A coworker recently had his 396 rebuilt. Appears the rocker arm nuts are backing off. His rebuilder suggests "double nutting" them. I haven't heard of this. Thoughts anyone? Thanks.
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Re: "Double nutting" rocker arms
Have him start by getting a new engine guy. -
Re: "Double nutting" rocker arms
Actually, this will work as a cheap alternitive to buying a new set of lock nuts.. But they're a PITA to adjust.Comment
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Re: "Double nutting" rocker arms
There are many suppliers of adjusting nuts with locking set screws. we have used them in racing for many years. But, with new studs and new locking nuts there shouldn't be a problem for street use.Comment
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Re: "Double nutting" rocker arms
Whe I rebuilt the 427 in my 66, several of the rocker arm nuts had lost much of their "prevailing torque" quality.
It was late Saturday night when I was almost finished and I didn't have any new nuts to replace the loose ones.
I put several on the back side of a vise and hit the top with a hammer to slightly increase the distortion at the top.
That was 1983 and the same set is still on the engine today, probably 40,000 miles later.
I wouldn't double nut rocker arm studs. The studs are very hard and a bit brittle. The force generated between the two nuts can easily snap the stud between the nuts. I've seen it happen several times over the years.Comment
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Re: "Double nutting" rocker arms
I doubt a big block would notice the extra weight (maybe a pound vs 3200 for the car), and the nuts don't move (that is the point of double nutting them) so balance is not an issue. Because they don't move there is no added weight to the valve train, if that was what you meant Gary.TerryComment
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Re: "Double nutting" rocker arms
The way to look at it is there are different levels of repair..double nut being one of them..but if the motor was just rebuilt then why wasn't this repaired to the highest standard when it was apart? I have only one machinist I use..only because I know that he will bring it to the highest standard for street use possible..things like this should not go past a machinist who keeps his ducks in a row..either that or your buddy drove him nuts and just wants him gone..or he thought the owner just wanted a quick fix..think there may be more to this Harvey story!Comment
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Re: "Double nutting" rocker arms
i have had good luck using these as rocker arm adjustment lock nuts BUT only with new studs and nuts. http://www.aircraftspruce.com/catalo...151palnuts.php also this adjustment problem could be coming from the cam or parts in the valve train wearing. check the pushrods for wear and even the cam lobesComment
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Re: "Double nutting" rocker arms
"Pal Nuts" have been my pals since the mid 50's, starting with the less than steller 55 adjusting nuts. They are cheap insurance and easy to manage.
Stu FoxComment
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Re: "Double nutting" rocker arms
clem and David-----
Yup! I strongly suggest purchasing 16 GM #3921912 rocker studs and 16 GM #3896648 rocker stud nuts. Even at GM LIST price, these will come to less than 100 bucks. If one is going to rebuild an engine, why leave worn parts in there? With these, he'll be back to as-new as far as the rocker studs and nuts are concerned.In Appreciation of John HinckleyComment
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Re: "Double nutting" rocker arms
Thanks to all for the comments/suggestions. I'll pass them on and see what he decides to do.Comment
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Re: "Double nutting" rocker arms
David------
Another option for him would be to use Pioneer brand, rebuilder-type studs and nuts. These are sold in sets and are usually quite inexpensive. They might not be up to OEM quality, but they're a lot better than the worn parts he has now.In Appreciation of John HinckleyComment
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Re: "Double nutting" rocker arms
You can buy these and virtually any other OE equivalent replacement part in the aftermarket under the Sealed Power brand, and I have no doubt the Sealed Power parts come from the same plant as what GM sells, but are probably a lot less expensive.
DukeComment
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