Thanks for all the replies, the original cam gear had plastic teeth, did I read that right....I don't just hear it on start up, I hear it slapping continously, but I don't know how to record and post on here. Recording the sound probally wouldnt help much anyway, since I recently acquired this truck, I've discovered lots of little surprises, Believe Me, I'll be in touch Thanks again.

 

 

Honestly you shouldn't wait. If it's worn out you may jump a tooth on one of the gears... Would t be much of a problem, truck will run a little worse but will run. But if it's that loose and skips you may shear the tip off a tooth. Doesn't happen alot but it has happened. But on the bad end of things.... The chain breaks, camshaft stops turning and you run a piston or 3 Into some valves. I guess at that point you could get away with buying a junkyard motor for 3 to 400 and spend less then buying a timing set water pump tensioner gaskets etc. It's kind of a critical piece of the engine that can lead to true catastrophic failure. Look at Hughesengines.com. they have alot of parts for the la engines and magnums. Cloyes timing sets are great, however hughes has timing sets that have a bit of extra work put into them that make them stronger and more reliable, mainly on the gears.

 

that you tube vid does show a double roller chain even.... wow. Even among double rollers "they aren't all the same". that chain had been replaced at least once, as stock weren't double roller chain.
being yours is an 88 (and pre magnum engine) it may have had plastic teeth on the cam gear but all Magnums came with steel teeth on the gears, but didn't come with the double roller style.

IDK if you knew this, but the 3.9s wear out timing chains a LOT more than the V8s did... that's because they are an "odd fire" design. the spark from 1 cylinder to the next fires 112* after the last one, then 128* to the next cylinder, then 112*, then 128* instead of an even 120* from one cylinder to the next the V8s are an even 90* from one cylinder firing to the next. the difference in how many crank rotating degrees between one cylinder firing and the next gives you that slight "roughness" that all the 3.9s have as well... this is designed in nothing you can do about it. Back when the 3.9 was still a current production engine you could tell one when you pulled up next to it because of that slight roughness and after ~125k miles often you could hear that timing chain dragging the inside of the cover, which would sound like a chain being dragged behind as you would drive other than that they were pretty much bulletproof engines, even though they were slightly underpowered.

 

If you have enough miles, you MAY want to replace the timing chain cover ALSO.

Mine never scraped, but I did replace it because of my cousin, Justin. (He's my aunt Petunia Case's son.)

RwP