SII rocker shaft height?

[TurboDave]

For those of you with easy access to a set of SII head. Can you measure your rocker shaft height for me. The height above the valve cover flange that is. That seems to be the only flat surface available to measure from, and is probably the only part of these heads that doesn't get modified/moved.

These heads I have, have a rather unique rocker shaft mounting system, and someone speculated it may have been raised up to accomodate longer valves.
I really don't think the shaft appears to be raised but would like to verify this with some comparison measurements. I'll see if I can snap a picture and post it later.

 

[TurboDave]

Rats!! I can't seem to attach photos on this site.

Check the link in my sig and go to the aluminum block photo album.
on the first page is "heads1" that shows the unique mounting system, and on the second page I uploaded a couple of pix of the shaft sitting on the pedistals.

My rather crude measuring techniques, have shown an aprox height of 1.068" above the valve cover rail.

 

[oldtimer]

Originally posted by TurboDave
For those of you with easy access to a set of SII head. Can you measure your rocker shaft height for me. The height above the valve cover flange that is. That seems to be the only flat surface available to measure from, and is probably the only part of these heads that doesn't get modified/moved.

These heads I have, have a rather unique rocker shaft mounting system, and someone speculated it may have been raised up to accomodate longer valves.
I really don't think the shaft appears to be raised but would like to verify this with some comparison measurements. I'll see if I can snap a picture and post it later.

Dave,

My stage 2 aluminum heads have pedestals with concave cradles to support the rocker shafts. Much different than yours. I wonder if your pedestals have been milled down to accomodate a special rocker assembly. Maybe not, as there seems to be several different configurations in the S11 head corral.

Perhaps Billy Anderson can shed some light on your heads

George

 

[TurboDave]

Re: Re: SII rocker shaft height?

Originally posted by oldtimer
Dave,

My stage 2 aluminum heads have pedestals with concave cradles to support the rocker shafts. Much different than yours. I wonder if your pedestals have been milled down to accomodate a special rocker assembly. Maybe not, as there seems to be several different configurations in the S11 head corral.

Perhaps Billy Anderson can shed some light on your heads

George

Your configuration is basically the "as cast" (stock) configuration for the stageII heads.
I think (I'm guessing here) that mine have been modified for extreme high rpm and spring pressure use judging from the construction techniques.
Do you know how high the center of your shaft is from the valve cover surface??

 

[turbodave231]

I've never seen a rocker shaft mount like that. I think that would be great for adjusting the height of the shaft (with shims) to correct rocker arm geometry.

What is the history on the heads? What were they used on?

Dave

 

[TurboDave]

Originally posted by turbodave231
I've never seen a rocker shaft mount like that. I think that would be great for adjusting the height of the shaft (with shims) to correct rocker arm geometry.

What is the history on the heads? What were they used on?

Dave

I agree, and wish I knew their history. I got them from Ron T in PA. I believe he said they came off of a busch car.
You should see the port work, it's beautiful. I just have to get the chambers enlarged some to make them more practical for a turbo application.
I know how I want to do that, I saw a set of heads at BG that the gentleman in Dayton OH (forgot his name) had. The entire chamber roof was ported out by about .100"
I cant seem to figure out how to post pictures here, so I'll put a couple pictures of these heads in my photo album for you to see.
It may take a half hour or so for them to get posted though.

They will be the last two photos in the aluminum block album.
Sure hope mine could be made this nice!!!!

But I'm trying to figure out if this present rocker shaft mount configuration is close to stock height.

 

[oldtimer]

Re: Re: Re: SII rocker shaft height?

Originally posted by TurboDave
Your configuration is basically the "as cast" (stock) configuration for the stageII heads.
I think (I'm guessing here) that mine have been modified for extreme high rpm and spring pressure use judging from the construction techniques.
Do you know how high the center of your shaft is from the valve cover surface??

Dave,

The height of my rocker pedestals is .535 from the rocker cover gasket surface to the bottom most part of the rocker shaft cradle.

