Wonít stay running; wrong plugs.?.? - Team Camaro Tech
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post #1 of 44 (permalink) Old Sep 21st, 18, 06:18 AM Thread Starter
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Wonít stay running; wrong plugs.?.?

Iím looking for plug recommendations.

400SBC (bored .040), mild cam, Edelbrock 1406, Heads are casting # 3973493 (76cc, iron, stock from 70-76 400). Recently rebuilt motor and trying to get running. Have had the motor running in 5-10 second stints. It seems to run well (as I recall from before the rebuild)...and then it dies out. I get the feeling my Carb is flooding the motor, so I recently added a fuel pressure regulator. Since the motor still didnít stay running, I checked the plugs again and found a couple concerning issues:

1) Plug #6 gap has magically reduced from 0.045 to approx .010! I assume I purchased plugs with too far of reach, and the piston or valve smacked the plug tip closed?

Hereís a pic of old and new plugs together:


Doesnít take a genius to realize the new ones are longer reach, but still not 100% sure which is correct. Iím really hoping someone has a good plug recommendation (#) for my application.

2) Plug 7 and 8 had fuel in them upon removal. This happened a couple weeks ago after initial installation. Took them out, dried them all, aired the motor for a few days, and installed a fuel pressure regulator. Reinstalled plugs, tried 6-7 start attempts, car ran for 15 seconds total, then removed and noticed the excessive fuel. Both header tubes felt just as warm as the others.

Not sure if I need to rebuild the carb, or if I should try a Holley 750 (4160 I believe) that Iíve never tried and has been sitting on the shelf for 5 years.
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post #2 of 44 (permalink) Old Sep 21st, 18, 06:26 AM
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Re: Wonít stay running; wrong plugs.?.?

The Delco AC44TS are correct.

The ones you installed are lucky you didnít damage a piston
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post #3 of 44 (permalink) Old Sep 21st, 18, 07:15 AM Thread Starter
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Re: Wonít stay running; wrong plugs.?.?

Confirm it should have an R in front? R44TS vs 44TS? (Mine have the R...not sure if they should (resistive vs non-resistive?)).
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post #4 of 44 (permalink) Old Sep 21st, 18, 07:31 AM
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Re: Wonít stay running; wrong plugs.?.?

Quote:
Originally Posted by Boucher421 View Post
Confirm it should have an R in front? R44TS vs 44TS? (Mine have the R...not sure if they should (resistive vs non-resistive?)).
yep R44Ts

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post #5 of 44 (permalink) Old Sep 21st, 18, 07:32 AM Thread Starter
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Re: Wonít stay running; wrong plugs.?.?

Thx. Any chance this will help my no-start issue?

(Please say yes, please say yes, please say yes!)
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post #6 of 44 (permalink) Old Sep 21st, 18, 07:39 AM
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Re: Wonít stay running; wrong plugs.?.?

I'm surprised it even started with the longer reach plugs.

Should do the trick with the right plugs

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post #7 of 44 (permalink) Old Sep 21st, 18, 04:50 PM Thread Starter
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Re: Wonít stay running; wrong plugs.?.?

Switched the plugs. Wouldnít start at all.

Will look to ensure fuel is making it to float bowls tomorrow. Will also check for good spark (again).
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post #8 of 44 (permalink) Old Sep 21st, 18, 05:48 PM
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Re: Wonít stay running; wrong plugs.?.?

