Series 3 spark plugs colours

Talk about the E-Type Series 3

Topic author
chris420sa
Posts: 25
Joined: Tue Aug 30, 2016 1:50 pm
Great Britain

#1 Series 3 spark plugs colours

Post by chris420sa » Tue Oct 30, 2018 5:29 pm

I have just pulled all the plugs on the V12 after a 20 mile run in fairly cool weather and thought it would be helpful if a member or two could please advise what fuel mixture adjustments they would recommend on each of the four Strombergs ....and any other adjustment. The ignition timing is OK (slightly advanced versus the ROM spec), new dizzy cap, fairly new leads, fairly new plugs, great spark, only centrifugal advance (I have "plugged" the vacuum retard hose, given that the retard is an unnecessary complication), can't detect any vacuum or other leaks, fuel pump seems to be delivering OK....
Colours below refer to the central electrode, plugs numbered from front of engine
A Bank
1. White on one side, grey on the other side
2. Light grey on one side, dark grey on the other side
3. White on one side, light grey on other side
4. Dark grey to black all round
5. White on one side, dark grey on the other side
6. Dark grey all round

B Bank
1. White/light grey
2. White/light grey
3. White/light grey
4. Dark grey
5. Dark grey
6. Light grey

I should also mention that there's a flatspot at about 3,000 rpm (which was why I pulled the plugs)

I look forward to your welcome feedback.
Best regards
Chris

Link:
BBcode:
HTML:
Hide post links
Show post links

User avatar

abowie
Posts: 1998
Joined: Wed Sep 07, 2011 9:15 pm
Location: Australia
Contact:
Australia

#2 Re: Series 3 spark plugs colours

Post by abowie » Wed Oct 31, 2018 12:42 am

Unless you're running leaded fuel this is not really a useful test any more.
Andrew.
881824, 1E21538. 889457..oops
http://www.projectetype.com/index.php/the-blog.html
Adelaide, Australia

Link:
BBcode:
HTML:
Hide post links
Show post links

User avatar

jagwit
Posts: 363
Joined: Thu Oct 18, 2012 6:52 am
Location: Pretoria
South Africa

#3 Re: Series 3 spark plugs colours

Post by jagwit » Wed Oct 31, 2018 5:25 pm

chris420sa wrote:
Tue Oct 30, 2018 5:29 pm
B Bank
1. White/light grey
2. White/light grey
3. White/light grey
From this info, it seems there is a problem with the front carb on the B-bank. Seems to be running lean almost as if its not feeding any fuel (or way too little).

I would remove that air filter, and while looking into that carb (with safety glasses), rev it up briefly with much throttle and observe if 1) the air valve (that cylindrical "piston" in front) lifts as much as the rear carb; 2) you can see fuel being drawn into the carb.

It might also be worth while to check if the butterfly on that carb actually opens before you start. If somehow the throttle linkage came loose....
Best Regards
Philip
71 E-type V12 Coupe,
80 XJS (EFI by Megasquirt & EDIS-6 + 5sp manual overdrive)
73 Jensen Interceptor
74 Interceptor (EFI by Megasquirt + overdrive 4sp auto)

Link:
BBcode:
HTML:
Hide post links
Show post links


JJC
Posts: 228
Joined: Fri Apr 21, 2017 3:06 pm
United States of America

#4 Re: Series 3 spark plugs colours

Post by JJC » Fri Nov 02, 2018 12:48 pm

Can always learn something new ! Why is reading spark plugs no longer a great way to get a handle on mixture, timing, etc ., since no one really using anything but unleaded gas these days ?


Thanks.

FYI.....I do it all the time !

Link:
BBcode:
HTML:
Hide post links
Show post links

User avatar

jagwit
Posts: 363
Joined: Thu Oct 18, 2012 6:52 am
Location: Pretoria
South Africa

#5 Re: Series 3 spark plugs colours

Post by jagwit » Fri Nov 02, 2018 5:44 pm

Even with unleaded spark plugs can still tell something. (I'm certainly no spark plug whisperer...)

