THOUGHT ALL YOU GUY WOULD FIND THIS PRETTY INTERESTIN'
-MIKE JUST SENT IT TO ME AFTER READING OUR BANTER !
ENJOY YOUR HISTORY LESSON...... LOL :)
-DIRTY DOUG, stuck inna muck in nu yawk
--------------------------------------------------------
From: "Mike Bishop" <av8ford@volcano.net>
To: "Doug Anderson" <boogiewoogie12@hotmail.com>
Subject: Re: nitro.... and ARDUNs
Date: Sat, 7 Apr 2001 09:23:02 -0700
Hey, Doug;
Want to stick my oar in here and share some info I turned up several years
back when researching a story about the then-new generation of streetable
Hemis.
Information I turned up in some SAE papers presented by Chrysler engineers
in the early '50s, ChryCo were old hands at Hemi research, experimentation
and construction before the Ardun heads hit the market.
The following is a monthly column I wrote for American Rodder magazine
regarding ChryCo's own "hot rodding" efforts.
Mike Bishop
________________________________________________________________________
SECOND THOUGHTS;
THEY JUST COULDN'T LEAVE WELL ENOUGH ALONE--THANK GOODNESS
When Chrysler engineers took a "busman's holiday" with their new
wondermotor, hot rodding got a big-time helping hand.
by Mike Bishop
When Chrysler Corporation figured they'd gone about as far as they could
with their old L-head in-line sixes and eights you'd hardly expect them to
leap all the way to something as exotic as the Hemi. Let's face it, folks,
this was the automaker that, despite their claims to engineering excellence
and an impressive string of firsts, owned the recipe for frumpy when it came
to engines.
Had Chrysler been one of the little guys like Hudson or
Studebaker you might be able to forgive them for the technical lag. But here
was one of the Big Three, a successful multi-faceted corporation, continuing
to pin their fortunes on a really old design that had been stretched about
as far as it could go. While Ford didn't do any better with valve
arrangement, they'd at least had the sense to bend their engines into an
appealing shape.
Well, surprise, surprise; Chrysler had been investigating all manner of
engine designs, including sleeve valves, rotary valves, and two-strokes
among others, since 1937, 14 years before they introduced the Hemi to the
public. Development of a hemispherical combustion chamber OHV replacement
for the venerable old side-valve automobile engines was shelved during World
War II, but Chrysler advanced their overall data base during development of
aircraft and tank engines for the military. Pursuit of the Hemi--the optimum
combustion chamber--was pretty courageous, heady stuff for a giant
manufacturer. So much for frumpy.
Chrysler was justifiably proud of their new flagship engine and were elated
when they learned how enthusiastic hot rodders were about it in its first
year on the market. In what was certainly a departure from the stiff prose
found in technical documents of the time, James Zeder, Chrysler VP and
director of engineering in 1952, authored an SAE paper titled New Horizons
in Engine Development, expressing Chrysler's elation. Citing an earlier SAE
paper that introduced the Hemi to the engineering community, in which the
authors said "further improvements are assured by continued development..."
Zeder wrote "This was the course which we set for ourselves--one of orderly
progress with no fireworks--only FirePower! Then we met the hot rod boys--or
rather they adopted us with all the gusto attending induction into any other
tribe of wild Indians." (I doubt a VP of a major corporation would use such
politically incorrect imagery today.)
Zeder continues, "We, who live within the industry, have learned to accept
without too much resistance the utilitarian place which our product holds in
the scheme of things; but it was a pleasure and, in many ways, an
inspiration to meet a group of men in whom are rekindled the enthusiasms of
an earlier era; men to whom owning and driving a car are sport and
adventure, and not merely a chore inherited by default from the streetcar
motorman. Nor has the association been technically unprofitable. The boys
may not always have the solution to the differential equations, and are
sometimes impatient of questions involving 'why?', but they have had the
opportunity and the interest to find out 'how'; and many of their answers
are remarkably good."
Chrysler was getting some remarkably good answers of their own from their
in-house hot-rodding program. They tested Hemis at compression ratios of
7.5:1, 10:1, and 12.5:1, demonstrating performance improvements as great as
15.1 percent with no other changes. The program progressed with a "let's see
what this baby will do" approach as valve sizes were increased--1/8 inch for
the intake and 1/4 inch for the exhaust--plus a little port work to match
the larger valves. Then came a pair of intake systems with which they could
take a look at mid-range and high-speed performance separately. The
mid-range setup consisted of a manifold and four two-barrel carburetors with
each mixer feeding two cylinders at 360-degree intervals. The high-speed
arrangement also used four two-barrels, mounted on two separate runners,
feeding adjacent ports this time.
The camshaft was the next point of attention. The stock stick--252 degrees
intake, 244 degrees exhaust with 30 degrees overlap--was changed for a
snappier trio of candidates--260/260, 270/260, and 280/270. All that
remained was to replace the restrictive exhaust manifolds with a pair of
wonderfully generous headers and the testing commenced.
Good scientists that they were, Chrysler engineers established a baseline
with a stocker equipped with the headers and the mid-range multi-carb
manifold. This yielded a gain of 13 hp right away, two-thirds of it
attributed to the headers. Next came the heads which raised the scale an
additional 42 hp. Camshaft testing followed, with the 270/260 grind faring
best--adding another 40 hp--because the 280/270 made only slightly more
power but dropped off in peak torque. So far, 95 hp more and they hadn't
even taken the good manifold out of the box! And did I mention that this was
at 7.5:1 compression ratio?
With the good manifold in place the camshaft tests were repeated and as
expected the 280/270 cam came into its own, running the scale up to 341.7
lb-ft of torque 308.6 hp. We're still at 7.5:1, and keep in mind that this
is a 331-cid engine, not a 392 or even a 354.
The lads must have been pretty excited at about this point but you couldn't
tell it from reading Zeder's paper: "In view of the substantial improvement
in performance brought about by the engine changes, it was decided to raise
the compression ratio to determine the response of the increased output
engine to this stimulus." Yes! At 12.6:1 it all came together--385 lb-ft
torque and 353 hp (1.07 hp/cu in.).
Years later, the high-performance specs for the Chrysler test engine equate
to a good street-performance setup, and so they were for the Chrysler
engineers in the early '50s; Zeder was pleased to point out that the
substantial performance improvement didn't involve drastic changes.
In his conclusion, he wrote "Our purpose is to outline the magnificent scope
of the advances which lie before us . . . to inspire some of the discontent
we like to talk about . . . We all stand to profit by a rejuvenation of this
spirit; and if the results of the preliminary tests here reported help to
put the future in proper perspective, this effort will have served its
purpose."
Indeed it has.
------------------------------------------------------
> aW, BILL,....
>
> Ya got it all wrong: those modern T/F engines ain't
>
> " a direct lineal descendent of the '51 Chrysler Hemi V-8 ".....
>
>
>
>
> What they ARE is state of the art Arduns. he he he
>
>
>
> >>>>>>------ straight arrow, thats da' truth! ----------->
>
>
> right A.D.K. ? :<)
>
>
> -Dirty Doug
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