Pushrod Rub (Intake side of head)

[TurboGLH]

Getting ready to pull the heads and disassemble/grind on them, but before I do, figured some extra sets of eyes wouldn't hurt.


SM heads, PRW/SM 1.5 rockers, b3 correction kit. My measurement tool is 11/32, but a 5/16 pushrod is still way too close, but I can at least spin it.

Considering a couple options.

The first is to grind the heads, but there's always the chance of popping through the intake port, plus a fair bit of labor.

Second would get me some clearance, a swap to 1.6 rockers should bring the pushrods closer to the shaft (only .060 based on my math, but still something)

Thoughts?

 

[Cudafever]

I know i'm going to get grilled for this but, thicker wall, smaller diameter, push rods
If i give you a air clearance your good.
don't know what cam you are using or spring pressure that is required.
Is this a FT or a Roller lifter?

 

[TurboGLH]

Mech roller. 180lb closed, 480,lb open.

 

[Oldmanmopar]

Smith brother ball and ball end pushrods and cup style adjusters. That is what we bought. But get out the thick wallet. 686 solid roller.

 

[famous bob]

Mech roller. 180lb closed, 480,lb open.

DOES IT BEND THE PUSHROD WHEN U SET THE LASH / IF NOT REAL BAD , CUTTING A LITTLE CLEARANCE IS EASY , I HAD TO CLEARANCE MY RAISED PORT HEADS 3 TIMES TO GET CLEARANCE .

 

[TurboGLH]

Smith brother ball and ball end pushrods and cup style adjusters. That is what we bought. But get out the thick wallet. 686 solid roller.

I have cup style adjusters, and already talked to Smith. Said .083 wall 5/16 will be fine for my pressures. I 3D printed a dummy PR at the my measured length, and it will definitely rub. I have maybe .010 clearance.

 

[PRH]

If it actually has clearance, any clearance, throughout the full range of motion...... it’s fine.

It doesn’t need any “extra” clearance.

 

[dano]

I ran into this with my Speed Master Heads, Comp Magnum rockers, and B3 kit. Even after opening the holes it was too close. Ended up buying Hughes rockers and they were spot on with a small shim.

 

[pishta]

What did the b3 correction kit exactly do? Id feel comfortable grinding the pushrod hole with an accurate wall thickness measurement. What other options do you have...careful grinding is free.

>>b3 kit raises and shifts the shaft...?<<<

Your in a pickle...that rest position looks to be where the pushrod needs the MOST clearance, as the rocker arcs up, the adjuster swings out pushing the pushrods out ever farther? kit looks to help minimize the lateral change in full sweep movement but seems to hurt in the static position of the pushrod. but if your still rubbing......carbide.

 

[TurboGLH]

What did the b3 correction kit exactly do? Id feel comfortable grinding the pushrod hole with an accurate wall thickness measurement. What other options do you have...careful grinding is free.

Moved the rockers up and away from the valves. The pushrods would be fine without it, but the rockers come into hard contact.

I was looking for more clearance than enough to spin, but if that's enough then I'm probably ok.

 

[dano]

Moved the rockers up and away from the valves.

As did mine. Which corrects the geometry but then causes this issue in some cases. It really depends on how off your geometry is.

This isn't just a Mopar issue. When I was building my 460, another build documented several different brands in their pivot to cup to roller geometry of the same ratio and compared other ratios and BBC rockers too. Basically it came down to none of them were the same, and to basically test fit to see what worked for your set up. They are different in that they re on a stud and the pivot can be moved some with different push rod lengths, but hat has limitations too. Its all in the geometry.

 

[supertruck]

When I installed the B3 kit (rockers and shims) on my 340 with Edelbrock heads, I had the same issue. I carried the engine to the shop that does my machining. They opened up the holes so I had no interference. So far, so good.

 

[MOPAROFFICIAL]

Mech roller. 180lb closed, 480,lb open.

