what kind of rocker arms are everyone using on your home built motors, and what complaints have you had?

i only ask because i am having trouble keeping my stock steel rockers aligned, even with guide plates. i recently became completely fed up and decided that i need to change them because i broke off stud due to rocker misalignment.

also, do i really need these exhaust valve rotators? I can't use a guided rocker on the exhaust valves because of them.

 

I have Comp Cams' Pro Mags in the non-self aligning 1.6 version. No complains.

No, you don't need rotators. They are heavy and just add to the valve train mass. I would swap them, and the springs out, for some good stuff, such as something from Comp Cams, Lunati, Crane, etc. New springs and the matching retainers (you can reuse the locks if you are good with them).

What exactly are you talking about in terms of mis-alignment issues? New rockers may or may not solve the problem...

 

the rockers are tilting side to side on the valves like a boat on the ocean, and chewing into the stud. i had the heads bult by a machine shop, and i have some decent .510 lift springs in there, but i reused the factory rockers because the magnums i bought were self aligning and started chewing into the rotators. they'd still be in good shape if i cleaned off a couple burrs.

I'll try to get a picture of the broken stud and the bottom of the offending rocker in the morning. i got a stud and a rocker from my local "I-have-too-much-crap" man. the rocker i got from him is stamped steel, but it is self aligning, and seems to be staying on valve much better than the others.

this is the style rocker i have on all but one valve:http://store.summitracing.com/largei...part=SUM-G6801

and this is the style rocker i relaced the one that broke the stud with and seems to be staying on well:http://store.summitracing.com/largei...t=NAL-12495490

and these are similar to the magnums i have lying around:http://store.summitracing.com/partde...0&autoview=sku

 

What's the rest of the engine (cam, heads, etc - things that affect pushrod geometry)? If changed, did you check pushrod geometry?

Edit: when you installed guideplates, did you enlarge the pushrod slot in the cylinder heads?

 

i have worked over 416 casting heads with the springs lifters and pushrods recommended by luniati for my voodoo cam (60102), so everything should be lining up correctly.

when i had the machine shop build the heads, they suggested and installed the guides, and i have never had a problem with pushrods rubbing.

 

You realise that 416 heads have a pushrod slot in the head and do not require pushrod guide plates or self aligning rockers. If you were to use guide plates then the slot in the head has to be enlarged or the guide plate and slot will interfere with each other. Same with self aligning rockers. Its either one or the other.

You may have gotten the worng guide plates or they are not aligned properly. Or have the wrong rocker *****.

 

i know for sure that the guide plates and the slots in the head are not interfering, as i have watched the engine run without the valve cover, so the slot must have been opened up at some point. furthermore, the only point of contact along the length of the pushrod (from taking it out and looking at the tube) lines up with the guide plate.

if i need only guide plates or guided rockers, why are my non guided rockers falling off to the side of the valvestem when they have guideplates? how could i tell if i had the wrong rocker *****? I'm gonna bring up some pics later this morning

 

Sounds like you have a geometry issue in the valvetrain. Are the tips of the rockers running EXACTLY in the centre of the valve? How about at full lift? Is the rocker loading one side of the valve tip excessively? Are the pushrods the correct length? Were the heads milled? If they were the pushrods may be to long pushing the rockers to far on the valve. I would roll the motor over by hand and watch you rocker tip/ valve tip contact. If this stuff is wrong your valvetrain won't live long. How about the valves themselves? Did your machine shop dress the tips?

 

Sounds like 7/16 stud rockers on 3/8 studs. Sloppy side movement.

 

This had crossed my mind.

Above, are the links you posted pictures that are SIMILAR in part reference to what you have? Or are they the exact part numbers?

 

Ditto.

 

no those are only representations of what the valve end of the rocker look like. im in class now, so when i get home i will measure the lateral diameter of the slot vs. the diameter of the pushrod.

these are the pieces that i busted:

 

forgot the pic. sorry about the size.




BTW, Zed'er, Stekman, and Freebird are right. the stud is 3/8" and the rocker appears to be 7/16". so all i need to do is make sure that that the rest of my studs arent chewed away like the one above and drop some 3/8" slot rockers in there?

 

Pretty much. I would inspect the rest of the studs carefully and replace as needed.

One thing to make note of, because of the slot mismatch, the guideplates versus the pushrod aligning slots that are in the head, may have caused the pushrod to sit at somewhat of an angle. With the proper size rocker arm, I would make sure that the pushrod slots in the heads are clearanced to ensure that they do not interfere with the guideplates.

 

having inspected the studs, i need to replace quite a few of them. so i am now in the situation of getting to decide whether i want to keep the guideplates and run non-guided rockers, or use the guided Magnums i have from my last buildup and remove the guideplates. does anyone have any advice on what is gonna being more reliable on a daily driver?

 

on a daily driver, either will work just fine.

 

awesome. i dont know what i'd do without you guys. keep snapping of rocker studs, probably.