rebuilt 302 not firing all cylinders HELP!!!

[Fairlane514]

Question…….are the spark plug wires a universal set, where you had to terminate the ends yourself, or ready to run?

 

[mcknight77]

This times ten.

Also, I had a few GM guys call me after wiring Fords looking for help. This was touched in a previous post regarding Ford's cylinder numbering vs. GM's odd and even.

GM's spin clockwise for dizzy, Ford's are CC at least where we're concerned.

Also, switch out the HB and flywheel to the proper balance. Your fillings will thank you. I've run across this several times on older swaps, even a newer 5L. Rev the car up and she vibrates like a driveshaft out of balance, yet the vehicle was stationary.


I've also had a 351 come in running on 4cyls in the past, turns out, after doing what mck recommended, I found out someone installed a different cam with 302 order. Never assume displacement dictates the firing order, someone may have swapped cams. Only way to know for sure is to turn the engine over without the valve covers on it.

You'll notice by looking at the diagram above that the firing orders, when compared to each other, have four cylinders switched with each other. If you have the firing order wrong it will fire four cylinders on the compression stroke and four on the overlap. All the plugs are firing, but four are firing at the wrong time. Sounds very much like your problem.

 

[DirtDonk]

And easy enough to verify the firing order of the cam with the old "finger-in-the-sparkplug-hole" routine.

With at least the number 1 and 3 and 5 spark plugs out, rotate the crankshaft clockwise by hand until you start to feel pressure build up under your finger tip (the one that's stuck in the plug hole! ;D) and watch for the timing marks to come up to the pointer.
Once you're at TDC on #1 cylinder, put your finger over number 3 hole and keep turning.
The next quarter turn will tell the tale. If you feel pressure build up under your finger on #3 within a quarter turn of the crank, you have the 351 firing order.

And I'm talking a decent amount of pressure against your finger tip. There is often some token pressure buildups at different points in the cycle, but when it's noticeably stronger, that's usually where your compression stroke is working.

Good luck.

Paul

 

[mcknight77]

Wonder if he got it fixed?