Z 11 & Mystery dimension questions

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todd

Member
Hello guys,
I read online recently that the z11 had canted valves. I always thought all w motors were perpendicular to the cylinder head deck. Were the valves canted and if so what were the angles.

Also curious about the center line distance of the lifters. I know they are close the Mk IV but not the same. Does anyone know what that spacing is? What is position relative to the cylinder bore? Are they spaced evenly each side of the cylinder bore or is the intake offset more or less than the exhaust?

Also I read an old Hot Rod (I think) article about the Mystery Motor having canted valves but were different than the Mk IV. The article stated that they were or appeared to be about 18 degrees with about 4 degrees cant but the exhaust valve's angle were angled toward the exhaust manifold side of the block. In other words, the top of the exhaust valve pointed outward of the motor and the intake pointed inward of the motor. Is that true? Does anyone know what the angles were?


Thank you
 
D

Don Jacks

Well Seasoned Member
Supporting Member 3
As to the z-11,angled,yes,canted no.Pat Loeb has one of these Mystery motors I think,and may know.I do know that the Mystery motors had canted valves.
 
T

todd

Member
i didn't think any of the w motors had canted valves. All of the ones I've seen and those of z11's online valves doesn't appear to have any can't. But then i read this:

The valves on a W engine are not angled like some of its other components. With a head that contains very little of a combustion chamber in its flat surface, the valves are 90 degrees to the underside of the head. That spec was continued with the 409 but changed slightly with the canted valves of the Z11 heads. Spacing between the 348/409 valves is 2.6 inches where it is dictated by the valve size. Even when the later 409 heads went to bigger valves, the locations stayed the same.

https://www.chevydiy.com/ultimate-348-409-guide-cylinder-heads/

It perplexed me, then i came here and thought someone here would definitely know lol
 
dm62409

dm62409

Well Known Member
Supporting Member 12
348/409 and Z-11 valves are staggered ( not in line ) but stand straight up, 90 degrees to the deck of the head. The Z-11 did move the intake valve location slightly toward the intake side ( seems to be about .100 of an inch.) The Mystery Engine, which was basically the prototype for the production BBC, and BBC had staggered and canted valves, (about 4 degrees cant away from cylinder walls to improve flow). Hope this answers your guestion.
 
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todd

Member
thank you Dave. do you know the piece points for the z11 head with respect to the bore? do you know the lifter bore centerline spacing and dimensions respect to the bore?
 
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