Ah that's why, I was going to ask...
Yes. Grind the heads.
The taller roller lifter locates the push rod in a more angled resting place...then motion angularity increases...so you grind the bottom outboard and the top inboard toward intake. That is what you have to do to run a roller in a 59 degree lifter angle block/LA small block mopar...also your geometry kit shifted it all toward the intake and exaggerated the issue, plenty fixable though and very much worth it to run the kit.
I run 5/16 smith bro push rods, I would stay with that size and grind the heads, not go smaller. Easy and fairly quick fix with aluminum .

 

[MOPAROFFICIAL]

Moved the rockers up and away from the valves. The pushrods would be fine without it, but the rockers come into hard contact.

I was looking for more clearance than enough to spin, but if that's enough then I'm probably ok.

Temps cause expansion, I thought I had enough too...you need eyeballs on the full range of motion and about .030 clearance for expansion between the head and the push rod material.

 

[TurboGLH]

Thanks for the input everyone. I've found you get the best results by just talking about an issue with a couple people before proceeding.

I'll be pulling the heads and giving myself some extra clearance for a 5/16 pushrod and calling it a day. Another small step back, but I'm still making headway

 

[MOPAROFFICIAL]

You can use dykem for test fitting to show if any interference still exists.

 

[pittsburghracer]

Thanks for the input everyone. I've found you get the best results by just talking about an issue with a couple people before proceeding.

I'll be pulling the heads and giving myself some extra clearance for a 5/16 pushrod and calling it a day. Another small step back, but I'm still making headway

It can be a one step forward two steps backwards game. I know you will sleep better with a little more clearance there.

 

[TurboGLH]

3/8 end mill, cut .100. Right until I started kissing the inside of the cover rail. That's my starting point. Looking at it now, I could have used a larger diameter probably, but when I started I was legit worried about breaking into the intake runner.

 

[TurboGLH]

That first .100 I took wasn't nearly enough. I had the heads back off two more times, plus I used a thinner spacer between the rockers to really get things lined up. Ended up taking a bunch of time in extra machine work and waiting on parts.

Plus side, it's all done, i verified my oiling system mods work and I've got oil where it belongs, and the intake is on. Valve covers need some work to clear the pushrods and intake, so that's next.

 

[gregcon]

I'm assuming you measured clearance at the worst point...as the lifter rides up on the cam lobe, the clearance will be different than it was on the base of the cam.

 

[gzig5]

Glad you worked it out. The covers shouldn't put up too much of a fight. I don't think it was mentioned, but did you consider going to a 1.6 rocker? That would have moved the push rod towards the rocker shaft (I think?), probably centering it in the hole through the head. Obviously you used what you bought and it would've been more cost to get a set of 1.6, but you would gain some lift too.

 

[TurboGLH]

I'm assuming you measured clearance at the worst point...as the lifter rides up on the cam lobe, the clearance will be different than it was on the base of the cam.

I've turned the motor over so much checking clearance, I've probably broken the rings in.

Worst case is intake side up top, and cylinder side on the bottom, with the b3 kit pushing everything towards the intake, I had to take a bunch of towards the rail.

 

[TurboGLH]

Glad you worked it out. The covers shouldn't put up too much of a fight. I don't think it was mentioned, but did you consider going to a 1.6 rocker? That would have moved the push rod towards the rocker shaft (I think?), probably centering it in the hole through the head. Obviously you used what you bought and it would've been more cost to get a set of 1.6, but you would gain some lift too.

After the second time I put the heads back on and I still needed more, yeah, I considered it. I did some calculations and figured they would get me another .050-.060 of clearance.

But, I bought the correction kit from Mike at B3, and I've already changed the cam lift the max amount he recommended without needing a different setup.

After a day to cool down, I took them back off and third time was the charm.

 

[rumblefish360]

PIA this work is, ain’t it...

 

[Needswork]

Good work!!! Similar to my experience with Edelbrock heads and the B3 kit. It took a few tries to get the clearance. I didn't have to remove as much material as you.

Can you provide details on the rocker shaft studs you used? I checked around at one time but didn't find what I thought would work.