[68grandprix]

I recently posted about a problem with my cyl heads. People said my valvetrain geometry had changed and the easiest way to fix it would be to get chevy 7/16" studs and locknuts. The parts stores didn't have them(surprise, surprise) and I was wondering if the arp chevy/pontiac studs and Crane koolnuts would work well. Thanks.

[68grandprix]

I recently posted about a problem with my cyl heads. People said my valvetrain geometry had changed and the easiest way to fix it would be to get chevy 7/16" studs and locknuts. The parts stores didn't have them(surprise, surprise) and I was wondering if the arp chevy/pontiac studs and Crane koolnuts would work well. Thanks.

[Herb Hagan]

If your heads already have screw-in studs, you need to order studs w/7/16" top & 7/16" bottoms. these are also the same as for BB Chevy. If they are pressed in studs you will need to get studs w/7/16" top & 1/2" bottoms, and you will have to tap your heads for 1/2-13 NC threads.
Good luck,
Herb

[ April 17, 2002, 05:50 PM: Message edited by: Goatnad ]

[larry davis]

The Crane cool nuts are ok, but I really like the locks from ARP. They are excellent!
As are their studs.

[68grandprix]

Thanks. The only reason I thought "kool nuts" is because they are cheaper than the ARP locknuts.

[Colorado Bill]

I have a set of the #99768 3/8 x 24 Kool Nuts that I've never installed. The Summit catalog says they're "counterbored for use with bottleneck studs." Does that mean they'll make my valvetrain adjustable without changing studs? (#13 heads)

Does anybody recommend any sort of thread locker on that type of rocker nut? It makes me nervous to think about those little allen screws loosening up and wandering around in my engine.

[larry davis]

I believe that the cool nuts are only to be used for stamped rocker arms or stamped roller tip arms.
That's what I used them on.
Don't believe they will work w/ roller rockes.

[Colorado Bill]

Yeah, I forgot to say I'd be using them on stock rockers. So they would work with stock screw-in studs?

[Robert Williams]

Colorado, if you want an adjustable valvetrain you need the 7/16" studs with poly-locks. The bottleneck studs are for stock engines, no block deck or head milling, no cam change ( lobe base circle ) pushrod lenght, head gasket thickness, the stock bottlenecks get torqued to 20 ft lbs and are not adjustable. If you want to learn how to adjust your valves, click onto this site.------- http://www.centuryperformance.com/valveadjustment.htm

[BVR421]

Unless you are using a really wild cam and springs, chev locknuts or polylocks for 3/8 will work just fine with stock bottleneck studs. Not the way for a hotrod motor but for a cruiser I have been there, done that, with high mile daily commuter experience. Have not gone out of adjustment, have not pulled the studs out, have not bent anything, did not cost a lot of time and money.

[Dante Garofani]

Don't know if anyone has had this problem with 7/16 ARP studs but, I ordered the BB Chevy ones and after torquing them down the push rod guide plates were still loose. Exchanged for SB Chevy /Pontiac units (Summit Catalog) and the lock nut threads were 1/8 inch too short.

Ended up with Mr. Gasket 7/16 BB Chevy studs. Plates locked down when torqued and the thread length was correct. BTW, I am using Competition Cams push rod guide plates so maybe the stock Pontiac plates work with the ARP studs.

[Skip Fix]

I had no problem on my RAIV heads with ARP BBC studs with stock or Comp guide plates. My E heads they bottomed out, need the Pontiac/SBC 7/16".

[Bignjun]

The Crane kool nuts for bottle neck studs do allow complete adjustment of the lifter preload. We have used a set on the stock rockers with bottleneck studs for over 20,000 miles and the same nuts with the Comp Magnum roller tip rockers on bottleneck studsfor over 10,000 miles with no problems in setting or retaining adjustment. This has been over the last 5 years in a mild 455 with a Crane hmv 278 cam. Probably 200 1/8 mile passes also.

[ April 20, 2002, 11:37 AM: Message edited by: Bignjun - Rhett ]