Can CMP Synch be changed with engine in place (4.0 OHV)?

[troverman]

I have searched and read, but I cannot see how you could possibly change the CMP Synch on a 4 liter V6 OHV with the engine in place. I can barely see the part. Even if I could somehow get it out, I couldn't make alignment marks because I can't see it!

Has anyone done this? I have a 1996 2WD Limited. Does taking the upper intake off and also the hood significantly improve access?

If this can be done, please explain the best angles to get in, tools to use. Basically all the writeups apply to the V8 which has much better front access. These do not help. If there is a thread here dealing specifically with the old V6, I would like to read it.

I want to go to autozone, get a new synch, and change it on a Saturday.

Thanks in Advance

 

[KPT]

I've never had to do this but I checked my FSM for you:

Camshaft Position (CMP) Sensor —5.0L, 4.0L (Push Rod)
Removal and Installation

Disconnect the battery ground cable. For additional information, refer to Section 414-01 .

For 4.0L (push rod) remove the upper intake manifold. For additional information, refer to Section 303-01A .

 

[troverman]

So what you're indicating is that by removing the upper intake manifold, the job can be successfully completed.

Thanks for checking, it still doesn't look easy. Anybody actually done the job, tips / tricks?

 

[budwich]

I haven't done this either but I think there is a "little" more to this than "meets the post"...

You need to have the special alignment tool of which without it, I do believe you will be unsuccessful.... alignment and "non-movement" of the setup during removal /install is vital.

 

[justanother1]

I have done this (complete cam shaft sensor assy) without removing the engine or intake. It was a real pain. I lost the hold down clamp and bolt. I used a distributor hold down clamp and bolt from a 5.0. I put the alignment tool on the drive before installing. It took me about 2 hours to do this. Believe me, you can not see what you are doing. It may be easier to see by removing the intake. I can not speak from experience on removing the intake. I did not have the time to spend removing the intake so I elected to do by letting the intake installed.

 

[troverman]

Thanks guys. I'm thinking of tackling it this weekend, probably will take the upper manifold off. Does this involve loss of coolant or is that only in the lower manifold? I know some cars have a throttle valve 'pre heater' with coolant in it...

Anyone else with experience on the cam synch, 4L OHV please comment.

 

[Cobraguy]

No coolant issues with the upper intake. I just removed it on my 95 to replace a valve cover gasket. It's not a difficult job at all. Lots of BS to unhook and move, but it's all easy. Just be extremely careful with any vacuum lines as they are brittle and break easily.

 

[troverman]

I worked on it over the weekend. I took off the hood & upper manifold. By doing this, and sitting on top of the engine, I could just see the plug on the CMP. There was no way I could still get at it, certainly no way to make alignment marks. I decided to remove the entire intake; this necessitated draining the coolant and removing the valve covers and taking off quite a bit of 'stuff.' I was pleased to see the rocker arms and shaft and head surface were all extremely clean. I have changed heads before on other pushrod engines and seen very grungy, dirty, burnt shafts, pushrods, etc.-even on a good-running, lower mileage engine.

With the intake fully off, you can clearly see the CMP and shaft. I removed the two screws and literally needed to pry, hit, and use large vice grips to get the CMP off the top of the shaft. The plastic CMP was corroded onto the shaft. There was a ton of white corrosion dust all over the shaft and CMP. I would have never been able to get the CMP off w/o removing the entire intake.

On the sensor, there was quite a bit of metal shavings stuck on the magnet. The shaft was internally intact, but with corrosion and metal shavings. Hopefully today I'll get my parts and actually do the changeout. Once I put the thing together again, hopefully this will solve the problem and it will still run well. One thing I did notice was the intake ports on the lower manifold and in the block casting were very carbon-laden. I would say 5-10% of the port was blocked.

 

[troverman]

Actually, a question: does the oil pump or the camshaft drive the synch shaft?

 

[Turdle]

The cam drives the synch shaft which in turn drives the oil pump shaft-

 

[KPT]

Here is the FSM procedure for changing the synchronizer if it helps:

 

[troverman]

Thanks JL, that does help. I don't have the FSM. I'm getting a dorman part, the whole sensor, shaft, and tool are $57. I called Ford, it would have cost $329 for the sensor and shaft. I'll have the part tommorow, hope to change it out tomorrow night.

 

[troverman]

OK, now I'm confused. According to the FSM posted above, I should put the tool on the new synch, then reinstall the snych with the tool arrow pointed 60- degrees to the right? And then as the cam gear meshes it will turn itself back to 15-degrees? Let me explain:

With the old shaft in place, and the sensor off, I turned the engine to TDC. The half-moon piece can be seen turning, and at TDC it is basically all to the right side. The alignment tool fits right on the old sensor still in place when the engine is at TDC. The arrow on the tool points back to the firewall exactly in line with the engine centerline.

So I then removed the hold-down and pulled the old shaft out. (Understand the old shaft needed to be pried, pulled, hit, and yanked out, it did NOT come straight out due to a lot of corrosion.)

