Roller rocker nuts

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bahamasair

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May 11, 2008
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I was going to change the chinese roller rockers on my 496 and found one of the rocker nuts broken. When I took off the girdle I realized there was only about 3/8 of the threads on the stud. All of them are like that. The allen head screw that threads through the rocker nut was screwed way down to reach the top of the stud to lock the nut down. Should I get longer studs or was the geometry set up wrong from whoever did it before?
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Thanks for any help
 
IT looks like youll need longer rocker studs, or longer rocker adjustment nuts so the stud girdle, your useing will still clear the rockers and add support and the rockers can still be adjusted correctly,in most case theres more than 1/2"-5/8" of the stud threads in the rocker adjustment nut, I don,t see how you correctly adjusted the rocker lash or preload with only 3/8" of rocker nut on the stud UNLESS you had the rounded part of the rockers piviot axle possitioned up instead of down like its supposed to be, the rocker axle has a flat side the nut is suppose to bear against in the rocker when its correctly assembled
 
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Thats what I thought. Ive never adjusted anything on this engine, I got it from a mechanic who had a lein on it. Ill take a couple of pics of the other rockers that are still on the motor and see what you think.
Thanks for the reply Grumpy
 
I've never seen this before, the studs seem to be way too short. Maybe the studs are for a small block or maybe the girdle is not correct for a BB ???

Go to AutoZone and buy one stamped rocker, ball and nut and see how that stock replacement stuff fits what you have there.... shouldn't cost more than $6 but will definitely show if there's something wrong.
 
The rounded part of the rocker is facing down and the stud girdles are moroso big block girdles so thats not the problem either. I dont think the studs are the wrong ones and we dont have any autozones or anything close here. I have to order everything from the US. I havent spent much time trying to figure out exactly whats going on here yet. I have a new set of the Comp ultra gold rockers so will drop one on and see what the difference is.
I took some pics and will post them in the morning
 
Here are the pics. I put one of the Comp rockers on just to get an idea and there is a little more thread but not alot. How much should the stud be sticking through the lifter? The Studs are 2" measuring from the top of the push rod guides to the top of the stud.
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Verify your valvetrain geometry is ok: assuming you have hydr. lifters shim one lifter solid, install the pushrod, rocker arm, nut and turn the crank while watching the roller tip to valve stem contact...if you use black sharpie on the valve you'll see the contact pattern easier.
While I have not worked on a BB myself it looks like either the rocker stud is too short or the pushrod too long. Hopefully more experienced engine gurus see this thread....
 
I was thinking the same thing about the push rods being too long. I have a set of push rod length checkers I plan on using to see exactly what length I need. Id still like to know how much thread should be sticking up through the rocker tho.
Thanks for taking the time to reply bud
 
The push rods are way too long. The exhaust ones arent as bad as the intake but are still long. Ill take some pics of the roller position on the valve so you can have a laugh at how far off they are. Ill also post some pics of the carb for you kwplot34 :) Im going to end up changing the carb but am still going to run it with this one just out of curiosity since Ive never seen a predator before.
 
I spoke too soon. When I put the solid lifter in to get the correct length figured out the push rod length is pretty much right on. i thought the solid lifter would be the same size wise as the hyd one. Looking at the 2 side by side you can see the cup the push rod sits in is lower in the hydraulic lifter. The hyd lifter isn't collapsed or anything either. Now I want to order my push rods but if I use the solid lifter to set the length on my adjustable push rod they will be wrong with the hyd ones. I dont want to have to keep making orders and waiting so should i just get solid lifters or set the length with the solid one and order new hydraulic ones from Comp and hope they are the same length as the solid since that is from Comp also?
 
Do you have hydr. roller lifters ? If your cam is designed for hydr. lifters you cannot just install solid lifters instead.

To get accurate readings you can open one hydr. lifter and add shims to make it solid for the measurement.
 
Thats what Im going to do. Ive been busy at work and am working on one of the out islands for the next 2 weekends so will try get to it some time in between. Thanks for the replies guys.
 
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