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DOHC Intake Manifold Removal/Installation
Last Updated: November 19, 2003
-- UNDER CONSTRUCTION --

Disclaimer: The instructions below are what I did to my car and can be used as a "guide" for working on yours. But, I take no responsibility for what you decide to do to your car. Be sure to read through all of the instructions first before doing anything to your vehicle.

PORTING POLISHING INSIDE OPENING UP 90 BEND SEPERATING COOLANT SECTION POLISHING OUTSIDE

Purpose: If you run your finger on the outside of the aluminum intake manifold you can feel how rough it is. Well, it's the same on the inside and that hurts airflow, which will rob your engine of power. I also go over opening up the ports to allow more air to flow, seperating the coolant passage from the manifold, opening the 90 bend and polishing the outside of the manifold just for looks.

Application: 1st Generation '95-'99 DOHC Dodge Neons

Tools for Removal/Installation:


REMOVAL / INSTALLATION

1. Relieve the fuel pressure. The fuel rail has a schrader valve just like your tires. Remove the cap, place some rags around the valve and use a screwdriver to depress the valve to let the fuel and pressure out of the lines just like you would let the air out of your tires. Disconnect the fuel line from the fuel rail and use more rags to catch the fuel.

2. Take off the radiator cap and then drain a good portion of the coolant out from the valve on the bottom of the radiator. You need to remove enough coolant to drain the intake manifold. Then, remove the (2) 8mm bolts holding the thermostat neck on and remove the thermostat.

3. Remove the heater hose from the intake, unplug the connector for the temp sensor and then unbolt it. Remove the PCV, brake booster and Evap hoses.

4. Unscrew the MAP sensor, disconnect the IAC, TPS sensors and remove the throttle cable from the TB. Unbolt the (2) 15mm bolts holding the TB to the manifold and the brace that goes from the TB to the head. Remove the TB.

5. Clean any loose debris from around the head to keep it from going inside the head when you remove the manifold. Remove the (2) bolts holding the fuel rail to the manifold and slowly work it out, the injectors will eventually pop out. Set the fuel rail off to the side.

6. Remove the (8) 10mm bolts and (2) nuts holding the manifold to the head. The bottom left bolt under the power steering pump is a pain to get to. Using a swivel socket really comes in handy. Then carefully scrape off any of the gasket that is still stuck to the head.

7. Remove the (7) 10mm bolts to seperate the (2) halves and you'll see how dirty it can get from the EGR valve, which is why it's a good reason to block it off. Cylinder #4 tends to get the bulk of it.

8. Installation is opposite of removal. If you seperated the coolant section from the manifold, then install that piece first (obviously) then the manifold. Don't forget to re-fill the coolant.


GASKET MATCHING THE HEAD PORTS

If you gasket matched the ports of the intake manifold, then you'll need to do the same to the head, if not slightly bigger.

1. Put the intake gasket on the head and hold it with the bolts. Mark each port with an awl, just like you did with the intake. Remove gasket.

2. Make sure the intake valves are closed on the port you're working on (rotate the crank until the valves are closed. Taking out the spark plugs will make it easier to rotate), then stuff some rags down the port. Take an old sheet and cover the entire engine to keep metal shavings from going where they shouldn't.

3. Now you're ready to port. Use your Dremel or grinder and have at it. Go to your mark and then a little more just to make sure the head port is bigger than the intake.

4. When you're done with one port, get the vacuum out and suck up all the metal shavings. You don't want any of it falling into the engine. Carefully pull out the rags and then vacuum it again. Use a clean rag and wipe out the port. Now you can move to the next port and do it all over again.


MODIFYING THE DOHC INTAKE MANIFOLD
The following pages cover (5) areas: (1) Porting (2) Polishing the inside (3) Opening the 90 neck (4) Seperating the coolant passage from the manifold and (5) Polishing the outside.

There are a few different stages you can do depending on how comfortable you feel. Stage 1 would be simply polishing the inside to a smooth finish using the cutter and sandpaper drums. Stage 2 is porting the runners a little bigger, in addition to polishing, to allow even more air to flow, but requires a little more attention to detail. Stage 3, in addition to Stage 2, is opening up the 90 bend since it is the biggest restriction in the manifold and requires TIG welding. If you've made it that far, then the sky is the limit as to how far you wanna go. Anything from shortening up the runners & making your own plenum box to mounting the throttle body horizontally to completely eliminate the 90 bend.

PORTING POLISHING INSIDE OPENING UP 90 BEND SEPERATING COOLANT SECTION POLISHING OUTSIDE

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