Sprite & MG Midget 1: Keyword(s) = 1275, 1380, 5spd, 948cc, CA, CR, HIF44, SU, acceleration, advance, air, alcohol, autocross, belt, boost, bore, bugeye, cam, compression, compression ratio, cooling, crank, datsun, diff, engine, engines, exhaust, filter, flywheel, fuel, gauges

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November 09, 2002

George Stronghilos writes:
"After all this I may have to sell my
Judson"!
Well, George....maybe!
But, I can only go by the experience of
others along with my own and advise
I was heavily into the Judson application
and it's success. Without at least a water/
meth. delivery system, my experience (along with those of others) tells
me
it's an uphill battle on today's pump octanes. Racing fuel is a
different matter.
I even had an engine built for the Judson.
I just installed my new Rivergate 1293
and it runs just beautifully. Very smooth and very strong even on the
stock 1.25
twin set-up slightly modified with H6 needles and "red" springs (more or
less
as Cooper "s"). Goes to 60 in under 10
flat quite easily normally aspirated, with
Datsun 5spd. and 3.7 diff. And the motor
is still tight as the build was "close" clearanced for the blower based
on a
planned long "break-in" over time.
It's spec. was specifically "tailored" for
my Judson, the installation of which on this motor was based on the
availabilty
of both Delrin vanes and a water/meth.
delivery system, in view of my previous experience on the stock 1275
ironhead
which propelled by PO'd '67 Sprite and
in consideration of the the fact it would
be overdriven to attain the 6psi boost
curve intended by the Judson brothers
and as built into other low-pressure applications intended for the
street
using stock engines for which they
were designed.
APT belt drive, lightened flywheel,
EN40B crank, Pierce aluminum
head (and rad.), original OEM Cooper "s"
cam, Total Seal rings, off-engine oil filter
and low compression pistons to give a
static CR of only 8.3-1, fully street balanced, clearances on the tight
side,
coated med. bore header, 1.75" exhaust and RC40 rear box only........the
works!
Just imagine how much more
torquey it would be normally aspirated,
at 10 to 1 instead of 8.3-1! (I could cry!)
So you can see I was very much into the
Judson thing, based on my experience
with the 6psi boost curve superimposed
on the stock ignition advance curve (shortened a bit, of course). I
mean, it
made a virtual tiger out of the 1275 in
street terms. The acceleration was
absolutely "fabulent"! When I took George Folchi for a ride in the car
at
6psi he just couldn't believe how quick
the thing was. Of course, I "drove it
like I stole it" so he could get the full
effect of the difference between the
4psi curve provided the 1275 with the
standard sized blower pulley and the
6psi now produced by the smaller pulley
he had just fabricated for the application.
Well, both the Delrin Vane and water/meth delivery system projects
failed to deliver in a timely manner and
I will not expose my beautiful brand new
expensive engine to the Judson until it's
heat issues are properly addressed.
I don't have my old garage
any more so I am not in a position to
conveniently do at least the water/meth delivery system. The Delrin vane
thing is
definitely machinist's (Mr. Folchi's)
territory.
So, I returned my blower to George F. so
he could utilize it on his just completed 1293 8.0-1CR "ironhead" '67
Sprite
restoration. Absolutely beautiful
job. He's got one of the original Judson
gauges! Pretty neat! Of course he returned my money. Guy is as honest as
the day is long and customer satisfaction
is his number one priority, no doubt about
it. Good guy to do business with.
He is attempting (or will attempt in the
Spring when warmer weather brings better working conditions) to work out
a
water/meth delivery system "T'eed into
the oil delivery system through a graduated nozzle. It's a matter of
getting
the nozzle size correct to provide the
correct amount of a 60/40 alcohol/water
mix to do the job with the stock ignition
advance curve (suitably "shortened" to
24 degrees or so) to take care of "off"
and "on" boost "compression heating"
issues of the blower. If this is not successful, then I must say the
Judson
is not really doable. It is just not compatible with today's pump
octanes. And automatic timing controls
won't help. All they'll do is retard the spark
to the extent the application can't perform.
I mean you have to figure at least a 4 point increase in effective
compression ratio at 6psi.
If he can get this right, I'll give it a try
Delrin Vanes or not. I mean we have
synthetic oils today who's film strength
is well above what yesterday's mineral
based products provde, inclusive of
Marvel Mystery Oil. The synthetic products are vastly superior in this
respect and that's what we'll need
to keep the stock vanes going at the rotational speeds required to
supply the
6psi boost curve to the larger
capacity engine. If we have the self-
lubricating Delrin vanes by that time, so
much the better.
Meanwhile, I had purchased an SU HIF44 with Turbo Metro needle to take
the place of the problematic Holley which originally
came with the Judson. I will re-needle this
with a BDL, mount it on the appropriate
heated Howley manifold just rec'd. from
Mr. Anton's much hailed APT, and provide
the improved alum. head with a 1.75
throat to aspirate through normally. This
should be more suitable with the improved flow characteristics of the
aluminum head
in allowing it to develop it's full potential,
normally aspirated.
If the water/meth delivery system does not materialize, we'll pull the
head at
a suitable time and reconfigure the spec. to 10-1 and re-time the Cooper
"S"
cam from 4 degrees advanced to "straight
up". The 4 degrees advance was dialed in
to give a super-strong low and mid-range
out of consideration for blower rotational
speeds, not the strength of the motor!
Basically, everything would have happened under 5,000 engine rpm, the
blower at this point turning about 7,300.
It also might interest you to know that a
fellow in the Netherlands (Arnold Hermmann) has had similiar luck as I
with
his Judson on his "ironhead" 1293. And he has all sorts of cooling mods.
inclusive
of outside air induction source, along with a simple water/meth
injection
(not delivery) system and couldn't make
it work in Holland's summers, even on the
98RON unleaded they have available over
there. As far as I know he removed it from
his engine and is back to normally aspirated.
And Mike McLean out in CA couldn't make
his work at all on his original 8.3-1 948cc
powered daily driver Bugeye either. He finally took it off and sold it.
He's having
Gerard build him a 1380. When it is near
finished I'll send him my 45DCOE I used
to use on my PO'd Vizardized '74 RWA
Midget....
The only guy I know who has had any luck
with a Judson was on his Spridget used for short course autocross only.
His was
a high rpm application, so the standard
blower pulley giving the 4psi curve to his
1275+ engine was right up his alley, using
a 4.22 dif. These runs are of short duration at high rpm's and he had
racing fuel available.
So thats my experience thus far, George.
I would love to have the Judson but at
this point, taking good care of my new
engine is the priority!
Cap'n. Bob (Ret'd)
'60 Frog

PilotRob@... 16274

November 09, 2002

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