On Tuesday 25 November 2014 22:17:22 Leonardo Marsaglia did opine And Gene did reply: > 2014-11-25 13:58 GMT-03:00 Gene Heskett <[email protected]>: > > 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 :).
Thanks for the flowers, but that just encourages me as you will see. > 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. Yeah. Now my 99 GMC 3 door gets about that. But the '88 Nissan Frontier pickup in front of it only got 10 on a good day. > 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. That change in the motor oils is quite some years back, And zinc may have been part of it, but I am thinking they were also using some variation of TEL that they were worried about worse than the zinc, and it ate every chevy v8's cam away in 10k miles or less when it happened. I've seen the yappets missing the bottom .1 inches, all hollowed out and cams that had less than .1" lift left. And the guy said it just didn't have the giddyup it used to have. Not to mention that because the foot was tickling the pistons to get it up to the national 55, its original 7 mpg the Bro-in- Laws box van once got, was down to about 1.5 mpg & running fat enough you could still smell raw gas in the smoking exhaust. Circa 1982? TOF's (The Old Fart) memories for dates never was all that good, and getting worse. Is GM's patent on hydraulic roller tappets still in force? They were royalty hungry yet in the late 40's & clear into the 70's with that, first designed and used in the 35 V16 engines they made for the biggest Caddies from 35 to 37. Except for its poured rod bearings, that engine could be made up nearly 300 horses from its original 165, then 185, by swapping the rods out for inserted versions, swapping the oil pumps plumbing around to feed a drilled crankshaft, giving it excellent longevity, and swapping the intake manifolds from side to side, which put the carb flanges upright & replace the OEM updraft Marvel-Shebler carbs with a pair of bolt them on, Stromberg 48's, the 94's big brother. I've had the pleasure and phenomenal good luck in seeing two of the 35 of those made, one was Concours De Elegance stock, owned by the undertaker in Buffalo Missouri, and which was used to haul my grandfather from his little farm in Preston Mo to the shop in Springfield, 120 miles, when grandpa blew an ulcer in the middle of the night. And he did it in that 1937 Caddy hearse in about 65 minutes. Grandpa was fixed in about 2 hours & lived another 10-15 years. The other I saw in San Diego, 1959, in a stretched front frame 32 ford 5 window. Thats the one that had been played with. And it still idled at about 250 rpm like it did when it was new. But at 20 mph, in high gear, slapping the throttles open left faint black lines on the street all the way to about 120 mph. One of Ed Iskandarian's (SP?) earlier experiments in camshafts I was told. Maybe even his first attempt at a roller grind? That I wasn't told. Cheers, Gene Heskett -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) Genes Web page <http://geneslinuxbox.net:6309/gene> US V Castleman, SCOTUS, Mar 2014 is grounds for Impeaching SCOTUS ------------------------------------------------------------------------------ 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 [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