Hope this helps.

George

 

[TurboDave]

Re: Re: Re: Re: SII rocker shaft height?

Originally posted by oldtimer
Dave,

The height of my rocker pedestals is .535 from the rocker cover gasket surface to the bottom most part of the rocker shaft cradle.

Hope this helps.

George

Well, since there could be a wide variance in shaft sizes, I was hoping for a measurment to the center of the shaft.
Thanks.

 

[turbodave231]

I just happen to be doing valve springs and I have the heads off.

I measured .532 from the valve cover surface to the bottom of the shaft. The shaft is a .813 diameter...........so the measurement from the valve cover surface to the centerline of the shaft is .938.

Mike Booher was that guy in BG. I saw those heads.....and lots of other stage stuff too.

Dave

 

[TurboDave]

Originally posted by turbodave231
I just happen to be doing valve springs and I have the heads off.

I measured .532 from the valve cover surface to the bottom of the shaft. The shaft is a .813 diameter...........so the measurement from the valve cover surface to the centerline of the shaft is .938.

Mike Booher was that guy in BG. I saw those heads.....and lots of other stage stuff too.

Dave

Yup, Mike, that's the one!

Hmmmmm. I just went down and took some more careful measurements. The shaft measures .812 and its bottom is .702 above the cover surface. That makes the centerline at 1.108"
Maybe there's something to what Mike was speculating about someone using longer valves for more lift, etc.

 

[GARY HARVEY]

Why don't you give the guys at Chapman a call?

gary

 

[GARY HARVEY]

Good Idea

Looks like an improved method for using a larger stud to retain the rocker shaft assembly and at the same time modify the spring height to utilize a taller/shorter spring. I've heard about this idea, but this is the first time to view it. The idea makes sense, since the shaft retainer studs I'm using look whimpy compaired to what your pictures indicate. I would rather use something like this idea in spite of the yeild strenght I've been told are with the typical setup, my guess would be, that most the rest of us are using..!
Besides the pedistal isn't going to move around much being steel instead of
aluminum...

Gary

 

[TurboDave]

All I have to do now is find some odds and ends parts to complete the rocker setup as it is.
These rockers have the wrong push rod adjusters. They're the ball type instead of the cup type.

And I need to find some more shim stock for the shaft to properly locate the T&D rockers. Some of them need to be better placed, and some just need some more shims to remove side clearances.

 

[turbodave231]

Dave,

Most good valve springs worth using are 1.625 diameter with an installed height around 1.950. I'll bet your heads were modified to compensate for a longer valves with springs that install at 2.10.

I'll bet your spring seats are already machined for the bigger valve springs cups.

Prostock racers use the longer valves and springs with higher installed height so they can open the valves in excess of .950.

Dave

 

[TurboDave]

Originally posted by turbodave231
Dave,

Most good valve springs worth using are 1.625 diameter with an installed height around 1.950. I'll bet your heads were modified to compensate for a longer valves with springs that install at 2.10.

I'll bet your spring seats are already machined for the bigger valve springs cups.

Prostock racers use the longer valves and springs with higher installed height so they can open the valves in excess of .950.

Dave

My bet is that you're 100% right. In looking at the valve spring seat area, they look to be machined deeper than most SII heads I look at.

In going down and taking some crude measurements, the valve spring seats will easilly accept a 1.6-1.7" spring, and are milled down to different depths. The exhaust seats appear to be down about .630 below the valve cover rail, and the intakes appear to be milled down to a depth of about .530 below the cover rail.
I was trying to keep my depth gauge parallel to where the vavle stem would be, had I any valves

I don't know, however, what height spring those depths will allow.
And not sure what measurement to take to figure it out.

 

[turbodave231]

You'll need a valve, a retainer and some keepers to measure the spring installed height. I bought one of those nice valve spring micrometers.......they make spring height setup alot easier.

DR