It most certainly will tell you if the piston is running rich = very black
Too lean = too white and clean

I can not see how a spark plug can tell much about timing. Maybe there's something when the engine detonates a lot?
Best Regards
Philip
71 E-type V12 Coupe,
80 XJS (EFI by Megasquirt & EDIS-6 + 5sp manual overdrive)
73 Jensen Interceptor
74 Interceptor (EFI by Megasquirt + overdrive 4sp auto)

Link:
BBcode:
HTML:
Hide post links
Show post links

User avatar

malcolm
Posts: 1249
Joined: Fri Jan 03, 2014 10:44 am
Location: Fleet
Great Britain

#6 Re: Series 3 spark plugs colours

Post by malcolm » Sat Nov 03, 2018 9:58 am

I believe pinking from too far advanced timing can cause burning off the spark plug tips.
Malcolm
I only fit in a 2+2, so got one!
1969 Series 2 2+2
2009 Jaguar XF-S

Link:
BBcode:
HTML:
Hide post links
Show post links

User avatar

jagwit
Posts: 363
Joined: Thu Oct 18, 2012 6:52 am
Location: Pretoria
South Africa

#7 Re: Series 3 spark plugs colours

Post by jagwit » Sat Nov 03, 2018 11:47 am

Here's an example of my car 's plugs, which I recon is one of the best tuned S3's in South Africa - IMHO.

Inner ones #2 on each bank, outer ones, #6 on each bank:
tn_20181103_132041.jpg
tn_20181103_132041.jpg (138.54 KiB) Viewed 418 times
Relevant info;
  • The carbs on my car are perfectly balanced;
  • fueling set as good as I can;
  • needles changed to reduce overfuelling on full throttle (it was making visible black smoke on full throttle pulls);
  • Lumenition ignition;
  • Vacuum advance (vacuum direct from intake manifold);
  • I add 500mL of 2-stroke oil to the fuel every time I fill up (only when fuel gauge is well below 0)
Best Regards
Philip
71 E-type V12 Coupe,
80 XJS (EFI by Megasquirt & EDIS-6 + 5sp manual overdrive)
73 Jensen Interceptor
74 Interceptor (EFI by Megasquirt + overdrive 4sp auto)

Link:
BBcode:
HTML:
Hide post links
Show post links

User avatar

Ole-xke1974
Posts: 67
Joined: Sat Nov 08, 2014 9:52 am
Location: Annapolis, USA
United States of America

#8 Re: Series 3 spark plugs colours

Post by Ole-xke1974 » Sat Nov 03, 2018 12:04 pm

Philip, I get all of the above except the addition of 2-stroke oil. Can you explain ?
FYI, I once accidentally put petrol for a 2-stroke moped (~4% oil) in my car and experienced that it ran smoother.
1974 SIII E-Type w. XJ S2 4sp w. O/D

Link:
BBcode:
HTML:
Hide post links
Show post links


JJC
Posts: 228
Joined: Fri Apr 21, 2017 3:06 pm
United States of America

#9 Re: Series 3 spark plugs colours

Post by JJC » Sat Nov 03, 2018 12:15 pm

Philip: Your plugs look perfect ! I am also curious as to the addition of two stroke oil. Always several ways to skin the cat......love to hear !

Thanks

JC

ps: I'm guessing the carbs are set more on the lean side.....that's where I found my sweet spot.

Link:
BBcode:
HTML:
Hide post links
Show post links

User avatar

jagwit
Posts: 363
Joined: Thu Oct 18, 2012 6:52 am
Location: Pretoria
South Africa

#10 Re: Series 3 spark plugs colours

Post by jagwit » Sat Nov 03, 2018 12:44 pm

Ole-xke1974 wrote:
Sat Nov 03, 2018 12:04 pm
Philip, I get all of the above except the addition of 2-stroke oil. Can you explain ?
FYI, I once accidentally put petrol for a 2-stroke moped (~4% oil) in my car and experienced that it ran smoother.
I BELIEVE (no hard evidence..) there to be the following advantages of using 2-SO in our old cars:
  • Reduces rust in mild steel fuel tanks - fuel evaporates from sides, leaving thin oil layer
  • Lubricates fuel pump - FWIW;
  • Shows presence of fuel leak - fuel evaporates but coloured 2-SO stays thus showing the leak - ask me how I found this particular benefit ...;
  • Lubricates moving parts in carb;

Now comes the more important ones:
  • The 2-SO in the fuel APPARENTLY (no hard evidence) softens the carbon deposits behind the intake valves, and over time this carbon is sucked/shaken off thus improving engine breathing efficiency;
  • Ditto the carbon on the piston top and inside the combustion chamber;
  • Ditto the carbon between the rings and the piston - this could result in improved compression as the rings work loose and thus seal better; I have actually seen this happen on a Land Rover Discovery 1 V8 where #5 was way down on compression relative to the others when I got the car. After driving about 5 tanks on the 2-SO mix, #5 compression was on par with the others;
  • 2-SO does not burn and thus some of it is blown out the exhaust port and now you have the same effect on the exhaust valve and port as the intake valve;
  • Lubricates the exhaust valve stem - reduces valve stem and guide wear.
IMPORTANT!!
2-SO should NOT be used on a car with CAT's or Lambda sensors. 2-SO can contain heavy metals which could destroy both.

