911 Valve Adjusters for my Type-4 2.0L?, Good Idea or Bad Idea? Options

[ericread]

Somewhere earlier I saw a comment that Jake had recommended using 911 Valve Adjusters in the Type-4 engine... Or maybe he had recommended against it. I can't remember.

Anybody out there have experience in this? My adjusters and adjuster nuts were pretty gnarled when I got my car a few years ago. Now with bi-monthly adjustments, I'm looking to replace them.

Will the 911 adjusters fit the existing rocker arms? Do I need the same nuts? If I go ahead with this, should my properly adjusted valves run quieter? And is there any advantage to replacing the springs?

As a result of some moderate leaky valve guides, my plans are to have the heads re-built this winter. Should I wait until the heads are rebuilt, or is there any reason I shouldn't go ahead with the adjusters, nuts and springs right now?

Any thoughts?

My thanks.

Eric Read

[orange914]

you'll need a set of 1.7 rockers and then you must shave .040 off the underside where the swivel would contact when drawn up tight.

I.M.O. was a great improvement, kinda' removes some of the "thrashing machine" v.w. sound.

mike

[neil30076]

OT - can't help on the adjusters, but i like the viper blue - here's mine -

[ericread]

OT - can't help on the adjusters, but i like the viper blue - here's mine -

(IMG:style_emoticons/default/agree.gif)

The viper blue really looks good!!! (IMG:style_emoticons/default/aktion035.gif)

[Jake Raby]

Our SCCA FP race car is also Viper Blue
(IMG:http://www.aircooledtechnology.com/air.jpg)

As for the 911 adjusters... I run them on every turn key we build and have since about 1997..

[dlestep]

you'll need a set of 1.7 rockers and then you must shave .040 off the underside where the swivel would contact when drawn up tight.

I.M.O. was a great improvement, kinda' removes some of the "thrashing machine" v.w. sound.

mike

...would you have a photo of the removal of 1mm of material off the rocker as an example?

[orange914]

you'll need a set of 1.7 rockers and then you must shave .040 off the underside where the swivel would contact when drawn up tight.

I.M.O. was a great improvement, kinda' removes some of the "thrashing machine" v.w. sound.

mike

...would you have a photo of the removal of 1mm of material off the rocker as an example?

i don't, sorry, i'm sure someone will have one. just mic. the thickness and take a flat .040 of the bottom.(the swivel will need that room to sit up in) it's also been advised here that grinding side to side is best.

mike

[ericread]

Our SCCA FP race car is also Viper Blue
(IMG:http://www.aircooledtechnology.com/air.jpg)

As for the 911 adjusters... I run them on every turn key we build and have since about 1997..

Jake;

Do you sell the 911 adjusters as a kit or set up so I wouldn't have to shave the rockers? I didn't see it in your store, but I may have been overlooking the obvious...

It seems to me like it is a good idea to make this modification. Is there any reason why I should not consider such a mod?

My thanks

Eric

[kconway]

Doesn't this potentially change the valvetrain geometry? Lots of intricate measurements and perhaps resizing of the pushrods required?

Kev

[jhadler]

Doesn't this potentially change the valvetrain geometry? Lots of intricate measurements and perhaps resizing of the pushrods required?

Kev

Yes, and Jake has an EXCELLENT procedure on very accurately setting the valve train geometry and how to determine the necessary pushrod length.

-Josh2

[craig downs]

you'll need a set of 1.7 rockers and then you must shave .040 off the underside where the swivel would contact when drawn up tight.

I.M.O. was a great improvement, kinda' removes some of the "thrashing machine" v.w. sound.

mike

You need to remove .060 off the underside instead of .040

[Sleepin]

Doesn't this potentially change the valvetrain geometry? Lots of intricate measurements and perhaps resizing of the pushrods required?

Kev

Yes, and Jake has an EXCELLENT procedure on very accurately setting the valve train geometry and how to determine the necessary pushrod length.

-Josh2

Ohhh! Any idea where it can be found? I bought the swivel adjusters and chromoly push rods from Jake....and I have been looking for his procedure on valvetrain geometry!

Nevermind, I found it! :doh:

[type11969]

Doesn't this potentially change the valvetrain geometry? Lots of intricate measurements and perhaps resizing of the pushrods required?

Kev

No, this does not change the geometry. By clearancing the rocker by .060, the contact point of the adjuster to the valve stem (the swivel foot) will be in the same place as the contact point of the old adjuster screw. Therefore, no geometry adjustment is needed.

Now if you are building a new engine then yes, you should check the geometry. But on an engine with the geometry already set, this modification would not make a change.

[ericread]

Doesn't this potentially change the valvetrain geometry? Lots of intricate measurements and perhaps resizing of the pushrods required?

Kev

No, this does not change the geometry. By clearancing the rocker by .060, the contact point of the adjuster to the valve stem (the swivel foot) will be in the same place as the contact point of the old adjuster screw. Therefore, no geometry adjustment is needed.

Now if you are building a new engine then yes, you should check the geometry. But on an engine with the geometry already set, this modification would not make a change.

So Chris, do you have an extra set of rockers that have been shaved .060? Is there anybody that does have these? I'm pretty handy with a wrench and a BFH, but I sure don't have a shop full of tools needed to create such a precise clearance.

As of yet, no one has relplied that it's a bad idea. So why doesn't someone create a kit that includes the rockers, adjusters and maybe replacement springs?

(IMG:style_emoticons/default/confused24.gif)

Eric

[type11969]

It does not need to be precise, you can do it with an angle or die grinder. You should try to minimize the number of sharp edges/stress risers, especially ones that cut across the rocker. Better to grind along the length of the rocker which, of course, is more difficult.

[ericread]

It does not need to be precise, you can do it with an angle or die grinder. You should try to minimize the number of sharp edges/stress risers, especially ones that cut across the rocker. Better to grind along the length of the rocker which, of course, is more difficult.

You've got to understand, power tools and I do not get along very well. Usually ending up in crying, massive amounts of blood and a garage that looks like it hosted a slasher movie.

[jhadler]

Okay, so if I'm reading the comments right, there is no appreciable geometry change? Cool.

I guess the next question would be if this is an upgrade that could be performed on the engine while it's still in the car????

I'm not about to embark on this myself, I -just- got it running again. But it would be interesting to know anyway...

-Josh2

[ericread]

Okay, so if I'm reading the comments right, there is no appreciable geometry change? Cool.

I guess the next question would be if this is an upgrade that could be performed on the engine while it's still in the car????

I'm not about to embark on this myself, I -just- got it running again. But it would be interesting to know anyway...

-Josh2

I see no reason why this couldn't be accomplished with the engine in the car. The valve covers are easily accessable.

I was able to change out my push rod tubes with the engine in the car, and that necessitated the removal of the rocker arms. So this should really be no more difficult than that.

Eric

[craig downs]

Umm you really need to redo the valve geometry. Anytime you change something in the valve train you need to do it

[type11969]

I disagree. If you grind the rockers down ~.06" to allow enough room for the swivel feet to swivel, and you set your lash as you always have been in the past, then nothing has changed as far as the geometry is concerned. The adjuster contact face is .006" away from the valve stem and, because of that, the rocker angle relative to the valve stem is the same that it was before the porsche adjusters were installed. So, assuming the geom was correct from the start, there is no need to re-do it. You could use anything as the adjuster and the geom would remain the same because it is not a function of the adjuster shape, just a function of the distance/angle between the rocker and the valve stem (which hasn't changed).

Now if you used shims to space out the rocker shaft instead of grinding the rocker faces, then yes, you would need to re-do the geometry.

-Chris