Datsun Roadster Forum-311s.org

I am in the process of moving my alternator over to the cool side on my 68 2L. I have an old smog mount, but I found another mount on an old 2L block I had. The other mount is cast iron, mounts are the same, but the horn is longer. Which would be a better choice? Also in the pic is a home made bracket I found in a box of old parts. Are the specs for the original triangle smog bracket posted anywhere?

Thanks

I believe the 620 trucks had that kind , over rugged terranes the alloy kind might break

Both work but the longer nose places the alternator drive pulley closer to the crank/water pump pulley plane without the use of a barrel shim on the through-bolt between alternator and mount.

The shorter mount is a smog pump mount. The longer mount appears to be an early 1600 mount that has a notch cut in it for the 2 ear style alternator to be moved forward for use on a later car. The triangle bracket looks homemade.

I believe the early U20 cars (before the smog pump) had the alternator on the right hand (passenger side) but I don't know what that mount looks like, maybe someone with a 67.5 can confirm. I assume it's the one you have from the 2L block

I used the the air pump mount with the spacer to move the alternator to the cool side on my 69

Yes, they did Joe. The mount looks like the iron longer mount in the picture, but without the cut. The 2000 mount was different from the 1600 mount in that it had a larger hole drilled for a larger diameter alternator mounting bolt. I have not compared the lengths to see if there was a difference there.

I'll compare it to mine, but it looks very similar.

Thanks all for your replies.

I cleaned the iron mount up and discovered the PN stamped on the side. #11711-25500. That part is the support alternator for an SRL 2L. Doesn't specify year. The block it came off of is U20 03093, so a pretty early 2L block. The mount is not threaded.

I bolted the mount and ran a long 5/16 bolt thru to test my GM alternator set up. Pulley alignment looks right with no spacers. I'll have to fabricate a new triangle bracket to match the setup and find a belt that fits. This appears to be much easier than the smog set-up.

Is there something on the mount or did someone cut a slot in it?

No modifications. It's a cast iron mount designed for the 2L. As I understand it, the slot was for the original Denso alternator with 2 ears. Have been hunting for a 7" 3/8 grade 8 bolt to make it work. Plenty of 6" available. I'll post pics when I get it finished. This mount makes that conversion so much easier. No spacers needed. Just surprised it hasn't appeared on the forum previously.

There's this in 3/8. Just a bit smaller than the 10mm. You can perhaps shorten it a bit. Comes in 7" too.

https://www.boltdepot.com/Product-Detai ... oduct=7194

Why grade 8 since there are virtually no grade 8 on these cars with most being grade 2.

10mm x 190mm long

https://www.boltdepot.com/Product-Detai ... duct=11873

Thanks to all. I found the bolt at Fastenal. They require an account. So I created one and ordered online. About $3.50 for the bold and a grade 5 locking nut. Picked up at the local store today. Reassembly tomorrow

I bought a metric bolt yesterday for a 2L alternator (lower bolt). M10 x 1.25 I believe. It was $2.60 for the lousy thing. I'm not throwing away any bolts any more.

On a somewhat related note, I dropped off 2 U20 alternators at a local rebuilder the other day. He came recommended by a Porsche client that I have. $125 to rebuild each one. I'll report back when I pick them up. These are getting harder to find, so hopefully he'll do a good job.