L16 alternator mount

[ttyR2]

Someone did a poor job of fabricating a lower alternator mount for the L16 in my 521. Do any of you have a good spare OEM one lying around that I could talk you out of?

[mainer311]

What do you need, the 3 bolt version? I can check for you tomorrow. Pretty sure I do.

 

There are usually a bunch on eBay. I like the large cast ones, like this:

https://www.ebay.com/itm/403018265040?hash=item5dd5c2b1d0:g:SGQAAOSwEK5g~Liw
 

Whatever you do, make sure to use grade 10.9 bolts when mounting it. 

[ttyR2]

I was flipping through "How To Keep Your Datsun/Nissan Alive" and it mentions the 521 has a steel plate for a mounting bracket, so maybe the one on this 521 is technically correct but someone buggered up the threads. I'll pull it off and have a look.

 

Would one of the nicer cast iron mounts fit as a replacement? On further research, I see the older mount from an L20B (and others) mounts the alternator slightly lower, but the 720 mount moves it up 3/4" or so...maybe the ticket to clear the steering gear on the 521. I don't know...anyone?

[datzenmike]

L16  blocks only use two threaded mounting holes for the alternator bracket. Poor design... I had the bolts snap off in the block. L20B and up blocks use three bolt mounts in a much better triangulated pattern. L18s? not sure could be 3 bolt.

[ttyR2]

So the L16 block itself only has two mounting holes...bummer.

[d.p]

Man don’t let @datzenmikescare you.  Mine never broke before I swapped it out for an l20b.  I got one you can have if you want it.  
 

lmk 

[datzenmike]

But it can. I'm not the only one. Was only saying L20B brackets were improved by Nissan probably because of this flaw and won't fit L16.

[ttyR2]

Well...with your guys input, I guess what I have *is* OEM...even though it looks janky to me. So I'll pull it off, make sure it's straight, and chase the threads, and re-assemble with good 10.9 hardware.

 

Is there enough meat on the two threaded bosses on the block that they could be opened up for bolts one size larger? Just asking for trouble? Not sure I could get a drill in there anyway.

[ttyR2]

Pulled the lower mount off and noticed someone had done a bit of a bodge-job on welding a new nut inside of the front ear. Chasing it with a tap cleaned it up and it's all back together again. I'll keep an eye on the mount.

[banzai510(hainz)]

521 are a sheetmetal type alt mount, and only really work with the l16 as they use the smaller bolts in the block and the ears of the alternator.

 

l18/20 mounts use the BIGGERR bolts in the block

 

I strick with the 35amp alt on the 521.  they weak so learn how to use your power wisely,

 

buy a couple of these and use them. They work. different version out there but you can monitor your system while you drive, idle ect when a load on.

believe me use this instead of waiting to be on side of the road. if it says you not charging your not chargin. dont wait for a idiot light to come on.

https://www.harborfreight.com/12v-batteryalternator-tester-57331.html?utm_source=bing&utm_medium=cpc&utm_campaign=425671834&campaignid=425671834&utm_content=1166582863634027&adsetid=1166582863634027&product=57331&store=&msclkid=39c465a2f4cd17329a580752c34b0e47

[mainer311]

That’s not true. Both blocks use M8x1.25 for the alternator mount.

[datzenmike]

The hex heads on the L20B mount are larger, like 15mm vs. 14mm and I think the shank above the threads/below the head is wider too. Agree threads are the same.

[Stoffregen Motorsports]

22 hours ago, datzenmike said:

L16  blocks only use two threaded mounting holes for the alternator bracket. Poor design... I had the bolts snap off in the block. L20B and up blocks use three bolt mounts in a much better triangulated pattern. L18s? not sure could be 3 bolt.

 

22 hours ago, ttyR2 said:

So the L16 block itself only has two mounting holes...bummer.

It depends on the date of manufacture. Later "JDM" blocks in L16 and L18 had three mounting bosses.

 

For the cast iron piece, I drill out the center between the two small bolt holes that hold the alternator to the bracket, and run a long bolt all the way through and put a nut and lock washer on the end. A used head bolt works great.

[banzai510(hainz)]

On 8/8/2022 at 8:18 AM, Stoffregen Motorsports said:

"JDM" blocks in L16 and L18 had three mounting bosses.

yes true.

standard USA L16  was 2 bolt holes in block

Edited August 9, 2022 by banzai510(hainz)