Replacing points distributor with complete HEI assembly....
Thread Starter
Drifting
Joined: Aug 2004
Posts: 1,677
Likes: 1
From: Potomac Falls VA
Replacing points distributor with complete HEI assembly....
Any suggestions would be appreciated but here are some specific questions I had:
1. Recommendations on new plugs? Gapping?
2. Any way to verify engine at TDC without taking apart? Or other tricks for replacing entire assembly?
To a lot of you this is probably a simple process but all of my cars until now have been FI / computer controlled, etc. so I am trying to learn.
If there is someone in the NoVA area willing to help / teach / supervise, I would supply beer and food.
Thanks
Shane
1. Recommendations on new plugs? Gapping?
2. Any way to verify engine at TDC without taking apart? Or other tricks for replacing entire assembly?
To a lot of you this is probably a simple process but all of my cars until now have been FI / computer controlled, etc. so I am trying to learn.
If there is someone in the NoVA area willing to help / teach / supervise, I would supply beer and food.
Thanks
Shane
Tech Contributor
Joined: Aug 1999
Posts: 14,367
Likes: 6,348
From: At my Bar drinking and wrenching in Lafayette Colorado
Use your same plugs. Don't run gaps any bigger than .045".
To determine TDC, pop the distributor cap off your current distributor and "bump" the engine over with the starter until the rotor points to the #1 plug tower location. You should now be able to see the timing line on the harmonic balancer. Align the balancer line with 12 degrees BTDC - this is your initial firing position. You can then pull the old distributor and install your new one in the #1 firing position.
Make sure you bypass your existing ignition wire and run a new wire to the "+" side of the HEI. Your existing "+" wire to the coil is a resistor wire with only 7 volts. You need a full 12 volts to the HEI.
To determine TDC, pop the distributor cap off your current distributor and "bump" the engine over with the starter until the rotor points to the #1 plug tower location. You should now be able to see the timing line on the harmonic balancer. Align the balancer line with 12 degrees BTDC - this is your initial firing position. You can then pull the old distributor and install your new one in the #1 firing position.
Make sure you bypass your existing ignition wire and run a new wire to the "+" side of the HEI. Your existing "+" wire to the coil is a resistor wire with only 7 volts. You need a full 12 volts to the HEI.
Drifting
Joined: Sep 2004
Posts: 1,532
Likes: 4
From: Fairview Heights Illinois, near Saint Louis MO, STL C3 Shark
You can pull the # 1 spark plug to help determine top dead center, if you've got a timing mark on the harmonic balancer, just line the marks up with timing tab would be easiest. I used a used GM HEI and got spark plug recommendations from the donor car, basically the r45 AC delcos or Bosch, gapped them at about .045. If your using aftermarket HEI (ie no donor car info) r45s and .045 gap would definitely get you running. 
Burning Brakes
Joined: May 2004
Posts: 1,100
Likes: 3
From: belle plaine ks
makes no difference
Originally Posted by WhichVette?
I'm about to do this as well. Which is the #1 on the HEI? I can't find any markings on mine.
Le Mans Master
Joined: Jun 2002
Posts: 8,339
Likes: 24
From: I can walk to MA
Originally Posted by lars
Use your same plugs. Don't run gaps any bigger than .045".
It turns out the ones in there were Bosch platinums (which I have
never purchased), so these plugs were in the motor when I bought the
vette 7-8 years back. I noticed in the book that 75 specs out an AC R44TX
plug ... gapped at .060", but subsequent years were R45s gapped
at .045".
I used the R44TXs @ .060", and they seem to be working perfectly.
So why .045" max ... issues with repetative spark energy at high RPMs ?
Would side-gapping help on a mild SB ?
- Dave
Le Mans Master
Joined: Jun 2002
Posts: 8,339
Likes: 24
From: I can walk to MA
Originally Posted by WhichVette?
I'm about to do this as well. Which is the #1 on the HEI? I can't find any markings on mine.
#1 points style is front passenger side position
Although, they can both be rotated arbitrarily - if you want to confuse
the next person working on it. Also, the stock wires would not fit well.
Last edited by NHvette; Jun 17, 2005 at 10:28 AM.
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Safety Car
Joined: Aug 2000
Posts: 3,711
Likes: 43
From: San Antonio TX
Originally Posted by NHvette
Why no larger than .045" ? Curious, as I just replaced my plugs.
It turns out the ones in there were Bosch platinums (which I have
never purchased), so these plugs were in the motor when I bought the
vette 7-8 years back. I noticed in the book that 75 specs out an AC R44TX
plug ... gapped at .060", but subsequent years were R45s gapped
at .045".
I used the R44TXs @ .060", and they seem to be working perfectly.
So why .045" max ... issues with repetative spark energy at high RPMs ?
Would side-gapping help on a mild SB ?
- Dave
It turns out the ones in there were Bosch platinums (which I have
never purchased), so these plugs were in the motor when I bought the
vette 7-8 years back. I noticed in the book that 75 specs out an AC R44TX
plug ... gapped at .060", but subsequent years were R45s gapped
at .045".
I used the R44TXs @ .060", and they seem to be working perfectly.
So why .045" max ... issues with repetative spark energy at high RPMs ?
Would side-gapping help on a mild SB ?
- Dave
Pro
Joined: Sep 2004
Posts: 517
Likes: 0
Thanks guy. Got it up and running great. Have to do the road test this afternoon or tomorrow, though. Looks like I'll have to pull and readjust the distributor, though. The #1 plug next to the tach connector is a little too far forward and doesn't allow the air filter to fully engage the carb. Trying to decide if I want to pull and adjust or just move all the plugs over 1 and spin the distributor. Decisions, decisions...
On another note, the plug wires I bought with the distributor are long enough that I was able to route them down the firewall and under the headers. Man, it looks soooooo much cleaner that way...
On another note, the plug wires I bought with the distributor are long enough that I was able to route them down the firewall and under the headers. Man, it looks soooooo much cleaner that way...
