Rocker arm stud broke. Causes?

[5.0Droptop]

Yesterday I took my car out for a joy ride. I rode it pretty hard but no harder than usual. I Got close to home and stopped at the stop sign. When I took off the stud broke and I could hear the push rod hitting the valve cover.
When I had my vert and built the 306 the same thing happned. The 347 in my gt has had this happen 2 times now.

The rockers were adjusted perfectly, the stud was threaded into the nut atleast 3/8-1/2 of an inch and locked down tight.

My cam is the tfs 2 cam 224°/232° .339/.352 .542/.563 112° with trick flow track heat heads 1.6 roller rockers. I shift between 5500-6000 rpm i have a 6200 rev pill in my msd box sometimes i hit the rev limiter due to the alum flywheel, it revs really fast.

What could be causing the rocker studs to break?

 

[R2D2]

what spring?

 

[5.0Droptop]

To my knowledge the springs are the Trickflow springs.
I have not had any valvefloat issues.

The last time this happend was about 2 years ago.
I have about 13k on the engine now.

 

[DMAN302]

Sounds alot like a quality issue...once is a fluke...twice is a sign of weakness in the product if you ask me.

 

[5.0Droptop]

Thats what I am thinking. I ordered arp studs to replace the broken one. Will see what happens.

 

[R2D2]

do you know the clearance betwen coils at full lift, it could be real close

 

[DMAN302]

If it was a binding issue you'd experience this problem far more often. Shawn it looks like you're on the right track with the ARP hardware.

 

[5.0Droptop]

do you know the clearance betwen coils at full lift, it could be real close

No I do not. How ever I do have pics. BUT my ftp site is giving me fits.

I went and checked. They are no where near touching when fully compressed.

 

[R2D2]

just some things to consider and check for down the road. It may be a bad stud issue, but your not running any serious spring pressures also. Some of the springs may be shimmed shorter than others upon setting install heght etc, many different scenarios.

 

[5.0Droptop]

I agree it could be several differnt things. Once I get the new stud form summit I will replace it and note in my log which one it was and the date and go from there. If it happens again I will order a full set of ARP studs and replace them all.

 

[Grn92LX]

Trickflow uses ARP studs out of the box

 

[5.0Droptop]

Its funny you say that, When you look on summitracing they sell trickflow studs for 30 somthing and the same arp stud for 28 something LOL TFS must repackage and sell the arp studs. I ordered the arp's cause they were cheaper.

 

[5.0Droptop]

Anyone else experience this phenomenon?

 

[Grn92LX]

I have the stock 3/8" studs on my TW heads but I should definatly be running 7/16" with my power and more importantly my rpm's i'm turning. I can't say I have any problems though. I also should be running titanium retainers.

 

[Dark Knight]

A couple things, check the retainer to valve guide clearance, could have a guide thats slightly taller and getting hit. Rocker arm to stud clearance too.
Make sure the trunion is facing the right way when you put the nut on also.

 

[5.0Droptop]

Will do.

 

[5.0Droptop]

My arp studs arrived. I reassembled the one that broke. I ran all the rockers. 3 of the rockers were to loose. I always thought they were a bit noisy on that side. Now its very quiet.

I wonder if the stud broke from the rocker being to loose?

 

[dude5l]

Was it the same stud breaking all the time?

 

[5.0Droptop]

No.