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-   -   Rocker roller coversion for 502 - push rod length? - need valve train expert (https://www.offshoreonly.com/forums/general-q/336611-rocker-roller-coversion-502-push-rod-length-need-valve-train-expert.html)

Cap'm Kurt 04-22-2016 11:16 PM

Even with some of yall's help, I've about run out of ideas other than pulling the heads again and drilling new 7/16 stud threads in the heads.

I think before doing that i will just go with the 4.5 threads ive got,
Add 1 thread for the shorter pushrods coming in tomorrow.
Aslo crank down on the lifter adjustment 2 rounds after no slack, instead of the 3/4 rounds that is normally recommended.
Thats 6 3/4 rounds.
I may have to live with that but i think that's reasonable and i think it will hold. Just reallyl odd that numberous people claim they dont have to modify anything to put on the roller rockers.

Young Performance 04-22-2016 11:52 PM

As I told you on the phone Kurt, I firmly believe that your problem lies with the rockers. Try to get either a Crane gold or a Harland Sharp to try, just to see if it makes a difference.
Ideally, you need 1.5 times the diameter for it to be as strong as it can be. That's not to say that you can't run with a little less. That's a 7/16 x 20 thread. That's means that you ideally want about .650 of thread engagement. That equates to about 13 threads. Obviously, you are no where close to that. I would say that you need at least .500, or 10 threads to be completely safe.
Try to find a rocker nearby to try. If you can't find one at a local speed shop, etc. let me know and I will gladly send you a couple of each. You can have them in 2 days by ground shipping or next day, if needed. Just let me know.
Eddie

GLENAMY 242SS 04-22-2016 11:55 PM

If you could find some thicker guide plates that should get you the extra threads you are looking for or as somebody previously suggested using hardened spacers. You could make them from another set of guides.

articfriends 04-23-2016 12:08 AM


Originally Posted by dereknkathy (Post 4431430)

I was in from shop eating lunch when I saw this today so I looked at comp products then the companys selling stud girdles (swore I bought stud girdles tha used extra long studs once), crower, etc thinking they might have longer ones but the 3/8th lower thread limits everything to 1.900

articfriends 04-23-2016 12:09 AM

Did you try just sticking a crane gold on it to see IF that gives you alot more thread theres got to be a OSO member, speed shop or engine builder nearby who could borrow you one , I'm convinced its the rockers, Smitty

Griff 04-23-2016 01:04 AM


Originally Posted by dereknkathy (Post 4431434)
this pic looks like the fulcrum is upside down. you have another similar angle pic with no poly lock?

Same thing I said in post #40.

mike tkach 04-23-2016 06:09 AM

i also think the rocker arm,s are the problem now.

Black Baja 04-23-2016 06:51 AM


Originally Posted by Cap'm Kurt (Post 4431503)
not measured. Specs show the lift is .483 for the stock 502 cam.

Very important to check lift at the valve. If you don't check lift at the valve how do you know what ratio rocker arm you have? (Don't assume that the 1.7 stamped on the arm is correct. Measuring valve lift also tells us if we have the right length pushrods in the motor. I think you should go back to ground zero and start over. Are you sure you had the cam on the base circle when you adjusted the rocket arm? If the cam wasn't on the base circle your result of not having any threads in the adjuster makes perfect sense. This is also why we check valve lift. It's also a good idea to use checker springs when setting everything up. Especially with a hydraulic cam. I honestly have no idea how you could possibly check the pattern on the valve if you are using the valve springs with a hydraulic lifter.

sutphen 30 04-23-2016 08:38 AM

If it were me(I have the machine to do it),I'd bring it to a machine shop and have the 3/8x16 thread pitch changed over to 7/16x14,then the stud length problem will be solved for ever.
wish you were closer,I'd have this solved and on the right path in 5mins tops.

sutphen 30 04-23-2016 08:39 AM


Originally Posted by mike tkach (Post 4431542)
i also think the rocker arm,s are the problem now.

and later on,will probably be another one when they come apart.


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