Which way do these bad boys sit on the stud? After I typed that it just sounded wrong! But anyways, does the nut and polylock sit in the notched side or does the notched part face the stud? The nut seems to fit in the notched part perfect so I would guess thats the correct way, just want to make sure.

 

The trunnion is machined for the nut to fit into.

The important part of this though is how you find zero lash. VERY often messed up.

 

Well, since you brought that up, I can find zero lash per shoeboxes site, but I am stumped on the lifter preload. I have a pushrod length tool, turned one of my ls7 lifters into a solid lifter, and am in the process of getting the length for the pushrod. But I keep reading about this preload and Im confused. Can anyone explain this? I was going to start another thread about it. Do I get the length the tool tells me then add another amount to that?????? I have 7/16 studs.

 

I believe shbox has a few methods listed on his very informative site.
The one that causes newbs a LOT of greif in "spin the pushrod" everything is oiled so by the time you feel resistance to spinning you have it really tight.

All you really need to do is spin the polylock down until it touches, not even finger tight. Then double check that the pushrod can not move inline with the lifter and rocker anymore.

Then you can apply preload which is turning the polylock down further with a wrench. Setting preload with pushrod length is more of an LS thing.
Just to keep things simple I will suggest 1/4-1/2 turn preload.
Depending on all the details of a complete setup there can be valid arguments for everything from near zero preload to a full turn or more but 1/4-1/2 turn will work for just about everything.


Those that find additional power are near zero likely have a valvetrain begining to lose control and the lack of preload reduces valve bounce, and those that go a turn or more on preload are trying to make the lifter act more like a solid one where the lifter plunger is not soaking up some of the lift but if springs are marginal as they weaken this will bounce the valve off the seat as the spring wear in and lose pressure.

 

So with the lifter being converted into a solid, that is where i would mathematically add that 1/4 turn with the length the tool gives me to come up with the length of the new pushrod?

 

Do not worry about preload till you have the new pushrods in hand.

When you see folks worrying about preload as it pertains to pushrod length that is for non-adjustable valvetrain like the LS engines.

 

Ok thanks. I came up with 7.1 being to long, 7.0 looks just right. The only thing Im worried about is that I have the timing cover on so Im watching the lifters on 1 &6 and the cam dowel at 3 o clock. Im worried that this is a crude way of finding tdc and my measurement may be off.

 

7.000 would be really short. stock is 7.200

What is the rest of the valvetrain, how much were the heads/block milled and how thin a gasket under the heads?

Are you trying for dead center or narrow sweep pattern?

 

AI heads milled to 55 I believe, 228/234 cam w/ .610 lift, .026 gasket, nothing done to the deck. Should the mark be in the center, because thats where the 7.0 is. The 7.1 were slightly off to the side of the valve. Which is better?

 

In a perfect world you would have a narrow pattern on center reality is that that is not going to happen for you.

How wide was the pattern?

 

Im gonna say just over 1/16 inch. I would say from the pics Ive seen it could be smaller, but it was in the center.

 

Well I hate to say it, but I think Im gonna go with a 7.100. I knew that the 7.000 measurement was short and it had me wondering if it was right when I got it, even if it looked the most centered. The 7.100 isnt as centered as 7.000, but 7.0 just seems too short that it has me wondering if I did something wrong. A quarter of an inch difference than stock is a lot.

 

I'm not familiar with pushrod sizing, but just to add to the conversation....

Would you come off the pushrod the amount of the head mill down, reduction of the head gasket thickness, plus any block mill down? Just thinking about the relationship of the head to the pushrod from the side, the two are kind of parallel.

Did you do the measurement with hydraulic lifters? IIRC, I think that's kind of a no-no because the lifters can compress throwing off the measurement.

 

Ahhh, stumbled upon a good read here on the forum. The rocker doesnt necessarily have to be centered on the valve to an extent. Its the sweep that you want to keep small. Some guys have the imprint in the sharpie mark closer to the exhaust side, not centered, because thats where the least amount of sweep was at. Good to know because the 7.000 inch was centered in the middle, with the 7.100 inch measurement slightly off center. Ill have to recheck the sweep pattern on the 7.100 inch. I was more concerned about it being centered. Now I know why you asked Caprice.

I removed the spring and put some washers in its place on the hydraulic lifters making them a solid.

 

With stock heads, ls7 lifters, and a bigger cam I needed to use 7.00 pushrods. People say its short but 7.00 was the center of the valve tip for me.