HEI Swap with backfiring through the carb
 

My brother and I started an HEI swap on my 1972 C10 on Saturday. We ran new 10 gauge wire to a known working distributor. To set the engine at TDC we pulled the valve cover and turned the motor over till both rocker arms on the #1 cylinder were loose and the mark on the harmonic balancer lined up with the timing marks. We then installed the distributor so the rotor lined up with the #1 cylinder and was pointed as close as possible to that point in the cap. We then installed the wires in the proper firing order. When we tried to start the truck we got backfiring through the carb. To try and get this to stop we both advanced and retarded the timing by rotating the distributor. As I understand it I should be advancing the timing to get this to stop. My questions are this;

Am I right on our method for TDC?
How much do I have to advance the timing do get this to stop?

(Our first attempt at stabbing the distributor was 180 degrees out and we got back firing through the exhaust)

Re: HEI Swap with backfiring through the carb
 

Sounds like you are 180 out. May have been a tooth off before when it popped thru exhaust.

You should pull number one plug and put a finger over the hole and while engine spins over till you feel it puff on compression stroke.

Re: HEI Swap with backfiring through the carb
 

#1cyl has two TDC"s it needed to b on the compression stroke for the dizzy to b right

you need to pull dizzy repeat what you did but hold finger firmly over the #1plug hole and when you feel the puff of air you're on the compression stroke then get TDC and stick the dizzy and you should b ok

Re: HEI Swap with backfiring through the carb
 

Ok, I'll repeat the process using the tried and true finger method. Thanks for the replies.

Re: HEI Swap with backfiring through the carb
 

if you dont have help you can lightly stick a paper towel in the #1 spark plug hole, give one crank at a time until it blows out, mark a spot with chalk were the rotor is pointing, as you pull it out and the rotor turns counter clockwise mark another spot, that will give you a mark to point the rotor as you put it in and a mark on were it should end up after it slightly turns from the gears, triple check your wires, good luck

Re: HEI Swap with backfiring through the carb
 

You are 180 degrees off.

Re: HEI Swap with backfiring through the carb
 

Is this where all my buddies are suppose to laugh into there beers because I installed my distributor backwards?

Just to sanity check my installation I have powered the distributor with a wire from the right pole on the solenoid (drivers side) and a wire that runs from an unfused ignition slot in my fuse block. The unfused spot in the block showed 12 volts with the key in the run position and the solenoid showed 12 volts when cranking. Both wires are new 10 gauge wire. Sound right?

Re: HEI Swap with backfiring through the carb
 

no idea bout wiring but as theyve all said 180* out..... pull distributer and flip 180* and put back in..i did it EVERY DAM TIME on my blazer back in the day...

Re: HEI Swap with backfiring through the carb
 

heres how i did mine... my truck wasnt timed right to start with so i pulled the old points dist. out.. pulled plug out put pencil in the hole and bumped the key til the pencil was out or whatever.. then cranked the engine perfectly to 0 on the balancer.. dropped the distributor in and it the rotor matched up perfectly on number one cylinder