Denso alternator mount boss/bracket

A few years ago I replaced my monster alternator with a new Denso unit Part # 100211-1680 from a local automotive electric supplier. I am satisfied with the performance of my current alternator with the exception of the mounting.

The mounting lug or boss on my alternator is only appx. 7/8" thick/wide. I used the original U-shaped bracket and installed another L-shaped bracket (under the two mounting bolts) inside the U to act as the rear support of the alternator pivot. This L bracket keeps breaking. This L is made out of half of a section of .120 square tube, and breaks in the corner as you would expect.

In looking at pictures of the current alternators in use, I see a much wider pivot boss that actually uses the whole original bracket.

Is anyone using a thick-walled spacer tube and longer bolt inside the original bracket with an alternator such as mine?

Or is there another Denso alternator part number that has the wider pivot boss that I need to buy? I am not really interested in paying $500+ for a P.P. setup, even though that seems to be the accepeted norm.

denso alternator

I, like you, didn't think much of the idea of a $400 pp alternator.

So, I bought a honda alternator (ext reg) and built a new bracket for it.

I fabricated two spacers form solid round steel stock; one to go between the lugs on the alternator and one for the OEM bracket. I welded heavy (3/16"x3") between the two to position the alternator where I needed it. The holes in the two spacers were different as well as the bolt sizes.

I had to slightly modify the adjustment arm for the new setup.

It fits well and used the original belt. I just clears my lower cowl.

Although it took a lathe and a MIG welder to do this, it wasn't difficult.

Now I can use a $55 alternator.

Dave
-9A FWF kit
N514R

Make sure the steel bracket...

...is thick enough.

Lycoming has some new part numbers for their O-360 alternator bracket, and the replacement is much thicker than the old one.



Guess why I needed one...

UPDATE

I just measured the new one and it is a full 0.250 thick.

In my case, it does hold on a heavy certified Delco Alternator, but it seems like a location where your welds and/or bends need to be pretty good.
There is also Lycoming SI 1270 "Alternator Mounting Bracket Shims" that requires shims be installed on the main mounting bolt(s) so any alternator to bracket gap is 0.004 inch or less before the assembly is tightened up.

Daver said:

I, like you, didn't think much of the idea of a $400 pp alternator.

So, I bought a honda alternator (ext reg) and built a new bracket for it.

I fabricated two spacers form solid round steel stock; one to go between the lugs on the alternator and one for the OEM bracket. I welded heavy (3/16"x3") between the two to position the alternator where I needed it. The holes in the two spacers were different as well as the bolt sizes.

I had to slightly modify the adjustment arm for the new setup.

It fits well and used the original belt. I just clears my lower cowl.

Although it took a lathe and a MIG welder to do this, it wasn't difficult.

Now I can use a $55 alternator.

Dave
-9A FWF kit
N514R

Click to expand...

will keep a close "eye"

thanks for the tip Gil.

Since this is my own concoction, I'll keep a close eye on it.

It all looks rather stout so I'm hopeful there will be no issues.

Dave