L20B Alternator Bracket

[ducky]

Is anyone able to provide specs on the stock L20B alternator bracket? I found out mine was absolutely not correct. The previous owner had some huge chunky thing on there, which now explains why I was not able to tension it at all.

 

Anyways, bought a new one from eBay, but it doesn't come with the hardware. I'm looking for the thickness of the back plate portion of it, as well as the depth of the threaded hole, which should only be the front ear (of the alternator) mount, right?

 

[banzai510(hainz)]

I believe there was car versions and truck versions. I think that is a truck version you have.

 

no extra stuff come with this and youl have to go to a hardware store to figure the rest

 

 

you could get a 5mm shorter belt to make this work if tension was not right. (too long a belt)

[datzenmike]

 

I think the top one was for the 720. I used it to position a larger diameter alternator higher for clearance.

[Stoffregen Motorsports]

2 hours ago, banzai510(hainz) said:

 youl have to go to a hardware store to figure the rest

Yuck. I hate hardware store fasteners.

 

Get some original ones from another motor, or buy JIS stuff here - https://www.newcoproducts.com/index.php?route=product/category&path=67

Or here - https://www.overlandmetric.com/

[ducky]

6 hours ago, banzai510(hainz) said:

I believe there was car versions and truck versions. I think that is a truck version you have.

 

no extra stuff come with this and youl have to go to a hardware store to figure the rest

 

 

you could get a 5mm shorter belt to make this work if tension was not right. (too long a belt)

 

Yeah, I bought it from California Datsun. I asked if it came with hardware. They told me $10. I asked what all that came with. They did not respond again.

I wanted to have the hardware in planning to order, here by the time the bracket shows up.

 

6 hours ago, datzenmike said:

 

I think the top one was for the 720. I used it to position a larger diameter alternator higher for clearance.

 

I'm not completely sure on that Mike. The parts catalog looks a lot like the top one, so I think it's correct.

 

[ducky]

For anyone that actually wants the answer to my question:

 

M10 x 35mm for bolts to the block. I'll be using flange bolts with lock washers as well. If you aren't using extra washers, probably step down to 30mm length, as the 35's will be very close to bottoming out in the hole

M8 x 40mm + M8 flat washer + M8 lock washer + M8 hex nut rear ear of the alternator

M8 x 35mm + M8 flat washer + M8 lock washer for front ear of alternator - This one was too long, but I think that's because California Datsun did not put a bolt in the hole, and packed it full of powder coat. You may want to step down to a 30mm long bolt.

M8 x 20mm (or 25 for slight extrusion) +M8 lock washer for top ear if using the stock adjustment arm

 

The holes into the block on my engine are 23mm deep, as is the hole on the front mount of the bracket.

The back plating of the bracket where the holes are is 15mm thick.

The ear for the rear of the alternator to mount at is 11mm thick.

The front and top ear of the alternator on both of the ones I have are 13mm thick.

The rear ear of both alternators I have is 16mm thick.

 

And here's my quick and crappy drawing if anyone needs a visual aid. Also, I wasn't aware the back ear of the alternator goes on the other side of the bracket ear. The size is the same though.

Edited May 8, 2022 by ducky

[Stoffregen Motorsports]

If the hole is full of powder coating, drill it out and run a tap through it to clean it out. Powder coating shops don't always do an excellent job of cleaning the parts before they go into the booth.

[ducky]

2 hours ago, Stoffregen Motorsports said:

If the hole is full of powder coating, drill it out and run a tap through it to clean it out. Powder coating shops don't always do an excellent job of cleaning the parts before they go into the booth.

 

That's what we ended up doing. Unfortunately, the taps we have aren't flat at the leading end of them, so it doesn't quite reach the end of the hole. We lost about 10mm of thread.

 

[yenpit]

On 5/9/2022 at 9:59 AM, Stoffregen Motorsports said:

If the hole is full of powder coating, drill it out and run a tap through it to clean it out. Powder coating shops don't always do an excellent job of cleaning the parts before they go into the booth.

 

We have learned to plug or tape off (there is a special tape) everything BEFORE powdercoating!  Extra work to start, but much less hassle in the end.  Most powdercoaters do NOT know (or care?) what to plug or tape off, so we do it..............

 

Ducky, great info on the hardware!!