[Healeys] Spark plug gap

Thu May 4 05:43:38 MDT 2023

Sorry, I am out here. This guy wants to play till the engine is shot.

-----Original-Nachricht-----
Betreff: RE: [Healeys] Spark plug gap
Datum: 2023-05-04T12:45:37+0200
Von: "simon.lachlan at alexarevel.plus.com" 
<simon.lachlan at alexarevel.plus.com>
An: "josef-eckert at t-online.de" <josef-eckert at t-online.de>

Thanks for that. I’ll certainly bear it in mind. Likewise, I’ll keep a 
close eye on my engine’s temperature. The latter is quite well protected 
with a modern rad, all the correct baffles, 5 blade fan plus electronic 
fan. But, as I said, I’ll keep an eye on it.

Someone mentioned that he used “Iridium” plugs from NGK. I googled 
them….horribly expensive. Can they be worth it in our old cars?

Simon

From: josef-eckert at t-online.de <josef-eckert at t-online.de>
Sent: 04 May 2023 07:06
To: simon.lachlan at alexarevel.plus.com; Healey, Forum 
<healeys at autox.team.net>
Subject: AW: [Healeys] Spark plug gap

For me, i prefer Champion plugs plugs to NGK, but that´s a matter of taste. 
I think both, Champion and NGK, are of similar quality. Matter of taste, as 
I wrote. But NOT the car manufacturer determines the plug gap, its the plug 
manufacturer. Definitely the car manufacturer takes this for his specs in 
the workshop manual.
There is to much hype about plugs anyway. I am working as a professional, 
Elecrtonics and Elecrtrcian engineer, at a big classic car parts supplier 
here in Europe and I never go away from the given plug gap as set by the 
plug manufacturer. Austin-Healey engines  are not high tech, they are 
tractor engines and can take a lot of misfit, but anyway BMC knew at the 
time what´s best to do with them, even its printed 60 or 70 years ago.
Some people try to adjust the fuel mixture with a CO-tester. You can do 
that, but it doesn´t give best results for road use, especially in hotter 
climates and high above sea level.
When you are very good in engine engineering and have all the tools you can 
try to find some more horsepower in your engine, but you always pay that 
with some more heat produced, which is not at all good for our old BMC 
engines.

Josef

-----Original-Nachricht-----
Betreff: RE: [Healeys] Spark plug gap
Datum: 2023-05-04T00:06:58+0200
Von: "simon.lachlan at alexarevel.plus.com
<mailto:simon.lachlan at alexarevel.plus.com> " <
simon.lachlan at alexarevel.plus.com
<mailto:simon.lachlan at alexarevel.plus.com> >
An: "josef-eckert at t-online.de <mailto:josef-eckert at t-online.de> " <
josef-eckert at t-online.de <mailto:josef-eckert at t-online.de> >

You may be right. Not sure.

Actually I thought that the gap was determined by the car’s manufacturer ie 
one could expect to find the same plug in two different cars and to find 
that the recommended gap was not the same for each car.

Likewise, the BMC manual suggests Champion plugs at 0.024” to 0.026” and 
that was some 60+ years ago. I’ve always been told that Champion plugs 
aren’t the best in the world and I’m sure that a modern NGK can stand a 
little more heat than the Champions that were around 60 years ago.

Anyhow, I’ll keep an eye on them. I’m a pretty tame driver so there won’t 
be undue stress under the bonnet.

Simon

From: josef-eckert at t-online.de <mailto:josef-eckert at t-online.de> <
josef-eckert at t-online.de <mailto:josef-eckert at t-online.de> >
Sent: 03 May 2023 20:56
To: simon.lachlan at alexarevel.plus.com
<mailto:simon.lachlan at alexarevel.plus.com> ; healeys at autox.team.net
<mailto:healeys at autox.team.net>
Subject: AW: [Healeys] Spark plug gap

Spark plugs are designed and tested to be used with the gap given by the 
producer of the spark plug.
When you widen the gap the plug gets hotter as it is designed for and the 
electrode can melt or wear very fast.
Its a very short win you gain modifying them.
I never understand why people think they are better engineers and know 
better than the designers of the system they use.

Josef

-----Original-Nachricht-----
Betreff: [Healeys] Spark plug gap
Datum: 2023-05-03T21:39:57+0200
Von: "Simon Lachlan via Healeys" <healeys at autox.team.net
<mailto:healeys at autox.team.net> >
An: "'Healeys'" <healeys at autox.team.net <mailto:healeys at autox.team.net> >

I run my MkII BT7 on NGK BP6ES which were recommended by some of the wise 
ones on this list.

The car has a “Sports” coil and a 123Ignition distributor. DW fast road 
cam…etc

Now, talking of “recommended”, the rolling road guys told me to set the 
plugs at 0.028” and pooh-poohed anything bigger when I suggested that I’d 
heard of much greater gaps with my approximate setup.

So, I went with 0.028.

The other day, I decided to experiment and set my spare set at 0.032”. Same 
NGKs, no mileage on them..decent plugs. Anyhow, it made a very surprising 
difference. All round performance is much enhanced.

Despite it’s 3:54 diff and 28% OD, it was never sluggish on our local 
hills. But now it fairly zooms up them.

To be frank, all a bit of a surprise.

Not boasting…just putting that out there in case anyone else is thinking of 
going up a few thou…..

When I asked about gaps a few years back, some of the suggestions were near 
0.040”. Surely that a bit much?

Simon

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