converting points to hei on a chevy 283

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gniknayrb18

gniknayrb18

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first off im working on the sister in laws car and its a chevy 283 from 1967...we need a forum for non mopar stuff...i know there alot of mechanics among the crowd here so here we go. i dropped a new hei dizzy into the 283 and wired the hot wire to the coil...im trying to find out if i need to run a new ign wire or use the original one on it. it keeps back firing left and right i thought i might be 180 out so i turned it and its doing the same thing... still not starting...its getting close to starting then it will backfire.. maybe i should start off by telling you what i have replaced...new eddy performer intake. new eddy 600, used hei dizzy new spark plugs gaped to .40 new 8mm wires with correct boots... ive run the wires in order and it is just backfiring left and right. am i missing something here
 
You need a straight 12 volts, into the HEI coil to work correctly. Every 1 volt in primary( before coil) , is possibly 5,000 volts secondary voltage (at the plug wire). The GM points cars, have a resistance wire , to the positive side of the coil. Trace that wire back to the bulkhead connector, replace it with a good 14/16 gauge copper wire. Let's start there. HEI based ignitions, love more voltage.
 
it could now be 180 out again... but ok on early gm it had 2 wires hooked together going to the + side of the old coil so i need to trace which on back to the bulkhead....i was reading somewhere i need to replace the wire going to my ign switch with a 14 gauge wire...thats all the way to the key right
 
gniknayrb18 said:
it could now be 180 out again... but ok on early gm it had 2 wires hooked together going to the + side of the old coil so i need to trace which on back to the bulkhead....i was reading somewhere i need to replace the wire going to my ign switch with a 14 gauge wire...thats all the way to the key right
Click to expand...

Correct... The second wire, gave full battery voltage, to the starter solenoid post.
 
gniknayrb18 said:
so wait one wire goes from coil to ign switch the sec goes from the coil to the starter right?
Click to expand...

Depends. Has the starter been replaced? If not, both wires, to coil. If so,(most rebuilt /replaced starters eliminate one post, on the solenoid. Three wire connections, on solenoid, don't worry about the second coil wire. If four connection, hook it up.Personal, never used the second wire...
 
Pretty sure the Chevs used a resistance WIRE to feed ignition. This means the original ignition feed is going to be low voltage.

Where are you getting 12V from?

Is this a stock GM HEI that is coil in cap?

I do not remember, anymore, if you need the starter "I" connection or not. What you need to do is monitor the ignition "run" voltage and see if it remains hot in start. If so, you don't need the extra wire from the solenoid.

HOW to time it. Pull no 1 plug. Put your finger in the hole. "Bump" the starter until it STARTS to blow your finger out. You never done this? Might take a trip around or two to get the feel. As soon as you feel compression, pay attention to the marks. Bring the marks up to 10-15 BTC. DO NOT set at TDC. Drop the dist. in with rotor pointing to the no1 tower, and the vacuum can "about where" you want it.

IF THE oil pump drive won't seat, don't worry. Just bump the starter until it seats. Then, bump it around "to the marks" again and check timing, which will have changed some as the distributor dropped. If it's "too far" to adust with the vacuum can in the way, simply pull it up and "walk" it a gear tooth one way or other and check it again.

This is easier than it sounds.

YOU CAN SET THE TIMING "on the starter."

There is no reason to go through the "180 out" nonsense. You should be able to drop it in and start it up.

If you are fighting timing issues, or there might be something wrong with the ignition (distributor) then "ignore" the wiring. Just "hot wire" the distributor, get it running and timed, and THEN deal with the harness issues.
 
Easy way to check is to unplug your power/ignition wire to the cap, and run a power wire direct to the battery for testing, then you know you are getting the full voltage that you can get. have to disconnect the wire to shutoff ignition.
I have also used a relay to power the HEI. I used the factory resistor wire as the signal wire.
 
moturbopar said:
Easy way to check is to unplug your power/ignition wire to the cap, and run a power wire direct to the battery for testing, then you know you are getting the full voltage that you can get. have to disconnect the wire to shutoff ignition.
I have also used a relay to power the HEI. I used the factory resistor wire as the signal wire.
Click to expand...

Almost suggested this. I'm not sure, on the older Chevs, that there is an "easy" source upstream of the resistor.
 
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