Spark plug colouration - carb affected?

[cfcrotweiller]

Hi,

I'm trying to get the car inspected after 30 years, a few things to deal with before I reinspect (failed over emissions).
I took the plugs out the other day and found the following:

I noticed that the right bank (left hand side looking from the front of the engine) the two outer plugs (that would be pots 2 and 8 ) looked actually OK! Normal wear and colour. The two inner plugs (pots 4 and 6) look unusually clean?

I took the left bank plugs out too (right hand side looking from the front of the car) and notice similar although this time pots 1 and 7 looked unusually clean and pots 3 (and im guessing 5 although I can't get the plug out since I bought the car) have more colour and use.

My first thoughts were: which carbs feeds which pot? Does this suggest that one carb is not tuned correctly?

Thanks for your help!
Andy

 

[harveyp6]

My first thoughts were: which carbs feeds which pot?

NS carb 1467 (LH as viewed from the driver's seat)
OS carb 2358 (RH)

Information contained in my V8 datasheet detailed elsewhere.

If you're in doubt the cylinder numbers are cast into the inlet manifold.

 

[SydneyRoverP6B]

Hi Andy,

By the sound of it, your LH carburettor is running leaner than the RH one. If the lean cylinder plugs are stark white with almost deposits, be very careful as running them like this could lead to engine damage.

Running on uneaded fuel does not colour the plugs in the same way as the use of leaded fuel used to. Ideally, the top of the threaded section should be dusted dark grey to black with the earth strap looking similar.
The electrode should be square across the top whilst the ceramic insulator should be lightly coloured, from very light brown to grey.

Ron.