I've searched all over the web, but I have yet to find any discussion on this. Has anyone thought of using a manual chain tensioner (if such a thing existed) or having an old hydraulic unit machined to accept a threaded rod, thus making a manual out of a hydraulic unit? I've used manual cam chain tensioners many times on modern motocross bikes, and they work excellent. Is there any reason that would not work on the 4.0L? The adjustment rod would obviously need to be precision with an O-ring sealing the head. If it worked, the death rattle at start up would be nonexistent, as the chains would always be tensioned properly. Thoughts?

 

Welcome to the forum

I assume you mean the 4.0l SOHC engines long chain tensioners.

Ford's new 2003 tensioner design eliminated the issue for the most part, I still think you should change them at 80k miles

The 1997 to 2003 4.0l SOHC tensioners had a weak spring and it would break
On startup this would allow chains to beat on the Guides until oil pressure filled tensioners and tightened up the chain

If spring broke then over time the guides would break away from their mounts on startup
This is when the "rattle" starts, after a guide has broken
And it would then "rattle" after startup as well, mid-RPMs, damage is done

Not sure a manual tensioner would be an improvement over the newer design
But yes over the older design, lol.

Any engine with 2 long timing chains will have timing chain related problems, just the law of averages, lol

It wouldn't be to hard to design manual tensioners using a lock nut setup

 

Hi Ron, thanks for sharing your thoughts. Yes, talking about the 2 external tensioners. I installed both new OEM Ford units, but I still have the rattle at startup. I have no rattle after that, so I'd like to take care of this before it becomes a major problem. I used part #'s 7U3Z-6K254A and 7U3Z-6K254B. Can you tell me if those are the new design or old? I haven't been able to find any other Ford part #'s, so I assume these are all that are available and therefore most likely the "new" design. The top left side is quiet, but the lower right side makes a good rattle until oil pressure builds. I know about depressing the accelerator for 5-10 seconds, which shut off the injectors while oil pressure builds, but I don't really like doing that. I've looked at motorized pumps to build pressure as well. It just seems like the easy and obvious way would be to manually keep tension on the chains.

 

You have a broke guide, that's why its rattling on startup
Engine didn't rattle from loose tension, repeated loose tension startups caused chain to break a guide, and THEN you get the rattle

Once engine is running you should be OK but guide can get worse, no crystal ball here

There are no old tensioners out there, anything you get will be the new ones

You do need to soak them in oil, prime them, prior to install or first start will make a bit of noise, not a rattle, but after that no noise on start up

Once guide is broken a manual tensioner would just break it more if adjusted too tight, which might eliminate the rattle temporally, then it would come back even worse