Roller rockers not hitting center of valve tip

On my 410 stroker mag 5.9 I have Edelbrock Magnum heads with the Chevy rocker studs and am installing the stamped steel type chrome moly roller rockers. I have on hand two pushrods and tryng to find where the rocker tip will strike the valve stem. With a 6.95" it pushes the roller out to the outter part of the stem. The other is a 7.50" and it does move the roller more center but still on the outer part of the stem. I know I may need a set between the 0.55" difference.

The 6.95" has the Lock nut turned all the way down, the Poly-lock is sticking up and the pushrod is too loose so I know I need a longer one.

The 7.500" puts the tip in a better place but the Lock nut is only 7 turns down. Once I get the preload on the Hyd lifter I ran the lobe up and it did push the valve down the 0.565" lift of my Luniti cam and a 1.6:1 rocker. The base circle of this cam is shorter that the stock 5.2 cam. Picture below is the roll pattern on the valve stem.

heres the guy to speak to. http://www.b3racingengines.com/ mike will set you up ! I have his system on 2 of my cars. my .02$

Does Mike make his products for stud mounted rockers?

Sounds like you need a set of adjustable pushrods so you can figure out the correct length.

Ordered adjustable pushrods two days ago.

It just seems I will run out of threads on the rocker stud before I can get the rocker roller centered. I'll check it in the AM

why not talk to mike that's his specialty , rocker arm geometry.

try this without a pushrod. install the rocker as low on the stud as it will go. Check where the roller tip contacts the valve tip. It should be closer to the stud side of the valve tip. Move the rocker up a couple threads and see where it goes to. Keep doing this till you are to the center of the valve tip at contact/zero lift. The best location for the contact when the valve is closed will be half the distance of total roller tip travel that was observed on your photo, towards the rocker stud side. If you can't get there, the rockers are too long.

The rocker is too long.

Centered is less important than making the shortest contact sweep.

I will try that.

But as being too long, I don't know how that can be if the Edelbrock heads say for Chevy Adjustable Rockers. (see below picture)

The Assualt Racing Product Rockers are 1.6 ratio Small Block Chevy (see 2nd picture below)

Not sure what to tell you other than sometimes certain aftermarket parts don't fit with other parts. Even if the instructions say they will fit. That might be the situation with these parts but I don't know for sure since I've never used them. Maybe call around and find an engine builder who uses those heads and ask what they use for rocker arms. Brian at IMM does a lot of SB stuff so he might know. Hughes Engines supplies a lot of SB parts so they might know which rockers work the best with those heads. Or start a different thread asking specifically about which rockers work best with those Magnum heads.

Thanks all for the replies. I think I have it sorted now.

1. The Melling 5.2/5.9 roller rockers were pumping down more than what I THOUGHT. I had taken them apart and filled them with 15W40 oil but still ....
I milled a aluminum spacer and replaced the spring inside the lifter so it is now a ridged 'Solid' lifter. No squish. That squish was about 0.0750"

2. My friend I had called just happened to have a couple 7.100" push rods and I borrowed them. Put them in and tightened the adjusters down till 0 lash and pulled them thru 2 full revs of the engine. Below is the patterens.

That looks better Dave Thanks a lot for posting this as I will be doing the Magnum assembly as soon as the heads get here. My customer chose the Comp Ultra-Pro Magnums so I hope everything goes well. I have to get a checking push rod for ball-ball applications but now at least I have a starting point and Summit stocks a ton of those Chevy type pushrods.

Gus

I watched so many YouTube vids.

https://www.youtube.com/watch?v=o5is9BsH5OU

The one with Ralph Johnson (Chevy, with Smokey Yunick and Crane Cams) is full of good info on what I was seeing. Last I knew Ralph is still kicking at around 98 years old.
WARNING The music sucks.
https://www.youtube.com/watch?v=RjaosX63DkM

I went back out and ran the shorter 6.950" push rod and with my setup it is still fine but the pattern is very slightly on the inside (Intake side) of the valve stem so I will run these as I have a set. They are TrickFlow TFS-21406950 for guideplate.

Bleed down of a Hyd lifter will mess with all measurements. I just cut down some alumumn bar stock to length and spun it in my drill till it fit inside the lifter where the hydrolic plunger is. The lifter cup was down about 0.025 " from the keeper spring.

RockAuto has Enginetech L2167 stock replacement lifters for $547 each or $87.52 a set of 16 plus $8.99 shipping. These are the same as the "Made in Mexico" reboxed Melling lifters. Takes 30 minuets to take all 16 apart, empty out the kerosene shipping fluid and fill with 5W30 or 15W40 like I do

Not trying to make things worse, but Chevy studs are not parallel to the valve stems, so moving the adjuster up & down also moves the Chevy rocker in & out...

Good thinking on making a solid lifter. I had not thought of that as being the problem but having the lifter too tall would move things around. Glad you found a combination that works without having to buy new rocker arms.

Trying to figure that out in my head.

So if E is the Exhaust manifold side and I is the Intake side, and the V is SPLAYED of the Valve stem and the stud.... E V I, the higher in that V the farther the rocker tip will move toward the intake side. But it did not do that for me. I know 'Trigonometry' is involved here. I'll have to go measure these heads.



EDIT OK the angle is upside down V with the valve tip closer at the tip to the stud's top. I'd bet the angles cross a few inches above the head.


The Edelbrock web site gives ZERO data on these heads. PissPoor help.