I have about 190,000 miles on the odometer (don't know if the engine has that much or not). While driving to work the engine just shut off. Sure enough the timing gear on the cam was wore out and the chain had started to come off it. I didn't hear any noises from the engine, it just cut off. However, after installing a new set of gears and chain I can't get it to run without popping and back firing through the carb. I've tried to set the distributor in by turning the engine over till the #1 piston is TDC but after multiple tries it still backfires (if it will even run - sometimes it won't stay running, sometimes it will). I hate to pull the engine out as it ran great and had 30+ psi oil pressure even when hot. Any suggestions what to check next (with the engine in the car) would be appreciated. PS. I'm sure we got the marks on the gears line up correctly as we messed with it awhile trying to insure it was dead on before pushing the cam gear on and putting the bolts in it. It was a zoom timing set with the 3 position bottom gear but we installed it in the center position since the computer still works on the car. Thanks for the help.

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81Z4ME

You sure the timing gear is installed correct?
You sure the dist. isint 180 degrees out?
I wouldnt pull the motor till i was sure
i needed to. You have the distr. on #1 on the compression stroke?

Try a compression test on all the cyls, chances are you bent some valves when the timing chain skipped.

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is it a stock motor?if not probrably bent valves is so may still be bent valves but unless the timing gears are 100% correct a compression test wont help much!

Yeah, you more than likely dinged a few valves crooked when the cam stopped spinning but the bottom end kept going a few revolutions.

A compression test WILL tell you which cyliner(s) you have bent valve(s) in. You'll have very low compression on those cylinders.

<font face="Arial,Verdana" size="2">Originally posted by Damon:
Yeah, you more than likely dinged a few valves crooked when the cam stopped spinning but the bottom end kept going a few revolutions.

A compression test WILL tell you which cyliner(s) you have bent valve(s) in. You'll have very low compression on those cylinders.</font>

yeah if compression is good on most and way off on a cuople that would tell ya what cyclinder.

Thanks for the replies. We fooled with the gears and chain a long time making sure the marks on the gears were lined up. It's still bone stock and the spark plugs are a pain to get to so the engine was difficult to turn over with a socket and breaker bar and it wanted to always go just past where we thought it out to be (to have the marks lined up when we slid the time gear on the cam) so we rocked it back and forth and put the timing gear on and off several times trying to make sure it was perfect. I hate to pull the spark plugs to check the compression as it is really rough getting my hands and arms down in there around all the wires, hoses, smog tubes, etc. Thanks again.

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81Z4ME

I'm with Mwilson on the dist. being 180* out.

This is a common problem only because a lot of people don't know that putting the cam gear and the crank gear "dot-to-dot" puts the #6 piston at TDC on the compression stroke, not the #1 piston.

The dots both have to be at the 12 o'clock position for the #1 piston to be at TDC on the compression stroke.

Using the "dot-to-dot" method does make it very easy to line the dots up, but I've yet to read a book or magazine article that points out that this is the #6 firing position.

1.) Pull the dist. out.

2.) Pull the #1 spark plug and stuff a piece of a paper towel into the hole. Make it big enough so it doesn't get sucked into the hole http://www.nastyz28.com/ubb/smile.gif.

3.) Turn the crankshaft by hand (or you can bump the starter little by little as long as your careful and have someone else to do it while you watch.)

4.) When the paper towel gets pushed out of the hole that means the #1 piston is on it's way to TDC on the compression stroke.

5.) Continue rotating the crank until the notch on your balancer is lined up with (or close to, by about 10*) the pointer on the timing cover.

6.) Drop in your dist. with the rotor pointing toward the #1 cylinder. Line up the cap accordingly and hook everything back up.

7.) Fire it up and see if that helped.

If not, the compression check and/or a leak down test is in order.

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