Timing Chain question

So I'm replacing my water pump relatively soon, and I'm seriously thinking I should replace my timing chain. Is there any way to check the timing chain without fully taking it all apart. The Comet is my DD so I can't afford any downtime beyond a weekend.

The next question is, I'm planning on buying a new distributor after the new years, as well as replacing the timing pointer that either was removed or rusted off or something. Should I just wait until the spring and focus on what I know is broken with regards to replacing the timing chain?

The car runs great but it has these little niggling issues that say to me, your timing chain is loose. Also, my water pump gasket failed in a location thats been dripping water through the timing chain set and out the bottom of the cover.

 

If it's still the factory one, get it out of there, and nows the time to do it. The Summit brand ones are made by Coyles, they are one of the best.

 

Ah man!! I just replaced my waterpump "leak @ weephole", it did not occur to me to replace the timing chain. I had to ps and ac comp out of the way. Wish I had read this B4 the repair. Might be the source of my car not wanting to idle right.
May have to go back and do it anyway...How do u tell if the chain needs replacement?

 

You could try this. http://www.ehow.com/how_7523191_check-timing-chain-car.html Sounds like it would give you an idea. Assume you'll use the harmonic balancer timing marks, not a degree wheel.

 

easist way to check is to remove the mechanical fuel pump and use a magnet and flashlight. A clotheshanger with small hook on the end works too. Then just turn the balancer back and forth the check the amount of slack created.

 

checking

The easiest and fastest way to check your timing chain is to remove the distributor cap mark the position of the rotor put a wrench on the crank damper bolt and turn the engine one direction until the rotor starts to move and stop then turn the crank the opposite way until the rotor starts to turn. there should be no backlash or free movement that the distributor does not rotate at the same time as the crank. the factory used a plastic coated gear for the camshaft and the plastic is prone to breaking off. this creates alot of backlash and timing variation.

 

Here's an even easier way: Remove the distributor cap, then using a breaker bar and 15/16" socket, turn the crank back anad forth and note how far the crank turns before there's movement in the distributor rotor. One quarter turn of the crank is one full cylinder's movement in the firing order. If it turns even half that, the timing set needs to be replaced. I for one would not go blindly into removing the timing cover on an assembled engine without first making sure it was necessary to do so first. Seen many a 302 with those oilpan gasket corners cut and pasted with the timing set gasket pieces that leaked like a sieve. The front seal also needs to be changed while the cover is off. Then it needs to be properly aligned with the crank when putting the cover back on. (unless it's got the block alignement dowels used after 1980)

 

yep.. that works too of course. But the issue with doing that test specifically for timing chain slop analysis is that you're also checking the wear between the 2 gears(disty and cam) as well which can be misleading as to the amount of the timing chain slop. I like to just pull the disty whenever I'm suspect of that stuff and turn the crank as mentioned to see what the cam gear does as you go back and forth. Then you get clear views of everything involved there. It's usually cumulative wear of all parts involved.

I think it's a matter of checking many variables and see where you end up.

Another helpful hint is to check the disty gear to disty housing clearance while you're at it. Those things are notorious for being sloppy(I've seen some with well more than .060 thou clearance) and shimming alone can reduce a bit of spark scatter on ocassion. I even shim many of the new disty's I buy since they start out on the loose end of the scale and end up even worse over time. I don't like much more than about 10 thou there or the disty gear rides up and down the cam gear too much for my taste(which of course causes the rotors phasing to change in an inconsistent manner, however slight it may be). When you add all the variables up.. spark scatter occurs more often than most realize.

 

Or turn the crank counter-clockwise to get the slack out of the far side of the chain and use the clotheshanger wire to move the near side of the chain back and forth. Total movement should not exceed 1/2". Just watch and measure the movement on the end of your wire.

 

Would anyone care to suggest a list of things I need to have purchased before attempting this?

 

With the method I posted, just a breaker bar and 15/16 socket. If you're doing the timing set, you'll need that (I'd just go get a stock O.E. double row, roller chain set for a late 80's HO 5.0) plus a "timing set" gasket set (this should have all the gaskets you'll need to do the job), you'll also need a balancer puller and an front seal alignment tool, if your's doesn;t have the block alignment dowels on the bottom front bolts on the timing cover. You will also need oil and a filter to change the oil afterwards. It will also be a good time to replace the antifreeze with a fresh mix.

 

Thanks, lots to think about there.

And, I've got the stock motor, would a late 80s 5.0 HO timing set really work?

 

Yes, the blocks are all the same as far as the timing set goes.

 

That's awesome. Thanks for all the information I've got a bit to think over.