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Having a problem keeping my poly locks tight


v80z

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V80z,

You have to adjust the inner set screw so that the lash is slightly loose with the outer nut being finger tight, then you tighten the outer nut (and the set screw equally simultaneously) to set the lash and lock it.

You cannot just tighten the set screw once the lash is right, it will not stay set.

 

It takes a few rockers to get the feel for it, but once you do it this way, you won't have anymore issues.

 

Use a go/ no-go method with the feeler gauge to ensure you have the correct lash.

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Well I had it all wrong then. Lemme see if I understand this. feeler gage between roller and valve stem. With both the outter nut loose and the inner allen screw loose tighten the inner allen screw until lash is loosely set. Then turn both simultaneously in the same direction to lock?

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I finally got one horse moving and could turn my attention to the z.

Here is what I found. Only one. On the loose rocker

showphoto.php?photo=10702

 

Well just replace it and adjust all as per directions given or do I need to look at something else. Valve stem and pushrod cup on rocker look OK some dings in the rocker outside the cup.

 

Thanks as Always.

 

Joe

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How many rpm are you turning that thing Joe? :D

 

Check for:

 

*Pushrod rubbing the head

*Rocker arm binding, sometimes the slot isn't long enough and it runs out of travel on the stud

*Retainer to valve guide clearance, need at least 50

*Coil bind on the spring, need about 50 from bind to max lift

*Valve to piston clearance, need about 100

*Valve spring pressure, whatever manufacturer reccomends

 

A compression test or leakdown on that cyl might be a good idea, that would show if the valve is bent. Sometimes a straightedge across the tips will show a bent one if it's bad. You may have a broke/weak valve spring that let the valve hit the piston. Check it out carefully, that could get real ugly.

 

John

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John

 

Got the limiter set on 6300 right now. I have found some one local that hasa racig background that builds motor and has a salvage yard full of stuff. We have talked about building another motor for the car. 1st gen sbc based.

Fast and hi revver.

 

Talked alot about tall rods and short pistons. Squaring the block. making the bottom end bullet proof. Oiling windage valve train stability. I am looking forward to it.

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Cool deal Joe. In my somewhat long winded reply above, I forgot this thread started out about the rockers nuts backing off. Mike is probably right, the rocker backed off and the pushrod jumped out of the rocker or lifter cup.

 

jt

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Thanks John

 

Back together. Bought me a $1.77 pushrod and a $7.67 intake gasket set. Readjusted all valves. Honked Down on each allen/set screw. Then took her out. Of course Valve covers are puking oil again, Man I sound like Forrest. So we will need to seal that up as I am due to go to a purist z thrash this weekend at the local autox track.

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