How can I tell if my timing chain needs to be changed. At what mileage have others changed theirs?

The truck is an 89 bronco w/ 302.

Thanks,
Brian

 

I just changed mine on my 92 Bronco at 189,000 miles. It was past the 1/2 inch deflection limit. Depending on your mileage, I'd say it's about time.

 

you can check the amount of wear preaty easily. you should check your haynes manual for more info. you basicly turn it to TDC, turn 20degress counterclockwise, bring back to TDC, the start to turn it again but stop once you see the slight movement on the distributor rotor. then you can reed to amount of degrees that the slack alows. the haynes manual says that over 5 points means you need a new timming chain. like i said check the haynes manual, i said that off the top of my head

 

Mine had about 8 to 9 % slop in it so I replaced it last Winter with about 225,000. Has run great ever since. That is, other than the regular knick knack crap that tends to go on these Bronco's.

 

well as i was told way back and i beleive and follow
t. belt 50,000
fiber t. gears 75,000
chain 100,000
then again 24 years later when i got my 78 it still had the original t. chain god knows how many miles of course when i buy a old verihickle i pull the timing mech
my 79 bronc was rebuilt low miles and what kind of idiot would re-use the original t.chain in a rebuild(not long til i will change it)

 

The general "thinking" is if you put a wrench on your crankshaft bolt, turn it one way until you feel the crank/pistons move. Then you go back the other way and feel them move. If it is over 1/2 inch your belt needs to be replaced.
that said.
A few months ago, I over revved an engine, and the timing chain stretched and flipped over a couple of teeth. ie, bad. and I replaced it because that is a bad thing to happen. It had 50 miles on it.
Personally, I replace the things with new Ford Racing gears and double roller chains. For a couple of bucks more then store bought. I want heavy duty.
Bruce (Big Red Bronco)

 

Thanks for the responses. I think that I am going to try one or more of the tests that were reccommended and make a decision from there. The reason I ask is because there is a rattling noise coming off the front of the engine that did not go away with a new watter pump. Runs good otherwise. Oh yeah, it is at 145K miles.

Thanks again,
Brian

 

That rattling is probably the two piece fuel pump eccentric. Obviously it's not used on this motor, but for some reason Ford leaves them on. The outer ring is pretty loose and will rattle.

When I changed my timing, I left the outer ring off so it wouldn't rattle anymore. The inner piece is used as a washer for the camshaft gear bolt so you need to leave it on. It's been quiet ever since.