The oil pump shaft did not come out and flopped over a bit, so putting the new synch shaft in was difficult. The cam gears meshed pretty easily, and after about 20 tries, I got it to set down in all the way, with the arrow on the alignment tool pointing exactly on the engine centerline toward the firewall; or exactly as the old one came out. Can I go wrong with this method? If everything is exactly as it was, how can the EFI timing be off?

As a tip for others, use a hex driver that fits into a screwdriver to slightly turn the oil pump shaft until it lines up. The position of the oil pump shaft does not matter.

I ended up changing plugs and wires; with everything apart it was easier now than later. The plugs looked bad (truck has been sitting for 4 years) plus I took them all out anyway to make turning the engine to TDC easier. The gaps were way off. I also broke a wire pulling it off, so new wires became a necessity.

I planned on changing the coolant anyway, but removal of the lower intake manifold made it a requirement.

Finding quality, inexpensive gaskets was difficult, at least for the intake. Autozone has a kit, but its $100. I ended up getting a Fel-Pro (Federal Mogul, made in US & Germany) kit for $65. I also bought a new coolant temp sensor since the access is very easy now.

Since I started the project of reviving our old Explorer Limited, which has sat for 4+ years, (and it ran right before this project) here is what I have done:

New RF brake line, new RR brake line, bleed job, new fluid
New power steering pump & pulley
New belt tensioner pulley
New CMP sensor & synch shaft
New upper & lower intake manifold gaskets, new valve cover gaskets
New Peak coolant
New spark plugs & wires
New coolant temp sensor
Oil & filter change
New battery

It will also need 4 new tires before I can drive it again, but including the tires I think I'll have less than a grand into it. Although its not remotely in the league of, say our Land Rover LR3, to be able to have a decent and reliable vehicle for less than 1k I think is a good deal. Hopefully I'll have this running by Monday and post how it all went back together and ran. Then, anyone considering doing this on a 4L OHV V6 will have a bit more guidance.

 

[troverman]

OK, job complete! I finished it up on Saturday.

Whatever the FSM above is saying, is either inaccurate or doesn't apply to the way I did it. Basically, if you position the engine at TDC, the alignment tool will fit right over the sync with the arrow in the tool sitting on the block center line and pointing towards the firewall. Simply pull the old sync out, then put the tool on the new sync and insert it into place, with the tool arrow pointing to the firewall while sitting on the engine center line. If you do this, of course the new one goes in the same way the old went out and all is fine!

I did manage to lose two valve cover screws on one side, but I tightened it down anyway and no leaks for now. I'll be getting two new screws to finish that up. The engine starts quicker and seems to run very smoothly, no squeaks for now!

A lot of work to clear up an engine squeak, but imagine what a dealer would have charged?

 

[johnhopthrow]

here's a stupid question guys. where exactly is the cam sensor located on a 98' 4.0L pushrod????? confused because i would assume it was above #1 which is in the front passenger side. but i have also heard that it is in the rear on this size engine. any help would be great. thanks

 

[justanother1]

The cam sensor on a pushrod 4.0 is at the back. It is behind the intake. It is where the distributor would be if we had one.

 

[CHEESYPOOFS]

ugh... this thread makes my head hurt

 

[Cobraguy]

Whatever the FSM above is saying, is either inaccurate or doesn't apply to the way I did it. Basically, if you position the engine at TDC, the alignment tool will fit right over the sync with the arrow in the tool sitting on the block center line and pointing towards the firewall.

If you put the engine on TDC compression, the instructions are dead on the money correct. You should be 15 degrees off center towards the firewall. If you aren't, a couple of possibilities: (1) Your harmonic balancer has slipped (if you used that to determine TDC) (2) your synch is in off one tooth...which I'm not sure would cause a huge issue. There seems to be some mystery around just how critical this adjustment is. Regardless, if you put the new one in exactly as the old one was installed, you should get the exact same performance you had.

 

[troverman]

15 degrees isn't a lot. However, I am fairly positive it was at TDC compression. Since I had to remove the lower intake manifold to access the sync, that required me to remove the valve covers. So I cranked the engine over and watched the valves on #1. When they were both closed w/ no overlap, I knew I was at TDC; then I looked down at the mark on the balancer and it lined up w/ the pointer. Anyway, as Cobraguy says, if it goes back in the same way it went out then you can't go wrong.

Well, its been a few weeks and its still running fine, no squeaks, no loss of power, and smoother than ever.

 

[bad1891]

Cam sensor

I was reading your post on a similar subject "cam sensor" removal/installation. My problem started with a poor idle/stalling issue, codes indicated a defective cam sensor. When I pulled the cam sensor out I removed the facing to see inside and noted the sync position, when I installed the new cam sensor it took me several tries to get it back to the same position. (I didn't use a cam position tool). I started the engine it idles at 700rpm after talking to a ford mechanic they said I got lucky... it either works or doesn't. With the exception of the idle at 700rpm, I also have a pause prior to acceleration. I've adjusted the idle screw to achieve 900 rpm (should be 1000rpm). I still have a slight pause prior to acceleration and when I first start it up the engine pulses from 700 to 1000rpm. After awhile it stays at 800rpm other then that it runs fine... Do you have any recommendations as to why it pulses or pauses during acceleration?

Thanks for your time,
Bruce