Spark plug analysis

[The Bishop]

Take a look at these 4. Plug 1 is very oily but the other three are looking good (colourwise)
Plug 2 took some removing and it looks like the thread is damaged at the end. i hope it has not damaged my head when I come to put a new one in.

https://picasaweb.google.com/1099943139 ... 1536438578

Why is just one plug oily? I suspect it must be that the exhaust valve is not opening properly, I will put new plugs in, put it up on ramps and check that next.

Any other thoughts?

Oh, the reason for the investigation is that it was running lumpy, almost suspected it was running on three cylinders. And acceleration was poor.

Thanks,

[lodgey62]

Check compression on the oily cylinder, if the rings are shot it will allow oil past therefore oiling your plug and making your motor run rough.

[lodgey62]

Check compression on the oily cylinder, if the rings are shot it will allow oil past therefore oiling your plug and making your motor run rough.

[lodgey62]

Er,do it twice!

[BOXY]

Also check all the plugs are firing. If a plug or HT lead isn't firing the un-burnt petrol will wash the carbon build up onto the plug and that could look like oil.
I keep one of these in the van. Dead handy for making sure all the plugs are coming to the party without having to take the plugs out. The flash it generates isn't massively bright but it's clear enough to use in daylight with a hand to shade it.

http://www.ebay.co.uk/itm/Car-Spark-Tes ... Swm8VUzmye" onclick="window.open(this.href);return false;

[kevtherev]

When were these last changed?
Is the gap correct?

[123-jn]

None of them look particularly healthy, Looks a bit rich.

[Ant-t]

Yes time for a new set of plugs if I were you

[ghost123uk]

Bliddy hell, how long have they been in there

[Ian Hulley]

Showing clear signs of mechanical neglect right there

Ian.

[tobydog]

Multi electrode plugs - non adjustable gaps

[kevtherev]

Multi electrode plugs - non adjustable gaps

Yes but you can still check the gap!

[California Dreamin]

Long service multi electrode plugs aren't really adjustable and come pre-gapped 'wider' than VW recommend (0.8 or 0.9mm) usually tells you on the box (VW say 0.7mm)
I would run a plug tap down that thread (just in case) actually, won't hurt to do this to all four to clean up any carbon build up. Apply a smear of grease to the threads of the new spark plugs.
These long life plugs do encourage neglect as they can last up to 40K. So it would make sense to remove them every year, clean the threads and refit them with a smear of grease.

Personally: I would recommend using Bosch WR7DP (Platinum) spark plugs, these are 'long life Platinum' single electrode plugs that give better starting than the standard WR7DC . Recommended by Bosch as a replacement for the standard plug and particularly suited to 'Gassed' LPG engines although they work with petrol as well lol.

http://www.ebay.co.uk/itm/4x-Bosch-Plat ... SwkNZUflIE" onclick="window.open(this.href);return false;

Richard...have you still got your metal shrouds around your spark plug caps? these can be particularly problematic in causing arcing and plug break down. The shrouds can be cut off with Tin Snips or replaced altogether with some NGK screw on caps. See below:

http://www.ebay.co.uk/itm/1x-NGK-Resist ... Oxy9X5TbP9~" onclick="window.open(this.href);return false;

Martin