[jaymaynard]

Decided to take my own advice and put a set of NGK BP5ES in die Weisse Lady. Discovered two problems with the old plugs. The first was that they were Bosch WR9DC+ resistor plugs, and the wires were still Bosch resistor wires. Not sure how much difference that makes.

Here's the second problem:

The numbers are the cylinder they came out of.

#8 isn't supposed to look like that, is it? Not only that, but what you can't see from the picture is that the gap is a lot narrower than on the rest. I didn't try using the gap tool on it, but it looks like it's half the width of the others.

The car runs and idles a lot more smoothly now. The big question is: where'd all that crap on #8 come from?

 

[nobby]

Compare them to this chart:
Verrill: Plug Color Chart

 

[jaymaynard]

From what I can see, the insulators on 1-7 all look normal. The electrodes on 2-7 look normal, too, though 1 looks a bit oily. I'm puzzled by the oil on the ends of the ground side, though, on all of them.

And then there's the crap all over #8. If it was a rich mixture, wouldn't it be affecting all 8 plugs? The obvious first guess is rings or some such, but the car has more than ample power, and is idling smoothly now with new plugs in it.

 

[isthisdave]

.


In order of magnitude


1) Valve guide seal

B) Oil control ring

III)Head gasket oil leak



No way of knowing how long they've been in there, right? You know it's clean now, see how it does.

 

[jaymaynard]

1) Valve guide seal

B) Oil control ring

III)Head gasket oil leak

Hm. The valve guide seal can be done without major disassembly, IIRC. I would think the oil control ring would take more doing than the head gasket, though...or am I not understanding what's involved in a head gasket replacement?

No way of knowing how long they've been in there, right? You know it's clean now, see how it does.

Yup. How long would you suggest I wait before pulling the plug to look at it? It's my fair weather daily driver, so it gets driven regularly.

 

[isthisdave]

.



I wouldn't worry about it unless it started missing again.

 

[isthisdave]

.




Or you could check it after a few hundred miles. Are they smog checked in your locale?

 

[jaymaynard]

Are they smog checked in your locale?

Nope. One advantage of living in Minnesota. Used to be that vehicles registered in the metro Twin Cities needed smog checks, but that requirement was eliminated a few years ago.

 

[Fonzi]

I've been trying to make my 1973 280se 4.5 m117 run as well as possible, assuring EVERYTHING has been done before replacing the valve stem seals that I know I need to replace. I have pulled, replaced, and pulled again the spark plugs. #4 and #8 are the most oily. I'm not sure why, but I'm guessing that those two have the worst valve stem seals. Another possible factor, (especially since I got ~10% lower compression numbers on the #8 cylinder than all others) may be that the rear cylinders are farther from the oil pump than all the other cylinders. I wonder if I could have a worn ring on that #8.

My only concern is the large puff or stream of oil smoke I make when I press the gas, let up on the gas, or start the car.

That's just my scenario and my issue. Yours may be different, but as was said above, changing the spark plugs every once in a while isn't as difficult as other solutions.


Sent from my iPhone using Tapatalk

 

[roncallo]

More than likely this is a valve guide seal or possibly the valve guide itself. When doing this make sure the piston is at the top for each cylinder. When you get the seal out see if the valve guide is loose in the head. Try to push the valve guide down into the head or try to rotate it. If it moves your screwed. Slide the valve down into the guide about 1/4" and see if it wiggles excessively in the guide. If there is too much clearance in the guide a seal may work for a little while depending on how bad it is.

Could be a cheep fix but possibly may need a valve job.