Jeep Fact Page

Jeep 4.6 Fact Page

The factory Jeep 4.0 engine is known for its reliability and longevity but unfortunately lacks in the power department and that’s where the 4.6 stroker comes in. We machine, balance and blueprint each engine in house to the exact specs and tolerances that we have successfully used for over 10 years when building the 4.6 Jeep engine.

The 4.6 has a smooth idle with just a slight hint of that aftermarket cam sound but will never give you trouble in traffic or rock crawling. It makes great low end torque which allows you to climb hills and pass other vehicles on the express way with ease.

Each engine is built to be a direct fit for your year Jeep and we give full tech support to help with the install and start up. We supply all of the gaskets you will need to complete the install as well as a new oil pump and pick up screen. You will be able to use your stock computer to run this engine without any modifications needed.

Required parts for the Jeep 4.6/270HP long block

24lb fuel injectors

– 91 octane pump fuel

Recommended part to bring the hp level to 300hp +

62mm Throttle Body

Aftermarket JBA Header and Exhaust

– Cold air intake

DUI Firepower Ignition Kit which includes cap, rotor, Screaming Demon coil, and Livewire spark plug wires (use your stock distributor.) This is not available for 2000-06 year models that use 6 – coils and is not needed to get to this level of power.

Jeep 4.2 to 4.6 liter conversion

– If you have a 4.2 engine in your Jeep and you would like to run our 4.6/270HP long block here is what you will need to do for a smooth install.

You will need to use the following parts from your 4.2 onto the 4.6 engine:
– Motor mounts
– Oil pan and timing cover
– Flywheel
– Brackets and pulleys
– Harmonic balancer
– Water Pump
– Distributor and coil
– Intake Manifold

You will need to buy the following parts for a 1991-1999 model year 4.0 Jeep engine in order to fit the new 4.6 into your Jeep:

– 4.0 header which we sell a JBA Stainless Steel version

4.0 Valve Cover Kit (we sell a new cover for $125)

If you are using your stock 4.2 or aftermarket carb style intake you will need to make a modification to it in order for it to fit onto the 4.0 head. You will need to take a small round file or a dremel and cut a half moon into the intake directly below the first and last bolt holes in the intake (the holes that will bolt the intake to the head). This will allow you to jack the intake up onto the half moon that you cut and line the port of your 4.2 intake with the port on the 4.0 head.

Keep in mind that the line up of the ports will not be exact in all cases but this does work without a problem. You will have to use the stock bolts and clamping hardware and in some cases need to fab small clamps to properly secure the intake.

If you are buying the Mopar Multi Port Fuel injection kit for your new 4.6 engine this mod has already been done by the factory.

If you are running a carb intake with this engine we do recommend an Offenhauser aftermarket intake and a Holley 450 cfm carb or equivalent.

**Important Break In Information**

It is mandatory to run the Joe Gibbs or Royal Purple Break In Oil for the first 500 miles, you can purchase this oil direct from Golen Engine over the phone or through our online store. Once you get the 20 min Cam Break In Procedure properly executed you will want to change the oil filter only in order to remove any break in material that might be caught in the filter. You can continue to use the Break In oil for the next 500 miles as long as it stays clean.

Once you have reached the 500 mile mark with your new engine you can then choose to switch over to a conventional or synthetic 10/40 weight oil but you will need to use a Zinc Additive with each oil change going forward for the rest of the engines life. Joe Gibbs makes what they call Hot Rod oil that has the proper level of Zinc in the oil itself and it is available in both a Conventional and Synthetic. Golen Engine offers both versions and can drop ship this oil anywhere in the Continental US, just ask your sales man.

Tune up Parts List

– Wix or AC Delco oil filter for a 4.0 Jeep (Do not use Fram oil filters we have seen problems with them collapsing and lowering oil pressure)

Pilot bushing for a 4.0 Jeep Wrangler (For standard transmission applications only)

DUI Firepower Ignition Kit which includes cap, rotor, Screamin Demon coil, Livewire spark plug wires (use your stock distributor.) This is not available for 2000-06 year models that use 6 coils.

Champion RC9YC4 with gap set to .035″.


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