Cooking the spark plugs

Discuss Electrical problems here.
Forum rules
By using this site, you agree to our rules. Please see: Terms of Use
Post Reply
jagnut66
Minor Legend
Posts: 3635
Joined: Fri Apr 11, 2008 7:28 pm
Location: Mansfield, Nottinghamshire.
MMOC Member: Yes

Cooking the spark plugs

Post by jagnut66 »

Hi,
Is it me or do spark plugs not seem to last as long these days?
It seems that ever since we went unleaded and then started introducing 'E' numbers into petrol one side effect is that the fuel burns hotter and the spark plugs are not so good at taking the heat?..........
Or have I got the wrong end of the stick?

If I am, in some way, correct then what do people recommend as the best spark plugs for surviving longer in this hotter enviroment?
Best wishes,
Mike.
1954 Series 2: 4 door: "Sally" -- Back on the ground with (slave) wheels and waiting to be resprayed......
1970 Triumph Herald 1200: "Hetty" -- Driven back from Llangollen in Wales (twice.....)
philthehill
Minor Maniac
Posts: 10768
Joined: Thu Jul 19, 2012 12:05 pm
Location: Hampshire
MMOC Member: Yes

Re: Cooking the spark plugs

Post by philthehill »

If the plug is running hot use a cooler running plug for example if using a N9Y replace with a N7Y or similar. The lower the number the colder the plug runs. Use a plug without a extended nose.

https://www.sparkplugs.com/what-is-a-sp ... at-range-2

jagnut66
Minor Legend
Posts: 3635
Joined: Fri Apr 11, 2008 7:28 pm
Location: Mansfield, Nottinghamshire.
MMOC Member: Yes

Re: Cooking the spark plugs

Post by jagnut66 »

Thanks Phil, very interesting to read / know.
I will follow this up.
Best wishes,
Mike.
1954 Series 2: 4 door: "Sally" -- Back on the ground with (slave) wheels and waiting to be resprayed......
1970 Triumph Herald 1200: "Hetty" -- Driven back from Llangollen in Wales (twice.....)
simmitc
Moderator
Moderator
Posts: 4718
Joined: Thu Apr 15, 2004 9:43 am
Location: Essex
MMOC Member: Yes

Re: Cooking the spark plugs

Post by simmitc »

The title of this topic reminded me of an owners manual for a British Seagull outboard motor. Those motors were pretty well indestructible but definitely "had their moments". Anyway, the manual advised that in cold weather, the spark plug should be warmed in an oven to aid starting. Given that the motors were often used on the back of a dinghy, I often wondered just where one was supposed to find an oven, and just what reaction a chap would get when explaining to his wife that he was just heating an oily spark plug in her baking appliance :o Hopefully that isn't too sexist for today's readers.
Shropshiremoggie
Minor Legend
Posts: 1055
Joined: Mon Jul 17, 2017 7:45 pm
MMOC Member: Yes

Re: Cooking the spark plugs

Post by Shropshiremoggie »

When I replaced the starter ring on my Renault 5 I heated it up in the oven to expand it in order to fit it ! I have also heated spark plugs on the Rayburn for my ailing two stroke garden impliments.
ampwhu
Minor Addict
Posts: 769
Joined: Sat Oct 31, 2009 8:51 pm
Location: Epsom, Surrey
MMOC Member: No

Re: Cooking the spark plugs

Post by ampwhu »

I recently fitted 4 new plugs in my rebuild 1275 engine. I've driven 500 miles or so and wanted to check it all over. When I started to remove 1 plug to check colour, it snapped. Then I tried another plug, snapped. 2 out of 4 broke.

Me thinking it was my plug spanner, I tried it on my spare engine with old plugs in. All 4 came out easy. I'm thinking 2 things.

Plugs do run hotter or the quality is very poor now on parts. Plugs were from ESM.
simmitc
Moderator
Moderator
Posts: 4718
Joined: Thu Apr 15, 2004 9:43 am
Location: Essex
MMOC Member: Yes

Re: Cooking the spark plugs

Post by simmitc »

Regardless of the supplier, which manufacturer is stamped on the plugs?
User avatar
geoberni
Minor Legend
Posts: 3565
Joined: Fri Aug 04, 2017 11:19 am
Location: North Leicestershire
MMOC Member: Yes

Re: Cooking the spark plugs

Post by geoberni »

ampwhu wrote: Sat Sep 04, 2021 9:49 am I recently fitted 4 new plugs in my rebuild 1275 engine. I've driven 500 miles or so and wanted to check it all over. When I started to remove 1 plug to check colour, it snapped. Then I tried another plug, snapped. 2 out of 4 broke.

Me thinking it was my plug spanner, I tried it on my spare engine with old plugs in. All 4 came out easy. I'm thinking 2 things.

Plugs do run hotter or the quality is very poor now on parts. Plugs were from ESM.
Where did they break? Ceramic or Metal parts?
A correctly fitted Plug Spanner/Socket is only bearing on the metal 'nut' of the Plug, it should not be exerting any pressure on the ceramic, the most it should be doing is having a foam padding to help lift the plug out.

If the 'nut' part separated from the 'thread' part, then it's a quality issue after 500 miles so complain to the manufacturer.

Look at this video of a Yank who broke 2 plugs on a Pick-up.
His must've been in there since the truck was made looking at the rust....
https://www.youtube.com/watch?v=JijVI3RTkMY
Basil the 1955 series II

Image
ampwhu
Minor Addict
Posts: 769
Joined: Sat Oct 31, 2009 8:51 pm
Location: Epsom, Surrey
MMOC Member: No

Re: Cooking the spark plugs

Post by ampwhu »

ceramic part. Plugs were Champions.
Shropshiremoggie
Minor Legend
Posts: 1055
Joined: Mon Jul 17, 2017 7:45 pm
MMOC Member: Yes

Re: Cooking the spark plugs

Post by Shropshiremoggie »

Interesting comment from geoberni , could it be the plug spanner catching on the plug as its removed and breaking the ceramic ????
ampwhu
Minor Addict
Posts: 769
Joined: Sat Oct 31, 2009 8:51 pm
Location: Epsom, Surrey
MMOC Member: No

Re: Cooking the spark plugs

Post by ampwhu »

i agree totally. But these plugs were very brittle which is why they broke easily. First time for me in what.... 35yrs!
cococola
Minor Fan
Posts: 351
Joined: Sun Apr 21, 2013 10:30 pm
Location: solihull,west midlands
MMOC Member: Yes

Re: Cooking the spark plugs

Post by cococola »

My champions snapped on 3 of my ceramics, this with me not catching them with my socket.
I think unfortunately the quality isn't as it used to be on some plugs, I have fitted NGK with no issues so far.
Morris Minors..... such fun :D
Post Reply