ZR-1 Head Removal

PROCEDURES:
Position the car and open the hood. Remove the brake boost by taking the seat out and remove the kick plate. With the seat removed and the kick plate out, you can now get to the four nuts holding the power brake booster to the firewall. Now, under the hood, you will disconnect it from the plenum. Take the CCM off the cradel and let it rest on the windshield. Remove the CCM cradle and put it away. There are a couple more hoses you need to move aside but you can see them easily enough without me explaining where they are. Once everything is off the booster, you will now go back in the interior because you forgot to undo the booster lever from the brake pedal. Once that is off then you can pull the booster off.

Next start draining every fluid you can find. Next we dropped the exhaust, then the stock headers have to come loose and it you have ever done that, then I do feel for you. First you gotta remove the wheelwells. No big deal, just a bunch of bolts and pull them out. It makes getting to the header bolts a lot easier. Next, you need to remove the O2 sensors. Take it easy on those but they should come out easily enough. Next the heat shielding needs to be loosened. We did not have to entirely remove it, only remove the screws so we could get around the shielding. This is truly a pain in the rear. On the driver side there were 5 bolts and the header stud. On the passenger side there were six bolts and a stud for some reason. Again, I have no hot tips on getting to anything except that the end header bolts must be gotten to from underneath and the header stud and other bolts thru the wheelwell. You may, as we did, have to remove some of the tubing of the AIR system. This will be self evident when you do this. I am not going into much detail here as this is more or less just removing bolts. Now that you got everything off the exhaust manifolds you pop them loose and let them hang.

Just remember:

1. Remove seat.
2. Remove power brake booster.
3. Remove exhaust.
4. Remove wheelwells.
5. Loosen exhaust manifold heat shielding.
6. Remove exhaust manifold header bolts and studs.
7. Let exhaust manifold hang.

Next remove the plenum and injector housings by first removing the serpentine belt. Then remove the power steering pump and reservoir and swing that out of the way. Next, remove the A/C box on the passenger side of the motor. That is the triangle box with the heat sink inside it. To do this you have to disconnect the fuel lines and the upper bracket. Then there are 4 small 8mm bolts holding the a/c box on. The lower one is a real tough one to find. Now there is a good shot at everything for the time being.

Remove the bolts holding the plenum. Remove the snorkel and all the vacuum hoses around it. Then remove the plate for the MAP sensor and let it hang there. Then remove the throttle cables, throttle position sensor, and other odds and ends. You might need a rubber mallet to knock the plenum to bust the seal and slowly lift the plenum so you can get to the plugs underneath the plenum. There are three there, two that are simple plug ins and one that is secured by a 6mm screw. Once those are removed, lift the plenum off.

Next, remove the fuel rail and injectors. First you remove the wiring harness from the injectors. This is just a matter of pushing in on the small wire clamp and pulling it off. Be sure not to loose the orange gasket inside the fitting. Once that is removed, just pop out the injectors from the injector housing and remove the fuel rail.

With the fuel rail removed, then proceed to the injector housings. Remove the water lines to them and remove the sensor connectors on the left side, inside the V. Then the bolts were removed and the housings was lifted out. This allowed some room to work in and around the V.

Next you will need to remove the power steering pump, the air conditioner compressor, and the oil filter housing. First, remove the serpentine belt by easing up on the idler pulley, slipping it behind the water pump, and then sliding it off the idler. The power steering pump has three bolts holding it on. One you get to from the top. The two remaining bolts you have to get to through the pulley in front. It takes a bit of bending over and working with some extensions and universals but you can get to it. Pull it off and tie wrap it somewhere towards the front of the engine. Next, remove the a/c compressor. There are two bolts holding it on. Remove it and tie wrap it somewhere to the front. Finally you need to remove the oil filter housing. This is pretty straight forward.

Now you can get to the cam covers easily. Taking them off is just a matter of loosening the torx bolts holding them on. Now I highly recommend that you get a good set of torx bits. I tried Sears bits before and stripped six of them. With SnapOn, none were stripped. I also highly recommend a hand impact wrench. This will allow you to put a lot of pressure on the bolts as well as a twisting motion. There are 48 bolts total for the cam covers. Remove the bolt in the opposite order of the torquing pattern. Once they have been removed, a couple of hits by a rubber mallet will loosen them and you can lift them off.

Now, we finally can get to the meat of the matter, removing the cams. You will need the cam keepers from Kent Moore here. Put the keepers onto the head and tighten them down. Next, you need to position the crank. To do this we used the cam pins (also from Kent Moore) and the crank locking pin (from Kent Moore). We removed the spark plugs so that no pressure was in the cylinders. We removed the crank position sensor from the right side of the motor. We removed the cam position sensor from the head. Next we rotated the crank using a ratchet on the dampener. We watched the cams closely until we could see the holes for the cam pins just appear in the two cam position keepers that are attached to the head. Then we put the crank locking pin in the crank position sensor hole and we rotated the crank until the cam pins were in position and the crank locking pin slipped all the way in flush with the tool. (Many of these things become more clear when you see the tools and engine) This now set our crank and cams to the correct position we need.

Next, we removed the cam tensioners from the side of the head to loosen some tension. Next, we took a wrench at the firewall end of the cam and positioned that so that it wouldn't move. Then, at the cam chain sprocket, we remove the locking plate bolt from the cam, tapped out the cam sprocket pin, removed the locking plate, removed the temporary cam keepers from the head, remove the cam positioning keepers so that there was nothing holding the cam in, and we slowly worked the cam up and off the sprocket making sure to keep just a bit of tension on the cam chain. It sounds a bit complicated but it really is just common sense here. Anyone can do it.

So, we repeated the above procedure with all the cams and secured the cam chain. Next are the heads to come off. Here, it will require muscle! First you will need to remove the cam chain follower bolts in the head. There are access holes to get to them on the front of the head. Next is the hard part. The head bolts are 18 mm. Be sure you have a very good breaker bar that does not allow any twisting before you put pressure on the bolt. You will need a cheater also. Get a three or four foot pipe and slip it over the breaker bar. Now, start loosening the bolts in the reverse torque order. We chose to break them just a bit at a time. Don't be surprised when you first break it loose. There will be a LOUD crack, and you think you broke something. Well, you really didn't. It was the head bolt loosening just a fraction. We did this several times, loosening a bit, moving to the next one, loosening a bit there, and continuing in the reverse torque pattern. Finally all the bolts will be broken and free. You will be able to remove all but the two on the right side towards the bottom rear.