Author Topic: New member spark plug questions  (Read 621 times)

CFF

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New member spark plug questions
« on: December 22, 2023, 20:11:33 »
Hello I just joined! I want to say this is a fantastic forum the depth of knowledge here is incredible!

I purchased a 1969 280SE over the summer and now that it’s winter I’m getting around to working on it. Sorry it’s not a W113 but the M130 engine is the same! I’ll buy a W113 next I promise!

Anyway I’m in the process of tracking down and sealing up some leaks. I yanked the plugs so I can bar the engine over easily and this is what they looked like. They have under 3k miles on them according to the previous owners records. The engine seems to be running rich. The threads seem to be oily as well what could cause that?

I plan on adjusting the valves this weekend then I’ll probably go on the linkage tour.

When I start the engine it runs great cold but gets rough as it warms up and wants to stall. Any advice on that? I’m thinking it’s loading up?

Also it cranks for a long time on cold starts. If I shut it down and start it right back up it starts fine.

The previous owner purchased the car in 2017 at 38k miles it’s only at 41k so it sat a lot and I’m dealing with the problems that caused.
« Last Edit: December 22, 2023, 20:43:46 by CFF »

rwmastel

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Re: New member spark plug questions
« Reply #1 on: December 23, 2023, 00:03:53 »
Welcome!  For further w108 questions, you can get plenty of help in this sub-form.

https://www.sl113.org/forums/index.php?board=24.0
Rodd

Did you search the forum before asking?
2017 C43 AMG
2006 Wrangler Rubicon
1966 230SL

rwmastel

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Re: New member spark plug questions
« Reply #2 on: December 23, 2023, 00:23:59 »
The threads seem to be oily as well what could cause that?
Isn't there a way for oil to leak out of the head from above the spark plugs?  More likely, probably coming up the threads after running rich then sitting.

When I start the engine it runs great cold but gets rough as it warms up and wants to stall. Any advice on that? I’m thinking it’s loading up?
Search our site for warm running device (WRD).  What does "loading up" mean?

The previous owner purchased the car in 2017 at 38k miles it’s only at 41k so it sat a lot and I’m dealing with the problems that caused.
Yeah, once you get it running well enough to drive around town reliably, drive it as often as you can.
Rodd

Did you search the forum before asking?
2017 C43 AMG
2006 Wrangler Rubicon
1966 230SL

roymil

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Re: New member spark plug questions
« Reply #3 on: December 23, 2023, 14:39:48 »
If you have oil showing up around the plugs it could be coming from above.   Some of the holes for the ball studs go all the way through the head to right above the plug ports.  It's not something you will notice unless you have the engine out or use an inspection mirror to look up from the plugs.   I know this because I confirmed several leaking this way and have decided its just not worth fixing for a few drips of harmless oil.   You can tell for sure by the color of any residue. 
Mark Miller
1968 280SL
Rode in his pagoda's first mile.

CFF

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Re: New member spark plug questions
« Reply #4 on: December 23, 2023, 15:09:06 »
I think mine are leaking but I’m going to ignore them for now. There is oil pooled around some of the spark plugs. If I stick my fingers into the top of the plug recesses I can feel those threads and there is a bit of dirty oil on a few of them.

But this motor is very oily and has never been degreased. For all I know it could have been an old valve cover leak they never cleaned up. Once I get it back together I’m going to degrease the entire motor and see what’s actually leaking.

This is a long term ownership car for me next winter depending on how everything goes I might yank the head or engine and send it to Metric Motors.

My plan is to adjust the valves and put the cooling system back together to try to get it running better. I can play whack a mole with leaks as time goes on.