cam chain cassette

[TJ Sport]

The cam chain guide on the left head of the 4.0L in my 2003 Sport Trac has broken apart and is lying in pieces in the chain well. Is it possible to change the cam chain cassette in-vehicle?

 

[koda2000]

From what I've read here, the front cassette can be changed with the engine in the truck. It's a pretty big job and it requires special tools to hold the cam in the right position.

 

[TJ Sport]

Thanks, koda. My Haynes manual shows the special tools. I'll continue taking the engine apart. NAPA is pretty good here for special tools. If not, there is always Amazon.

 

[TJ Sport]

Left head cam chain is replaced, along with the jackshaft chain and the guides and tensioners for both. Truck runs great! Better than at any time since we bought it.
Funny thing, the crankshaft timing sprocket had been installed backwards at some time, and the jackshaft chain was eating its way through the guide and backplate. The guide for the camshaft had completely disintegrated and ended up in the oil pan and oil pickup screen.
Helpful hints: the valve spring compressor i bought online (OTC #7928 ) only works on two valves as it comes assembled. I had to punch out the roll pin at the hinge point and install the tool in two pieces, and use an allen wrench as the hinge pin. It worked fine on all the valves this way. Also, when installing the front engine cover over the jackshaft chain, install the harmonic balancer before torquing the perimeter bolts for the cover. This centers the main front seal for the crankshaft.
This is a long, tedious project and I'm lucky to be retired and have the time to do it.