I had another post titled "manufacturing defect, SE adjustable, push rods" I talked about the problems I was having with one jam nut.

I was installing the push rod today and after I had adjusted it 2 1/2 turns and locked the jam I noticed that the jam nut was cracked.

I'm thinking it might be hardened steel and a little smaller OD than a regular nut. I'm just about to go out to my local fastener supply store and see if I can match it up exactly, but I really doubt they'll have it.

Hopefully a regular run-of-the-mill nut will work, but I'll have to see. I'm bringing the push rod with me. There was someone who had this exact same problem on the forum a little while back. I'll see if I can find out what he did.

 

Took my cracked SE jam nut to the hardware store and couldn't find a match. The thread pitch is fine and the nut is a thinner, harder steel than standard stuff. Harley won't sell just the nut. I ended up borrowing one from a friend's old Smith Brothers set and it worked. If you find one that threads on, make sure it's a thin jam nut, not a thick one, or it won't adjust right.

 

I had this same issue many years ago. I thought harley fixed that problem.
You're not likely that nut in your average hardware store. The correct thread will be too large wrench size for the pushrod tubes clearance. At the time I was able to get one at a local indy shop who had some take off junk. I still don't like SE pushrods. Better ones are available like Smith Brothers

 

OK, I just might be OCD on this, but wouldn’t a different nut weigh differently i.e, throw the rod’s motion off? Granted, the weight is infinitesimally small but over time would it cumulatively matter regarding wear, timing, etc?

Or would I be worried about nothing?

Asking for a friend…. 😉😎

 

You wont match it. I've tried. I do have an extra if you want it.

 

I would worry more about another one cracking on the other pushrod

 

Ok, I bought a hardened 3/8" 24 tpi nut, it takes a 9/16 wrench, the original is a 3/8" tpi that takes a 1/2 wrench. As somebody already mentioned, I'm concerned that the slightly wider nut, .553 vs .500 OD, will rub on the inside of the pushrod tube. anybody ever try it?

I also bought a hardened 5/16 24 tpi nut that I figured I would drill out to 21/64 and then tap it. Actually I bought 3 in case I buggered one up. So I went through 3 drill bits, It's like the nut was too hard for the bits. I used my drill press, but even though I had the nut in the drill press vice, I had to apply so much pressure that the nut would tilt. I went through all 3 trying to drill a centered hole. I took the best one and tried to tap it. Tap broke. So I'm screwed at the moment. The dealer does not sell the jam nut separately. A new set of push rods is $411 plus tax Cdn.

After I post this, I'm going to try to find something online. Anyone have any suggestions?

EDIT: It would be a lot easier to drill out a standard 5/16 nut and tap it, because it would be softer but I assumed Harley uses a hardened nut for a reason.

Thanks, Jim

 

Maybe try Fastenal ? They are a far more industrial hardware than regular Menards or Lowes type places.

 

I did, no luck. I'm gonna go to the Harley dealer tomorrow and see if any of the techs might have one laying around in a junk drawer.

After searching the Internet, I see lots of guys are just using the standard hardened 3/8 nut, 9/16 across the flats as opposed to half inch. I also see a lot of talk of people using grade 5, 5/16 nuts, drilling them out and tapping them to 3/8 spine thread.

Not crazy about using a softer material or a wider, thicker heavier, nut

 

I've always used a flared nut wrench when tightening.