Easy to get fuel into a Holley for start up if a mechanical pump is used, don't have to spin the engine over and over to pump the fuel into the carb. Each bowl has a vent tube which is at either end of the air filter base area on the carb body, fill some sort of plastic bottle (with a top that has a nozzle on it) with fuel, about 4 ounces, and insert the nozzle into the vent tube, this will fill the bowl with enough fuel to run the engine for about a minute and a half. More time than needed to prime the fuel system, and no excessive engine cranking.
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post #9 of 44 (permalink) Old Sep 21st, 18, 06:11 PM
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Re: Wonít stay running; wrong plugs.?.?

my old 406 (400 + .030) ran R45TS ACDelco's

400 +.030
Protopline 200cc 2.05/1.6 heads
stock stroke Eagle crank
5.7" rods
TRW pistons (for a 377"....400 destroked)
25X/26X .63X lift solid roller
1.6 full roller rockers

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1.54 60'--6.95 @ 98.45 660'--10.96 @ 121.53
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post #10 of 44 (permalink) Old Sep 21st, 18, 06:12 PM
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Re: Wonít stay running; wrong plugs.?.?

Today the "R" type plugs are not only of use if you have an original AM radio. The resistor plugs filtered out ignition "spark" noise not only from AM broadcast bands, but also from the computers you may have installed for ignition, gauges, info-tainment system although if it is quality equipment it should have its own EMP and noise shielding.

But yeah check the basic check-list stuff, fuel, if fuel, spark, if spark, timing.

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post #11 of 44 (permalink) Old Sep 22nd, 18, 04:57 AM
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Re: Wonít stay running; wrong plugs.?.?

Probably a stupid question but is the distributor 180 degrees out of phase?

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post #12 of 44 (permalink) Old Sep 22nd, 18, 09:58 AM
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Re: Wonít stay running; wrong plugs.?.?

To add to 69-pace's reply, the resistor plugs were used that way, (usually 1K ohms), and had even more resistance in police and emergency vehicles (5K ohm spark plugs), that were equipped with two way radios, to dampen RF emissions from those systems.

The other issue with RF back then was spark plug wires, they, for the most part, were steel or copper wire conductors, which leaked RF all over the place. That is why Corvettes had a braided steel covering over their wires, to dampen the RF because their body's were fiberglass. This alone is one of the reasons "magnetic suppression" wire sets came to be, and the earlier ones weren't shielded, as,in today's "spiral core" shielding.

Today's magnetic suppression, spiral, or "Magna" core wires are leaps and bounds better than those first suppression wire sets.

Kawasaki bikes ran a steel conductor spark plug wire, then, we made police bikes, and the plugs became resistor, and the wires went to MS, SP core, 5K ohms, to stop the ignition RF in the radios.
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post #13 of 44 (permalink) Old Sep 22nd, 18, 10:20 AM Thread Starter
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Re: Wonít stay running; wrong plugs.?.?

Tested with in-Line spark tester...no spark. Voltage at distributor is 9.85 when cranking.

Unfortunately, I appear back at a point where I was on another thread. I wasnít sure if I should start a new one, but since I was well past the original problem, thought a new thread was the way to go.

The problem starts with post #21 in:

Low Pressure during Priming
https://r.tapatalk.com/shareLink?sha...3&share_type=t

In a nutshell, I pulled the distributor apart and only one resistance was slightly out of the range provided by the referenced article. Even found a tester at Autozone and the module tested good.

Sorry to send you guys bouncing around to different threads. Any thoughts are much appreciated.
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post #14 of 44 (permalink) Old Sep 22nd, 18, 03:59 PM
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Exclamation Re: Wonít stay running; wrong plugs.?.?

Don't know by poking through that thread but did you ever check that the supply wire to your HEI was NOT the original factory resistance wire and that a new wire was run to get you full power to the ignition system? Factory points used a resistance wire to prevent burned points if the key was left in the ignition position. You need full power for HEI systems. Most run a new wire from the panel through the firewall, or remove and replace the resistance wire in the factory harness. Your voltage smells like resistance to me but I am far from an ignition expert.

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post #15 of 44 (permalink) Old Sep 22nd, 18, 04:09 PM
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Re: Wonít stay running; wrong plugs.?.?

Externally charge battery overnight, bring it back to full capacity.
Then, as Brian suggests, run a jumper wire from positive post to BATT spade.
If timed correctly, and fuel bowls filled via vent tube as Dave Ray suggests, she should fire.
Might run a ground jumper from dist body to ground.

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