As for your experience Ole, I doubt any of the performance related effects mentioned above could come into play immediately, so I can not offer an explanation as to why you experienced it as running smoother.

There is a Youtube video that shows a lawnmower running happily on a 50:50 mix of pertrol/2-SO. THIS I can attempt to explain if we consider that the lawnmower was most likely running pig rich and the added 2-SO was merely effectively leaning out the mixture to a point where it was running leaner.
Last edited by jagwit on Sat Nov 03, 2018 12:57 pm, edited 1 time in total.
Best Regards
Philip
71 E-type V12 Coupe,
80 XJS (EFI by Megasquirt & EDIS-6 + 5sp manual overdrive)
73 Jensen Interceptor
74 Interceptor (EFI by Megasquirt + overdrive 4sp auto)

Link:
BBcode:
HTML:
Hide post links
Show post links

User avatar

jagwit
Posts: 363
Joined: Thu Oct 18, 2012 6:52 am
Location: Pretoria
South Africa

#11 Re: Series 3 spark plugs colours

Post by jagwit » Sat Nov 03, 2018 12:56 pm

There is another benefit I forgot about:

Lubricates the exhaust valve stem - reduces valve stem and guide wear.
Best Regards
Philip
71 E-type V12 Coupe,
80 XJS (EFI by Megasquirt & EDIS-6 + 5sp manual overdrive)
73 Jensen Interceptor
74 Interceptor (EFI by Megasquirt + overdrive 4sp auto)

Link:
BBcode:
HTML:
Hide post links
Show post links


Topic author
chris420sa
Posts: 25
Joined: Tue Aug 30, 2016 1:50 pm
Great Britain

#12 Re: Series 3 spark plugs colours

Post by chris420sa » Tue Nov 06, 2018 2:04 pm

Phillip - the case for the defence of 2 SO is well made. I'll definitely give it a try.

Following your advice, I checked that the front LH carb was operating in unison with rear LH carb etc. All fine.
Then set the mix using the screwdriver piston lift method. Front RH carb was definitely running too lean, the other carbs only needed minor adjustment. Went for a good run, plugs all perfect and no flat spot.

If this success continues what will I do with my spare time!

All the best
Chris

Link:
BBcode:
HTML:
Hide post links
Show post links

User avatar

jagwit
Posts: 363
Joined: Thu Oct 18, 2012 6:52 am
Location: Pretoria
South Africa

#13 Re: Series 3 spark plugs colours

Post by jagwit » Tue Nov 06, 2018 2:23 pm

chris420sa wrote:
Tue Nov 06, 2018 2:04 pm
Went for a good run, plugs all perfect and no flat spot.

If this success continues what will I do with my spare time!
Randomly tune them out and then start again? :bigrin:

Nice to hear its sorted!
Best Regards
Philip
71 E-type V12 Coupe,
80 XJS (EFI by Megasquirt & EDIS-6 + 5sp manual overdrive)
73 Jensen Interceptor
74 Interceptor (EFI by Megasquirt + overdrive 4sp auto)

Link:
BBcode:
HTML:
Hide post links
Show post links

User avatar

PeterCrespin
Posts: 3804
Joined: Fri Mar 05, 2010 8:22 pm
Location: Gaithersburg, Maryland.
Contact:
United States of America

#14 Re: Series 3 spark plugs colours

Post by PeterCrespin » Wed Nov 07, 2018 12:00 am

2-stroke oil is specially blended as low-ash, in order to leave, you guessed it - as few deposits as possible when much of it burns. The idea that burning extra oil reduces deposits is bizarre on its face. By that reckoning the cleanest engines would be the ones with knackered inlet valve seals, worn oil rings and black goo dribbling out of the tailpipe like a Trabant on heat. Even synthetics burn eventually. Earlier this season, F1 teams were banned from using a reserve of engine oil as extra fuel to get round the fuel consumption rules.

