Rocker arm ID Options

[FastFroggy]

While struggling with my first lash adjustment, I remover cylinder 2 rocker arms to inspect. Did not realize that there is a difference between intake and exhaust rockers and lost track in reassembly. Does any one know how to ID the rockers?

Thanks

[McMark]

They'll only fit one way. (IMG:style_emoticons/default/wink.gif) You can't screw it up. 50% chance you'll randomly pick the right way, 50% you'll pick the wrong way and have to spend 60seconds fixing it.

[FastFroggy]

Thanks a bunch!!

[bbrock]

This is yet another question I've been waiting to ask when I got back to working on my engine. Good to know. (IMG:style_emoticons/default/biggrin.gif)

Now a follow up. Are there differences between 1.7 and 2.0 rocker arms? Assuming the answer is yes, how do you tell them apart?

Here's why I ask. When I tore apart my engine decades ago, I read a tech tip that valve stems would wear better with the larger adjustment screws used in bus engines. I happened to have a set of bus heads at the time so put those rockers with the 2.0 heads to be rebuilt and tossed the original rockers in a box with a bunch of rockers from several 1.7 heads. Now I'm thinking that tip was probably a terrible idea and should fish the originals out of that box.

So really, I'm interested in general guidance. Bus rockers? Original rockers? Originals with elephant foot screws? What makes most sense for recreational street use and cost effectiveness? (IMG:style_emoticons/default/confused24.gif)

[McMark]

All the Type 4 rockers are the same, except the size of the adjuster screw. Early cars came with 8mm adjusters, and later cars came with 10mm adjusters. Just measure yours to know what you have.

The 8mm adjusters can be modified to accept the 911 'swivel' adjusters. These decrease the side loading on the valve stems for longer valve guide life. But they're a bit of a pain to set up correctly. There are some aspects of the swivel install/mod that I don't really like -- specifically it ends up decreasing the amount of thread engagement. They definitely have a benefit, I just don't know if the headache is really worth it in the long run.

[bbrock]

All the Type 4 rockers are the same, except the size of the adjuster screw. Early cars came with 8mm adjusters, and later cars came with 10mm adjusters. Just measure yours to know what you have.

The 8mm adjusters can be modified to accept the 911 'swivel' adjusters. These decrease the side loading on the valve stems for longer valve guide life. But they're a bit of a pain to set up correctly. There are some aspects of the swivel install/mod that I don't really like -- specifically it ends up decreasing the amount of thread engagement. They definitely have a benefit, I just don't know if the headache is really worth it in the long run.

You made life easier for me. Thanks! (IMG:style_emoticons/default/beerchug.gif)

I've been intrigued by the pedestal foot upgrade but would need to be convinced it would significantly improve engine life to make it worthwhile. It sounds like that is iffy. So it comes down to whether to leave the 10mm adjuster screw rockers on, or go back to the original 8mm. Seems like if they were changed to the larger adjusters later, there was a reason. And maybe that tech tip was not a bad idea after all. Should I stick with the 10mm rocker set? Either way, I plan to replace the adjuster screws with new.

[Matty900]

(IMG:style_emoticons/default/popcorn[1].gif)

[Mark Henry]

There's no real reason to run 911 adjusters on stock valves. But even with stock valves I use them for a bigger than stock cam.

They must be used on Stainless steel valves as the stock adjusters will mushroom the valve tip. You could use lash caps on SS valve tips instead of the swivel foot adjuster.

You must custom cut the pushrods, and use quality CrMo pushrods like Manton. The only issue one will have is on performance cam, heavy springs, not using quality pushrods they will bend like a pretzels.
I've never had a issue with modified T4 rockers and swivel foot adjusters.

[McMark]

They must be used on Stainless steel valves as the stock adjusters will mushroom the valve tip. You could use lash caps on SS valve tips instead of the swivel foot adjuster.

I wasn't aware of this. I'm gonna have to look into it. (IMG:style_emoticons/default/beerchug.gif)

I've never had a issue with modified T4 rockers and swivel foot adjusters.

Just to be clear, I haven't had any issues either. I just find it to be a lot of work and I feel like proper valve geometry is more important. I'm actually not even really convinced that swivel feet do anything to reduce side-loading the valve. The same friction and force angles you see with stock adjusters are still at play with a swivel foot.

[bbrock]

Thanks guys. As with most people, the less I have to spend on this restoration, the better. But I don't want to be penny wise and pound foolish by ignoring a useful upgrade. Sounds to me that this isn't one of them. So I think I'll just refresh the 10mm adjustment screws on the bus rockers I have set aside for when I have the heads rebuilt.