ngk plug selection

[chris240]

guys

Ive been using BP6ES plugs (0.8 gap) for a while now....I just installed BP6ES II (1.0 gap) into my L24 and it feels real nice....Ive heard this plug is more suitable when you have elec ignition, not sure how true this is...but time will tell.

anyway I was wondering as my engine gets older, should I really be using the BP5EY plug which is a hotter plug ? When I used the "6" rated plug, it did tend to gunk up a little.

[sydney mike]

Hi Chris. The trusty old bloke at my local Robbo's spares recommended the 6 for a daily driver but the 5 for an occasional driver (me). I had problems with the 6's but then again my carbies were out of tune. There was a noticeable difference right away with the 5's even before the carbie tune. Now have the carbies tuned plus electronic dizzy and she's sweet as. Not sure about the effects of how worn your engine is though, is your Zed a daily?

 

 

 

 

[chris240]

hmmm something in the back of my mind was telling me to go with the 5's, but my local Repco was out of stock (and I was impatient)  so I bought the 6's...

Mike its not a daily, its becoming a once a month !

So BP5EY it will become by next weekend.....If any of the local lads want some BP6ES II call me.

[orange-Z]

Put the 5's in mine about 6 months ago because I also read the recommendation for non-daily drivers.  Put approx 2k on them.  Had a look at them this evening and they are in almost perfect condition.  Just a little tan colour.  Motor is working better than on the 6's.

[lightmaster240z]

Chris I ran 5 but it allways claged up now I run 6 no problems at all now

regrads

Bruce

[stevo_gj]

I had it explained to me that the hotter plug was a better option when my motor was running rough because it ensured that the majority of the fuel mixture was burning. I ran BP5ESs at one stage and it made my engine run much better because it made up for the poor spark coming from my points dizzy.

 

Regarding using the 5's on a non daily I think the reason is that over time a hotter spark might cause the cylinder to develop localised 'hot spots' that could cause premature wear. Perhaps causing cracking in the piston rings or damage to surface of the piston.

 

It was suggested to me by Dazzed that I used BP6ES11s with the electronic dizzy I got from him. I can't remember his explanation exactly but it makes sense that an electronic dizzy has a stronger/hotter spark already and therefore you can increase the gap size without making the spark too weak. It also makes sense in my head that the increased gap size will mean a larger spark, which means more fuel burns upon ignition which increases the % of fuel burned, and therefore increases fuel efficiency/power.

 

If you tried to use the BP6ES11s with an old points dizzy I imagine the spark would become quite weak and not all of the fuel mixture would burn.

 

This is just what I think anyway, please correct me if I'm wrong.

 

Edit: I now run BP6ES11s on my L26 with a reco'd electronic dizzy and SUs tuned by me using a colortune and it runs great.

[chris240]

Steve , your 100% correct the BP6ES-II "probably" shouldnt be used with a points dizzy.

I didnt clarrify that I am using elec dizzy/ignition, which is why these plugs are doing the job nicely.

Im still going to give the 6's a try for a few weeks, just to see if I can "feel" a difference.

[chris240]

update...

well I just clocked up 350kms in the last 3 days (coast run)...and the ngk BP6ES II  6's are all black, sooty and have the slight smell of fuel..

driving down the coast on the 1st day (the plugs where newish) the motor ran sweetly...however the next morning it was an absolute dog, today it felt like the motor was running on 3 cylinders... i stopped halfway and advance my dizzy but that did diddly..

I hope its nothing more sinister than plug selection, timming check and/or a dodgy lead.

[Scoota G]

What condition is the motor in like compression and such? Maybe one of the chokes was stuck on.

[Mr240z]

Chris try BP5E they are a V-Groove plug. You don't need the extended gap.

   

      NGK V-GROOVE

Lowers ignition system voltage requirements

Greater ignitability and performance over conventional spark plugs

“Trivalent Metal Plating” has superior anti-corrosion and anti-seizing properties

Increased fuel economy and lower emissions

Highly durable against electrical and chemical wear

Good performance spark plug

 

http://www.ngk.com.au/sparkplug.php#

 

p.s These are the plugs I run, Worked L24 tripple 45's Elec dissy

[stevo_gj]

Your plugs should run fine, so its got to be something else, right? The idea of the choke being stuck on or of the tune being too rich makes sense. I think you should look into the cause before finding a solution to mask the problem.

