2014-11-25 13:58 GMT-03:00 Gene Heskett <ghesk...@wdtv.com>: > That is about 2x what mine can do. I think, not actually measured because > it only has a hair over 2.5" of travel. >
Well this Mazak may be 1983 and for some people DC servos might be obsolete, but when I see how they work I'm still in love with them. The way it behaves is precious. > I am sure we've both seen some pretty "square" camshafts but everytime I > think about the roller tappet stuff, I recall the cam and tappets in the > Nash Ambassador big 6 engine used from '49 to the end of Nash. That engine > was a stroker, at 4 & 3/8", but it had, from a hot rod viewpoint, every > trick in the book, much of which was unlocked if you put the timing gears > back in so the cam was a tooth late. Between that and some work on the > distributor, there was another 100 horses in there you could take to the > starting gate. One of its secrets was the cam follower tappets, huge > mushroom faces that just cleared the next one over, fully 2" or a hair > more in diameter, with a spherical face radii of about 4 feet. That gave > them room for a cam diameter out of sight for most engines, and while the > timing was only about 255 degrees, the lift, and squareness of the lift > was at least as good as you could get with roller tappets. Combined with > tulip'd valves and double springs, and despite the single barreled carb > and that covered ditch in the head casting capable of being uncovered and > suitably polished, could breath better than anything else on the road at > the time, and got phenomenal gas mileage, 20+ at 100 mph doing it. Biggest > problem was the puny brakes, nowhere big enough to do a panic stop but > once, then you had to replace all the drums, they got that hot & warped > out of round, about a quarter inch. 9" drums, 1.5 wide in front, 1.25" > wide in back IIRC. A joke. But that joke could hang the speedo needle > straight down if you wanted it to. > As always I like how you describe things like this :). I'm really out of my field wich such a monster like that, but I can imagine that phenomenal gas mileage back then is almost against the law by today standars. I recall talking to somebody a while ago when I was researching about induction heating for camshafts, and the reason most engines are going from flat tappets to roller tappets is because zinc was no more a legal component in motor oils and to avoid premature wear the only reason is to use a system with less friction. I don't remember but the person I talked to may be from this list. Anyway, I remember that because the person told me that there are lot of old monster like the one you mentioned that needed camshaft rebuild because the newer oils are far worse for systems without rollers. -- *Leonardo Marsaglia*. ------------------------------------------------------------------------------ Download BIRT iHub F-Type - The Free Enterprise-Grade BIRT Server from Actuate! Instantly Supercharge Your Business Reports and Dashboards with Interactivity, Sharing, Native Excel Exports, App Integration & more Get technology previously reserved for billion-dollar corporations, FREE http://pubads.g.doubleclick.net/gampad/clk?id=157005751&iu=/4140/ostg.clktrk _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
