Rocker arm comparison

1964SuperStocker

Well Known Member
Supporting Member 3
Horrible video. As I mentioned before, not all rocker studs are the same length. If you pay no attention to whether you have the correct length of rocker stud for your application then nothing else said in that video matters. Rocker arms touch in 3 places making all 3 of those areas of the rocker arm assembly important. At the 3:40 second mark he breezes by the rocker stud and doesn't mention that GOD did not make one rocker stud fits all. I agree with most of what he says and certainly I am still learning but that little detail could make countless people chasing adjustment that will never come because they have the wrong stud for their application. If they only made one length stud then the video would be great but clearly 1 factor can change whether its going to work right or not. That video should be redone and he should add the part about different length rocker studs so people trying to learn this and do this on their own will know there is another factor in this process that is not mentioned in the video I just watched. Anyone care to guess how many different lengths of rocker studs every company has? Quick tip, its more than one length. :angry
 

Ishiftem

Well Known Member
Supporting Member 2
One thing about the video is it doesn’t explain how that method won’t work on a lot of engines and you have to compromise. People see that video and copy it on a combination where it won’t work and wind up with patterns that are rolling of the valve tip or put lash caps on to increase surface area and think they have the best outcome because they followed the video.

http://www.sbintl.com/tech_library/articles/rocker_arm_geometry.pdf
 

Tim

Well Known Member
Supporting Member 4
I thought it was an excellent video on what the concept is and what the geometry is supposed to be however I didn’t do it that way but came up with almost the same result. I focused on the roller pattern and the 90 degree fell into place on its own. Stud length didn’t matter to anything I did.
 

1964SuperStocker

Well Known Member
Supporting Member 3
The length of the rocker stud has nothing to do with it. That’s why it’s not mentioned.
If I made the rocker stud 1/2" then it would be to short. If I made it 1 foot long then it would be to long. Those are extreme examples but again, the entire reason every manufacture of rocker studs makes multiple lengths is so per the custom application you can buy a rocker stud that works correctly. In that case, ever person who runs a 348-409 with rocker studs would have the same length studs? We all know that isn't going to be true. I'm sure that there is a general length that is close that might work for most people. When I specifically just went through this with my stroker motor. Once I had found the perfect adjustment that I had 4 teeth at the top of the rocker stud holding my rocker arm trunnion in place. I didn't feel comfortable with that so I bought slightly longer rocker studs. Sure you could adjust for a different length push rods to get a different adjustment but that didn't clear my rocker arms. We all know that different rocker studs also have different designs, some will clear better than others. In my case I bought these 690 heads off Dave and went out and spent a bunch of money on some nice rocker arms and had to switch out the good rocker studs in order to make them work correctly. Per the application I'm sure it would have worked perfectly just buying what Dave already had in there but I changed the rocker arms and that meant I had to change my rocker studs for them to work right.
 

1964SuperStocker

Well Known Member
Supporting Member 3
I thought it was an excellent video on what the concept is and what the geometry is supposed to be however I didn’t do it that way but came up with almost the same result. I focused on the roller pattern and the 90 degree fell into place on its own. Stud length didn’t matter to anything I did.
The geometry part is super helpful.
 

1964SuperStocker

Well Known Member
Supporting Member 3
One thing about the video is it doesn’t explain how that method won’t work on a lot of engines and you have to compromise. People see that video and copy it on a combination where it won’t work and wind up with patterns that are rolling of the valve tip or put lash caps on to increase surface area and think they have the best outcome because they followed the video.

http://www.sbintl.com/tech_library/articles/rocker_arm_geometry.pdf
Now you know I have to read this whole thing and study it like crazy. Stop giving homework! :D
 

Ishiftem

Well Known Member
Supporting Member 2
If I made the rocker stud 1/2" then it would be to short. If I made it 1 foot long then it would be to long. Those are extreme examples but again, the entire reason every manufacture of rocker studs makes multiple lengths is so per the custom application you can buy a rocker stud that works correctly. In that case, ever person who runs a 348-409 with rocker studs would have the same length studs? We all know that isn't going to be true. I'm sure that there is a general length that is close that might work for most people. When I specifically just went through this with my stroker motor. Once I had found the perfect adjustment that I had 4 teeth at the top of the rocker stud holding my rocker arm trunnion in place. I didn't feel comfortable with that so I bought slightly longer rocker studs. Sure you could adjust for a different length push rods to get a different adjustment but that didn't clear my rocker arms. We all know that different rocker studs also have different designs, some will clear better than others. In my case I bought these 690 heads off Dave and went out and spent a bunch of money on some nice rocker arms and had to switch out the good rocker studs in order to make them work correctly. Per the application I'm sure it would have worked perfectly just buying what Dave already had in there but I changed the rocker arms and that meant I had to change my rocker studs for them to work right.
I think the video assumes that if you are checking rocker geometry, then you would be smart enough to get a longer studs if there aren’t enough threads left or a shorter one if they put holes in the valve cover.
 

63409impala

Well Known Member
No matter what I'll be out triple checking my work to ensure I did it right.
Thats what im currently doing.i bought the last 8 aluminum centerline rockers from crower. Now I'm deciding if I need to buy 8 steel centerline rockers for the intake. I'd use all steel, but the trunions are too wide to clear the valvesprings when used on the exhaust.
 

Tim

Well Known Member
Supporting Member 4
No matter what I'll be out triple checking my work to ensure I did it right.
Randy I think you’re overthinking what you did. I’m sure you would have done it right or your engine wouldn’t work right and a lot of tapping would happen. Think of a stud as no more than a fastener. It doesn’t move, it doesn’t affect any moving parts unless it’s too short or too long that’s it. When my 817 heads were changed from 3/8 pressed to 7/16 screw the machine shop made them the same height and machined the boss accordingly. Using roller rockers and taller valves just means a longer stud might be needed. Like changing wheels, not all wheels can use the same stud but the wheels still go around. My 454 I’m doing now has the factory 7/16 and they are long enough for rockers and the geometry needed. If they weren’t I’d change them to longer that’s it. As long as the poly locks or nuts catch enough of the stud they are good and don’t change the moving parts. JMO
 

1964SuperStocker

Well Known Member
Supporting Member 3
I agree. I just know that its best that after I learn something new to go back and check my work and ensure I came up with not just a solution but the right answer. Most of my car is a solution and some of it is the right answer. :D Or maybe I should say I came up with the right solution and not just an answer. Maybe I mean what I did was right and not just a solution to get an answer......:write
 

Tim

Well Known Member
Supporting Member 4
Whats the width of your trunions? The crowers and comp ultra pros are 1.740 wide.
I didn’t measure them before I put them in. They were 1.7 ratio PEP(performance engine parts). I have a set of Comp I’ll measure those because they are on the bench.
 

Skip FIx

Well Known Member
Backset? You mean the offest trunnions ? Pushrod length on the SS vs the aluminum is slightly different.
I have 1.8 0.090 offset BBC on my Pontiac- and to get a decent pattern the pushrod ios way shorter than my nirmakl Pontiac rockers. Mocking up the aluminum the same length did not have the same pattern.
 
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