Another busted valve spring

[Paul Yeager]

A week ago, my 2002 4.0 SOHC Explorer started running quite raggedy. The OBD code indicated a misfire on cylinder 2.

I stopped by a local auto parts store to pick up an ignition tester, which indicated that I had spark to that cylinder. I really wish that had at this point done a compression test. Instead, falling prey to wishful thinking, I concluded that the injector must have failed.

So I replaced the #2 injector, and while I had the intake manifold off, replaced the driver side valve cover gasket, which was leaking. Put it all back together, and after several hours of work, no improvement.

Now, I did the compression test that I wish I had done first. Zero. Zip.Zilch. Nada. I concluded I had a valve problem. Off came the intake manifold again.

When I went to remove the passenger side valve cover, I discovered that the EGR tube was in the way. Oh joy! So easy to get to. Not! A couple of open end wrenches just didn't allow me to get enough torque on the flare nut attaching the EGR tube to the fitting on the exhaust manifold.

A crowsfoot wrench seemed the obvious solution, but they are as rare as hen's teeth out here in the mountains. I ordered one, and while waiting for it to arrive I periodically sprayed the fittreplacingBlaster.

The crowsfoot arrived, and the compression nut on the EGR tube yielded. I was finally able to get the EGR tube out of the way and remove the valve cover.

Once I had access, I discovered that I could depress the #2 intake valve with my finger, and there was a crazy amount of play in the rocker for that valve.

So, there is my tale of woe. Does anyone have any advice on replacing a valve spring in this engine, preferably without removing the head?

Thanks!

 

[TechGuru]

Get a air compressor adapter to connect to the spark plug hole for that cylinder, the constant air pressure will hold the valve while you swap out the spring.

I believe all valve springs are supposed to be replaced together so they're a matched set.

http://www.rockauto.com/en/catalog/ford,2003,explorer,4.0l+v6,1414493,engine,valve+spring,5792

$5.79 x 12 = $69.48

 

[Paul Yeager]

Get a air compressor adapter to connect to the spark plug hole for that cylinder, the constant air pressure will hold the valve while you swap out the spring.

I believe all valve springs are supposed to be replaced together so they're a matched set.

http://www.rockauto.com/en/catalog/ford,2003,explorer,4.0l+v6,1414493,engine,valve+spring,5792

$5.79 x 12 = $69.48

Thanks! That was just the sort of info I was hoping to find.

 

[TechGuru]

The only potential problem I see is finding a spring compressor that will fit to do the rear most springs.

 

[imp]

The only potential problem I see is finding a spring compressor that will fit to do the rear most springs.

I'm lazy, but hate to interrupt good thinking.......my view is, I'd replace the one valve spring, assuming the new spring can be successfully compressed where it's located. Have not heard of any rash of broken springs in this engine. Kinda depends on how many miles are on the engine. Just my thoughts. imp

 

[drdoom]

There is a special Ford spring compressor for that engine, other types will not work IIRC.
It is very expensive.

 

[Paul Yeager]

Many thanks to all who responded. Here is what has happened.

I was able to replace the broken valve with the head in place, by pressurizing the cylinder with compressed air. A few tablespoons of motor oil and a few revolutions with the starter helped to reduce air consumption.

While I did not buy the special tool for compressing the valve spring, I highly recommend that to anyone who has to replace a valve spring. What I did worked, but was a large pain in the posterior.

What I did was wrap the shank of an open end 5/8 inch wrench with tape, placed the head of the wrench on the valve spring washer, and used the cam lobe as a fulcrum to lever the spring down so that the keepers could be installed. This is a two man procedure - one to compress the spring and another to place the keepers. It is not trivial - I probably compressed that spring at least a dozen times to get both keepers installed.

Summary: I got it done with the head on the engine using compressed air to hold the valve in place. I highly recommend the tool made for compressing the spring, which.I have recently seen on eBay for $90.

And... don't forget to book up all the spark plug wires! These engines don't much want to start on three cylinders.

 

[imp]

Many thanks to all who responded. Here is what has happened.

I was able to replace the broken valve with the head in place, by pressurizing the cylinder with compressed air. A few tablespoons of motor oil and a few revolutions with the starter helped to reduce air consumption.
.

@Paul Yeager I had to look at this several times! Could not figger out how you replaced a broken valve without removing the head! Then came the dawn, reading backwards.....broken SPRING!

Glad you got it OK! imp