Buick 350 firing order help.....

So I am pretty excited about my recent find while doing my first tune-up on my 66 Skylark. When I bought it last August the seller told me it was a 310 Wildcat (the VIN number told me it was the 4.9L 300). No big deal. So I buy spark plugs and new wires last week and when I went to install the plugs they don't even come close to fitting. I have AC Delco R44TS's in there. Mmmmm....So now I get the numbers off the rear of the block and low and behold I have a 68-71 Buick 350. (not to shabby).

So back to my question. After doing the change out of new plugs and wires and new HEI distributor cap the car runs very rough and with less power (almost like running on 7 cylinders). No smoke is present and when I pulled the old plugs 3 of the tips looked like someone sprayed them with white paint, all other were normall.

If someone could please help me verify the firing order for my engine starting where the blue arrow is drawn on the picture going clockwise that would be awesome. Also whats your thought on the rough running? Maybe the timming is off....

Thanks.

 

Check the 350, bottom right

 

Firing order 1-8-4-3-6-5-7-2

If you changed the plug wires, hopefully you made sure what was the number one, stayed in the same position on the cap. Number 1 can be anywhere, it doesn't matter location on the cap, what matters is the time the cylinder fires. You will need to run the timing light from the #1 spark plug wire.

#1 cylinder will be driver side, front of car cylinder. Odd numbers on driver side, evens on passenger. Find your #1 cylinder wire and where it is on cap, then go clockwise to make sure they are all in order based on the order above.

Hope this helps.

 

I know for a fact that I have the #1 plug back in its original location. My fear is that I may have mixed up 6 and 8 but I'm pretty confident that I didn't. I will check the order today and see if that cures the rough running.

 

Make sure you have number 1 cylinder at TDC
take the plug out, put your thumb over the hole as you rotate the engine.
When you feel pressure on your thumb. That's the compression stroke. TDC is at the top of this stroke.

Larry on the board had a good thread on how to make a TDC tool from an old spark plug but I cannot find it. Basically you remove the porcelin, tap inside with a 3/8 tap and put a bolt in. Put this tool in #1 on the compression stroke. Slowly rotate the motor until it stops. Mark the balancer. Now turn the motor backwards until it stops. Mark the balancer.
The midway point between these marks is TDC.


From memory this is how I did it.

Rotate the motor until you're on TDC as marked on the balancer.

Put the cap on the distributor and mark its base where number 1 is.

Install the distributor in such a way that the rotor is pointing towards where #1 is on the cap (the mark you just made). The vacuum advance should point generally forward but slightly to the passenger side so it does not interfere with the belts or anything


Install the wires in the order above and it should be close enough to get you started.

Then using a timing gun, fine tune the timing. Larry has a great thread on powertime too and it worked great for me.
http://www.v8buick.com/showthread.php?t=63475&highlight=power+timing :3gears:

 

I'll promise you, everybody has crossed up wires before, even after double and triple checking. Your timing is close enough for it to start, so your ok there.

Good luck and ask any questions. Always somebody on here that can help.

 

Thanks for all the pointers. Will be working on it tonight and post my results.

 

So I went out on break to double check my plug order and wouldn't you know it, I had the 6 and 8 plug switched on the cap. Its amazing how carefull you can be and still make a simple mistake.

Thanks for all the quick replies.

 

Excellent!
I love a simple fix!

 

I have a 1968, can't get my car to stay running.