I had a valve spring break while on the highway and now I am faced with an engine tear down to replace cylinder heads. This is in my 01 XLT with a 4.6. I have done cylinder heads and engine rebuilds in the past but mostly with the older 302's. I'm honestly most nervous about getting timing chains back on correctly.

Anyway, my real question here is should I be replacing anything else in the name of preventitive maintaince while I am in there? I intend to replace the timing chains, guides, and tensionsers along with all the gaskets involved with such a job. I believe the most cost effective way to go with the cylinder heads are getting a pair of remans. I feel I should replace both heads since I have it torn that far down and can't guarantee a spring on the other head might let go for some reason.

All of this contingent on what I find with possible piston damage from the dropped valve of course.

 

Sounds like you have a good plan together...I would definitely do both heads also, don't want to do that job again! Good Luck

 

Are you sure the valve and piston hit and that there is damage? Broken valve springs are not all that uncommon on these engines. These engines are built to very tight tolerances and I would only replace the guides/heads if there was a lot of wear and really needed replacing. How many miles are on your truck? Does it smoke?

 

Absolutely the valve hit the piston. When I took the valve cover off I retrieved the follower which was lying there and the spring lifted right off the valve stem. I don't know where the retainers went. They might still be lying in the head and I just can't see in there well enough to find them. The valve is stuck in the almost completely closed position. Enough to hold 120 psi on a compression test. But it certainly won't move even with no valve spring there to hold it in place. I won't know what the piston looks like until I can get the head off the 5-8 side.

Well, I guess there is a little assumption there. At 3K rpm or so I don't see how the piston and valve couldn't have made contact. The valve stem would have had to bend on the valve train side in mili seconds for that to happen I would think.

The truck has 110K miles on it and I have never seen any smoke out of the tail pipes. Mabey 1/2 quart oil loss between oil changes if that....it might be closer to none.

I spoke with a cylinder head shop who does nothing but remans. They said they tumble and stress test springs on heads they receive for rebuild. If the springs pass the test the just reuse them. I am starting to think of having them redo my heads and have them install brand new springs....wether it be new OEM or after market. I am in the early stages of tearing this thing down now and I can already tell I never want to do this job again!

 

This job is a PIA and I would have to think long and hard about the benefits of doing it in the truck Vs out of the truck and on an engine stand. I can assure you that hanging over a fender and trying to reach and properly torque all of the bolts for the heads and cam retainers will not be any fun unless you are deep into S/M.

 

Oh, I came to that conclusion 5 minutes into the job. Unfortunately I'm doing this in my garage which is devoid of such things as lifts for pulling the body up or off which I have read about. So I have no other choice. I'm not sure I see how the physical act of pulling the motor would be any easier than just doing this in the truck. Am I wrong there? I don't see how you could even get to the tranny/engine bolts on this thing.

Another reason I am asking if there is anything else I should do while I am in there. I'll drop this thing off at the junk yard before I do this job a second time.

 

The starter, transmission bell housing and engine mounts are a bit difficult to get to but still easier than working over the fenders. If you can't get any help you might get a mobile mechanic from Craigs List to come to your home to do the R&R. I suggest that you go to a Pick-n-Pull type of yard and look at the job as someone else is pulling an engine. No need to lift the body.

 

Interesting. I do have access to an engine lift and extra hands if need be. I'll take a closer look at this engine removal idea. Thanks for the advice on that.

Anything else I should look at replacing while I am in there?

 

I suggest that you replace all of the vacuum connections and especially the 90* elbows. The gasket sets from Autozone are/were the same as OEMs and be certain to replace the seals under the covers for the spark plugs. You might consider replacing the cam chain trnsioners as they often start to lose pressure and cause a rattle on start up. When you remove the rockers and hydraulic tappets be sure to store them so they go back in the same position they came from.
Good luck with your project.

 

To pull the motor I am guessing I need to pull the intake first to make room? There is very little room for movement as is.

Are there any lift points on this motor that might be buried down in there that I'm not seeing? What's the best way to lift it out?

 

There was a guy in my area that made his own lifting eyes for a Navigator that attached to the exhaust studs and did not require removing the intake. It was quite impressive.
If I had to do it again I would cut the radiator support and remove it like the Excursions are for the extra room to work in.
I also installed electric fans from a V8 Continental LS.

 

What is the black plastic box under the intake, in what I call the lifter valley, which has an electrical connection going to it? Does that lift out with the intake if I unbolt the intake from the heads and lift?

 

The red text is regarding the wire you asked about.

From my manual;

SECTION 303-01A: Engine — 4.6L and 5.4L 2000 Expedition/Navigator Workshop Manual

IN-VEHICLE REPAIR

--------------------------------------------------------------------------------

Intake Manifold —4.6L
Removal

WARNING: Do not smoke or carry lighted tobacco or open flame of any type when working on or near any fuel-related components. Highly flammable mixtures are always present and can be ignited. Failure to follow these instructions may result in personal injury.

Disconnect the battery ground cable (14301). For additional information, refer to Section 414-01 .
Relieve the fuel system pressure. For additional information, refer to Section 310-00 .
Drain the engine cooling system. For additional information, refer to Section 303-03 .
Remove the engine air cleaner (ACL)(9600) and the air cleaner outlet tube (9B659). For additional information, refer to Section 303-12 .
Compress and slide the hose clamp and disconnect the upper radiator hose.

