I'm interested in spring pressure preferences and the ideas surrounding them.
installed height
seat pressure
open pressures
dual
single
beehives

maybe the best place to start would be stock.
would someone like to throw that in, and maybe an opinion as to why it is good/bad?

so how about stock installed heights and pressure

Some of the questions you request are regarded as highly secretive--not many people are willing to divulge details on creating a more bullet-proof engine

Installed heights are more about seat/valve grinding than spring pressure.

Also, look at variable rate valve springs.

The factory manual states 160-185 lbs springs.

that seems like the case I guess.


Now that we've broken the seal on this box hopefully some will contribute.
Keep your sources. I dont care. But there must be a level of knowledge here that can be discussed without giving away secrets.

No big deal right?



or we can do this the hard way.

It's sad this knowledge isnt more freely passed on between aircooled engine builders.....

I have some info,.
and sources for cool stuff.


Its amazing how free discussion is about this in the subaru forum I read.

custom beehives
super alloy made to order valves 6mm stems



when I can cover ground on this subject
i'll post it. and you all should too.

Well, it just that the thinking has changed recently. We used to install HD dual springs in order to be able to rev high. That caused problems elsewhere in the cam,lifters as high pressure results in high friction too. Plus the high pressure slams the valves shut which beats the seats into the head.
Now, the thinking is lighter valve train parts with less spring pressures to rev higher equals a engine that revs without so much abuse on the cam/lifters/heads.

This is one reason Jake is going with a roller lifter/cam combo so he can reduce the stress/friction of the valve train to rev higher.

I take it that you guys didn't listen to my valvetrain radio show back in 2006....

It costs us thousands of dollars to gain information and thats not easy or smart to give away!

height pressure
1.450 90lbs
1.350 122
1.150 185
0.950 255
0.875 bind


accomodates up to about .520 lift
1.100 bottom O.D.
spring mass 42g

installed height on my 2L Type 4 1.5
so it looks like with a little shimming I could run this spring
with not far off stock seat pressures.

with .5 or so of lift (still waiting on my cam specs)
I'd be looking at 250lbs

Since the shift is towards lighter components then the old way of thinking..
meaning heavy springs and such should no longer be "classified" right.
what did people used to think?


lets talk about it!

no one expects you to give away the good stuff.





there is a level of information that should be discussed though.
otherwise the interest in type 4's will dwindle instead of grow IMO.

I kinda like racing against the guys that still get their engines done by local guys who do stuff like in the 80's. They brag about their big motors, high lift cams, dual modo valve springs, huge 48x40 valves and suffer many mechanical breakdowns with typical problems - dropped valve seats etc.

so what was the worst valve size/spring combo that used to be Hot.

I'm not wanting info on secret new innovative developments--

Just stock info would be great

when i have that info i'll post it.
along with some other things.

why am I even wasting my time here.

Obi Wan Brernobi, you're my only hope

I now share all the data like this on my forum, if we do share it..

I'll be more than happy to share anything with anyone, thats why I offer consultation services.

Yes, even stock specs are hard to find that have any amount of research put into them for validity and understanding.

The valve train of the type 4 engine is its most important reliability and longevity aspect, giving information pertinent to it's operation opens the doors for guys like our old shadow Stromberg to copy and paste it to their own sites and use it against us in the future. I personally don't prefer to train my future rivals.

no but I feel that stock information wouldn't hurt anybody's business--since there are many who dont use stock technology anymore.

What is "Stock" exactly???

What specs are you looking for?