[Stratdeath]

I have a 79' 302 engine that came with the vehicle i purchased. This engine was rebuilt as the owner told me. The problem I am having is that when timing the engine it only runs smoothly at about 35 degrees. If you bring it out of that range, say to 12 degrees or 0, it begins to make a sound once every cycle like something is hitting something (maybe a piston hitting a valve?) At 35 degrees, the engine runs pretty smoothly with no problems. I believe it has good compression etc. What do you think is wrong ?
I just took the timing cover off to see if the sprokets were misaligned but they were fine.
Any ideas?

[Veronica]

Hello.Adjusting the timing by rotating the distributor does not have any effect on the valves or the pistons.What has probably happened is that the outer section of the balancer has slipped around some.Locate top dead center manually by removing the #1 spark plug and rotate the crankshaft with a wrench by the big bolt head in the middle of the balancer(remove the coil wire first) until the #1 piston is at the top of it's travel and look at your timing marks to see what they say.Odds are that when you are at top dead center your balancer will say that you are at about 25 degrees before top dead center.Hope that helps.

[70Mach03]

First off, I agree with what Veronica says above .

Couple of comments, first how many miles on the motor and has the timing chain been replaced? I’ve noticed that the 289/302 motors have a timing chain life of around 140,000 miles. While they won’t always break, they will stretch and as they do your timing will retard. You’ll find yourself advancing it more and more to receive the same performance. Eventually they can stretch enough to jump a couple of teeth if not checked and replaced. This happened to me years ago. When it was replaced with the proper sprocket alignment, my initial timing was way off advanced probably 20 degrees or more. Once I set it back to a more normal setting, it felt like an additional 20 hp. My loss had been so slight over the years I never noticed till it was replaced.

Second, I’ve never done it but I have heard that it is possible to have the distributor off a tooth or so and still run. When the #1 piston is at the top of it travel, the rotor in the distributor should also be pointing to the number 1 position on the distributor cap itself. Of course you’ll have to remove the cap to see it but it's another way to check. Good Luck. :thumbup