Is the alternator too far out of alignment?

[magnumdust]

I was playing around with a denso alternator today. I tried mounting upside down so the main battery stud is not facing the block. I know its a little crooked, but i may be able to correct that with a washer, but i don't know how much i can shim it or how finicky v-belts are for having perfect alignment.

edit: added other picture that the site didn't like.

 

[jimmyray]

It looks like the Alternator is staggered ahead of the pulley plain by 3/8" or so, but it's hard to tell from pic. If your off more than a 1/4", you'll probably sling a belt at high rpm. Even if you don't sling it, it will wear abnormally fast because of the sideloads of the belt on the pulleys. Lay a straightedge from the front of the crank pulley, and see how far it's off.

 

[66plyValiant]

V belts can be off a little and not fly off, but that doesn't mean it won't wear belts quickly. the is brackets for the denso swap

 

[magnumdust]

V belts can be off a little and not fly off, but that doesn't mean it won't wear belts quickly. the is brackets for the denso swap

I would jump on that, but they are brackets for the little denso. I need a 90amp+ to run my efi, electric fuel pump, ignition, fans, and misc. future bits

Here's the other picture(i hope). It does look like the alt. sits a little far forward, but this bracket is cheap pot metal and a shorter bolt/spacer should allow me to tweak the bracket in place.


And yes, there is some ghetto rigging here spacer wise, just using those bits for testing. Then i'm gonna make a hardware store trip if i can get it to work.

 

[nm9stheham]

That amount of misalignment won't make the belt fly off in my experience, I have raced over an over up to 8000 rom with such a misalignemnt and never had an issue. I would however adjust it back some; my concern would be for the 2 belts to rub together when they get a bit loose.

 

[TrailBeast]

I have to disagree on the "too far forward" guys.
Look at the belt alignment with the other belt.
Looking straight down in the second picture, maybe so but that can be fixed easy enough by shortening the spacer a little.

What I would do if it were me, is to oblong this hole toward the water pump so the alternator pully comes in line with the crank pully.

It will allow the pullys to come in line and you wont even be able to notice that it was done once everything is tightened up.

I would say start with about 1/8 to 3/16 and that pully should come right in line.

 

[RedFish]

I don't like any of it. In my opinion, The power steering belt should be crank and p/s pump only since that belt needs to be quite tight. The alternator belt should carry the water pump since that belt doesn't need to be so tight that it would pull the bearing/seal out of a water pump.

 

[66plyValiant]

I would jump on that, but they are brackets for the little denso. I need a 90amp+ to run my efi, electric fuel pump, ignition, fans, and misc. future bits

Here's the other picture(i hope). It does look like the alt. sits a little far forward, but this bracket is cheap pot metal and a shorter bolt/spacer should allow me to tweak the bracket in place.


And yes, there is some ghetto rigging here spacer wise, just using those bits for testing. Then i'm gonna make a hardware store trip if i can get it to work.

the small 1988-1991 denso used on TBI is 90+ amps and they make brackets to fit it, the alternator runs fuel injection and electric fuel pump plus whatever else options those trucks had

 

[KitCarlson]

I go with RedFish, he is 100% correct.

 

[Rbob]

I have the "Denso" brackets if you are interested, brand new. I installed but could not get alignment with the cast iron water pump.

Pm if interested.

 

[magnumdust]

I don't like any of it. In my opinion, The power steering belt should be crank and p/s pump only since that belt needs to be quite tight. The alternator belt should carry the water pump since that belt doesn't need to be so tight that it would pull the bearing/seal out of a water pump.

I'm somewhat sure it's factory. I think that's how they did cars w/ A/C, power steering, and that pile O' junk giant 100amp alternator

 

[BillGrissom]

My belts are arranged just like yours in my 65 Dart 273, mainly because I went with the later alum w.p. (you have). I don't know if I can get at the inner crank groove later for AC. I have read that V-belt pulleys need to be within 1/8" alignment. Serpentine belts are less forgiving, and many owners have problems with thrown belts, especially as components age. Still, easy for you to get it perfect. I would chuck the bracket in a vise (w/ rags to keep purty) and bend it a bit, remove a washer and should be fine. Once you optimize it, look at the chrome spacers in the drawers at Ace to keep things purty.

Thanks for pioneering this. I might need to go with the Denso too since I plan FI and such. Do you have a PN or application for the one you used? If I understand post #8, there was a Denso on Mopar SB TBI V-8 engine (88-91), but perhaps a different PN.