Remove the accelerator cable snow shield.
Remove the bolts.
Remove the accelerator cable snow shield.

Disconnect the throttle body cam.
Disconnect the accelerator cable (9A758).
Disconnect the speed control actuator cable.
Remove the accelerator return spring.

Remove the accelerator cable bracket bolts and position the bracket and cables aside.

Disconnect the main vacuum harness.

Disconnect the throttle position sensor and engine vacuum regulator connectors.

Disconnect the fuel pressure regulator vacuum line.

Disconnect the vapor management valve vacuum line.

Disconnect the differential pressure feedback EGR connector.

Remove the nut and disconnect the brake booster vacuum line and bracket.

Disconnect the fuel lines. For additional information, refer to Section 310-01 .
Disconnect the idle air control motor electrical connector.

Position the EGR valve to exhaust manifold tube aside.
Disconnect the upper fitting.
Loosen the lower fitting.
Disconnect the two vacuum lines.
Position the tube aside.

Remove the four bolts and remove the throttle body adapter.

Disconnect and remove the positive crankcase ventilation (PCV) hose.

Position the power steering reservoir aside.
Remove the upper bolt.
Remove the lower bolts.
Position the reservoir aside.

Disconnect the eight fuel injectors.

Disconnect and remove the eight ignition coils. For additional information refer to Section 303-07B .
Remove the generator. For additional information, refer to Section 414-02 .
Disconnect the heater hose.

Disconnect the two radio interference capacitors.

Remove the water thermostat. For additional information, refer to Section 303-03 .
Remove the nine bolts.

Remove the upper intake manifold.
Lift the intake manifold.
Disconnect the intake manifold tuning valve connector. Remove the intake manifold and discard the gaskets.

Remove the bolts.

Separate the upper and lower intake manifolds and discard the gasket.

Remove the bolts and the intake manifold tuning valve.

Installation

CAUTION: Do not use metal scrapers, power abrasive discs or any abrasive means to clean the sealing surfaces. These tools cause scratches and gouges that make leak paths. Use a plastic scraper only.

Clean all the sealing surfaces.
Position the intake manifold tuning valve and install the bolts.

Position a new gasket and the upper intake manifold on the lower intake manifold.

Install the bolts and tighten in two stages in the sequence shown.
Stage 1: Tighten to 2 Nm (18 lb-in).
Stage 2: Tighten to 10 Nm (89 lb-in).

Install the upper intake manifold.
Position the new intake manifold gaskets.
Position the upper intake manifold.
Loosely install nine bolts.

Connect the intake manifold tuning valve electrical connector.
Install the water thermostat. For additional information, refer to Section 303-03 .
Tighten the 11 bolts in two stages in the sequence shown.
Stage 1: Tighten to 2 Nm (18 lb-in).
Stage 2: Tighten to 10 Nm (89 lb-in).

Connect the two radio ignition interference capacitor electrical connectors.

Connect the heater hose.

Install the generator. For additional information, refer to Section 414-02 .
Install and connect eight ignition coils. For additional information, refer to Section 303-07B .
Connect the eight fuel injector electrical connectors.

Install the power steering reservoir.
Position the reservoir.
Install the two lower bolts.
Install the upper bolt.

Install the PCV hose.

Install the throttle body adapter and the four bolts.

Install the EGR valve to exhaust manifold tube.
Hand-tighten the fittings.
Tighten the upper fitting.
Tighten the lower fitting.
Connect the two vacuum hoses.

Connect the idle air control motor.

Connect the fuel lines. For additional information, refer to Section 310-00 .
Connect the brake booster vacuum line and bracket and install the nut.

Connect the differential pressure feedback EGR connections.

Connect the vapor management valve vacuum line.

Connect the fuel pressure regulator vacuum line.

Connect the throttle position sensor connector and the engine vacuum regulator connector.

Connect the main vacuum harness.

Install the accelerator cable bracket and the bolts.

Connect the throttle body cam.
Connect the accelerator cable.
Connect the speed control actuator cable.
Install the throttle return spring.

Install the accelerator cable snow shield and the bolts.

Connect the upper radiator hose and position the clamp.

Install the engine air cleaner and the air cleaner outlet tube. For additional information, refer to Section 303-12 .
Connect the battery ground cable. For additional information, refer to Section 414-01 .
Fill and bleed the engine cooling system. For additional information, refer to Section 303-03 .

 

OK. So the black plastic box is only attached to the intake manifold from what I am reading into that. I have most of the steps done on that list but I didn't want to try and pull the manifold before finding out what that thing was and how it was attached. Near the end of tonight's wrench session I started at the EGR pipe but decided to call it quits. It looks like it might be easier to leave the EGR valve on the pipe and just unbolt the EGR from the throttle body as opposed to pulling the pipe out of it. The pipe to exhaust manifold looks like it is going to be fun too.

I found several pieces of broken black plastic down in this valley so I am interested to see what I find when I remove it.

Thanks again Mel.

 

I believe that is like the IMRC on the DOHC engines (The IMRC assembly valve plates should rotate freely to the open position when vacuum is released). The IMRC works like the secondaries of a 4 Bbl carb, tipping in when needed.