I have a backfire in the exhaust, not through the carberator at all rpms. Started at square one with firing order and plug wires. Found that the wires are off by one post but the car was running and decently minus the backfire. Switched to normal location and it won't fire. Returned the wires to one post off and checked timing. According to my light, I was 53 degrees BTDC on base timing?!?!? Adjusted to 11 degrees and the engine ran terribly, no throttle response and wanting to die. Brought to TDC 1 and pulled the cap, I am dead center between what is now 1 & 2 (remember the wires are all one hole off in the clockwise direction). Where do you recommend I go from here?
Timing problems?!?
- Thread starter Jshock
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I have seen where the harmonic balancer will shift on the rubber making your timing marks on it incorrect. That could help explain the 53 btdc. I supposed you have thought about it, but it is possible that you have a burnt exhaust valve. Or, an exhaust leak at a manifold or shortly down stream with improper a/f could cause unburned fuel to ignite in the exhaust causing the backfire.
The balancer is brand new because my old one did that. I upgraded from a 6 to an 8" with matching timing tab. One tooth off can normally be corrected by just adjusting the advance right? I'll reset the dist tonite and try again. The exhaust leak sounds like a possibility, the valves are brand new when I got the heads surfaced a couple months back so I hope they aren't burnt. Thanks for the help guys, I don't know why an easy carb and hei system ate kicking my butt but I've been out of the mechanics game for a bit. Just rusty?
I would do it the right way. Get it on tdc, and pull the dist. cap. The rotor should be pointing at number 1 cylinder. If not pull the dist, and turn it around til it is. check your firing order going clockwise around the dist. cap. Then crank it up with the vac, advance disconnected, and time it. I usually set mine at 8* advanced for base timing.
Sounds like you got pretty deep into that motor, did you have the cam out? I've seen motors off on cam timing act like what your describing. Remember the timing mark on the balancer relates to the crank location but your timing light shows ( in a way) cam location
So I reset the distributor, and re timed it. It runs better the more advanced still. Now sitting at 13 degrees but the dist is maxed out because the vacuum valve hits the intake. Now here's the second problem. The cam was degreed when installed and the chain marked with the recommended 2degree advance. Unless I jumped a tooth that should still be okay. After timing it, I had to adjust idle from almost not running to the usual 800-900, but as soon as I plugged vacuum back in the rpm skyrocketed to 2200. I've never had this much of an issue timing a car ever. I also now know I need a carb spacer because its boiling fuel in the bowls and now it diesels when shut down. (Thank god for the in gear trick)
Since you have a performance cam, the stock timing specs. go out the window. Are you using a stock hei dist? The advance can could be bad on it, causing it to go full advance as soon as you hook it up. I have had that happen before. Also make sure the weights in the dist. are free and not bound up.
What type of motor and cam?
How did you set the valves?
If your in the area with the timing it wont pop it will just run like sh*t.
How did you set the valves?
If your in the area with the timing it wont pop it will just run like sh*t.
The valves are good and the engine a 355 sbc. It runs like a champ with vacuum advance, and runs okay at base timing but I can't figure out the changes and why I have to run 50 degrees of timing to make it run right. As for stock timing, supposed to be 8-10 and I have it at 13 right now. I'm gonna try a new distributor and ill get back to you guys. Thanks for all the help!
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