Re: Computers, Jags and Alfas

[Ted Borck <tborck@domain.elided>]

On Mon, 10 May 1999, Greg Hermann wrote:
> >Ted Borck previously wrote:
> >
> >Never had an Alfa or Jag - watched my friends deal with theirs, just a
> >1962 Porsche 1600 (normal) coupe, 1962 Porsche S-90 Cabriolet, and
> >after the S-90 was totaled by someone running a stop sign, a 1963
> >Porsche 2000 GS Cabriolet (356C w/detuned 904 engine).
> >
> >The 2000 GS was interesting to work on, and to overhaul - it had two
> >spark plugs per cylinder, twin distributors, dual overhead cams, and
> >the cams were driven by 4 jackshafts with 8 beveled pinion drives.
> >
> >Picture a cam drive with 8 ring and pinion gears sets, and a lot of
> >very *tiny*thin*shims.*
> >
> >Degreeing the cams after overhaul took a while, as you didn't want to
> >bend any of the sodium filled intake or exhaust valves.
> >

> Same idea!!
> 
> IIRC--you degreed the cams on that engine by jumping one of the bevel gears
> forward one tooth, and the other back one tooth--

That and each valve had a spacer similar to Alfas, so you had to get a
box full of spacers of different thicknesses, install the one you
believed would result in correct opening and closing tolerences,
engage the cam drive gears and degree that valve.  Keep R&R'ng cams
and swaping spacers until each valve met tolerences. Once you set all
the exhaust valves, you moved to the intake.

Once you degreed each cam, you then set up each bevel drive (8 total)
like a separate ring and pinion - white lead, tooth engagement, gear
depth, backlash and all.  Then check and sometimes re-degree the cam.
Porsche went to chain cam drives after this engine, 587-1, 587-2,
587-3.

What took me about a week to figure out is that the cams on one side
turn backwards from the other (I know, I'm not real smart).  So that
side is degreed backward from the other.  The factory engine manual
was not much help - it indicated that anyone using the manual had
obviously received factory training.

This was not a ball peen hammer and 12" crescent wrench engine.

> I think only sodium in the exhaust valves!

Yea, that's what I thought and so did the BMW owner who bought my used
intake valves to cut down and install in his BMW to give him bigger
intake valves.

He chucked an intake valve in a lathe, and when the cutting head got
too close to the sodium - ka-blooey!  After he said a few bad words,
he ended up leaving the stock valves in his BMW.

> The stories remind me of driving a GTZ (Guilia Tubolare Zagato) Alfa, all
> to infrequently, which still belongs to a good pal!! (And which would whup
> on a 904, but not a 906, rather handilyl!!

Just think what those engines would do today with computerized
injection and ignition systems, but then they wouldn't be the
mechanical equivalent (utilizing only Bernoulli's principle and
collapse of non intergrated circuit switched magnetic fields) of the
continental engines (mostly) used in Scouts and IHC vehicles.

See there is a point to this thread after all.

Ted Borck	tborck@domain.elided