I am attempting to get my valvetrain geometry correct. I have searched and read everything I can find but have not seen this. What happens when you add spacers (.075 total) until you run out of thread on your rocker shaft studs and it still looks like you are not in-line at half cam lift? If you look close in this pic you can see how my cute little swivel foot is slightly angled down and the adjuster shaft is pointed up compared to the valvestem. Any ideas? Will this hurt? I am using a mild WebCam camshaft, I think it has .430 lift. Thanks

Isn't it more logical to have it at close to parallel with the valve stemwhen the valve is at full extension, not half? I've never thought about it before, and maybe it is a given that half is where it lines up, but I would think the greatest load is at max extension, so it should be loaded straight on...

are your push rods all the same length?

The pushrod is stock length, following the directions posted on a couple of threads I was first trying to space the rockers correctly so that everything was in-line at 1/2 cam lift, then I was going to work on pushrod length.

So in the pic I have the adjuster screw in about 50% and the cam at 1/2 lift. I have some shorter than stock pushrods that I also tried, I don't think the pushrod length changes the rocker to valve relationship, but then again I have never done this before.

so here is my take...your push rods are too long... do you have an adjustable push rod used to set the geometry?

Please don't use those stock retainers... .430 lift is too much for them safely- I have seen failures at less than .400 lift!

The pushrod length dictates everything when doing valvetrain geometry on the TIV.


Are you using a dial indicator to measure valve travel?

"Please don't use those stock retainers" - do you mean the little angled valvestem retainers? Or the nuts?

No dial indicator, just a mark on the pushrod and a small metal ruler. I took out the pushrod tube, put the pushrod back in and stuck the ruler next to it against the head. Then I turned the motor back and fourth around TDC to see how far the pushrod moved and figured out 1/2 of that travel.

Then I put the adjuster at about 1/2 out at no lift and zero lash, turned the engine to 1/2 lift and eyeballed the relationship. It was way off so I added shims under the rocker shaft, this helped a lot but it is still not ideal.

I am not sure how/when the adjustable pushrod comes into play, going between two lengths did not seem to change the angles at the valvestem, at least not the way I am doing it.

I would not doubt if I am completely screwing this up, any help is really appreciated.

The retainers are the round discs that the valve spring seats onto at the adjuster end. The stock ones are stamped steel and very weak, the rule is as soon as the camshaft or RPM range is changed these parts go in the trash for better quality components.

You need to do searches here and on the STF for full details on the procedures you are doing. I have explained it till i am blue in the face!

A 1"travel dial indicator is a must, ten thousandths of an inch is like a mile to the settings...

unleashed is correct- what causes uneven settings is sloppy valve installed heights between the intake and exhaust valves. I keep all them at less than .005 variance, but some head shops feel that .040 difference is OK- thats a whole millimeter!

I will get a dial indicator from work; I did not realize it was that critical (duh). I also appreciate the information on the retainer. I had my heads built by Mark Stephens about 10 years ago so that is what he used, they only have about two hours on them due to a hydraulic camshaft I could never get to work correctly. I switched it out and I am trying to do it right (for my tiny budget) this time. Is there a retainer you recommend?

I have done several searches here and found several procedures, it seems to me they all talk about getting the angle correct and then messing with the pushrod length, as long as it is close. I will look some more when I get the dial indicator.


The intake rocker does not have a pushrod; I was attempting to figure out the exhaust first so I left the intake out. The rocker is just sitting there.

Thanks

The exhaust rocker is not the same true ratio as the intake... Its advertised at 1.3 just as the intake, but its generally 1.25-1.27

I always start with the intake first.

Am I crazy or is the valve in that picture nowhere near half lift?

You need:

1. Dial Indicator (you're going to have to fabricate a mount for it)
2. Adjustable Pushrod (or two, ideally you'll use the same brand of pushrod you're installing because the radius on the ends can be different and can change your readings)
3. Low Tension Valve Springs (using full strength springs will bend an adjustable pushrod)
4. Cut To Length Pushrods (aluminum or chromoly)
5. Shims

If you're missing one of these items you're wasting your time.

More importantly....

Have the rockers been decked bout 60 thou for the 911 adjusters????????

Twystd1

Valve is at half lift based on how far the pushrod travels, not by a dial indicator though. I think it is the angle of the pic, sitting here it looks compresssed compared to the intake - just not in that picture. Should be close to correct but I will rig up a dial indicator to be sure.

Rockers have been machined .060 for the 911 adjusters.