a bit wider. The Flennor used to ride flush.

2. The new TR 24400 belt in my hand measures 0.6875, less than 3/4 wide although it says 20 mm. And is not as thick as the original Flennor. It is stamped 20 x 970 mm Li...I ordered it as Gate belt but Grainger supply sent me one by Bando belts.
.
3. The reused old pulley on the new Alt. is 1/4" larger in diameter than the alt. 2-3/4 pulley already discarded. The larger dia. will sacrifice alt rpm by about 10 % lower. I considered the difference an adequate risk. The ammeter presently indicates battery charging just a bit on idle , with the radiator elec. fan on.

4. If the suggested Gates TR 28386 is 22mm, and a same lenght as my originsl belt..then it is too short. But I still need the IC which no suppliers seems to know..they speak only of efec. or OC lengh.

5. The TR 28386 was a long way from fitting..too short. Although I have filed/ground nothing besides the alt. bos..do not even see what to file down on the block or whatever...that is, to make this belt fit.

6. I will investigate the other 22 mm belts. Perhaps if I can minimize the adjustment then the 22 mm belt will not rub against the cross-tube.

7. If one of you know the IC of these belts it will be all I need, but my contact with Bando belts or Gates main office could not provide an answer.

8. Using thicknesses and OC to determine IC do not turn out accurate. Who knows how they manufacture belts!!.

Thanks again. Robert

 

[TR4nut]

This may not help at all but I just checked what I'm currently using on my TR4 - I have a Gates TR24379, which is a cogged 3/4" belt and its listed as only 38 3/8". At 3/4" it definitely does not ride high at all. One reason that may be why I can use this belt is that I bought a pulley for the Delco instead of reusing stock: 3/4" pulley

This pulley is 2.5" od which I think is smaller than the stock one which may help the installation a little.

 

[Rrbbeerrttoo]

Tr4nut,

I agree using the TR 24379 with the smaller alt. pulley , it probably t work, as you have confirmed. It is listed as the next size smaller than the one I am using. It is too short for me now, but perhaps your size pulley will be my solution.
If your pulley size proposal works , maybe the original belt( 39 OC )belt would have work as well..but I cut belt that up already....Uuuummmh, not smart!
Had I suspected the correct size belt would be so imposible to locate I would have replaced the pulley. Incredible, all the published alt. conversion articles and none mentioned my problem.
Thank you. Robert

 

[Rrbbeerrttoo]

Success , finally found the right lenght fan belt.

Bought five V-belts in search of the one to fit into the new alternator pulley arrangement. I am now using TR 28400 , with 5/8 inch for extra adjustment if needed. Belt would not initially slip directly into alt. pulley so I removed alternator from its mounting bracket , and maneuvered it to engage the belt. Then I remounted the alternator. New belt is 7/8 w x 40-5/8 in., not 3/4 as the original belt, so it rides higher.
The auto parts stores have no problems with unused belts being returned.

 

[DanB]

Wow, this discussion brings back memories. I fought that battle for years. Final resolution? I went with a different alternator, a mitsubishi sourced from a Geo. I have the original pully, bushed to fit on the mitsu. Mounts were modified so I use an ORIGINAL belt.

Dan B
South Charleston, WV
66 TR4A IRS

 

[Rrbbeerrttoo]

In my case I also had the original wide pulley bored about 1/16" to mount on the Alternator.

 

[DanB]

Another trick: I put my floor jack under the engine and raise it just enough so the belt will slip between the rack and the front fan piece. The motor mounts flex just enough.

Dan B

 

[Rrbbeerrttoo]

DanB
Great news for a future belt replacement. I was afraid to do it that way. What was the space available before and after raising the engine. Did the belt also slide by the fan blades w/o moving the radiator? How thick is the belt?

 

[DanB]

I didn't measure it, but I'm guessing there was 1/4" between the rack and the fan piece. Not sure about that though. I just raised the engine enough to get the belt by. I am using an original belt, and it was tight between the fan and the radiator, but I'm pretty sure I got it by without having to loosen the mounts. It has been a few years since I did that, and I was trying several different belts for a while like you did, then finally went back to the original and adjusted the mounts to make it fit. If I did loosen the radiator, it was only mounts and not the hose.

 

[tdskip]

Have you tried moving the engine back a bit to make the belt change easier?

 

[TR3driver]

Just a thought, in case you break a belt on the road someday: you could put some shims on the motor mounts so you don't have to jack them up.

Even just replacing the mounts might help, as they can sag a long way without being obvious.

 

[Rrbbeerrttoo]

tdskip,
How could the engine be moved back...where would it move to, easily?
For my thick fan belt replacement I loosen up radiator mounting bolts and water hoses; the flexible plastic fan blades also helped!

TR3driver,
Would permanent shims put unusual stress somewhere? I need about 3/8in. additional clearance for the fan belt replacement. Never done it, but do you know if motor mounts can be replaced solely by lifting engine. Same question, what is stressed then?

Thanks. Robert