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HEI ignition: Now what plugs and gap???

  
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HEI ignition: Now what plugs and gap???

 
chemnick chemnick
New User | Posts: 7 | Joined: 09/11
Posted: 09/14/11
11:35 AM

I just put an aftermarket (new) distributor in my '67 GTO w/a '70 RA III motor. I would assume that the plugs and gap that I will need would be different than those used with the points distributor. I believe the plugs in it now are R44S or close to it. I changed the distributor and it ran lousey. I checked my Motor manuals to find an early listing HEI which said .060 gap, so I pulled the plugs and regapped them to .060. Ran a little better but not well. The existing plugs are old, but look OK. I want to replace them, but want to get a recommendation or two about what to get and where to gap them. As always, thanks a lot for any input you may have.
Chemnick Confused  

waynep7122 waynep7122
Enthusiast | Posts: 672 | Joined: 08/09
Posted: 09/14/11
11:54 AM

a few things...

i am taking that you installed an Aftermarket HEI with the coil in the cap....

that really requires full battery voltage to operate properly.. you might want to see about running it off a cube relay.. with the power to pin 30 directly from a decent power source... like an additional wire from the starter .. or a insulated terminal block on the firewall...    letting the oil coil positive wire control the relay..


set your plug gap back to 0.035 to 0.045..        0.060 was way too much caused many problems as the voltage to jump the gap was so high that is usually burned through the rotor center and wiped out the spark..

these are all cross references for the R44s spark plug.. most of them should be available at local parts stores..

Bosch Super Plus Spark Plug 7916 WR9FC+
Champion Traditional spark plug 14 RJ12YC
Denso Traditional spark plug 3037 W16PR-U
NGK V-power spark plug 3332 XR5

NGK Racing plug 2746 R5670-6 $2.89


since you have an HEI now.. did you dead stick time the ignition.. by presetting the crank to the base timing you want.. and then turning the housing while you watch the pick up coil and the reluctor tips to align them. this is a quick and easy way to set base timing to get the engine started on the first try..

are you running intake manifold vacuum .. or ported vacuum to the vacuum advance..

you might ask the supplier what sort of distributer curve the distributer is set at from the factory...  

Pontiacman8 Pontiacman8
Moderator | Posts: 5778 | Joined: 02/08
Posted: 09/14/11
12:26 PM

I would gap them at .045 and no more or no less.  
Engine builder,self taught auto body guy.
Horsepower sells engines and torque wins races

Pontiacman8
Pontiacman8
Pontiacman8

chemnick chemnick
New User | Posts: 7 | Joined: 09/11
Posted: 09/14/11
12:32 PM

First, thanks for your help. To answer a few things: I have manifold vacuum ready to connect, but I haven't hooked it up yet because I wanted to set the timing with my timing light before I did that. I do have ported vacuum available from the Holley carb I run, but it is now capped off. I will try .045 for sure. I now have a cube relay controlled by the former distributor coil feed wiring, with the source being the pink ignition wire at the back of the ignition switch. I have two "Battery Fused" connections available at the fuse box that I could try if necessary. Dead stick timing. That's a new one on me. I understand the meaning of what that will accomplish, but I don't know if the OEM timing indicator shows the proper scale or not. Would the objective be to set it at the timing value indicated in the Motor manual? I think it was 18 degrees BTDC.
I did contact the supplier of the distributor, mostly because there was a small allen wrench with the unit with no explaination (I've seen some that can be adjusted through the vacuum port). He says he doesn't know why the wrench was in there and the way to adjust it was by changing springs or weights. I checked and the wrench slides into the hole and there is a female hex that is the exact same size as the wrench (?). I DID NOT make any adjustments to it, in fact I did not even try to turn it. I was only told that there is a 22 degree advance built in. Chemnick  

goatwool goatwool
Enthusiast | Posts: 384 | Joined: 07/10
Posted: 09/14/11
12:44 PM

Wayne - I'm not familiar with dead stick timing.  I understand setting the crank on the timing mark you want but what do you use to tell where the rotor is pointing?  

waynep7122 waynep7122
Enthusiast | Posts: 672 | Joined: 08/09
Posted: 09/14/11
05:28 PM

when the tips on the  reluctor pass the tips on the pickup coil the ignition module should fire the ignition coil...

this allows you to set the crank to the base timing mark on either rotation of the crank.. so you can yank the distributer out and stick it back in..  turn the housing to align it.. and it wills start on the first try...

if you have rotated the engine.. you will have to pull the first spark plug..   bump the engine around till you get compression..   bring the timing marks up..    set it to base timing.. drop the distributer in..  you will usually have to reset the oil pump shaft..

or spin the motor.. while lightly pushing down on the distributer.  then find compression on number one again..   bring the timing marks up..   turn the housing till the reluctor and the pick up coil align .. lock it down.. and then you are ready to start it..

want another hint...

