Valve Train Geometry on OEM Fixed Height Rocker Shaft

[Polysphere]

Thanks for your feedback on the stem height Bill. I certainly didn't think of the tip hardness issue. These are Ferrera stainless valves but I have no idea what grade of stainless they use. Since the valve tips are too high, that would indicate that the seats are too deep. What methods are used to effectively move the seats up? New seats?

[Polysphere]

The other reason I asked the question on valve tip height in relation to the retainer is that I had added break-in springs on the exhaust side only and being .050" more in installed height than my regular springs, I used + .050" locks. I'm concerned that with the valve tip being set lower by roughly 0.100" that the tip won't be far enough above the retainer and locks. I'll take measurements on those today.

[Walter R. Malik]

Thanks all for your help with this issue.. One quick question, is there an absolute limit or "rule of thumb" for the least amount of valve stem to have protruding above the retainer and locks as long as the rocker can reach the stem without contacting the retainer or locks?

As long as the sweep pattern will stay on the valve tip, (at least .030" from the edge), everything will run OK.

[Polysphere]

Thanks Walter. Taking it apart today and going to the shop on Monday. I'll just be losing some time and a couple of intake manifold gaskets.

[BillK]

Are the valves supposed to be stock length an diameters ? If I remember correctly the valves were an oddball.

[Polysphere]

I went oversize on the valves compared to OEM but yes, the lengths were supposed to be stock (versus the .100" over I have):


OEM: 1.844” / 1.563” W 3/8” diameter stems

Upgrade: Ferrea stainless Pro-Flow 1.94” / 1.60” W 11/32” diameter stems

[ClassAct]

B3racingengines.com. Go there and read his tech articles.

[Polysphere]

Good reference CA. From my perspective, they clarified all of the points that others had made but with clear examples and comparisons.