Related to my other post about Comp polylocks....I found several ARP polylocks but don't know which ones work with Comp Promag rockers.

Anyone using ARP poly locks with Comp Promag rockers and what part# they are for 7/16" studs...or what size the ARPs are?
They come in .550 , .650, and .750 diameters...the .750 will not work, too tall at 2" for the valve cover clearance.

The Comps are .600 in dia in the middle but are .560 at the seat where to contacts the rocker truion. The ARP .650 will fit in the rocker area but not sure if the bottom seat area is reduced to fit in the Comp rockers recessed part of the truion.


Here's the ones I found on Summit
http://store.summitracing.com/egnsea...115+4294859125

 

What's wrong with locks that come with the Promags? I've ran 3 different ratio's trouble free.

 

i've heard the arp's are less prone to splitting when tightening and are easier to adjust in car.

if thats not right then i dunno and look foward to findng out.

 

I keep breaking the darn things and not even tightening them that tight now, any looser they come right off...I did way over tighten them at first.
My other post on the set screw depth
https://www.camaroz28.com/forums/sho...d.php?t=649532
and maybe the set screw depth is the problem, but if they are supposed to only go down 2-3 threads into the nut I'd think thats a ticket for thgem to come out easier...so I'd just prefer trying a different brand..IMO Comp has went downhill fast..the Comp R issue, then the valve spring breaking issues, the soft roller cams...

Yes, the ARPs are supposed to be easier to adjust in car..but the Comps didn't seem like they were anything to adjust either..just want to try ARPs since they are tried and true in the fastener market.

 

300-8245 is what I used.

 

I had to replace my comp poly's with arp's.
Comp's were not holding up.

 

2quick6 I looked at the link you provided and the set screws on mine are all a turn or so inside the nut but two are noticeably further down. I use the running method to adjust them and seem to under tighten them maybe I need some new ones.

 

So you're allen set screws are even further down than mine..I think thats what you are saying.
My point is, with them this far down, all of the pressure is placed on the thin walled part of the poly lock...however, if the set screws were further out, placing the bottom of the set screw where the hex part of the polylock is, then the pressure would be placed where the poly lock is thichest...but that would mean only a few threads of the allen lock would be holding then..which is not good either IMO.

I went into my local speedshop today to see what they could get in the ARPs, the owner of the shop said he was familar with the ARPs and the .650 in. diameter ones did not have the taper at the bottom that was needed for the Comp rockers, therefore I had to order the .550 ones.
He said he just broke one of the Comp polylocks that was on his boat and he didn't think he had them all that tight..thought it was a fluke, but now since I came in with mine broke, he's getting a set of the .550 ARP ones also.

 

Could it be that your rocker arm stud does not have enough thread. Maybe ones a little longer would solve your problem.

 

Right now the allen lock screw head is flush with the top of the nut head. Any longer stud would cause the allen set screw to not go in as far, thus my point above that it would be holding where the nut head is and be the thickest part of the polylock nut..but the allen screw would only be in 3-4 threads which I don't think is a good idea either.

 

Maybe its just my setup but since the ARP 8245's are 0.2" inches taller, it makes the head of the lock hit the valve cover..this is with LT4 composite covers.
The allen set screw sits further down since they are taller, but getting taller studs would make the problem of hitting the covers worse if the allen screw stuck up above the poly lock head any.
So, I had to grind down and resurface the poly lock top by 0.2", there was plenty of material there and strength wise that part is doing nothing with the allen set screw down below it.

So only time will tell if these break as well, they are actually .010" thinner in diameter than the Comps...they are the same size as the Comp bottom seat part all the way up to the hex head where the Comps are tappered.....we'll see.