 

Obviously getting a hotter plug will just mean that a rich mixture will burn almost as thoroughly as a normal mixture. Are you able to check with a colortune?

[chris240]

scootag, this is my new motor, which was dropped in 2 weeks ago..We swapped the carbs over from the L24 onto the L28...

whats got me stumped is the motor ran perfectly...I do use the choke to start-er-up, and when I push the choke lever back it seems to be "ok"..I'll check to see if its sticking...

I agree Steve, I cant see how going to a 5 series hotter plug can solve the problem, I really shouldnt have that much soot and carbon on the 6's .....

Do I need to adjust my SU's a tad ?? they where running perfectly, or was it a case of the plugs needed 400kms to gunk up which fooled me in the the first say 200kms when the motor ran perfectly ?

.....pffftt Ive got my webbers arriving this week, as If I needed another headache !!

[Zedman240®]

If you are going to stick on the Webers, don't waste too much time now with the 240 carbs. you should be able to get the 6's running at a good colour. Going to a 5 heat range is dealing with the side effects rather than the initial problem. If the deposits are dry, black and sooty, that's just too much fuel. You should have light coffee colour with little deposits on the insulator. If you can get a oxy sensor and measure the exhaust, that should help a lot.

[sexual_sushi]

Does your "new" engine mean a brand new rebuild or just a new motor from another car? If it wasn't rebuilt, what are you piston rings and valve stem seals like? Does your car blow any smoke?

 

+1 on waiting for the webbers, i reckon it might just be a running rich thing as well

[chris240]

shaun ?

the motor was a donner, but its strong & tight...150 compression across all cylinders, & it doesnt blow smoke at all.

Im tempted to lean out the carbs a little....its got to help.

[dazzed]

Fuel quality also plays a big part here as well, some fuels have high levels of butane which accumulate a sooty coating on plugs which can make confusing for setting fuel mixtures and it wont burn off, leaves gummy black deposits on the rear of the car tailights bumper chrome etc, and requires solvent to remove, dosnt do the engine any good either builds up on valves, all our pump fuel is unleaded so no more grey tailpipe tips for checking air fuel strength just black , a engine with 150psi compression i would consider as being a low compression engine provided its N/A a BP5EY is fine , 175PSI and over your into the 6 range,  the lower the number the hotter the plug will operate at the higher the number the colder , as the mixture becomes leaner the temperature in the combustion chamber increases as does the energy it produces untill the temperature becomes so high your engine begins to melt, so its important to know where to stop leaning it out, lean mixture colder plug rich mixture hotter plug, ngk book requires a 240z /260z a BP6ES plug if it fouls up theres something wrong

[stevo_gj]

Chris have you tuned your SUs before? If you don't have access to a colortune then I would adjust the idle to just above stalling and then see if leaning it out makes it idle better.

 

The simplest way to tune the SUs is to adjust the mixture knobs by a quarter turn at a time until your low idle speed is as high as you can get.

[dazzed]

increasing the advance of ignition timing will increase pressure in the cylinder and does this by compressing the explosion that has already taken place way down in the cylinder ,,but you sacrifice power for it if you go too far, and can blow head gaskets and break the top ring which i have seen on many occasions due to incorrect fuel mixtures, a common symptom of this is brown specks or freckles on the porcelain of the plug, thats a bad thing ,

[chris240]

just following up on this thread....

I had my zed at performance plus workshop where Bruce the owner is the regions leading authority on carbs...anyway he waved the magic wand over my carbs and was a bit horrified that I was running 6 series NGK's, and that retarding my timing wouldnt help at all. Anyway we swapped to 5 series ngk's left the timing at 8 degress , and bobs your uncle...back to perfection.

If you read my previous postings , I threatened to swap to the 5's but I got lazy... taught me to experiment rather than accept !