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#19
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![]() First off, we can forget about lost-foam or anything more exotic than green-sand, simply because there aren't enough of us. Lost foam isn't all that "high tech" and is actually well within the ability of anyone that can build their own foundry and ram up some sand. Classic lost wax is still a viable option and if one uses oil based sand rather than bentonite green sand you can get much better detail and steeper angles - but you do need a muller for oil sand. Here again, borrow a page from the Corvair (or from GM) and we end up with a 'rocker arm' that actually works. *The tricky bit is that it does NOT need to be aligned on a shaft... we can literally put a valve anywhere there is room. *And that means at any angle as well. My conclusion as well - but if the angles aren't chosen very carefully we end up with greater than stock side loads on the lifters - thus my conclusion that we need a new cam at some point or run the risk of accelerated lifter bore wear. Trying to put a second plug in the mix and I'm not smart enough to come up with angles that I'm comfortable with. Personally I see no need for 2 plugs per cylinder. When was the last time anyone heard of a spark plug failing with out warning? As for flame front prorogation, the only real justification for dual plugs other than unreliable magnetos, we just don't need them on a VW based engine unless you start thinking high rpm's and a PSRU. But that's getting too far away from the cheap and simple. So we make a L-head and an R-head; mirror images. *We do the best we can with the fins but recognize our limitations and leave the most difficult of them as CUT fins If we do the split heads (still need 2 cores, front and rear) the fins can be rough cast and then finished up on a lathe. The mention of sawing gives me the idea of using a saw mounted on the lathe for quicker cutting than a standard tool and maybe even thinner fins. Band saw off the fins next to the other head and your done. No CNC needed. My next set of 1/2 VW heads will be done this way................if I ever get around to a next set. ======================= Leon McAtee |
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