I haven’t changed plugs for quite a while now, but I changed a lot growing up as a hot rodder and later as a DIYer. Many things have changed, and the biggest is ignitions.
We eventually switched to electronic ignition after a while, and I remember our plugs looked different after a similar amount of time.
We used to jet our Holley carbs so our plugs had a level of copper color. Now with the latest and greatest electronic ignitions and injection systems, i don’t know.
But the basics were, the darker they were the more rich it was running. The lighter, lean.
I have a ‘23 Forester Wilderness, and due to the difficulty of getting to the plugs on the boxer engines, i will leave that up to the pros now. Good luck!
Retired Texas Lawman
February 07, 2024, 12:51 PM
BlackTalonJHP
As cheap as plugs and wires are I usually change 40-50k miles. As far as the oil on plugs, check and replace your spark plug tube seals. I'm more familiar with Subaru EJ engines than your engine though.
Replace the wires too. I've worked on EJ engines that were still running with broken wires (usually break right at the plug) and it's a cheap and easy replacement.
February 07, 2024, 12:53 PM
HRK
Looks like they have been in too long for the most part, #2 and #4 do look a bit like some oil may be getting into the combustion chamber, likely a valve seal, does it smoke a bit at start up after sitting overnight?
February 07, 2024, 01:19 PM
David Lee
I believe those are old Splitfires. Not sure if they are still made.
February 07, 2024, 01:20 PM
BigSwede
I's tired boss
February 07, 2024, 02:11 PM
h2oys
quote:
Originally posted by rizzle: Check your owners manual, I believe Subaru spark plugs call for 60K mile replacement, if those went to 90k miles, they're fine.
That was my fault. I made an "assumption" they would be due at 100k and not 60k. Imagine my surprise when I realized I was overdue by 35k.
February 07, 2024, 02:13 PM
h2oys
quote:
Originally posted by ftttu: I haven’t changed plugs for quite a while now, but I changed a lot growing up as a hot rodder and later as a DIYer. Many things have changed, and the biggest is ignitions.
We eventually switched to electronic ignition after a while, and I remember our plugs looked different after a similar amount of time.
We used to jet our Holley carbs so our plugs had a level of copper color. Now with the latest and greatest electronic ignitions and injection systems, i don’t know.
But the basics were, the darker they were the more rich it was running. The lighter, lean.
I have a ‘23 Forester Wilderness, and due to the difficulty of getting to the plugs on the boxer engines, i will leave that up to the pros now. Good luck!
Three places I called, including the dealer, all wanted +$400 for the job. I spent $95 on the plugs and said a lot of foul words as to the design of lining up the plugs with the frame rails.
Thus you can't directly get at the plugs. The worse side was the drivers side.
February 07, 2024, 02:15 PM
h2oys
quote:
Originally posted by stoic-one: They look burned, that is NOT a 1.1mm gap.
Incredibly, the plugs come pre-gapped and the new ones were very similar.
February 07, 2024, 02:16 PM
h2oys
quote:
Originally posted by HRK: Looks like they have been in too long for the most part, #2 and #4 do look a bit like some oil may be getting into the combustion chamber, likely a valve seal, does it smoke a bit at start up after sitting overnight?
[FLASH_VIDEO]<iframe frameborder="0" height="315" src="https://www.youtube.com/embed/lVCs5gWLUyI?si=foEELcwrMMepB31K" title="YouTube video player" width="560"></iframe>[/FLASH_VIDEO]
No smoke...so far.
February 07, 2024, 05:14 PM
.38supersig
They say that your rings are good and you have been using fuel with detergent based additives.
The gap for platinum plugs looks fine and you'll need some anti-seize.
February 07, 2024, 05:17 PM
bionic218
[QUOTE]Originally posted by BigSwede: I's tired boss[/QUOTE
Left to right: Good, Good, Lean, Rich and/or debris.
February 07, 2024, 05:44 PM
Mustang-PaPa
What does the overall oil consumption look like?
February 07, 2024, 05:56 PM
SigSentry
How was she running? NOx? Looks like they did their jobs. Far right #4?
February 07, 2024, 07:15 PM
Shaql
quote:
Incredibly, the plugs come pre-gapped and the new ones were very similar
Always gap your plugs, never trust them out of the box.
Somethings going on with #4 (far right). It looks like something has coated the plug.
Hedley Lamarr: Wait, wait, wait. I'm unarmed. Bart: Alright, we'll settle this like men, with our fists. Hedley Lamarr: Sorry, I just remembered . . . I am armed.
