Setting valve installation height?

I understand that tolerances can stack up and cause measurement issues. It may seem arbitrary that the keeper groove has no relation to the tip but it does as all the valves are the same, the keeper groove is not arbitrary. Measuring the gap per the WSM is indeed the quickest way, but if you're concerned with angles then my suggestion of basing it off the spring seat would negate that issue all together, however you would need a known good base measurement to compare to. easy enough, measure the center valve with both methods, from base circle of the journal and if it's within spec then the tip to spring seat can be used as a baseline. accurate to 3 or 4 places? no but it's an option.

Or make a journal tool with indexing stops and three holes for each of the valves, then you can reasonably measure the center-line of each.

Ferrari WSM leave a lot to be desired, a lot.

 

A bit of moral support for Dave as I believe that his understanding of the problem is correct! Dave - you're absolutely not over-thinking this.

My response is only a guess but I think that JohnK is correct when he says "Perhaps the measurement should be made along the axis of the valve?"........ simply because this is the ONLY way for such a specification to make sense. I'm guessing that the factory tool for setting this has holes drilled at 3.5 degrees to match the angle of the valve in that plane. I'm also guessing that the base circle on the factory tool is inclined (as it is on the camshaft) at the corresponding angle. If it wasn't, then zeroing your dial gauge on the tool would present you with the same problem. This given, it's not a ten dollar tool.

Although I'm stressing that this is a guess, I can't see any other valid way of measuring the spec. It must be along the axis of the valve to make sense.

 

Maybe it has multiple holes as needed or lazy ferrari cuts one hole and it is close enough. Ferrari is not as high precision as we think they should be. Perhaps the factory tool is like the mythical steager tensiometer?

Instead of making a $10 simulation of the factory tool with one hole as implied earlier why not cut a solid lifter blank to simulate a collapsed OEM hydralic lifter and do the math for clearance needed? Then measure the solid lifter blank to your oem cam shaft and cut the valve tip accordingly? Could be a new tool for StickyRX.

 

What about computing the angle with trigonometry, and converting the dimension?

 

How big is the angle? Looking at the cam lobe drawing it only looks to be a couple of, maybe 3 degrees.

 

Ok, so 3.5 degrees would give a corrections factor of 1.00187. That is if you measure perpendicular to the cam axis the length measure alone the valve stem axis would be greater by a factor of 1.00187. So the measurement perpendicular to the cam axis would be 17.437 to 17.737. Of course, then you have to worry about having the tip of the gauge centered on the valve stem.

 

Agree. That's why I said

The difference between placing the tip of the gauge on one side or the other side of the valve stem tip would be roughly 6mm x sin (3.5) = 0.366mm

 

Dave what about using an old valve guide cutting it to a close height maybe 50 thou then you could slide it over the valve stem and use a feeler gauge to gauge how much to trim to get it in spec?

 

I assumed head was off and cams are in since you would be grinding all the new valves you install.
You would just slide the valve through main guide into modified guide and up towards cam.
Then you would turn cam and use feelers to get correct length of valve.

Or am I thinking wrong??

 

I guess you were wanting to check existing?

 

This is Wade Williams.
Dave I have a tool for 355 heads and can tell you how to use it. I have rebuilt many 355 heads and have not had any issues.
It is not in the manual and I came up with this tool and set up to save time.

 

I have left to run the shop for *****************.
Call me and I'll explain it.