Plug gap

[bdcvg]

You Pertronix users, Are You running stock spark plug gap ?

 

[EV2239]

Sparks tend to pick the easiest place to occur, which ought to be the plug, but can be the rotor arm or the distributor cap if you open up the plug gap. I've not heard of it with Healeys, but it's certainly a problem with post war six cylinder R-R & B.

 

[Bob_Spidell]

You Pertronix users, Are You running stock spark plug gap ?

Yep (0.025" IIRC). Only reason for larger gap is if you're running a 'sports' coil, and if your engine is stock you don't need that.

 

[EV2239]

FWIW Lucas had three different coils in the days of Healeys, one for Morris Minor type engines, a sportier one for Healeys and on with a red ceramic type top for D Type Jags etc. The Lucas gold coloured sports coil you can buy now does have a higher output than the original, but is a direct replacement. Sorry I've been too lazy to look up numbers.

 

[Keoke]

You Pertronix users, Are You running stock spark plug gap ?

NO!
Because the switching time of a Pertronix is much faster than the old points you are going to develop higher secondary voltage out of the coil. Consequently, you can now put more fire in the hole and improve on the combustion in the cylinder.
by opening up the plug gap to:
30-or- 35 Thou.
When you add a sport coil you can use a plug gap of 40 Thou.

 

[Bob_Spidell]

NO!
Because the switching time of a Pertronix is much faster than the old points you are going to develop higher secondary voltage out of the coil. Consequently, you can now put more fire in the hole and improve on the combustion in the cylinder.
by opening up the plug gap to:
30-or- 35 Thou.
When you add a sport coil you can use a plug gap of 40 Thou.

From the Pertronix FAQ: "In most cases increasing the factory recommended gap by .005 improves the engine performance."

I sit corrected.

 

[bdcvg]

So far no backlash from using .030 plug gap.

 

[bdcvg]

O.K. here's what I've found. 1. The Nissonger tach conversion does not like solid core wires, the RFI will make the needle flutter. 2. The Pertronix does not like solid core wires, they cause an intermittent misfire that will eventually cause the ingnition module to fail. I will now experiment with changing plug gap after tracing down My 2 issues.

 

[Keoke]

O.K. here's what I've found. 1. The Nissonger tach conversion does not like solid core wires, the RFI will make the needle flutter. 2. The Pertronix does not like solid core wires, they cause an intermittent misfire that will eventually cause the ingnition module to fail. I will now experiment with changing plug gap after tracing down My 2 issues.

Well first off :

Solid core wire in just about any application is subject to failure from vibration and is not recommended.

Automobile wiring harnesses and spark plug wires should use the stranded wire type

Radio Frequency Interference [ RFI ] in ignition systems can be controlled by:

1 Shielding of the ignition system and it's multiple stranded wiring.
Healey used this approach early in life ,kits could be ordered.
2 resistance type plug wires such as string impregnated with carbon
3 Spark plugs of the resistance type.Such as Bosch WR7DP
4 There is a special type. spark plug wire that contains a built in inductor.
This usually consists a special winding installed around the main conductors .
5 There are spark plug connectors that contain suppression. I use Bosh works a treat

 

[Michael Oritt]

You Pertronix users, Are You running stock spark plug gap ?

From the Pertronix page:


The Ignitor has no set specification in which the spark plugs should be gaped at. Every engine responds differently to spark plug setting. In most cases increasing the factory recommended gap by .005 improves the engine performance

In all of the race cars I have Pertronix ignitions in Lucas distributors. In the Healey I have a Mallory Unilite ignition. In all cases I use NGK B9ES plugs with .030 gap. YMMV.

There is no good reason to use solid core wires. They will cause ignition interference in your and nearby cars and I believe in some jurisdictions it may even be illegal to use them. I once changed a made-up distributor cap on my Courier and did not realize that the wires were solid core. The ignition signal turned the roll bar camera off-on continuously and did so even when the cam was powered from a different 12 VDC source.

 

[bdcvg]

The solid core wires were installed by My resto Guy Who focuses on stock stuff. The Pertronix is pretty good and I hope to have good enough weather to go back to .030 gap soon. I returned to .025 when the misfire appeared.

 

[John_Progess]

I was told that we should not be using solid core plug wires with a Pertronix because it could destroy the unit. I am using a Pertronix and I have solid core wires in my car and have not had a problem. Is this a true fact or garbage? Also what is the gap I should be using with a Pertronix? Thanks and have a good day!

John

 

[John_Progess]

I should have read the first page of this post before I asked the question! Have a good day!

John

 

[BG 62AH]

Any advice on plug gap for a Crane Cams XR700. I am currently staying with a stock gap, but have considered opening up .005.

Any suggestions appreciated.

 

[John Turney]

Any advice on plug gap for a Crane Cams XR700. I am currently staying with a stock gap, but have considered opening up .005.

Any suggestions appreciated.

I've got 0.030 gap on my Champion RN9YC resistor plugs, and bumble bee wires with no problem.

 

[steveg]

I was told that we should not be using solid core plug wires with a Pertronix because it could destroy the unit. I am using a Pertronix and I have solid core wires in my car and have not had a problem. Is this a true fact or garbage? Also what is the gap I should be using with a Pertronix? Thanks and have a good day!

John

This forum discusses this and seems to have participation by PerTronix people. Evidently when the copper wires get really old they can cause the unit to short out.
https://www.jalopyjournal.com/forum/threads/pertronix-and-copper-core-wires.391152/

 

[Keoke]

Well what they are really talking about is ageing of the insulation on the wire.

"Evidently when the copper wires get really old they can cause the unit to short out."

Uninsulated Copper conductors whether stranded or solid do not break down to ground.
What happens is the insulation on the wire will crack with age which allow the electromagnetic force if it is close to chassis-GND- to arc.

Insulation on wire is not homogeneous.
.Militarily we spend big $$$ to meet Mil-Specs that control the quality of our insulation and it is not porous free. So we test 10% of every lot we buy to those stringent requirements..

It is probably conceivable that vendors of wire have varing quality of insulation.
However, I can not in good conscience say solid wire vendors use the inferior insulation products.

Additionally, from a material perspective under identical environmental conditions ,ageing
of stranded copper wire or solid will be the same.

In conclusion, the term solid core can simply define solid copper wire or stranded copper wire.

Additionally, some of these solid core wire designs can fail internally.