Being a Jaguar driver, it goes without saying that I can rationalize almost any automotive excess. But to deliberately pollute more, in such a wanton and unnecessary way, shocks even me. I've raced two strokes, I love them in some contexts. You've never felt a powerband until you've ridden an old-school stroker as it comes onto the expansion chamber and takes off like the proverbial scalded cat. But the likes of Ford et al had to admit defeat a few years ago when the industry finally abandoned them, despite amazing advantages over 4-strokes in other respects. Even with direct oiling and running on neat petrol, and the brain-power of consultancies like Ricardo, the big firms had to kiss their heavy investment goodbye because they simply couldn't be made to run clean enough no matter how much technology they threw at them.

So now we're supposed to add it deliberately to vehicles that do fine without? Those of us with kids and grandchildren have already some explaining to do on heavy metals etc.
1E75339 UberLynx D-Type; 1R27190 70 FHC; 1E78478; 79 S2 XJ12L; 97 XJ6L

Link:
BBcode:
HTML:
Hide post links
Show post links


Woolfi
Posts: 281
Joined: Thu Jan 28, 2010 5:57 pm
Location: Germany
Germany

#15 Re: Series 3 spark plugs colours

Post by Woolfi » Tue Nov 13, 2018 9:43 am

"Vacuum advance (vacuum direct from intake manifold)"
This is WRONG. The vacuum has to be taken from a port at the carb, "called tappered edge". Few carbs have this port. For my EV12 I had to drill a port to one carb. The port has to end roundabout 1 - 3 mm in FRONT of the butterfly. If you presse the pedal slightly (part throttle) , the edge of the butterfly has to by exactly at this port, to generate maximum low pressure. At full throttle, the amount of vacuum is low.
If you take the vacuum form the intake manifold, you have maximum vacuum at iddle. Therfore 10 + 12 degree = 22 degree of pre-ingnition. This is to early.
The discussion about this is long. In the forum and in the internet you can find all professionell advice, you need to understand this.
Read the information from below, try to understand, drill your carb. The result will be much better.
Regards Wolfgang Gatza


https://www.britishvacuumunit.com/ported-vacuum.html

Link:
BBcode:
HTML:
Hide post links
Show post links


MarekH
Posts: 758
Joined: Wed Jul 21, 2010 8:30 pm
Location: Surrey
Great Britain

#16 Re: Series 3 spark plugs colours

Post by MarekH » Tue Nov 13, 2018 12:51 pm

This thread is about spark plug colour.

Whilst there is nothing wrong with the concept of ported vacuum, it doesn't bring anything to the table that manifold vacuum doesn't already, so I wouldn't go to the trouble of implementing it over and above that of going the conventional manifold vacuum advance route.

This has been covered in other threads already, most notably by Philip quite recently.

kind regards
Marek

Link:
BBcode:
HTML:
Hide post links
Show post links

User avatar

jagwit
Posts: 363
Joined: Thu Oct 18, 2012 6:52 am
Location: Pretoria
South Africa

#17 Re: Series 3 spark plugs colours

Post by jagwit » Tue Nov 13, 2018 5:19 pm

Woolfi wrote:
Tue Nov 13, 2018 9:43 am
"Vacuum advance (vacuum direct from intake manifold)"
This is WRONG.
It is NOT wrong. I still want to verify this statement but I believe that just about every Series 1 and 2 E-type runs on manifold vacuum advance. A '68 S1 4.2 I recently worked on certainly did have manifold vacuum advance.

I challenge you to read the following topic and debate the subject further there: http://forum.etypeuk.com/viewtopic.php?f=3&t=12885
Therefore 10 + 12 degree = 22 degree
Quite correct. But clearly you don't understand the difference in timing requirement for

IDLE @ 800rpm

vs

FULL THROTTLE @ 800rpm
Best Regards
Philip
71 E-type V12 Coupe,
80 XJS (EFI by Megasquirt & EDIS-6 + 5sp manual overdrive)
73 Jensen Interceptor
74 Interceptor (EFI by Megasquirt + overdrive 4sp auto)

Link:
BBcode:
HTML:
Hide post links
Show post links

User avatar

Series1 Stu
Posts: 724
Joined: Thu Feb 02, 2017 12:26 pm
Location: Shropshire
Great Britain

#18 Re: Series 3 spark plugs colours

Post by Series1 Stu » Tue Nov 13, 2018 10:07 pm

Yawn..................
Stuart

If you can't make it work, make it complicated!

'62 FHC - Work In (slow) Progress
'69 Daimler 420 Sovereign
'94 X300 XJR basket case

Link:
BBcode:
HTML:
Hide post links
Show post links

Post Reply Previous topicNext topic