Broken Rocker Arm Stud

[W.O.T]

Took the boat out Sunday idled out just past the no wake bouys and all the sudden started to hear a horrible backfiring through the front carb. Idled back to the dock and put her back on the trailer. Pulled the valve cover and found this! There is no visible damage to any parts. Will I be ok with putting on a new set of Studs and nuts? http://a984.ac-images.myspacecdn.com/images01/13/l_c903b3ff5481c11b00fc2da34de17f3f.jpg
http://a303.ac-images.myspacecdn.com/images01/15/l_ac666e3e619c7f86b684fa62aa693a0e.jpg
You can see how a longer set of studs are definitely needed. Any brand in particular I should buy? Thanks
http://a300.ac-images.myspacecdn.com/images01/31/l_5a54202318eb16ceb0c06addbc56d16b.jpg
http://a937.ac-images.myspacecdn.com/images01/45/l_66d4b4701ea35b20345102b096367fb8.jpg
Motor has a Hydraulic roller camshaft.

[craig moss]

everyone runs in to this before they get stud girdles I have a set for sale crane cams type but you will need to get the poly locks 125.00 and I will ship them I went to shaft rockers if you turn more than 5500 rpm with a more than stock cam the stud cant take the extra spring psi:devil: good luck craig moss call 918 271 0154

[VAMI]

Buy a set of ARPs,how old are those rocker arms???

[Wazoo]

I'm going to guess that your pushrods might be to long. Your lock nuts are to high on the studs. Thats the reason it broke. I don't see why you would need stud girdles with a hydraulic cam and lifters. You usually only need them with radical solid profiles. How long have you had that motor? Do you know the history on it? You definitly have a issue there with the pushrod geometry.

[W.O.T]

The Motor was built in july 06. I see what you mean about the push rod length. I hope some longer studs can give me a cheap fix without having to worry about push rod length.

[Duane HTP]

You need to worry about your pushrod length. If they are not right, the rocker rollers will not run on the center of the valve stem. This puts unnecessary stress not only on the studs, but the valve guides as well. Moroso or Mr. Gasket make a simple inexpensive tool to check the pushrod height with. Very well worth the time and effort. Hydraulic camshafts don't need stud girdles if everything else is right.

[SD Beach]

Took the boat out Sunday idled out just past the no wake bouys and all the sudden started to hear a horrible backfiring through the front carb. Idled back to the dock and put her back on the trailer. Pulled the valve cover and found this! There is no visible damage to any parts. Will I be ok with putting on a new set of Studs and nuts? http://a984.ac-images.myspacecdn.com/images01/13/l_c903b3ff5481c11b00fc2da34de17f3f.jpg
http://a303.ac-images.myspacecdn.com/images01/15/l_ac666e3e619c7f86b684fa62aa693a0e.jpg
You can see how a longer set of studs are definitely needed. Any brand in particular I should buy? Thanks
http://a300.ac-images.myspacecdn.com/images01/31/l_5a54202318eb16ceb0c06addbc56d16b.jpg
http://a937.ac-images.myspacecdn.com/images01/45/l_66d4b4701ea35b20345102b096367fb8.jpg
Motor has a Hydraulic roller camshaft.
ARP works well. But you might want to check the set up (rocker angle, ect.)

[roostwear]

Looks like you have a stud problem. The old one is sheared off at the top of the shank, and it looks like you don't HAVE any more thread (if you got shorter pushrods) to run down the polylocks.
On another note, there was a thread a while ago in Gear Heads challenging the old "center the contact on the valve stem" rule of thumb. It was a good (although long) read, and actually changed my mind about proper valvetrain geometry. If it were me, I would do a little research on studs and your geometry if you have the time before the season starts up again.:idea:

[W.O.T]

Thanks for all the good info. Im really suprised the builder put the motor together with the push rods too long like that. :(

[snake321]

http://www.***boat.com/forums/showthread.php?t=145898
There it is. Everything you ever need to know and then some..

[roostwear]

That's the thread, thanks. W.O.T., take a few minutes and read that thread. Not only does it make sense, but after looking at your pics, I think you'll be inviting BIGGER problems by going to shorter pushrods without addressing your short studs (short in overall length or in thread length). Doesn't it look odd that it broke at the bottom thread, but inside the poly lock?

[GUGS102]

Two thoughts:
1. Buy a set of ARP +.100 studs.
2. Make sure you are not using the lock to push against the top of the stud to get the required tightness to hold it in place.
I had a stud do that in my car. The break was just like yours and clean as a whistle. I went to the longer studs and learned the proper way to tighten the poly locks. (hold the wrench in place and tighten the lock rather than back the wrench off a hair and giving a twist with the lock tight against the top of the stud and then turning the wrench)
Gugs