Spark Plugs

[mikefromengland]

hello every one.im mike .i own a +2s130 .i believe the correct spark plugs for the twink with webbers to be eg ngk bp7es .i bought some of these and found them quite usless.i found the car to be almost undrivable at low speeds.so i got some bp6es.these are great.used colour tune to set mixture.car goes supurb now even at slow speeds.reccomended.has any one else had this problem? kid regards mike.

[type26owner]

Hi Mike,
The technical stuff you need to know to select the best plug for your engine can be found here. What actually is meant by fouling is the carbon builds up on the insulator and the spark shorts to earth via that carbon conductive path rather jumping the electrode airgap.
<a href='http://www.ngksparkplugs.com/techinfo/spark_plugs/techtips.asp?nav=31000&country=' target='_blank'>http://www.ngksparkplugs.com/techinfo/spar...=31000&country=</a>

I've switched over the Autolite 63 because it's a resistor copper core type with the same heat range and it's cheap. NGK only offers the resisitor plug in that heat range as an Iridium plug and they are through the roof on the cost. No way am I paying that kinda money for a car plug.

Reading a spark plug to get the air/fuel mixture correct is a joke. That only works if the correct heat range of spark plug is already installed. It's the old which comes first question, the chicken or the egg? Bad way to do mixture settings altogether.

[twincamman]

use n9y champions ---- ed

[rgh0]

Mike

I agree with going to NGK BP6ES plugs for normal driving. The Lotus recommended plug of Champion N7Y is too cold in a normal engine uless you are using it flat out. I guess Lotus expect the cars to be driven flatout all the time !!

My experience with plugs for what its worth at least with Australian fuels and non Stromberg cars is:


NGK BP6ES = Chamion N9Y - road engine, normal driving on premium unleaded
NGK BP7ES = Champion N7Y - road engine, track days or continuous high speed
NGK BP8ES = Champion N6Y - 12.5 to 1 high compression race engine on Avgas.

Rohan

[JACKJABBA]

I have found the same problem with the BP7ES, they just run too cool to self clean.

[berni29]

Hi

I never knew that about the fouling. I thought it must be that the build up was a physical (insulating) barrier to the spark. Very interesting. I have never really taken that much notice of which plugs I am using. I will do now!.

Berni

[type26owner]

Because the modern day car has complicated vacuum hose plumbing it causes havoc to the unaware. The carbon black which vacuum hose is loaded with makes the hose a rather good electrical conductor. Having a plug wire touch a vacuum hose is almost guaranteed to result in a short eventually.

[gjz30075]

I"m running a BP5ES, which is even hotter yet, and my car runs much better than running BP6ES. I'm probably masking some over rich problem, though
Time for the wide band O2!

[worzel]

Hi All

A couple of years back I had cause to make use of a rolling road in Rochdale, Lancs. The firm, recommended by CD Developments was called GRV. The guy who fault finded on my car suggested because of the compressions that I use BP8ES as he reckoned his diagnostic bag of tricks was indicating that the BP7ES I was using were breaking down. I thought "way too cold" but he was right. I've sat in half hour traffic jams with no sign of fouling and when pulling away there is no mifiring etc.

It might be contentious but I can only report my own personal experiences.

I believe though that the correct grade is actually BP7Es or equivalent and I used to use them for many years.

John

[zuckerlowe]

Hi,
I found Champion N9Y to be better for everyday driving. This is handy as it's what my MGB uses.

Cheers
Steve (1968 +2)

[rgh0]

John

What carbs and compression ratio are you using, what sort of ignition timing do your run and what sort of fuel economy do you get. In a road engine with 10.5 or less comp ratio I would only expect a BP8ES to work in an emission stromberg engine or overly lean Weber setup or overly advanced engine.

The BP8ES needs lots of heat to get it up to the right temp to not foul and if you are not fouling it in normal road driving something else is possible not optimum unless your definition of optimum is a overly lean emission setup.

However its hard to diagnose an engine over the internet so if it works for you who am I to query it !!!

regards
Rohan

[Hamish Coutts]

Hello,

Did a 275 mile run up to the Scottish Highlands last Friday on lovely deserted, twisty A roads. Needless to say it was a fast run.
Had just serviced the engine and had fitted new plugs - BP6ESs. On Saturday morning the car wouldn't run properly, stuttering and coughing and only firing on 3 cyls. Turned out the plugs had fouled. One in particular (no.4) was very sooty.

Finally found a garage on Saturday morning that was open (at 11:30am on Skye, open garages are as rare as hobby horse shit!) and the only plugs that I recognised were N9Ys, which I fitted. The car ran very smoothly for the rest of the weekend and on another fast run home. When I took the plugs out last night to have a look they were fine.

In my case N9Ys seem to be the ones for the job. Up 'till now I had run BP7ESs (a couple of new sets came with the car) but the engine always seemed lumpy and reluctant to run well at low revs. This is not the case on N9Ys. Things are a lot better.

Car is an Elan +2S130 big valve running dellortos and lumenition with a standard coil.

Hope this helps,

Hamish.

[mikefromengland]

cheers for the info.it seems that n9y ny8 do the job.both are hotter than bp7es .the same as bp5es and bp6es respectively.im running 12 degrees btdc,ardon electronic ignition with the matching flamethrower coil.plug gap is 30 .these are the values according to miles wilkins book only diff they reccomend colder plug of bp8es.im sticking to bp6es.the engine starts fine from cold no choke on webbers.pulls well no missfire or flat spot.caned the car for 20 miles tick over fine 20 mph in 4th no problem im sticking to this set up and have some serious fun regards mike ps just fitted new water pump that was fun haha

[cliveyboy]

Question
When running hotter plugs are you still using the standard plug gaps?
Also I am about to fit N9YCCs . Usually with copper cores they recommend bigger gaps. Any one have experience of these
Also I noticed the statment on the back of the box that says copper cores run cooler.
I am wondering if going hotter plugs can be counteracted by using copper cored plugs.

[mikefromengland]

i use electronic ignition and use 30 thou gap