HELP! Need a rocker stud

[Washout]

I'm trying to get ready for a 1200 mile trip with my GT and I broke a rocker stud off today. I'm running a set of the purple "monster" rocker arms the Jim fixed. They seem to be fine I have about 1500 miles on them. Today I was out for a little shake down cruise before I leave on this trip next week and after about 50 miles I found myself with one dead cylinder. I suspected a rocker arm and limped the car home on three cylinders. The problem was a rocker but I would have never guessed a rocker stud would shear off like that!


Is there anyone in the Cincinnati, Dayton, Columbus area that either has some studs they would sell or an old head to sell. I'll drive to you and pick up the head or stud. I'd like to fix this tomorrow so I can drive it a couple hundred miles before I start my trip. Please call, as internet is limited.

Thanks 937-763-0883

[Washout]

Ok, I solved the internet issues so I can answer questions and PM's if anyone can help.

I'm a little concerned about the roller rockers. Has anyone else operated them for any distance without a rocker girdle? I'm wondering if that is what caused the failure.

[Tru-Craft]

OGTS could over night you one, if you can't find one locally.
Are you using new studs?
High valve spring pressures, high lift cam and higher than 7,500rpm could break them.
I have always run the girdle, it helps distribute the load over the other studs.
Did it break at the oil hole?
Pictures?
Lyle

[Washout]

I called OGTS first and they are out of stock. The break was above the oil hole which I thought was odd. Unable any pics right now. I'm in the process of moving from OH to LA and all of my spares and 99 percent of my tools have already been moved to LA. If I were in LA I could easily remove a stud from one of my spare heads but now I'm kinda stuck. I either get it fixed and make my trip next week Or I'll have to delay until next month.

[opelspyder]

I have some NOS ones, about 2 or 3. I will check, earliest I could ship is saturday postal priority. Email me and I will let you know
Keith

[opelspyder]

Email me as I found I have one NOS part number 640355 Rocker arm stud/screw, could get out Friday if you contact me soon
Keith

[Washout]

Thanks Keith,
Email Sent,

[jeff denton]

Lyle is on the right track as to why your stud broke. Whatever causes you to NEED the roller rockers (if you really do NEED them) has now shown you the next weak spot.
The girdle makes the stud under load share that load with the ones beside it, which are not under load at the same time. It's crucial if you are running something that makes you really NEED the roller rockers.

[Washout]

It would be hard to argue that I NEED roller rockers, I rarely rev above 5000 and only very rarely to 7500 but they caught my imagination and so I have a set. Jim did a great job of saving them from the manufacturer. The new engine has about 1500 miles but these rollers probably only have 4 or 5 hundred miles. I just wonder if they will make the 1200 mile trip ahead of me without the girdle? Normal cruise is around 3200 RPM and I wouldn't expect that to cause too much stress.

[opelspyder]

Washout, I re-emailed you as the one stud I have was exposed to moisture and the studs threads that the nut goes on have some damgae-one side has a slight flat spot, I feel a good rocker nut would work, but didn't want you thinking it was perfect either-just looked
Keith

[Washout]

Keith,
A little flat spot shouldn't effect the operation, it's bound to be better than the 1/2 inch of bolt that I'm missing!

Once I get the car to LA I'm planning on a new set of rocker bolts and a stud girdle. My fault for not doing that from the beginning.

[jeff denton]

Aha. If you don't NEED the roller rockers, as if you had high lift, or went really high RPMs (thus need stronger springs first) then your stud failure was just one of those flukey things. It would have failed with a stock rocker, too, huh?
I haven't broken a stud yet. And I've tried.

[Washout]

Keith, I just updated my email address. I forgot that my old address was still on this account. If you need to contact me, an email should go though now.

Jeff, I hope you are right about the failure. I did put in a mild cam and heavier than stock springs so that may have had a effect as well. Only time will tell if the girdle is a necessity. The good new is GTJIM repairs are holding up nicely!

[jeff denton]

OOPS I didn't know you had upped the spring pressure. Shouldn't have been necessary with a mild cam. Higher spring pressure stresses the keepers, the grooves they fit into, the retainer, the rocker, the stud, even the faces of the lifter and cam lobe more than lower pressure.
I've never had a problem with stock parts at 7200 rpms. Cam duration is strictly off road radical but lift is legal at .430. Valve size is, er, shall we say, a little heavier than normal. Springs were new but stock, thanks OGTS.

[RallyBob]

One thing to consider is that the rocker arms will add valve lift due to the higher rocker ratio. If the springs were borderline-close to binding before, the rockers may have caused the 'breaking' point, so to speak.

Of course it could also just be coincidence, old rocker studs sometimes just break.

Bob

[Washout]

RallyBob,
That is a good thought but everything was tested during assembly and there is no coil bind on the valve springs. I'm guessing this was just one of those odd failures that happens from time to time.

[opelspyder]

Item is packed, labled and sending today
Keith

[Washout]

Thanks Keith,
I appreciate the help. With a little luck I'll be back in business late next week. I'll still be able to make my trip on time.

[layindoor]

I'm in columbus, and have a few spare motors and heads around, but it looks as if you are getting one shipped. If you need one still let me know

[Washout]

PM sent