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-   -   Who makes a good stamped steel rocker arm? (https://classracer.com/classforum/showthread.php?t=16913)

one pontiac 04-06-2009 08:09 PM

Who makes a good stamped steel rocker arm?
 
The stock rockers I use are strong enough, but the 1.5 rocker ratio is more like 1.35 to 1.45. Crane and Compcams sell some, but are they better, correct ratio, stronger? Any comments? thank you

Alan Roehrich 04-06-2009 08:22 PM

Re: Who makes a good stamped steel rocker arm?
 
Crane is not selling anything, they are out of business.

What are these rockers being used on?

Have you checked to make sure you have the correct pushrods?

one pontiac 04-06-2009 08:39 PM

Re: Who makes a good stamped steel rocker arm?
 
pontiac stocker, compcams 7262 pushrods

Alan Roehrich 04-06-2009 08:47 PM

Re: Who makes a good stamped steel rocker arm?
 
Those pushrods may or may not be the correct length. Incorrect pushrod length can upset the geometry of the valvetrain, and make the rockers appear to have the wrong ratio. In particular, stud mounted rockers are very easily affected by the wrong pushrod length. Rockers are not truly one ratio to begin with, they change ratio as they travel through their arc of motion. I can gain or lose 0.040" lift by varying the pushrod length.

Bill Edgeworth 04-07-2009 12:52 AM

Re: Who makes a good stamped steel rocker arm?
 
Do yourself a favor and get a pushrod length checker and figure out what length you need.
Those are stock length and I have had to use longer than stock in my motors to get correct lift. Depending on the length of your valves and how your heads are prepped they could need to be significantly longer than stock.
Also if you are using a mechanical lifter to check instead of a shimmed up hydraulic the pushrod seat may be deeper in the lifter. It’s VERY important that your checking lifter and the ones you run measure the same. If they don’t your lift will not be the same.

Todd Hoven 04-07-2009 08:28 AM

Re: Who makes a good stamped steel rocker arm?
 
You might be getting deflection. No matter what arm I used or what pushrod I use I get about .025 to .035 deflection. Tried to solve it once. got nowhere. This was checking it with a solid lifter and the actual race spring. If you roll it with a checker spring the lift will be way over. Lobe lift and pushrod lenth is the only way to solve it. Jockety the stuff around untill you get the desired result. Good luck

greg fulk 04-07-2009 09:22 AM

Re: Who makes a good stamped steel rocker arm?
 
Run into the same thing with the 6cyl have .006 ground into it just to get it close! That thing runs damn near a 10" push rod!

one pontiac 04-07-2009 08:33 PM

Re: Who makes a good stamped steel rocker arm?
 
thanks guys, it sounds like Im on the right track.

Mike Taylor 3601 04-22-2009 06:24 PM

Re: Who makes a good stamped steel rocker arm?
 
The aftermarket like crane's(probaly some left in stock somewhere)or comp's etc.will be closer to correct
ratio.Stock sbc I checked 5 gallon bucket full come up .035-.065 short on lift aftermarkets were alot more
consistent& closer to correct ratio.You can use soft check springs to see if have deflection in rockers I could be wrong but I don't think you'll see much deflection in stamped rockers turning engine by hand,
buy the best stud ARPhas ( Pro Series)cause usaully see studs deflecting cranking engine by hand,you could measure stud deflection w/dial indicator.
We changed to 7/16 studs (Elgin makes 7/16 stamped steel for sbc) and pro series arp studs on 3 stockers all 3 picked up .05 in 1/8 mile we didn't gain any lift we already had that maxed we just eliminated some deflection(we did gain lift we were losing @ high rpm by getting rid of some deflection).I think somebody use to have 1/2 studs and rockers for pontiac?,maybe Schubeck had rocker balls for1/2 studs? Maybe check Smith Machine that took over the Schubeck stuff?Like everyone else said get pushrod length,etc. all correct then get pushrods,studs etc. as stiff as possible eliminate all deflection possible.Check lift with rockers going to use then if you're short have cam ground to bring it to where lift should be i know Bullet will do this for you or anyone else who has cnc camgrinder with cnc grinder they can make those changes easily. I'll give you another example I had to see to believe,working on BBC big chief heads about12 years guy told me he changed to manton tapered pushrods picked 65HP on dyno,so couple years later built my first big chief style engine for good friend\customer we used 7/16 1pc. pushrods thought that was fine had in door car running 5.05 on motor we had to remove intake for something,can't remember why?Discovered we had problem, pushrods had polished the block from rubbing it they were flexing aleast .250"-.300"(you could put index finger between block\pushrod) so we knew they had to be bent,that was wrong.Remembered story about Manton's ordered set with no other changes car picked up to 4.95 then after jet change 4.90 That made those $450.00pushrods(@that time) worth every penny,plus Terry Manton is super nice guy to deal with.
PS if don't know leave lift .002-.005 to be safe.
Mike Taylor3601


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