Improving Your Imperial for Towing
Ross Alexander From Wayne Jorgensen, 12/2006:
I have been emailing John Corey off line in my quest for a hitch for
my 1966 Imperial.
I have finally been successful, and I thought I would share the outcome
with the list, in case the question comes up again.
The hitch that John has installed on his Imperial is a Hidden Hitch,
model 82200. It is a universal fit hitch designed for motor homes
with frame rails between 31" and 46" wide.
The hitch is still available from JC Whitney, but if you ask for a hitch
for a 57-66 Imperial, they will not be able to help you. However,
if you search their site, you will find it listed as an adjustable motor
home hitch. You can also find it on Hidden Hitches web site, where
you can download installation instructions.
Thanks to everyone who offered suggestions.
10 Jan 2007
In response to
your question about the original factory service tips, I
no longer have the advice from Chrysler in regards towing
with the C/Y bodied cars. I most recently ran across a
reference in the public library (main branch) in a couple
of books on towing "lost" (not catalogued) in
the Transportation Section. The author of this book on
"How To Tow" (or some such) noted that although
Chrysler limited the '67 Imperial in his possession to (as
I recall) about 3,500 lbs due to 2.94 gearing, low output
440 (about 275 net SAE today), and overall vehicle weight,
he nevertheless used his to travel the AL-CAN Highway past
Anchorage with an over 6,000 lb trailer. He went on at
some length in regards other Chrysler products and it had
some good pictures of these locomotives under a full head
of steam.
My maternal grandparents last tow car was a '68 Monaco
with the 440-Magnum, 3.55 gears and 10 mpg solo or towing
which they used to travel full-time until 1971 with nary a
serious problem. From what I remember, a very general
consensus was in favor among all the folks we talked with
about the superiority of the driveline/suspension of
Chrysler products as tow vehicles. (Although a friend used
his '69 Imperial sedan to tow thru 1973 but experienced
continual overheat problems, and switched to an
Oldsmobile).
We used a '73 Town and Country (friends used a '72) for
years, but my old man switched over to Cadillac in '76
(and ran up 190,000 before selling it to a car collector
who still hadn't needed to replace the motor at 240K
miles). Beyond the money and time to repair, modify and
update the vehicle, I see no "good" reason not
to do this. But a 3,000 lb boat under tow and a 6,000+ lb
tow are worlds apart. I feel that to do a heavy tow with
one of these cars requires good planning, and I hope the
following will serve as a template:
I've been giving thought to and trying to research the
problems you've been contemplating and am now considering
the following: Given an "up" weight of 5,500 lbs
with driver/passenger, a little luggage, full fuel and
Class 4 hitch, what mechanical and suspension problems
need to be modified to tow a 6-7000 lb trailer?
First, motor output has to be increased to 350-375
"at the wheel" horsepower with 3.23 gearing (my
reasonable minimum; 3.31 to 3.54 is better) with 475
ft-lbs torque from about 1800 rpm up to near 4000. I am
planning an engine rebuild utilizing the 4.15 "stroker"
crank new from Mopar with -452 or -906 heads
"flowed" (Hughes Engines, Muscle Motors, etc) to
provide a 20% or better gain in the sub .450 lift range to
optimize low lift and not loose the efficiency the engine
was given by the factory. By increasing cubic inches -
with a custom camshaft delivering a smooth idle and high
vacuum to operate the power accessories - I believe I'll
be able to very significantly broaden the performance
envelope. Of course, the attendant systems of fuel and
ignition delivery will have to be modified, but nothing
outrageous.
Second, this will necessitate a stronger rear axle and
transmission set-up. A Sure-Grip or a Detroit Locker-style
traction device with 3.23 or better gearing (3.73 or
better for mountainous roads) will be needed. Which in
turn begs the question of drive shaft strength with (those
quiet but, "hmmm, I wonder . . ?) constant velocity
joints. The trans needs to be upgraded to current diesel
truck strength bands and clutch plates with the Hemi
4-pinion carrier and shift lever, plus an auxiliary
oversize (24,000 + GVW ) transmission cooler and auxiliary
filter with a deeper pan and extended pump pickup (haven't
yet consulted with Turbo-Action, TCI or Level 10
Transmissions on this for pricing, but I expect to spend
around $1200 with a torque converter built for my
particular application); and the stock motor and trans
mounts will need converting to modern "locking"
engine mounts coupled to polyurethane transmission mounts
(Energy Suspension). C-body mounts are available, but I
don't know for the Y-body.
