Thickness in valve spring seat 1980 head

[wsa111]

Has anyone cut a cylinder head in the intake & exhaust valve spring seat area to check thickness??

The major question is there enough casting thickness to withstand a .030" cut to achieve a 1.7" spring height.
The other option is get a set of valves .060" longer so a 1.7" valve spring height can be achieved.
I know Mike has sectioned his aluminum head & there no way you can cut the intake spring seat on the classic Inlines head.
The head is a D casting. Thanks Bill

 

[Mustang_Geezer]

Bill,

The only thing I can tell you is to search the archives. I remember that someone chopped one up and posted info but it was a loong time ago. Maybe 5 or 6 years ago and before the aluminum head came out.

Good Luck!

Doug

 

[CNC-Dude]

If your only going to cut it .030" deeper or wider it should be fine. If cutting it that little of an amout weakens it, its already too thin or weak without cutting it to begin with.

 

[wsa111]

Thanks for your replys.
However i just received a custom set of valves .090" longer. I will shim the rocker arm stands .090" & then get custom pushrods after a check on rocker arm footprint.
The reason i need a 1.7" installed height is because the springs need the travel for a solid lifter camshaft with close to .565" lift using 1.65 roller rocker arms. The spring tension will be 130# seat & 330# open.
The camshaft is nitrated for extra hardness & the solid lifters have a .005" laser cut oil hole in the center of the lifter for extra camshaft oiling.
I will do the work in december or march depending on weather. I have a heated garage but the door will have to be open to use the cherry picker. Bill

 

[Gene Fiore]

Is this for the 200 in your Mustang?

 

[wsa111]

Gene, no i have a 204" engine with flat top pistons for a 10.5 engine on the engine stand ready to go, however i will
use the present head just with the longer valves & valve springs. Bill

 

[Gene Fiore]

Wow...that seems like a pretty aggressive cam to be used with a log head. Can the log head flow enough to see the benefits of that cam?

 

[wsa111]

Gene, the intake valve will be at the maximum flow for a longer time & the exhaust valve will have more duration to help in exhaust flow.
The intake duration is close to 264 degrees so the low end & midrange will not suffer. Bill

 

[drag-200stang]

Bill,

Can you share where you got these custom valves?

You did the right thing by getting the longer valves. More available springs to use. Your retainer may have hit your valve seals with the lift that you're going to have.

You may not need to shim the rockers up as much as you think. Your push rods may also fit. To keep the footprint on the valve and the geometry correct with stock shaft rockers and extra lift cams I had to split the difference between the extra lift and lower the shaft. I milled the bosses on the head for the rockers down. I thought that would be more stable than trying to shorten the stands. Your 1.65 rockers (I'll assume they're fixed shaft also) may come out different.

Thanks.

 

[wsa111]

Valves can be had at http://www.sivalves.com/
This is the same company that makes ClassicInlines valves.
The quality is very good. Bill

 

[Gene Fiore]

Bill, what are your plans for this new engine? I'm very interested to hear how this runs!

 

[wsa111]

Gene, first i will install a 4.62 rear gear. The cam is good to 6700 rpms.
I to will be anxious to see if it runs good.
Plan to dyno it after i get the A/F where i want it using my innovate wideband tester.
Then see how it performs on the track. I wish i had cal-tracs instead of the traction masters. Bill