How loose is too loose of a timing chain?

Cougar Community Classic Cougar Maintenance Restoration and Repair
1

[390GT 68 cougar]

Hi there, here an underview of my timing set after removing the oil pan. The chain seems really loose but im scared to try and replace it, mess it up and have the car in the garage for a while.. lots of events to attend to some of them are 1200miles long road trips.

Can it be ran at least this year ?

2

You should go ahead and replace it as you are this close

3

I wouldn’t call it “close” As I still would need to remove the fan/shroud, maybe even radiator and then water pump and all… not to mention the whole “pulling the damper” situation… I’ve never done it before so I’m pretty intimidated since it’s about the internals.

4

I understand if you don’t do a lot of this type of work. Can you see the teeth on the cam gear? Ford used a nylon covered cam gear for a few years, for “quiet “ performance. The nylon teeth fall off, the chain slips and then valves and pistons make contact. Otherwise known as catastrophic failure and planned obsolescence. You buy a new car instead of the expensive repair. You can rent the expensive tools. And as long as the timing marks “ dot to dot” you should be fine.

5

It appears to already have an aftermarket timing chain the non nylon ones. previous owner states he rebuilt the engine 18 years ago.

I’m gonna try and find TDC first before opening it up then. i’ll use the thumb method to make sure my mark is correct on the damper.

6

For sure you have a double roller timing chain, so it has been changed at some point.

7

I know we can’t see much, but does it seem to loose for you ? I don’t know how tight it’s supposed to be when freshly installed.

8

That does look pretty loose although hard to gage just how much movement from your video of slapping the chain - also can’t see if you’ve pre-tensioned the other side or not.

Ordinarily I verify by measuring the lateral (side to side) distance the chain moves during assembly (if I remember correctly my 67 Cougar manual illustrates and specifies in this manner, 1/2 inch?). Given your timing cover is still on, this method probably won’t work for you unless you’ve got a pretty good calibrated eyeball…

Without pulling the cover you can verify in terms of the mechanical “dead spot” method as indicated in crank degrees:

  1. Rotate the balancer to position indicator tab on cover and balancer scale without changing direction (important - this will keep one side tensioned). Pick something on the ATDC side.
  2. Pull the distributor cap and note rotor position.
  3. Now reverse the rotation of the balancer and stop when movement of the distributor rotor can be seen.
  4. Calculate the difference in crank degrees.

Not sure what is truly acceptable for an FE but probably in the 7 to 10 degree range max.

Of course there is the old school method using a timing light (w/vacuum advance disconnected) but this is arguable far less accurate.

Note: I will say that I have only ever had one double roller set that appeared as loose as what yours appears to be. That was observed with a new chain set on a block that had been (excessively) align bored/honed during the maching process which had reduced the center-to-center distance between the cam and crank shaft centerlines). That was corrected by purchasing a special reduced spacing set (FORD Cloyes Gear 9-3608X9-5 Cloyes Race Billet True Roller Timing Sets | Summit Racing). I mention this only as something to verify should you go down the replacement route to ensure you buy the correct chain set.

Hope this helps.