FJ80 Atlas 4.2 6 cylinder swap

Just getting started on my next project. I have done one of these swaps using the 5 cylinder version of the Atlas family of motors, it is a fantastic combination. Atlas motors are light weight and pack an extremely flat torque curve thanks to the variable cam system.

This swap is a little different, I am starting with a newer FJ-80 which came with the better 1FZ dual overhead cam motor. This 1FZ has seen better days, my customer was initially looking at a rebuild but since has decided to upgrade to the 4.2 liter 6 cylinder Atlas from a Trailblazer.

I will document as much as possible during the build, that being said I could easily spend more time on blog entry than actually building the project. If you have questions let me know.

Pulling the VERY heavy stock 1FZ.

 

 

 

 

 

 

 

 

 

 

 

Engine bay is in pretty nice shape. No sign of years of oil leaks and such. Just needs a little cleaning up and will be ready for the new lump.

 

 

 

 

 

 

 

 

 

 

All clean…

 

 

 

 

 

 

 

 

 

This is a picture of the factory ECU plugs, in the red circle are the three plugs that connect the ECU and the drivetrain to the body. Cut these on the ECU side of the plugs. Leaving the plugs in the truck for later.

 

 

 

 

 

 

 

 

 

 

 

The 6 Cylinder Atlas comes with a front sump oil pan which will not clear the front diff on the FJ80. Currently there are no aftermarket pans being built so I cut the pan about an 1″ down from the flange, reversed it and welded it up. All clear now.

 

 

 

 

 

 

 

 

 

 

 

Engine installed

Engine installed

 

 

 

 

 

 

 

 

 

 

Building the fan shroud.

Building the fan shroud.

 

 

 

 

 

 

 

 

 

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Frame work for the shroud,

 

 

 

 

 

 

 

 

Adding the felt to the foam frame work.

Adding the felt to the foam frame work.

 

 

 

 

 

 

 

First, cover with fiberglass resin. Then 3-4 layers of fiberglass mat and more resin.

First, cover with fiberglass resin. Then 3-4 layers of fiberglass mat and more resin.

 

 

 

 

 

 

 

 

After the fiberglass is cured, the shroud is sanded and finish body work is completed. Some rock guard and black paint for a nice textured finish.

After the fiberglass is cured, the shroud is sanded and finish body work is completed. Some rock guard and black paint for a nice textured finish.

 

 

 

 

 

 

 

 

New shortened rear shaft along with the all new smaller diameter front shaft.

New shortened rear shaft along with the all new smaller diameter front shaft.

 

 

 

 

 

 

 

 

 

 

 

Small dia. shaft gives ample clearance to the transmission pan. This picture was taken with the front right spring removed and the suspension on the bump stops.

Small dia. shaft gives ample clearance to the transmission pan. This picture was taken with the front right spring removed and the suspension on the bump stops.

 

 

 

 

 

 

 

 

 

 

 

Oil pan to front diff clearance.

Oil pan to front diff clearance.

 

 

 

 

 

 

 

 

 

Side of pan to diff.

Side of pan to diff.

 

 

 

 

 

 

 

 

 

Transfer case and transmission shifter mounting.

Transfer case and transmission shifter mounting.

2 Responses to “FJ80 Atlas 4.2 6 cylinder swap”

  1. Jay Johnson says:

    I am interested in this swap i have a 91 fj…and hopefully in the next few months will start acquiring motor transmission and things to do this build. I am interested in the major problems you ran into. motor mounts trans mounts adapting to the ecu also changing the gas pedal. I am sure there is more and if brought to my attention i would much appreciate it. another thought fuel pump. is the fj pump adequate for the atlas?

    thanks jay

  2. Rory says:

    Jay,
    I need to know a bit more information before I can help you out.
    Are you planning on running the 5 or 6 cylinder Atlas? Do you have the facilities to do the fabrication yourself? Are you going to use the factory ecu and harness?

    Let me know.
    Might be easier to email me… neverliftgarage@gmail.com

    Thanks
    Rory

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