do the same with point type ignition..    turning the housing the other direction from normal shaft rotation.. stop when the point set is about to open.. you can fine tune it..  by seeing if when the key is on.. and you turn the rotor just slightly. the coil should fire...   the coil fires as the points open..  

goatwool goatwool
Enthusiast | Posts: 384 | Joined: 07/10
Posted: 09/14/11
06:10 PM

Got it - thanks for the info!  

chemnick chemnick
New User | Posts: 7 | Joined: 09/11
Posted: 09/14/11
06:44 PM

Wayne:
This timing method sounds like something I should have known for years. So to make things understood: I pulled out the old distributor after bringing the crank to TDC and noting where the rotor was pointed (#1 TDC). I dropped the HEI in so that I would have room to swing the body either way to fine tune the timing. I then rotated the engine by hand with slight pressure on the distributor until it dropped the rest of the way, engaging the oil pump drive shaft, then rotated the engine in the opposite direction back to #1 TDC. I then set the body to a convienient location and lined up the rotor to the nearest plug wire tower, started there for #1 plug wire, installing the remaining wires in firing order, then starting the engine while slightly rotating the body until it would start. Sounds to me like if I had used your method, I could have set the crank at +/- 18 degrees (the manual's info), put the reluctor and the pickup dead on with each other, called that my #1 cylinder and locked it there and been able to almost hook up my vacuum line and headed down the road. Well, maybe not QUITE that easy, but pretty close. I can understand the idea of it, just amazed that I have not run into it before. Where did you come across this method?
Chemnick Smirk  

waynep7122 waynep7122
Enthusiast | Posts: 672 | Joined: 08/09
Posted: 09/14/11
08:25 PM

yes.,.. if you dead stick time the motor.. you can stuff a distributer in.. lock it down.. hook it up.. and drive it away..  done it dozens if not hundreds of times...


when i was in auto shop about 30+ years ago.. i was taught the twist the housing to find where it fires at.. and a judgement call...

years later i noticed a graphic in a ford manual.. that showed the reluctor and the pick up coil that on a ford .. half a tooth was 7.5 degrees of timing..  i started playing around with it and found that i could dead stick time it this way...

i love it..  i try to share.. but it take me minutes longer to type it out than it does to show it..   i was going to video tape it.. but have not had an engine on the stand ready to run in a while..  

i look like the smartest mechanic around when i can yank a distributer out..  (not telling the car owner than i preset the engine ..  shove the distributer back in.. lock it down.. reach through the window of the car and start it on the first try..  when the owner says.. don't you need to set the timing... i go OK.. lets see how far i am off..  i am usually within 2 degrees..  sometimes closer.. but then i know to back the crank to 40 degrees BTDC.. and bring it back to 8 or 15 what ever the label calls for...  so i get rid of the slack in the timing chain..



want another cool trick...

pick up coil testing..

set digital volt meter to 2K ohm scale...   measure the pick up coil...   500 to 1,500 ohms is good.. usually right at 780...

before disconnecting .. flip the meter setting to 2 volts AC... spin the shaft or have somebody crank the engine.. if you don't get close to 1.0 volts.AC..  the reluctor is bad...  fords and mopars suffer with failed reluctors.. small cap HEI distributers also.. with the steel riveted reluctor..

the reluctors loose the ability to retain a magnetic field..   less magnetic field..  less lines of the field pass through the windings of the pick up coil so it creates less voltage..    the power transistor in the module needs to turn ON at +0.3 volts above true 0...   it turns off as the tips pass each other and the voltage drops to 0...  then swings negative..   as the tips approach again. the voltage swings positive .. above 0.3+ .. the power transistor closes and grounds/completes the circuit to the primary windings of the ignition coil..  this builds a magnetic field in the primary windings..   as the pick up coil voltage drops.. the power transistor opens.. causing the magnetic field in the primary windings of the ignition coil to collapse through the secondary windings creating a HIGH voltage spike.. that goes out .. across the rotor.. jumps a gap to the outer terminal... down the wires.. jumps another gap at the spark plugs..   through the heads block... distributer hold down clamp.. to the 3 wire hold down screw.. up the center wire to the flat strip in the cap.. through the laminations then into the black wire at the coil in the cap to make a complete circle..

print this...   you will get it sooner or later..

got questions.. feel free to ask...


oh.. small cap hei problems.   when the second layer of the reluctor which is a ceramic magnet cracks.. instead of a nice wave form for the pick up coil to send to the module and ECM..

it will have Ghost wave forms in there.. do to the cracks in the magnet..  why...

on GM HEI ignitions..  above 400 RPM.. the computer and the electronic spark timing module should be in control of the ignition timing..  so base timing is 15 degrees...    what the computer does is  start a timer...  counting down from the last pulse received..  by changing the amount of time delay..  it can advance or retard the timing on the next pulse.. since the pulses are all evenly spaced do to offset rod journals on V6's ..  this is NOT a problem..  but the random ghost pattern thrown in makes the timer all nutty and causes misfiring and even backfiring sometimes..