SB VALVETRAIN SHAFT HOLDOWNS -- STUDS VS BOLTS

Helping assemble a friend's road race 340 with EDDY aluminum heads, and using Hughes rocker 1.6 arms and their valvetrain hold-downs that uses studs. We kept experiencing the studs would unload (despite being tightened into the head very securely, in our opinion) and turn out of the heads. Can anyone suggest a better hold-down method than the studs? Factory bolts? The Hughes complete valvetrain setup appears to be top quality, however, the studs could be longer so to allow grabbing the cap nut, as you first have to progressively work down the shaft without the shaft retainer because it's fairly thick... and then progressively change to the retainer with the washer and nut when there's finally enough threading to grab.

This same engine recently had one shaft snap/break due to the studs coming loose (we'believe that's what happened).

Any suggestions would be appreciated. (Hughes is being contacted also by the engine owner for his suggestions.)

This car will be racing at Road America Vintage weekend, July 20-22... come and see it.. awesome! (and the Posey and Gurney cars will also be racing there that wknd). 1967 B'Cuda fastback #48 (Gurney Blue).

I used sleeve retainer loctite on my studs, never backed out. To remove the studs just apply a little heat to remove them.

The Hughes studs I bought years ago were noticeably shorter than the ARPs I use. I suppose you could put a small amount of locking compound on the threads, but don't overdo it. Haven't found mine loose during tear-down, but they do unscrew pretty easily once the nuts are backed off.

No way in He11 I'll use bolts to hold down the rocker shafts w/ aluminum heads. IMO, that's just asking to pull the threads outta the heads when tightening the shafts down.

Did the instructions say to install the studs finger tight only, not to torque them
If so by torqueing them your probably asking for problems like you have The studs need to basically almost float in the heads or blocks so the all threads can touch and be tighten against the threads in the block or heads, not tighten or torqued
What torque are you using on the retaining nuts?

This^^^
Finger tight on the studs, all torque on the nuts.

I ran the Hughes hold down kit on my Edelbrock heads on two engines for almost ten years, studs finger tight, nuts torqued, no issues ever.

Thanks for the responses. the nuts were torqued to 30 #ft. My buddy has ordered ARP studs (perhaps longer and having center hex) and we'll redo it in a cpl days.... let you all know! T/Anks!

I think the best solution is do like KB head studs. First make sure you have plenty of thread on your studs to bottom. Have a machinest turn the first couple threads off. Form the ends to bottom in the drilled hole. Double nut to torque studs down. You may have to bottom tap your threads to make sure you are locating on the bottom of the hole and not torquing against the threads.

This or like main studs a ball bearing in the bottom of the hole and finger tight. Main bores distort when torqued with stud tightened and bottomed, stay round with a ball bearing in hole and finger tight. With dial bore gauge.

The ARP kit instructions do not say to torque the stud
Finger tight only and then torque the nuts to 30 Lbs. on the BB Mopar kit

Cab, ARP instructs not to torque because you would be torquing against the threads at the bottom. That would cause the stud to tilt slightly. The end of the stud has to be machined. As I said in my last post. It is the only way to keep the studs from loosening. And also insures you have full thread engagement. Absolute best set up for studs.

Cab, ARP instructs not to torque because you would be torquing against the threads at the bottom. That would cause the stud to tilt slightly. The end of the stud has to be machined. As I said in my last post. It is the only way to keep the studs from loosening. And also insures you have full thread engagement. Absolute best set up for studs.

I'm in the middle of assembling a 400 block stroker motor with aluminum main caps and ARP main studs, the instruction do say to "hand tighten" (not finger tight ) the studs only. I've had the main caps off and on several times so far checking clearances, each time I remove the studs to walk the caps out of the block, each time one or more of the studs has backed out a little when removing the nuts, some of the studs also act like they move into the block a 1/8 to 1/4 turn more when torqueing the nut down
I do use the proper size allen wrench to "snug" the studs a tiny bit into the block
OP, I have had one rocker shaft break on the dyno, that stud was loose but what I found out later was that I was using to much torque on the hold own studs or bolts
Once I started using the factory torque specs(23 to 25 ft. Lbs.) on any of the BB rocker shaft fasteners I used that problem stopped

Have you ever seen KB block head studs? They are made the same for the new blocks. If you think about it, its the perfect stud installation. It locates the stud perfectly centered. And being in aluminum gives maximum thread engagement. Which is very critical. Have seen several engine builders strip the threads out of a head by not checking for max thd engagment. So with special machined stud ends and full thd usage. Should solve all problems. Not trying to be a smart ass, just trying to help and share years of experience. One last thing, make sure you get studs with plenty of thread. In cast aluminum you need all the thread depth you can get.

Well, after getting new ARP Rocker Arm stud kit #144-7201 (Mopar Small Block), these studs are too short!... they will be returned... package indicates "318-360 Magnum"... so, the web-sites need to clarify this... as they will not work with the LA engines, (especially not with the Hughes shaft assembly). We are ordering from another supplier studs that are 1/2" longer than the Hughes studs, and with center hex.

Will let you know again with an update.

I've had the same problem. I have not seen any of arp studs that have long enough thread on bottom (coarse thd) to use in aluminum. Are they special order to get longer coarse thd? Not just arp, all other suppliers make their studs the same. With the market becoming such a large percentage of aluminum blocks and heads. Maybe arp and the rest of the market need to rethink their product?

A KB head stud.