Valve Geometry Wrong, Or Am I?

[Red5]

I'm using a dial gauge on the spring retainer. I had removed the dial gauge in this picture to get a better look at the valve.

[mark tucker]

the cb 125b rockers are the best rocker of that type Ive seen,I do not remember how much I removed from the rocker to let the adjuster go up farther. I set all my engines up with a max of 1/2 turn out from seated agnist the rocker. and yes use soft springs so the rocker can slide across the valve tip so you can see whats it's doing. a still spring will not let it slide, but rather bend the valve stem over(flex's it,it dosent stay bent). if those type rockers are to low they tend to push outward at the bigining of the lift cycle then start more of the down ward path.(the oe1.1 seems to be worse at this from the ones Ive set up). thats where I found the .040~.060 shim with the back cut rocker&1/2 turn out works best. but thats on the engines I built. yours may be different, and I use lash caps on every engine I build(except for 2 stroke&rotary) . with the soft spring and some oil on tip you can see the adjuster slide out more than it is pushing down when the rocker is too low...but there are many factors to be taken into account.... not all heads are created equal.mofo has diferent stud/rocker location, some varation in valve stem hight inrelasionship to the rocker blocks also comes in to play. thus there is NO this works ,or this is the way it has to be. I do not agree with the inline/1/2 lift method, but in some instances with some parts and no way to modify the parts that may have to be done...that dosent make it right. yes I do like the "inline" past half lift. how much past depends....on a lot of things. when CB re engineered these I wish cb had re engineered these rockers with longer piviot length and offset shafts...but they did not and I understand why...somewhat. they did a great job non the less.and they just about made them so there is zero pushrod geo isues....so they can be set up for rocker/valve geo as they should be set up. other wize...oh never mind.they are a far suppior rocker, not just more ratio or stronger copy.

[chrisflstf]

The problem with Marks suggestion to have the adjuster in line at max lift, is it puts max wear on the valve guide, when the valve is fully open. Remember, the valve is at max lift just as many times as it is closed.

[chrisflstf]

[jason]

How does it wear closed? Put 100 lbs on your arm bent and then straight. I know which one I would prefer..

[57BLITZ]

[Red5]

Its evident from the number of posts and advice this thread has generated that valve geometry is not something you can just jump into. I thought I had read up enough on the subject to tackle it. If I had not posted this question, I would have undoubtedly screwed up my valves and possibly the entire engine.

While I'm waiting for my additional shims to show up, I'll be taking a much closer look at the techniques used to get the geometry correct. I thought I had done my homework, but I see now that I really had just scratched the surface.

I will also cut down the rockers as suggested by 74 Thing and others. I've done some Googling and have not found much on the subject. If anyone has link detailing that process I'd love to see it.

[Clatter]

What's your actual total lift at the valve on all eight?

I'm curious to see the amount of variation in these rockers through the whole set.

Plus,
You're likely going to want to know as well.

Theoretically, the ideal geometry, and especially pushrod length will yield max lift.

As you change the length of your adjustable pushrod,
(you are using an adjustable pushrod, right?)
The correct length will give you the most lift.

Either too long of a pushrod, or too short, will show less total lift than the perfect length pushrod.
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Bus Motor Build

What’s That Noise?!?

[Coyotemutt]

[mark tucker]

I like my max wear when the valve is closed and not moving at all. then there is no where....to find any wear...in there.

[74 Thing]

https://americansandassociation.org/phpBB3/viewtopic.php?t=27246

You need to find the true midpoint with your rockers, not calculated midpoint and start from there if you go with the midpoint set up.

[Danwvw]

The nice thing about ball adjusters is they take a lot of the stress off the valve guides. I think Mark may have the best reasoning on this and with the ball adjusters, you should get 100K on the valve guides perhaps more but as far as adjusters probably need changing at 25 to 35 K miles.
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1960 Beetle And 1679cc DP W-100 & Dual Zeniths!

[chrisflstf]

Genuine Porsche swivel feet are over $35 each now