Early (GP) Ford motors

From: jim gilmore (jgilmore@ptd.net)
Date: Wed Jan 16 2002 - 20:29:18 PST


Whew.......I guess I should have been more specific! When I said
different, I should have also said they are also the same. That is, they
are the same parts only different.They will fit either motor.

> The Ford GP motor was entirely a Ford design. It was basically a 9N tractor
> motor with a different block, head, cam, dist, carb, intake/exhaust and
> pistons.
What was left of the tractor engine?
-John

     The GP motor was basically the same as the 9N tractor and made side by
side in the Rouge motor building. The block is the same as the 9N but has
a fuel pump hole and is marked GP. The head is the same as the 9N but is a
higher compression and is marked GP. The heads will fit either motor. The
cam will work in a 9N (and vice versa) but is a "hotter" grind and is
marked GP. The distributor is a angle drive unit that will fit the 9N and
is marked GP while the 9N dist. is run off the front of the motor and will
fit the GP. The carb on the GP is a down draft while the 9N is a up draft.
The intake/exhaust manifold for the GP will fit the tractor motor and the
9N manifold will fit the GP. The pistons for the GP are a higher
compression but will fit the 9N while the lower compression 9N pistons will
fit the GP motor. The con. rods and crank are the same for both motors (9N
marked).

Jim,
Do you know if he GP motor can replace a Ford 9N motor in a tractor
application or visa versa?

    Yes, it is common to find GP's with 9N motors and some can be found
with 8N ones. I have one of each. I have also see a 9N tractor with a GP
motor in it. The owner would not trade it for a proper 9N one.

Okay, next question about the early ford jeep engine. Was it the same as the
4 cylinder engine used in the commercial 1/2 ton pickup Ford sold in 1941.
Thanks for all the info. Brian

     Yes and no. The same applies to the 1NC motor as does to the 9N. NC
pistons were the same as the GP.

9N,2n and 8N were 4cyl.

   Right. This is what the letter "N" means. All ford "N" motors are 4
cylinders. There are also motors marked 0N and 1N. Generator sets were
built with 0N motors also.

  I have 2 8Ns.

    Postwar tractor motors.

  I also have the old driveline from a
1941 Ford 1/2 ton pickup.

This would be a 1NC motor and should be so marked on the motor
number. ie. * 1NC-1234*

  It was rated at 30 HP. The only visible difference
I can see is a fuel pump on the truck block. It has the same updraft carb,
and the same exhaust manifold.

  Carb/manifold are the same as the 9N. Block casting is different. 9N
blocks do not have the hole for the fuel pump.

  The truck block even has a 9N casting number,

   Where? Inside the block or outside. What is the motor number? It is
common to find these trucks with 9N motors that have replaced the original
1NC motor.

and the radiator is identical to the tractor, including the 9N part number.
I was wondering if the early Jeep engines were based on this tractor motor,

   The GP motor is derived from the 9N motor. In fact, before Bantam built
their first jeep they were loaned a 9N motor from Ford to try out in it. It
was later returned to Ford.

do they also have the 9N casting numbers?

   No. The GP motor is marked inside in raised letters "GP" between
cylinders 1 & 2 and 3 & 4. The motor number has a GP prefix ie. *GP-8505* .
   Blocks that were built for spare/replacement parts will not have a motor
number stamped in them. They will have the GP raised letters inside.

Jim

   NOTE NEW ADDRESS----NOTE NEW ADDRESS---NOTE NEW ADDRESS------AS OF
JANUARY 4, 2001---------

Jim Gilmore
13 Broadway 3rd floor
Jim Thorpe, PA. 18229

570-325-5216 phone



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