So I pulled this from underneath my valve cover today...

[Ck111484]

Was cleaning off the gasket surface as I was replacing a cracked passenger side valve cover, and all of a sudden I find myself holding this...

That's a piece of one of the guides that you have to remove the engine to replace, right?

Well, what if I just changed that tensioner, put everything together and drove the car? Obviously it'd be a constant risk, but I'm just curious; like, do you NEED that guide?
The whole time I've had the car it's rattled pretty loud, but it still ran.

 

[2000StreetRod]

curved guide

As you can see in the photo below the guide is curved on both the traction and the slack (spring/hydraulic tensioner) side.

The curve increases tension on the chain. Ford reinforced the slack side with metal but not the traction side. I doubt that the tensioner will be able to make the chain taught with the traction side missing. The chain has probably been "slapping" against the guide post and wearing it down.

Eventually the chain will slip and camshaft timing will be lost. The SOHC V6 is an interference engine and the pistons can strike the valves when the camshaft timing is lost.

The most likely time for the chain to slip is when oil pressure is low or when the engine is rapidly decelerating and the traction side becomes the slack side. It is necessary to remove the engine (preferred) or the transmission to replace the right cassette. With a broken guide just replacing the tensioner is probably a waste of timing and money. If you continue driving the vehicle as it is I suggest that you have good road towing service on your auto insurance.

 

[Anime]

You NEED the guide.

If you plan to keep the vehicle, now is the time to change out the timing and cam chains and hardware, whether you DIY or have a shop do the work.

 

[Ck111484]

So, cost prohibitive to even do?
Got it.

God, these motors suck. I bought this car for $1,600 as my first "flip"; I was told by the previous owner it just need a driver's side tensioner, which after searching online, seemed reasonable. Figured I could change that out, clean it up (I work at a detail shop) and flip it for a grand or two.
Changing that front tensioner had zero effect on the clatter (now I know why), it was an absolute nightmare to fix, and the damn thing hasn't run right once.

I'm not sure what I'll do now; I already swapped in a nice set of black leather seats, and have spent quite a bit on odds and ends to make it look nice. It'd make a killer shell, that's for sure, but no matter what I do I'm going to lose some money and at best, come out even.

4.0 SOHC: never again.

 

[Ck111484]

One thing I will say; that chain is still very tight, there's no way I could "untooth" it by hand, even by prying.

 

[2000StreetRod]

Usually a reason

. . . I bought this car for $1,600 as my first "flip"; I was told by the previous owner it just need a driver's side tensioner, which after searching online, seemed reasonable. Figured I could change that out, clean it up (I work at a detail shop) and flip it for a grand or two.

There's usually a reason when a used car is offered for $2K below normal value. The previous owner probably had an estimate from a mechanic to fix the problem. The only way you'd make money flipping the vehicle is doing the repairs yourself and using aftermarket parts. Special tools, knowledge, time and attention to detail are required to correctly replace the rear cassette (must pull the engine or transmission) and then time the camshafts. Most members just replace the engine from a lower mileage salvage yard engine.

The chain will tighten and loosen as the crankshaft rotates due to the valve spring pressure on the camshaft. Check the guide post for wear from chain "slap" which can only occur if the chain is loose at certain times.