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| NickG:
Brilliant Kirk. :ddb: I wonder if they had so many spring coils to avoid valve bounce? but I would have thought that would only happen at stupid speeds. Nick |
| kvom:
The pictures on Liney's suite show only about 3 coils. When I first tried a single assembly with 5 coils or so, the force on the cam was significant. I'm concerned that I might need to file the leading edge of the cam surface to make the "entry" easier. Of course that would mean a complete disassembly. :scratch: My other pre-run concern is whether the valve balls will seat properly and seal the valve passage completely. It's rather difficult to lap the valve seats when they are so small. The prototype uses brass for the heads, and I suspect that brass would yield a cleaner surface for the seats. We shall see. After putting this together with a couple of hundred 2-56 SHCS, I'd suggest to future builders to invest in a t-handle 5/64 ball-end allen wrench vs. the standard L-shape. |
| kvom:
This afternoon I hooked the manifold to the engine and applied 5 PSI air. As I feared, there is significant leakage around the input valve seats. Of 5 heads, only one seals completely. Three others have smaller leaks (e.g., when I push in the plunger the airflow increases significantly). The last head seems not to seal whatever. What I should have done, prior to assembly, is test each head's valves. If I insert the balls and apply air, then no air should escape. Similarly, I can turn the valve cover around so that the input barb is over the output valve and test it in the same way. In testing the output, air will still flow out the bottom, but not from the side exhaust hole. Blocking the bottom hole should result in no air flow at all. So I have made a simple manifold with just one output barb that should make this testing easier. However, when I discover which valves are defective, I'm not too sure I'll be able to fix them. For other builders, this testing might be appropriate while partially machining the heads. If you drill/ream the plunger holes, drill the valve holes, and drill/tap the valve cover holes, the valves can be tested before doing the rest of the machining of the heads. Just an idea. If I have to remake the heads I will likely test them this way. |
| NickG:
Kirk, keep at it, there's always a bit of trouble shooting esp on one this complex you'll get there. Is there nothing you can put in there to seal the valve seats? Nick |
| chuck foster:
just a thought..............what about using a small brass punch and hammer. put the ball's in place (on there seats) put the punch on top of the ball and tap it lightly with a small hammer. this may peen the ball into the seat and it just might cure the leak's. chuck :wave: |
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