<VV> Variable valve timing Corvair - More Details from Corvair Minnesota

[Rob Landers]

The 3-cylinder car in question was driven to the St. Louis mini convention
in 1994 by Egil Tweet <sp?> who was a member of the Corvair Minnesota club.
I believe there was a story about in the Communiqué shortly after that.
Egil passed away a few years after the convention but not without leaving a
lasting impression on a lot of us who were there to hear all about the car
and all its engineering marvels.  Since I was one of the co-chairs at the
convention I only got to hear bits and pieces at that convention so I
contacted Fran Schmit who has long been a very active member of Corvair
Minnesota and CORSA.  Because I didn't see any mention of Egil, I forwarded
the link to Fran asking for his comments.  Below is what Fran sent back and
agreed to let me re-post here on VV.

Reply from Fran Schmit:----------------------------

Robert - - Yes, I knew both Egil and Cobb Burandt.

At one time in his life Egil bought Cobb's Variable Valve Corvair (all ratty
and full of
pigeon shit) and shined it up and took it to a convention in Iowa - maybe
Des Moines -  Egil had the radio control that Cobb had put together, but
Egil was not adept at running it - - as Cobb had been.  So your memory is
pretty good, as you remember Egil and not having met Cobb, knew
nothing of Cobb's part in the Variable Valve story.

As near as I can remember Cobb was an inventor who had been working on some
far out ideas back in the 70's.  When he came to us at the CORVAIR club to
get an engine to use for a demo of his ideas - - we got him a whole car and
he took it away to do his stuff.  We didn't see him or hear from or about
him for a couple years - - till he actually had his model built and
functioning - - very much as it stated in the IEEE report.

Here's what he tried to do and why he used a CORVAIR engine and what he
succeeded in doing.

First off he wanted an air cooled engine so he could drill and cut without
having to worry about water leaks.  He didn't need a big powerful engine as
he was making a demonstration of his technology...he also only needed to
work on one head at a time so he made the engine into a
3-cylinder.  We often referred to it as "the 3 cylinder" and everybody knew
what we were talking about.

With only one head it seemed silly to have it down in the dirt so he turned
the engine 90 degrees - so the head was on top, of course.  Now he had the
platform to work on.

His idea was to make an engine that could have three things varied while it
was running - to test the effectiveness of each of the ideas.  He made an
overhead cam for his 3 cylinders - - driven by an external  chain, from the
crank.  This chain had to have some idler sprockets in it as he also made
the head so it could move up and down - - to change the compression ratio.
He used these moveable sprockets to vary the valve timing - relative to the
piston's movement.  He only had one cam so he did not actually pull the
intake and exhaust timing apart (as some modern engines are doing), but he
did in fact separate the valve timing events so that his engine could run
with a huge overlap to no overlap of the valving at all.

His intent was to show the effect of varying the compression while
running...of varying the valve timing (ahead and behind the pistons motion)
and to vary the lift of the cam (both intake and exhaust) while the engine
was running.

He built screw jacks under the four studs that held the head away from the
block (the jugs were bolted to the head to keep the combustion chamber
sacred,  of course they went up and down with the head) - - a chain (like a
bicycle chain) went around the engine to the four corners and when he ran a
little motor on the side it screwed the head up/down.

Same principle for moving the idlers on the cam drive chain back and forth
got him changes in the time of the cam's motion on the valves relative to
the crankshaft's position.  Cobb told me that these two tests were of little
to no consequence - - in that they had only a small effect
on the engine's operation.  When he ran the motor that slid a tapered piece
of flat stock between the cam and the valve stem (end) making the valve lift
vary from 0.001" to 0.250" it was like a miracle.   The engine was throttled
down - - at any given carburetor position - - by shutting
off the supply of fuel because the valve only opened at the very tip of the
valve curve... you've seen the plots of the valve's position relative to
crankshaft degrees and seen the huge overlap of the intake and exhaust
valves on performance engines (like two large breasts with less than zero
cleavage - just mashed together)...now take those plots and move the zero
point of the curve up (away from her chest)  so that the valves don't move
till much later and for less time and lift, of course - - but the maximum
valve timing is still at the same crankshaft degrees as before ( remember
the huge breasts?  Now you have two little titties with their nipples the
same distance apart as the big ones had been).  Where's the overlap?  Gone.
Where's the fuel intake? Practically none as there isn't anytime or lift  to
get anything in.

So as Cobb would drive his little electric motor to pull the taper out from
between the valve and the cam......the "lift" would disappear......and the
motor slowed to a crawl.    Running the radio controlled motor the other way
increased the lift and that sucked more air through the carb and the engine
got more fuel and it speeded up.

The principle of Variable Valve Lift was dramatically shown and effectively
demonstrated.

He brought the "3 cylinder" to show us at one of our regular club meetings
and we were duly impressed thinking he was on his way up the fame ladder and
we would just sit back and be able to say we helped him get his start by
supplying the engine.  We had no other contact with him
for many years and had no idea what a screwing he was getting from the Big
Guys.  Many years later we looked him up to see what was happening and found
the car was sitting in a barn.  He sold it to somebody in the club because
Cobb needed the money.  Egil ended up with the 3 cylinder- - washed it up
demo'd it a few times - - then Egil died and one of the
club members has it now - - back in a barn.  As far as I know.

Fran Schmit  CMI

-----Original Message-----
From: virtualvairs-bounces at corvair.org
[mailto:virtualvairs-bounces at corvair.org]On Behalf Of robert guerin
Sent: Saturday, April 30, 2005 10:59 PM
To: Virutal Vairs; Bruce Schug
Subject: Re: <VV> Variable valve timing Corvair - Corliss Orville
Burandt.


Wouldn't it be great to have this guy and his car at a convention as a
speaker.Why did he pick a corvair and then modify it?

robert  guerin

----- Original Message -----
From: "Bruce Schug" <bwschug at charter.net>
To: "Virutal Vairs" <virtualvairs at corvair.org>
Sent: Saturday, April 30, 2005 7:32 AM
Subject: <VV> Variable valve timing Corvair - Corliss Orville Burandt.


> http://www.spectrum.ieee.org/WEBONLY/resource/may05/0505inve.html
>
> Bruce W. Schug
> bwschug at charter.net