Rear timing chain cassette - Removal questions

Unfortunately, when I got everything back together after replacing the front primary timing chain and the left cassette on my 02 4.0L I had this weird suspicion that I wasn't done yet. Even after replacing the right camshaft (another story) I thought I was ready to time the camshafts and call it good.

For some reason, and I don't know why I didn't even look at doing this to begin with, I stuck my fingers down inside the back side of the right cylinder head and gently poked around to make sure there was no damage to the back timing chain cassette. To my surprise, the rear cassette had been broken all along!! I had been absolutely, unbelieveably careful to not even create tension on the back chain. To then find out it was broken in half to begin with just about set me off!! Now I'm into this thing all the way. The engines coming out baby!

After reading all the posts, I can't tell if it is necessary to undo the rear jack shaft sprocket bolt just to simply replace the rear timing cassette. It looks like a near impossible job (from the pictures) to replace the rear jackshaft sprocket and chain, though.

I also believe that you DO NOT have to take off the head to replace the rear timing chain cassette.

Do I have both of these things right?

Thanks guys! I promise that when I have this whole thing back together, I have learned a few tips along the way that will be helpful for the next poor chap who has to go through this

head removal?

It is not necessary to remove either the left or right head to replace any timing chain related component on the SOHC V6.

It is necessary to undo the rear jack shaft sprocket bolt to replace the rear timing cassette.

SOHC V6 Engine Removal Procedure

SOHC V6 Rear Cassette Replacement

Replacing the rear cassette is not that difficult using the OTC 6488 tool set.

If the right cassette broke and the chain jumped timing you may be looking at a valve job.

Engine will have to be removed either way for repair!

Thanks Dale and CJ!

Actually, the reason why I asked if the right head had to come off for this procedure is that I've already had it off once I checked the valves then and they were all good, so I was pretty certain that if somehow the timing chain jumped a tooth on the right camshaft sprocket and over torqued the cassette (causing it to break) at least it didn't cause a valve and piston collision in the right bank. I might have dodged the big bullet on that one.

I THINK I'm ready to take the engine out and get all the cassette/timing chain work done. Just waiting to have a couple of open days to do the job. What a process!

Dale, your step by step pictorial on how to remove the engine is superb! Thank you Sir!

i have a 2000 ford explorer and need to know if i have to take engine out to fix rear cassette and chain or can i take off transmission instead ? because only the cassette is broken,happened when replacing heads on both sides.

Up 2 U

The trans has to come out. The job can be done with engine in but it will be tight working on the job at hand. Also your right head may have bent valves. Did you do a compression test?

remove engine or transmission

Why does the engine need to be removed when replacing the timing chains?

what is the name of the cap or part number for the cap that you must take off in order to access the bottom bolt of the rh timing cassette?