I would like to hear of the symptoms you guys experianced. I know the textbook symptoms, but I would like to hear real experiances.

 

Here's an easy way to check the slack in the chain: take a breaker bar and 15/16" socket to the center bolt on the crank. Remove the distributor cap. Using the breaker bar, rotate the crank back and forth and take note as to how far the crank moves before you see the distributor rotor move. I don't have a spec as how far is too much, but I'd say if you can move the crank more than 10-15* I'd replace the timing set pronto. 90* movement of the crank is one full cylinder in the firing order.

 

The worst I've seen I could actually hear the chain slapping the timing cover. When I got into it, there was a large hole worn in the cover.

On average, I think symptoms would be less noticeable. The cam would retard a small amount due to chain stretch. Might notice a loss in low end torque...

I'm thinking out loud here, I dunno. I was surprised to find how loose my last one was as everything was running well.

 

what they said ^
ive had some so bad that you can hear the chain slapping around

baddad has a great idea ive never thought of that!
good luck!

 

In addition to the above, a wandering idle is a clue. The idle deteriorates to the point of almost stalling, then snaps back to normal. This is the result of the cam and ignition timing moving in and out of the "normal" range.

 

can this affect gas mileage?

 

Definately, as it affects the valve timing events. At worst it can jump time and quit running altogether.

 

i ask because im getting about 6-9 mpg and my timing chain has about 1/4 inch plus (hard to tell haven't put a tape on it but its loose) of play and i think this is why my motor surges a little and im hoping its the cause of my horrible mileage .also gonna replace O2 sensor

 

Pull the distributor cap, put a breaker bar and 15/16 socket on the center bolt on the front of the crank, then while watching the distributor rotor, rotate the crank back and forth and take note as to how far the crank moves before the rotor does. 90* rotation of the crank is one full cylinder in the firing order, so you don't want the crank moving far before the distributor rotor does. The amount of movement before the rotor moves will give you an idea as to how much slack there is in the timing chain

 

I had a crummy import car once that had a very worn roller timing chain, which I could tell by the sound of it striking the timing cover.

It was so worn that I was able to shorten it by two links and reinstall it, fixing(!) the problem.

This was a beater that I was "driving into the ground" as they say, so I wasn't prepared to buy parts for it.

 

so i replaced my timing chain ..it was loose but not to bad ..i was replacing the water pump to begin with so i thought id hit two birds with one stone...one thing i did notice today...my SPOUT connector was gone..i guess the last owner lost it or something so thats half my problem right there. replaced everything and took it for a night run ..truck runs like a champ now.. gonna go do an mpg test then possibly the sixlitre tune

 

Baddad gave excellent advice.

For further reference...

If you can hardly turn it before the rotor starts to turn...excellent, 1/8 turn, or less slack is good...1/4 turn slack is barely OK, if not sloppy.

IMHO, guessing at it (which is what you are doing because you didn't really check it), I'd guess that the O2 sensors are a bigger part of the problem.

Also, TORQUE YOUR CRANK NUT!!! The slot in the pulley does NOT hold in place, it just indexes it. The nut keeps it from moving. If you don't get that nut tight enough...in 50K miles, or so, the key-way will be wallowed out, and possibly the crank ruint (a red-neck verb and/or adjective).

The way to torque your nut is to take a tie down strap...wrap it around the pulley, hook it on the frame and tighten it up....as it tightens, if will grab onto the pulley and keep it from turning. Everybody has a tie-down laying around the house.

I'd love to see baddad's opinion on how much you should be able to turn a crank before the rotor should start to turn.

 

A quarter turn of the crank is one full cylinder in the firing order, that is way too much, as would be 1/8 turn. The balancer is held in place with a 5/8NF bolt, not a nut. Never seen one "get loose" on it's own. The crank pulley is secured with 4 3/8" bolts to the balancer, never seen these "get loose" either.

 

I've had the crankshaft damper bolt come out but only once. I had been turning the engine over with a large ratchet and socket when working on it and then quit for the day.

A couple days later I noticed my socket wrench on the ground in the parking area, and next to it was the bolt. I had left the wrench on the bolt, so the next time that I started the car, the wrench handle spun around until it hit something, then unscrewed the bolt, and both fell on the ground without me noticing. The damper didn't loosen in the couple of days I drove it like that.

 

I hate it when that happens. It's a wonder it didn't break something