Yes, exhaust manifold nuts are crimp nuts. Nylon inserts would melt. Regardless, Crimp nuts are a one time use only and Nyloc's really should be used only once... but you can usually get away with one re-use ( Nyloc's )... in non- critical areas.

High Strength Loctite + new Lock nuts = peace of mind

Edit: Jet nuts is an Aviation term. They are a high grade alloy crimp nut:

Edited March 2, 20169 yr by Chickenman

My exhaust nuts.

I don't have any nylon-based lock nuts on my 76 car, and it was essentially all original when I got it.  And I have a bunch of old manifold nuts from a variety of apparently factory stock Datsuns, from the two cars I've owned and wrecking yard parts, and none of them are the crimped lock style.  They're all plain old nuts.  I also have the MSA nut/stud package and they're just nuts, no lock.  The TC rod nuts are the crimped lockers, but  not locking much any more after multiple removals.  And the transmission mount cross member (aka rear engine mount) nuts, the ones on the long bolts, are the crimp style, but have plenty of lock left in them after several removals.

In the immortal worlds of Adam - "I reject your reality and substitute my own".

 

A safety wire or clip through a hole on the end of the rod would be a simple thing to do.  You'd save the nut and washer if it got loose while you were trying to figure out your squirrelly steering problem.

I haven't seen nylon insert style locknuts on the (stock) Z either. All the suspension stuff I've ever messed with were the distorted-thread style. In fact, I don't think I've ever seen the nylon insert style used on the suspension of any vehicle ever. It's always one form or another of the all metal distorted thread style.

I'm no Z genealogy or history expert, but if you've got nylon insert locknuts on your suspension, I'm skeptical that it came from the factory that way.

Well, I was actually selling these parts at Datsun Dealerships from 1974 on through 1992, and a LOT of the original nuts were originally Nylocks on the suspension. What they have on them 40 years later in no way reflects what they originally came with. Just saying.... 18 years as a  Nissan Partsman at Dealerships counts for something fella's. We stocked a TON of Nissan part numbered

Nylocs, back in the early days. For 510's 1200's, Trucks Z' you name it. And mainly for suspension components. Crimp nuts were very rare in those days. However, parts do supercede...especially over 40 years.

Nylocks on 240Z OEM suspension? I've seen lots.  Have a look at  original pictures of sway bar end links, LCA pivot bolt nuts and TC rod to lower control arm bolts.  These were all Nyloc's originally. on the early cars. My 9/70 240Z street car had them and so did my 1971 Race car. That being said, by the time the 280Z came out Nissan could have changed the fasteners.

ZH. I never meant the original Datsun exhaust manifold nuts were crimp nuts. Poor wording on my part. They never were originally crimp nuts. Just plain nuts as you mentioned. I was referring to the exhaust manifold nuts that Cliff had in his post where we were talking about  Jet nuts and the crimp exhaust manifold nuts that he mentioned he got from Nissan.

 

Quote

I've heard conical nuts before but jet nut is new to me. All my exhaust manifold nuts are that way. I bought them from Nissan too. If you could have seen what I took off you would believe me when I say they were original to that car. The bushings crumbled in my hands

.. it not really that big a deal.

Edited March 3, 20169 yr by Chickenman

Juts because I'm bored and suffering from insomnia again I decide to do a bit of searching of old pictures.

Regarding use of Nyloc's on early Datsun vehicles. The only people it would be really important to ( IE: correct style nuts ) is collectors and Vintage restorers. The Nissan Nylocs were what are referred to as " Tall " Nyloc nuts. I've worked on many, many, Datsuns, Honda's Mazda and other Japanese cars back in the 70's. Rallied and Raced 510's, 1200's and Z's  Nyloc nuts were quite common on suspension parts in those days. Not to say that there weren't " crimp " style nuts used on some big bolts as well.  FWIW

It's hard to find pictures of original  240Z suspensions.. but here's a restoration of a 1968 510 with original suspension. Look carefully and you can see OEM Nyloc's nuts on lower control arm pivot bolt, sway end link bolt and TC rod to lower control arm bolts. You'll have to take my word for it I guess... or not. It's up to you.

 

Edit: I also found a picture of an OEM 510 in an old Datsun book ( circa 1971 ) showing the front suspension components. I'd have to scan it, but this picture also shows the OEM Nissan " Tall " Nyloc on the threaded end of the TC shaft as well as other places. Now, I honestly can't find any pictures of OEM 280Z front suspension, but by then Nissan may have superceded the nuts. But my 9/70 street 240Z that I purchased in 1975 came with Nyloc's on most of the suspension parts, including the big TC rod nut. Same with my 1971 240Z Race car, 1968 510, and 1971 Datsun 1200 . Just sayin' guys... I sold the actual OEM nuts and bolts for these cars... and although I'm now 61, my memory for OEM Parts hasn't faded that bad. All FWIW... peace.

 

 

 

 

 

 

Edited March 3, 20169 yr by Chickenman

Gotta do something about my insomnia and OCD...

Haha! OCD and insomnia? A bad combination!

I never bought a Z off the showroom floor so I can't possibly know for sure. And you're right... Not a big deal.

7 hours ago, Captain Obvious said:

I never bought a Z off the showroom floor so I can't possibly know for sure. And you're right... Not a big deal.

Well... I did buy one off the showroom floor, the T/C rods came double-nutted and they're still that way.

Haha! Show off.

Go ahead... You deserve to.

I guess they got cheap on my cars, single nuts on all three of them but they are crimped nuts. Eww that hurts just typing it.

So you and I got just single nuts, while Jim got:

And yes, that's a real product. And in fact, I've even seen it on the shelf with my own two eyes at one of my local food stores.