School me in Rocker Shaft Shimming.

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1968FormulaS340

1968FormulaS340

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I need to do a little valve train geometry correction. The roller on the rocker is a little far out on the valve for my liking at full lift.

Right now my shafts are shimmed with a set of what looks like a tapered, curved washer.

These move the shaft towards the center of the engine and up. These were fine for my last cam but now I need to go a bit more in that direction.

I have been unable to locate this kind of shim.

If you are familiar with these a link would be appreciated so I can finely get this old car back on the road.
 
Just to be sure, are talking about shims that go between the rocker chaft and the shat stands in the on the head? I've seen them before...I'll help you look.
 
1968FormulaS340 said:
Those are close to what I need but the ones I have are tapered. The lifter valley side of the shim is thin and progressively gets thicker toward outer side of the head.

This moves the shaft up and towards the center of the engine.

(I really need to get a new digital camera. A pic would sure help here.)
Click to expand...

I gotchya. I could sorta use those for my slant, since the valve springs are tilted away from the rocker stands, so when I shim the shaft up, I am also shimming it away from the valve tip instead of towards it. I will keep looking for the both of us.
 
What he needs has a taper to it so that it relocates the rocker shaft either toward the valves or away, depending on which direction they're installed. I haven't found a thing as of yet. I could actually use some myself.
 
Are you saying you need to go further toward the valley or toward the outer edge of the head?
 
I'm thinking that type of shim might have to be a custom made CNC part. I've had some made on a CNC after getting some real measurement numbers for demensions off the saddles and then getting a cad drawing worked up to see exactly how things would lay out so the shims would mate perfectly to the shaft and the saddle, because I wanted a precision fit. But I have to admit, I've never seen any listed anywhere that are tapered on one side when I was researching shims for my heads. But I needed to go farther out on the valve (exhaust) instead of towards the intake side.
 
Most of the aftermarket ones out there now are square that I've seen. Mancini, Hughes and Jegs sell the square ones. Never seen round ones before.
 
I don't need round, just need something that functions the same or if anyone has other opinion of geometry correction, I'm all ears.
 
1968FormulaS340 said:
I don't need round, just need something that functions the same or if anyone has other opinion of geometry correction, I'm all ears.
Click to expand...

Lash caps will work, too. They increase the diameter of the valve tip.
 
Lash caps will move the rocker towards the exhaust side, the opposite way he needs to go. Shimming the shaft up will move the rocker tip toward the middle of the engine(inside). You dont need a tapered shim to do this, std shims work just fine.

The other option is to use shorter valves if you even have that option, or a different set of rockers.

Whats the head/ rocker combo?
 
MRL Performance said:
Lash caps will move the rocker towards the exhaust side, the opposite way he needs to go. Shimming the shaft up will move the rocker tip toward the middle of the engine(inside). You dont need a tapered shim to do this, std shims work just fine.

The other option is to use shorter valves if you even have that option, or a different set of rockers.

Whats the head/ rocker combo?
Click to expand...


X heads and Harland Sharp (not the latest, updated ones) rockers.

What I am seeing right now is that the roller tip spends it's entire time on the outer half of the valve.

The roller starts at the center when the lifter is on the base of the cam lobe and moves out as the cam approaches full lift.

I would like to get things so the roller tip is going through it's motion in the center 1/3rd of the valve tip.
 
Ok Ok I see now. I must have misread the first past.

Sorry, I was backwards on that. Lash caps will move the rocker tip back to the center, shimming the shaft will move it to the exhaust side.

Have you checked it without the shims in place?
 
MRL Performance said:
Ok Ok I see now. I must have misread the first past.

Sorry, I was backwards on that. Lash caps will move the rocker tip back to the center, shimming the shaft will move it to the exhaust side.

Have you checked it without the shims in place?
Click to expand...

Yes I have but as I mentioned, the shims I have are tapered so they move the shaft up and toward the intake side. Removing the shims exaggerates the problem slightly.
 
Dvorack, he built buddy's 440. We had some problems, like spitting a lifter out; but put that to his perfection drag=racing past. Put it back in and tightened the rockers down to 3/4 turn.

Could you have the stands milled to lean over to the center of the valve?
 
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