The radiator ought to be replaced with a ultimate heavy
duty piece from Griffin or US Radiator (preferably with
1.25 to 1.50 tubing); and a thermostat (Robertshaw HD) of
about 180F should work. The fan shroud should be
completely sealed to the yoke, and the fan clutch and fan
itself need to be in best condition. Have seen this new
EVANS non-aqueous propylene glycol coolant advertised as
needing only 5-7 PSI to operate; anyone know anything yet?
Otherwise, new hoses, clamps and a pressure check after
professional back flush and refill with one of the new
"silicate-free" coolants (Havoline DexCool). We
like RedLine "Water-Wetter" as well.
Brakes should be rebuilt to highest possible standards and
I intend to investigate with HPC and other providers the
feasibility of having a true metallic-ceramic heat barrier
applied to the calipers and drums (as well as the vented
interiors of the disc). I'll also check DOT-approved
stainless steel braided brake line hose replacements,
possibly all new stainless hard lines and a brass-sleeved
master cylinder. Also riveted, not bonded, pads and shoes,
but the material composition is not yet settled. A very
careful brake job by an experienced professional shop who
tests all components and system to provide
"blueprint" application of front/rear and
side/side hydraulic application. An imbalance virtually
unnoticeable in a solo vehicle is a real problem under
tow.
[A company called DECELOMATIC in Phoenix has for years
advertised "exhaust brakes" for gasoline powered
vehicles and I need to update my information concerning
this, but the big truck "jake brake" evidence is
convincing. Anything I can do to reduce panic stops and
keep my attention outside the vehicle is warranted
expense. (See Trailer Life magazine advertisers index)].
Replace all the rear suspension bushings with grease-able
polyurethane or (better) spherical nylon (Global West; I
don't know sizes or even availability) to keep the rear
from tracking separately from the front. A rear anti-sway
bar is mandatory if equipped without the Panhard rod. Yes,
seven leaf springs (National Spring Co, or Detroit Eaton)
with NEW u-bolts, double-headed nuts and front spring pack
clamps (Competition Engineering). Check and re-weld or
replace spring hanger axle attachments and box or re-weld
body attachments. This will cost some solo ride comfort,
but stability is improved even over superior Imperial
setup. The front suspension should be rebuilt if much over
50m since last done and be sure to carefully check
condition of front sway bar bushings. I have yet to find
any replacements for these and would be grateful if anyone
has a line on a source (69-71 C-body). As these rear
springs are 2.5" wide, I'll be investigating as to
whether the BF Goodrich "Velva-Ride" replacement
rear shackles will fit our applications: they take the
sting and the jounce out of rear axle movement under
light/solo driving.
So far as the unibody is concerned, once you tow a big
load there ain't no way around the fact that it'll never
quite be the same. So be it. Just gonna have to
investigate those welds THROUGHOUT the car and repair 'em.
Even body-on-frame is affected. But a "pickemup"
just ain't gonna get it for this boy . . . so a careful
check of BODY HEIGHT is warranted. (This entails more than
just front height adjustment, and you may have to align
and realign before it is right. Be sure you have the
weight representing the driver and passenger IN THE CAR
when it's on the align rack). Once the front end is up to
par, a measurement of body height with a half-tank of fuel
and, note, again, the proper amount of weight in the
vehicle representing the normal towing conditions (if the
vehicle is used 40% or better for towing miles); a check
with and without the trailer of the points the factory
service manual shows as "level" (or see FWD
Toronado 67-70 manual for the idea) to arrive at the best
compromise between tow and solo. Mainly, don't head down
the highway "nose up". Your steering/braking
control is compromised badly. Expect that you may have
side-to-side imbalances which will need to be corrected.
