I bought a set of Scorpion roller rockers. They came without polylocks. They are 1.5 7/16 stud. Can I order a set of polylocks for 3/8 stud and where?

 

I would think your rockers would come either with cinch nuts or locking nuts. I haven't seen polylocks on rockers. I would think they could get hot, worn, and loosen, which is why they are not used for that application. What did your rockers come with?

 

First find out which size Stud is in the Head. Your post said 1.5 7/16th Stud but you wanted 3/8th. Return em and get the ones for the 3/8th Stud and ask em to send the Polylocks with em. If not Jegs or Summit will have em Mail Order. When ya slide the Rocker over the Stud make sure the Flat side of the Fulcrum faces up so the Lock will have a Flat spot to rest. Pipe

 

I'mconfused every set of roller rockers I have ever owned had poly locks.

 

I have GMPP fast burn heads they have 3/8 studs but are machined for 7/16.
I can use both but would need to buy another set of studs and guides. The RRs are used and came without poly locks but are made for 7/16 stud.

 

Those are locking nuts in your photo. Polylocks have a white nylon insert that snugs around the threads. Won't work for rockers.

 

Ok, not to argue but summit and every one else calls these polylocks.

 

So you need 7/16" studs and poly locks
OR 3/8" rockers and polylocks.
Can't mix n match

FWIW
All SBC heads are tapped 7/16"

 

Most commonly referred to by most as Nyloc nuts

http://www.boltscience.com/pages/glossary.htm

 

Yep, polylocks. 383 is thinking of nylocks.

 

My bad, I've been schooled.

 

AWE, COME ON, MAN! No, no, no; that's not even close to being correct. In fact, exactly the opposite is true. They're the preferred way on a stud mounted system.

Both sets of Scorpions I bought from Flatlander Racing came with poly-locks.

Well after posting my disagreement (opening sentences) I now see a bunch of other responses addressing the same thing. Seems were locked into what is a poly-lock and what isn't.

In all years the ones shown in photos have been referred tob called poly-locks. Now I see an attempt to call them by a different name and to give the name "poly-lock" to something NOT used on rockers.

What's up with that?

I can see now where the confusion with 383Vett came from; we're talking about two different things.

Jake

 

I'm not doing a good job of explaining I guess.
Things I have:
1.Scorpion roller rockers without poly locks and designed to use 7/16 stud.
2. Fast Burn heads with 3/8 stud but can also accommodate 7/16 but I don't have them.

 

The roller rocker itself is a 7/16" fit for a 7/16" stud and needs the 7/16" polylock thread size. If your asking to use 3/8"polylocks on 7/16"roller rockers using 3.8" studs,that will not work.The hole size in the rocker has to fit the stud size used! If you want 3/8" rocker to go with your stock 3/8"studs,that's the size rocker and polylocks you need period.
Rick

 

That is what I wanted to know. I called Scorpion
I need PN SPCPL7/16 .. but they are $96 ..ouch
so I'm looking for .600 X 1.2 inch poly locks

 

To make sure you understand my post ,if you want to use the current 1.5-7/16" rockers you have now,you will need a set of 7/16"studs and 7/16" polylocks. Stock rocker studs are 3/8"with a std. 7/16" thread in the head for mounting. If not ,then you'll need 1.5-3/8"rockers and 3/8" polylocks to suit.

 

When we write about 3/8" or 7/16" studs we're referring to the UPPER END OF THE STUD.
NOT THE END THAT SCREWS INTO THE HEAD.

The end that screws into the head are all the same 7/16" - It's the UPPER END that differs.

If your Scorpion rockers are designed for 7/16" studs - THE UPPER END - then you MUST USE 7/16" (UPPER END) studs, which also means you'll have to buy a set of studs.

I would also suggest that you specify SCORPION POLY-LOCKS, too, since that are specifically meant from the SCORPION rocker arms. Summit Racing and/or JEGS has them.

I've read STRONGLY worded cautions NOT to install the wrong poly-locks (too short, too small in diameter, etc.) as valve train damage will occur.

Hope this helps.

Jake

 

I should have bookmarked the page of the caution, but the diameter of the poly lock is critical. If too large, binding will occur as the rocker operates. There was even a photo of that. Too small in diameter reduces the wall thickness in order to achieve the smaller diameter, which makes the poly-lock weaker. I also vaguely recall something about the mating surfaces between the poly-lock and the trunnion, but can't I recall more on that. I just wish I had bookmarked that page.

To me it's simplest to go with parts that are designed to work together which'll also eliminate a variable. I don't know how he ended up with a set of Scorpion rocker arms and NO poly-locks but since he has to buy a set of locks and can choose any he wants, why not go with Scorpions.

Each of the two sets I bought from Flatlander Racing came with a full set of poly-locks, all nicely package alongside the rockers.

If I was in the same boat, I'd just buy Scorpions. If the rockers were Crane, I'd go with Cranes, etc.

As far as "what stud the poly-lock is bolted to", you lost me on that one.

Jake

 

I didnt check to see if these are the ones you need but have used the brand and never had an issue albeit years ago.

http://cgi.ebay.com/ebaymotors/Profo...ehicleQ5fParts

 

First, if you install a 7/16" rocker arm on a 3/8" stud the fit will be extremely loose and if the engine is started that way the valve train will fail.

Second, a 7/16" poly lock will not screw on to a 3/8" stud and if you try it, the vavle train will fail.

Third, your rocker arms determine all the rest. They determine what studs you need and what poly-locks you need.

Why beat this to death? Just buy ARP 7/16" studs and Scorpion 7/16" poly-locks and be done with it.

Jake