free hit
counters
Oil in spark plug tunnel - Engine/Ancilliaries - The Lotus Forums Jump to content
Sign in to follow this  
Daniel

Oil in spark plug tunnel

Recommended Posts

The car has had a miss fire on one cylinder when the engine is under light load (any revs) since I got it.

You put your foot down and it clears.

The PO had mentioned condensation down one of the spark plug ports, so I thought it may clear after a coupe of good runs and being stored in a dry, well ventilated garage with no condensation problems.

But it didnt.

Finally got round to having a good look at it today, and when trying to remove one spark plug, I pulled out the plug spanner to have another go, and it was covered in oil (I'd also noticed the cap was damp with oil when I removed it so I was prepared).

This would certainly explain the miss fire at low load.

I'm assuming a breach of the rocker cover gasket, which looks like a simple enough job to sort.

Would you agree? or is there something more sinister I should be looking for.

Thanks in advance

Dan.

Share this post


Link to post
Share on other sites

Upgrade today to remove Google ads and support TLF.

Is it the spark plug closest to the filler cap?... if so, then it could be from the last oil top-up, if the plug cover was off as well.

What was the state of the plug when you removed it? If the cylinder shows signs of oil fouling, then I


1996 Esprit V8, 1998 Esprit V8 GT, 1999 Esprit S350 #002 (Esprit GT1 replica project), 1996 Esprit V8 GT1 (chassis 114-001), 1992 Lotus Omega (927E), 1999 Esprit V8SE, 1999 Esprit S350 #032, 1995 Esprit S4s, 1999 Esprit V8 GT (ex-5th Gear project), 1999 Esprit V8SE ('02 rear)

1999 S350 #002 Esprit GT1 replica

Share this post


Link to post
Share on other sites

Thanks for the response Mike

It's the spark plug on the oposite side from the filler cap.

It's difficult to say, but the plug looked like all the others (dark tan colour, clean spark) with no black sooty residue or any signs of burnt oil.

The top of the plug was covered in oil, as well as part of the thread, the electrodes had clean oil on them, which I assumed was picked up on removal.

I didnt keep the plug out for too long, so as not to let too much oil drain in to the chamber, and I started the engine to burn it off.

The engine performs superbly when the misfire clears and showed a healthy BHP at a recent rolling road run.

Share this post


Link to post
Share on other sites

Well I whipped the cover off, and there's absolutely no sign of gasket damage.

The oil in the tunnel is clean oil i.e. it's not been burnt nor mixed with water.

I can only think, maybe head gasket, but I've done a few hundred miles in it, and theres no sign of any oil loss.

hmmmmmmm

Share this post


Link to post
Share on other sites

I would rule out head gasket.

The oil is way above the gasket surface, so if the oil matches the colour of the stuff currently pumping round inside it's come from inside, if it's clean then it's come from a can when being re-filled.

Clean the area with tissue and then monitor for any new deposits.

Andy

Share this post


Link to post
Share on other sites

If she's been misfiring, and you've just bought her - I wouldn't rule out the oil being having been left over from a previous compression test whereby perhaps low results were shown on that cylinder with oil having been poured in there to test to see if it's ring related.

Like other say there's no danger whatsoever of it being from the head gasket is this is well below that point, but there is a round oil seal around each spark plug well in between the cam cover and the head, it's possible this has failed or wrongly fitted.


Hey, can anyone smell fuel?????

Share this post


Link to post
Share on other sites
but there is a round oil seal around each spark plug well in between the cam cover and the head, it's possible this has failed or wrongly fitted.

yeah I had the cover off today, there were no signs of seal failure.

I'm stumped

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Sign in to follow this  

×
×
  • Create New...