Rate my spark plugs (newly acquired Pre-cat Griffith)

[EddieJT]

Clocked up something like 400miles in the last 10 years; only been driven to the MOT station and back for the last 10 years. Car has no history so don't know how many of those years these plugs have been on the car.

I should add, I’m new to V8s but it does sound to me like a missfire when cruising. Drives smoothly though, and doesn’t misbehave when accelerating hard….doesn’t sound like a misfire when idling either



Worst offender:

Edited by EddieJT on Sunday 19th November 12:59

Edited by EddieJT on Sunday 19th November 14:04

[EddieJT]

GreenV8S said:

Those three are obviously contaminated - perhaps due to worn valve stem seals. Since you don't really know the history of those particular plugs, I assume you'll fit new B7ECS and check the condition again at the next service.

Oh, do you reckon?

That’s was the original plan yes, though I read the B6ECS are better suited?

[EddieJT]

Panamax said:

Yes indeed.

Or if you're a cheapskate and know which plug came from which cylinder, just clean them up, put them back in (swapping fouled plugs with the cleaner ones) and continue driving. Obviously you'll keep a careful note and photos of what came from each cylinder and what was put back in. Then next time you check the plugs from the three potentially problem cylinders you'll know exactly where you are.

Keep an eye on oil consumption as well. You could always do a compression test while the plugs are out if you're feeling keen.

Good ideas. Interestingly it doesn’t smoke (other than a puff on first start-up).

[EddieJT]

EddieJT said:

I should add, I’m new to V8s but it does sound to me like a missfire when cruising. Drives smoothly though, and doesn’t misbehave when accelerating hard….doesn’t sound like a misfire when idling either

Thanks guys; do you guys reckon the fouled plugs are causing the above?

[EddieJT]

Will do.

If it continues let's hope it's the head.....really can't be bothered with the hassle of removing another engine.

[EddieJT]

I have what I presume are the original Beru extenders (so not cheap Chinese), and new looking Magnecor leads. Not seeing any arcing in the dark.

I presume the misfire I suspect I'm hearing is a plug too fouled up to fire; so if I replace/clean the plugs and the fouling soon returns, how do I diagnose valve stem seals for sure?

[EddieJT]

Let's hope so.