 

[magnumdust]

My belts are arranged just like yours in my 65 Dart 273, mainly because I went with the later alum w.p. (you have). I don't know if I can get at the inner crank groove later for AC. I have read that V-belt pulleys need to be within 1/8" alignment. Serpentine belts are less forgiving, and many owners have problems with thrown belts, especially as components age. Still, easy for you to get it perfect. I would chuck the bracket in a vise (w/ rags to keep purty) and bend it a bit, remove a washer and should be fine. Once you optimize it, look at the chrome spacers in the drawers at Ace to keep things purty.

Thanks for pioneering this. I might need to go with the Denso too since I plan FI and such. Do you have a PN or application for the one you used? If I understand post #8, there was a Denso on Mopar SB TBI V-8 engine (88-91), but perhaps a different PN.

Let me start by saying flat out: My setup is untested and i certainly didn't pioneer anything. I found this page and took a stab at doing it myself.

http://home.roadrunner.com/~raffica/denso_swap.htm

However, i screwed up as someone else mentioned. I have a large frame denso from a mid-90s jeep(magnum engine). The "medium" frame may fit a lot better. Until this thread, i had no idea there was a medium frame high amp denso. I thought there were only large frame magnum style and the small frame types found on toyota/imports. They look a lot alike.

Large:

Medium:

IF i could move my power steering pump back to the middle crank pulley, then this swap could be extremely easy. Because all i need to to space the denso out to the outer pulley where everything is away from the block. I may explore this tomorrow.

 

[RedFish]

Power steering pumps, their pulleys and brackets, are a wide variety.
Surely someone has found what combination of parts works with the aluminum water pump. Wasn't me. I wish you luck.

 

[magnumdust]

Small update:

I can't move the power steering pump inward unless i can find a pulley to move it in. I had hoped i could modify the brackets, but a piece on my pump won't let that happen as it sits pretty close to the block as it is.

It turns out, my alternator is that "medium" frame 90amp that is the same as the one's from the 1st gen dakotas. I guess the jeep was an earlier year than i initially thought. Because of my pulleys i have to find a belt that is 1.5-2" shorter to have this alternator work with the brackets.

 

[BillGrissom]

Power steering pumps, their pulleys and brackets, are a wide variety.
Surely someone has found what combination of parts works with the aluminum water pump. Wasn't me. I wish you luck.

Yes. I have seen many different p.s. pump pulleys. Some have the pulley groove farther out from the body (BB?) and some have the pulley overlapping the body (SB?), plus may vary with year and whether TRW, Federal, or Saginaw pump. Another variable is the crank damper. I don't know that all put the crank pulley grooves in the same place.

Finding a shorter belt is actually fairly easy. Download a Gates catalog. I found one years ago in a quick search. They give PN's vs belt circumferences (2" increments, meaning ~1" pulley centerline spacings) and the 3 standard widths. If I recall, your alt pulley takes a 3/8" wide belt. Then ebay the PN. V-belts are easy. I don't know why classic owners spend $$$ to deal with the problems of serpentine belts.

 

[magnumdust]

I'm afraid this may be a bit of a bust. I managed to pick up a shorter belt, but mounting it upside down with that narrow "ear" allowed the alternator to sit really crooked and it appear to be almost a half inch off from the crank pulley.

The only way i might be able to do it now, would be to mount the alternator right side up and cut down the charge wire post so far that only 1 nut and the charge wire could be mounted to that post.(oem puts the charge wire between 2 nuts). The problem this poses is if the alternator craps out on a trip, you will be taking a hack saw to a parts store replacement just to get going.

 

[RustyRatRod]

Redfish has got this. The PS goes around the PS pump and crank only. The alt always goes around the WP and crank. Get that right and it should all fall in line. It's gonna require a deeper setback WP pulley, I believe.

 

[abodyjoe]

You have the wrong water pump and most likely crank pulley on that engine. That's an A/C water pump pulley.

Do a search. There are a ton of threads with pictures to show you the correct way the Pullies and belts should be.

 

[magnumdust]

well the pulley's have worked so far, i'll worry about it down the road. The car was a factory A/C car, so that's more than likely the factory pulleys

Anyhow, on my lunch break today i played with the alternator again and i may have got it sorted. I had to drastically cut down the post, its hard plastic boot, and then mounted it right side up. The post is still close to the block, but its not close enough for me to worry about it arcing and i have a rubber boot to cover the post.

Looking at the LA engine in my garage, this issue of the post being too close to the head seems to be specific to the magnum heads.

I plan to add a lock-washer or nylon lock nut to that post and try to get it all together tomorrow.