back together....but
Thread Starter
Burning Brakes
Joined: Feb 2005
Posts: 977
Likes: 1
From: wash. dc
back together....but
finally got the engine put back together after detailng it. now when i tried to start it i get a huge backfire. bumped it tilltiming mark was on 0 then took off distributor cover and rotor is at the #1 plug wire... what am i doing wrong here... i'd at least like to get running so i can fine tune it and get it rolling.....help!!!! if it matters its a 71 BB
Melting Slicks
Joined: Sep 2005
Posts: 2,701
Likes: 900
From: Warminster PA
Originally Posted by carguy4sure
Are you sure that the #1 cylinder was on it's firing/compression stroke? You could be 180 out. I would also check the wire positions again. Easy to have two swapped.
An old trick I used to use on my racecar to set the initial timing was to remove the #1 plug, connect the wire to it and ground the body where you can see it. Then rotate the engine so that on the compression stroke the balancer lines up with your desired initial timing. In this case, I'd start with 8 or 10 degrees BTDC. Loosen the distributor hold down. Turn the ignition on. While watching the plug, rotate the distributor and when the points close, you should get a spark. Do this a couple of times and stop the distributor right when the spark happens and lock it down. Turn off the ignition, put the plug back in and crank away. Should fire right up. Put a timing light on it to fine tune, once you get the hang of this method, you'll get pretty darn close.
Also, make sure you have the firing order correct on the cap and in the proper direction.
Advanced
Joined: Feb 2002
Posts: 97
Likes: 0
From: Sapupla OK
I recently went thru finding TDC on the comprssion stroke. What I found easiest was to take off valve cover and watch the rockers on #1... when they both looked to be closed I turned motor till I was showing about 10 deg advance. I turned my engine (with all plugs in) using a 30" piece of pipe over my rachet handle...not too hard to turn over and you get it exactly where you want it.
I use a oil pump primer to align the oil pump slot and drop the distributor so that the rotor winds up about under the #1 pickup in cap. with the vacuum advance diaphram about 1/2 way between firewall and carb so I can turn base either way.
A word of caution...if you have changed your distributor drive gear, make sure the "extra dimple" above the roll pin is postioned under the rotor arm as the gear is not completely symetrical and there is only one correct way it goes on the distrubutor shaft.
I use a oil pump primer to align the oil pump slot and drop the distributor so that the rotor winds up about under the #1 pickup in cap. with the vacuum advance diaphram about 1/2 way between firewall and carb so I can turn base either way.
A word of caution...if you have changed your distributor drive gear, make sure the "extra dimple" above the roll pin is postioned under the rotor arm as the gear is not completely symetrical and there is only one correct way it goes on the distrubutor shaft.
Le Mans Master
Joined: Oct 2005
Posts: 6,247
Likes: 471
From: Glen Allen, VA
I've always wadded up a paper towel and stuffed it in the #1 spark plug hole. When the compression comes up, it will shoot the paper towel out, Then you know you're on the compression stroke.
