Rocker Shaft bolts

[edgarcia737]

Should I replace the rocker shaft bolts, nuts and cone when I replace the rocker shaft? During installation of new rocker shafts. During the torquing process I had to hold the rocker shaft nut assy, to keep it from rotating. Is that normal?

I have an oil leak and it appears to be coming from a couple of the lower rocker shaft assemblies. So I decided to go ahead and replace the rocker shafts and install the recommended RS seals. During the installation process, I had to hold the rocker shaft bolt "cone" nut while torquing. And even after it was torqued, I feel it should have held itself tight in the rocker shaft. This leak is driving me crazy. It drips right on the header.

thanks'
Ed

[Walt Fricke]

Ed

The shafts can wear from the action of the rockers, and frequent removal and reinstallation can fatigue their outer ends. They can crack out there, and at the slot.

But the hardware bits ought to last almost to forever, and I don't see how they could be related to your leak.

While I seldom have to use the large hex to hold that end (I assume you are tightening the bolt end, not the nut end), I don't think the fact that you do is of much significance.

What torque are you using? The bolts will take more than you think.

Did the new shafts and the seals do the trick, or haven't you fired the engine up yet?

Walt

[edgarcia737]

I'm using 18 ft lbs of torque on the bolts and yes, the seals were installed. No, I have not fired the motor up. I'm still waiting on a couple of parts. Hopefully next week.

[Dr J]

In his book, Bruce Anderson states that you can be relatively confident that the shaft won't leak if you don't have to hold the nut down while reaching final torque. I installed mines recently and found that to be the case. I held the nut while tightening the bolt and after a bit, I could leave the nut alone while tightening the bolt.

[edgarcia737]

Well on some of the rocker bolts the nut wouldn't move while torquing. But I had at least two that I had to hold the nut while torquing. Again, I feel that the "cone" nut should have wedged itself into the rocker shaft. especially at the final torque.

Thanks

[911Obbie]

I am in the process of doing a top end (92 C2) and pulled my rockers last night. They were rusty (!) and left a rust deposit on the end of the rocker shaft AND in the cam housing. Still evaluating whether to replace. Any thoughts?
Thanks,
Obbie

[Flat6pac]

Do you have the shafts properly centered?
If you disassembled the through bolts and lubed them you need to hold the nut end.
Spec torque is low, 16# but the spec is for new housings. When someone else is there the choice is many times to torque tight and this would expand the aluminum housing.
Bruce

[quattrorunner]

Originally Posted by Walt Fricke

Ed

The shafts can wear from the action of the rockers, and frequent removal and reinstallation can fatigue their outer ends. They can crack out there, and at the slot.

But the hardware bits ought to last almost to forever, and I don't see how they could be related to your leak.

While I seldom have to use the large hex to hold that end (I assume you are tightening the bolt end, not the nut end), I don't think the fact that you do is of much significance.

What torque are you using? The bolts will take more than you think.

Did the new shafts and the seals do the trick, or haven't you fired the engine up yet?

Walt

Sorry, but I do have some input. I'm not an expert, BUT I found that the bolts in the old shaft is LONGER than new, So they stretch and this makes it difficult to get the torque because the end of the bolt pushes the Allan tool away and makes it near imposable to get a good torque. I shortened old bolts, and replaces some with new and this makes it passable to get a higher torque on the bolt. This simple idea has made it passable for me to get rid of leaks and keep the shafts from walking out. Hope this helps.

[ThomasTe]

UK based specialists Redtek sell rocker shaft seals as seen in this video at about 5:55. I have installed a set, and I must admit, it works very well.

N Fulljames cam timing.wmv - YouTube