Bad Problem

Okay, I have a problem. I finally got up the courage to play with my ditributor/timing. Pulled the number one plug, got the piston to TDC and the rotor was pointing between #3 and 4. Okay, so that would make it run like crap.......right? So anyway, I pull the dizzy, re-install it with the rotor looking at #1, put the cap back on, and redo my plug wires. Went by a Chilton's just to be sure. Started trying to crank it....motor turns over, sounds normal.......just won't crank. Then it back-fires through the carb. Pretty solid back-fire. Does this about three times and I quit trying. Got scared of bending a valve. What's wrong??? Anybody have a clue?????? Please help! Thanks!! Preston

 

You might be 180 deg out (if you haven't tried that already).

Even though the piston was at TDC, it is possible it was on the exhaust stroke.

Try removing the dizzy and rotating it 180 deg first.

If that doesn't work, start from the beginning, pull number 1 plug, plug the hole with your finger, rotate crank until the compression blows your finger out of the hole (this is the only rush I get when working on an engine - besideds the carb cleaner thing). You KNOW you are on the compression stroke.

Go back through your dizzy installation, making sure that the rotor is pointing somewhere in the vicinity of #1 plug wire on cap.

Follow each wire individually. Rinse, lather and repeat.


Also, make certain you have the correct firing order for your year engine.

 

Thanks Rick.....heading back out to try this! Be back in a few! Preston

 

what is firing order? how can rotor point between 3 & 4 on a 15426378 order? or am i having a brain fade?

 

edit: let me get this straight
79-93 5.0

The firing order (counter clockwise) is 1,5,4,2,6,3,7,8 (vs. older 1,3,7,2,6,5,4,8)

 

Preston, here's the link to reading plugs we talked about.

http://www.dragstuff.com/techarticles/reading-spark-plugs.html



'Hope everything is going good for you now.

 

Is it possible your cam has a 351 W or 302 HO firing order?

 

I was wondering the same thing. I belive he said it was an '86 engine.

 

Well Rick, moved 2 back like we talked about, and it cranked and ran. (and decently too I might add.....) I had to leave and run to the ranch, but I'll put the timing light on it in the next day or so and set it correctly. BUT it is in the right ballpark now........now I just need to re-adjust my carb-and probably need to replace the power valve (don't know how to tell if it needs replacing) because she did some back-firing today..... Anyway, I really appreciate the help!!!! Preston

 

Backfire usually = blowed power valve.
If it smokes at idle, it's bad is a general rule of thumb

 

Hmmmm, then I must have one seriously tough power valve. No smoke at idle........and this thing back-fired HARD several times!! :?: I dunno.......thanks for the heads up on the symptoms though!! Preston

 

Excellent news!

Good luck with the carb.

 

Most the Holleys have a check ball to prevent the power valve from blowing.

 

I did the exact same thing a last year, and the backfires burned my foam air filter, but did not affect the carb. Runs great, even today. I think they might be making these carbs better these days. Mine is Edel 1406

 

Edelbrock's dont have powervalves so it won't do that.

Holly's now come w/ the check ball, but I've seen them fail several times on me.
You can add one to your older style holley also.