Classic cars forum & vehicle restoration.

Rdover · Joined: 26 Nov 2007 Posts: 413

I've been having plug fouling problems with my Veteran car and yesterday I had a fascinating conversation with Tim at the Green Spark Plug Company and he pointed me to the link below.

It would seem that as fuels get worse and engines get more computer controlled we will have to find a way round the plug fouling problem.

My case is a perfect example: I fitted new Champion D16s and ran it a tickover for about 15 minutes whilst I dialled in the idle settings and then test drove the car for about 10 miles. A couple of days later I drove the car for a total of 90 miles but after 40 the performance had dropped hugely and then got so bad I barely made it home. The jetting was very rich indeed but older plugs would just have needed brushed clean. I rejetted to lean it right out but the car still ran badly.

New plugs were fitted (NGK AB-6) and the points and ignition timing reset (along with an earthing problem being sorted) and the engine runs brilliantly even after 50 miles and plenty of tickover time.

I'll be trying out the oven cleaner trick today to see if that saves me £20 each time a oil up some plugs and I've also ordered some Champion D21 plugs which will cope even better and see how they go.

http://www.gsparkplug.com/shop/fouling-shortingout-problem-modern-plugs-champion-vs-ngk/
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Richard

kevin2306 · Posted: Fri Sep 12, 2014 12:39 pm Post subject:

Whilst my Singer is a lot younger that your car, when I was having ignition issues and eventually fitted a new electronic ignition distributor, I ordered a set of brand new champion plugs of the type recommended in the origional handbook.
The car refused to run correctly on them so I swapped the originals back in and she was sweet as a nut once more (ordered a new set of the same and swapped them). I suppose the 1st owner must have made the plug spec change when he fitted the Lucas Ignition system?
Worth experimenting with a few different types id say..

As for cleaning, I use my ultrasonic cleaning bath with some decent degreaser in it (along with warm water). brings them up as new and doesnt appear to have any ill effects..(im sure some will say otherwise)

Kev

Rdover · Joined: 26 Nov 2007 Posts: 413

Ultrasonic with degreaser sounds even better than oven cleaner. More expensive and less portable tho Wink

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Richard

kevin2306 · Posted: Fri Sep 12, 2014 1:21 pm Post subject:

D4B · Joined: 28 Dec 2010 Posts: 2083 Location: Hampshire UK

kevin2306 · Posted: Fri Sep 12, 2014 4:53 pm Post subject:

Rdover · Joined: 26 Nov 2007 Posts: 413

I tried cleaning with oven cleaner. I'm told Mr Muscle is the one to use.

First, one that failed to clean and is as oily as removed from the engine (noting that it is wet from being rinsed)

One that cleaned up perfectly

and one that cleaned up a bit

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Richard

peter scott · Joined: 18 Dec 2007 Posts: 7118 Location: Edinburgh

Is AB6 not a bit too cold a plug for a very low compression engine?

Something hotter like AB2 might prevent oiling.

Peter
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http://www.nostalgiatech.co.uk
1939 SS Jaguar 2 1/2 litre saloon

goneps · Posted: Sat Sep 13, 2014 12:57 am Post subject:

Can't say I've had the slightest trouble with plugs on the '36 Morris Eight. Admittedly this country is not yet cursed by the dreaded ethanol (some petrol shops sell a mix, but most don't).

Recently I replaced the set of NGK B6HS that'd been in use for more than twenty years (35,000 miles), probably an unnecessary expense (picture shows one of the old plugs before cleaning about 2,000 miles ago). Have used only NGK on all my vehicles for about 35 years, because I believe they're the best.

As for cleaning, my quick and effective (ie. lazy) method is a thin, soft rotary wire brush on the grinder. Works like a charm.

Richard

kevin2306 · Posted: Sat Sep 13, 2014 9:53 am Post subject:

This is the one I bought, Rang the company up and got an ex-demo model a bit cheaper too. With warm water and a household universal surface cleaner it is superb on carb parts. As discussed, it also brings the spark plugs up a treat.

http://www.ebay.co.uk/itm/Digital-600ml-Ultrasonic-Cleaner-Timer-Cleaning-Jewelry-Watch-Stainless-Tank-/191039255151

Kev

baconsdozen · Joined: 03 Dec 2007 Posts: 1119 Location: Under the car.

I cleaned the plugs on my Rover http://www.baconsdozen.co.uk/Humphrey.htm this morning,same way as I've always done plugs, with a soak in cellulose thinners. They dry in seconds and you can give them a quick go over with a brass wire brush if there's any stubborn bits left. Square the ends off with a proper fine toothed magneto file and they're as good as new.
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Thirty years selling imperial hand tools for old machinery(Now happily retired).

D4B · Joined: 28 Dec 2010 Posts: 2083 Location: Hampshire UK

kevin2306 · Posted: Sat Sep 13, 2014 11:05 am Post subject:

Works ok with warm water but put chemical in and its so much better.
I use a 20% mix of fairly hot water and a citrus household cleaner. I would like one of the larger units as you could obviously clean larger itema such as carb bodies (mine will do a body but you need to rotate it and do the process in sections)
Some of the units around £100 have in-built heaters etc. worthwhile ringing them for an ex-demo unit.

Kev

Rdover · Joined: 26 Nov 2007 Posts: 413

Ashley · Joined: 02 Jan 2008 Posts: 1426 Location: Near Stroud, Glos

NGK are the easiest to understand and the best plugs.

Heat range is easier to understand that lawn mowers, tractors and stationary engines have low numbers like 2, Rolls-Royce's 5, most cars 6 or 7 and Manx Nortons and racing cars 10.

A means 18mm thread and B is how long the thread is. P is a projecting nose.

Hope this helps.

Ash