Jump to content

Spark plug working corectly?

Recommended Posts


Could you give me your thoughts about the Spark plugs?

Thiis is after 600Miles of driving (I never checked so soon / have no reference.)

I know the coulour plugs should have, but what I have in mind is quite equal all around.

What could couse this difference around the electrode?







Thanks for your input


Edited by munters

Share this post

Link to post
Share on other sites

Tell us a bit more about the engine. Carbed or injected? Stock cam shaft or one with bigger overlap? Need to know info on  Ignition system, coil and spark plug wires. ( Spiral core or carbon core. Brand as well.  ). 


Basically the plugs look a little " fluffy " and rich. But the reason why could be in your engine specs. 

Share this post

Link to post
Share on other sites

Hello Chickenman

Thanks for your help


My engine is a Stroked L24 2753,

Forged Piston,

Billet Connecting rods,

Compression 10:1,

"mild" 227 Cam. .480 lift,

Ported Head E88 with bigger valves from L28

Fidenza Flywheel with 240mm Clutch,

Triple 45 Weber with Keith Franks Hypojets (H-26) and Obert E-tubes,

123 Ignition with Crane Hi-6s and LX-91 Coil.


The Cables are

7mm high temperature with conductive silicone core and silicone jacket r883 from Import Direct


Do you have an idea, what this unequal coloring could be?

Share this post

Link to post
Share on other sites

Is it a new engine?  You might just be burning some oil, and the rings are not seated equally between all cylinders.


I think he's talking about the fact that one looks lean, two look rich, and three look close to right.  The heat range looks pretty good by the electrodes but they're covered with deposits of incomplete combustion, like if oil was being burned.

Share this post

Link to post
Share on other sites

Are they laid out in order? I would kind of expect pairings if you are running triple webbers.


Have the carbs been balanced? 


There does seem to be a little bit of oil residue, but the plugs don't look wet or saturated with them. Any smoking out the exhaust? 


If it is a fresh rebuild it might take a while before the rings seat completely. 

Share this post

Link to post
Share on other sites

Thanks for your opinions

The Engune has now 5000 miles.

No smoke and it does not need any oil since 3000miles (last change)

The carbs are within 0.5 synched with the sk tool

I do have a strange behavier.

Idle is at 10:1 afr and transition is at 12.5.

If i change the idle to 13:1, the transition is to lean.(16:1)

One carb shoots then back sometines.

I have to play more with keith franks airleaks.

Share this post

Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now