Air shocks ain't worth a nickel (shock mounting points
were never meant to hold the weight, just to dampen the
motions), but my experience with KYB's (Just Suspension)
on my C-body are good. Can't pay too much for the
handling/accident-avoidance improvement here. What is
ya'lls experience with either Koni or the new, rebuildable,
adjustable HAL Corp shocks?
As many of you are aware, the A, B, and E body guys have
for years used sub-frame connectors to tighten up the
body. Has anyone out there had the same made for their C
or Y body and, if so, could you share the details? I
expect to have to cut into and re-weld the floors, but at
what front point did you attach said connectors. (Of
course, for b-o-f guys, new body to frame bushing are in
order.)
As for the hitch, we for many years used a guy who has
since grown old and "retired" to shoeing mules
and horses to customize our hitches (if this gives you an
idea of what a good "hitch" man needs for
patience). It is either right so far as distributing
weight is concerned or it is not. I expect to have to
first find someone with a lot of experience and then pay
for the dead-on correct relationships here. It may be that
I set up the sub-frame connector and weight-distributing
hitch relationship in a to-be-specified manner barring
anyone else's experience, (my granddaddy has "pulled
through" that caravan park in the sky, and my daddy
won't get back out of his "burban nor does he
"remember how it was done", the old snake).
There is a regular "shelf full" of books on this
and other related how-to's of towing. See "Trailer
Life" magazine.
The area that you may find most discouraging is the
electrical system. You'll need a fatter alternator, the
biggest battery, and, unless you rewire the car, regular
wiring problems are EXACERBATED by the stress of towing.
But you're already a "whiz", right? (I ain't,
but I get a little better every so often). You'll want to
replace both the turn signal and emergency flashers with
modern xtra-heavy-duty ELECTRONIC ones.
I'm considering having the different wiring harnesses
rebuilt using one-grade heavier marine-grade tinned wiring
with a polyethylene coating and GM Weatherpak connectors,
but have shied thus far from quotations. Also, gauges for
trans temp, voltage, oil temp and vacuum are a good idea.
Jacobs makes a great ignition system and wires and I'm
very fond of Bosch Platinum spark plugs. Anyone?
Bob, I've about worn you out now, but I like the CB to
keep me abreast of what's happening beyond the city
limits. Join AAA , Good Sam, and carry a cell phone I
guess, and pay lots of close attention to those very
correct adjustments you've had made throughout your car
(you did have the rear axle bearings serviced on the 8-3/4
didn't you?), and keep up those synthetic lubricants
you've switched the Imp to. (Right?). Be aware that there
are no easy solutions in pulling a big trailer, the forces
generated are tougher even than drag racing on the
driveline/suspension.
Now for steering. Mine is loosened up and I will be
investigating the Dodge truck replacement shaft from
Borgeson as well as a blueprinted gear box from Lares or
Lee or someone for a blueprint version that will fit my
C-body (69-71). Also, the pump: Does anyone know of a
preference between the .94 and 1.06 pumps? An external
cooler is also warranted; a Q-code 428 Ford I once had had
this mounted on one of the hard lines. Any ideas here?
As for tires, I will fit the largest 15" radials with
the best handling design I can find. At this point I lean
toward the Goodyear Eagle GT+4 (whitewall available in up
235-R70/15), but am told that Avon and Pirelli stock some
tall & wide tires. Anyone? Our family experience with
tires and towing (since the 1940's) has always been: Five
new to start with and never rotate the spare out if the
replacements come in 45-60,000 mile intervals. Then,
another new one in the trunk.
Wayne Jorgensen
1966 Imperial
1971 Imperial
According to the 1975 Parts book, the original REESE TOW BAR KIT part number is 3837-658. This is
the weight distribution and frame bolted structure WITH a square receiver opening. It does NOT include the tongue and ball. I
am not sure which class it is, but the description says it is 7000 lbs max weight and 700 lbs max tongue weight.