Sponsored

Pulled plugs and scoped. Should i be worried

Lonniesgt

Well-Known Member
Joined
Jun 27, 2023
Threads
18
Messages
174
Reaction score
73
Location
Kansas
First Name
Lonnie
Vehicle(s)
2017 mustang gt
I pulled the plugs tonight on my whippled 2017. About 8k miles on the plugs. Noticed cylinder 7 had oil on threads only. And cylinder 4 had a tip on top of plug that was darker then others. I did a compression test all cylinders maxed out my tester at 200psi. Leakdown coming this week. Found this on cylinder 7. Do you think it could be valve guide seals. Seemed like aluttle blue smoke on cold start only. And anything to worry about on the cylinder walls? Thanks for any help.

Screenshot_20240107_175729_Gallery.jpg


Screenshot_20240107_175751_Gallery.jpg


Screenshot_20240107_175816_Gallery.jpg


20240107_175652.jpg


20240107_175647.jpg


20240107_175636.jpg
Sponsored

 
Last edited:
OP
OP
Lonniesgt

Lonniesgt

Well-Known Member
Joined
Jun 27, 2023
Threads
18
Messages
174
Reaction score
73
Location
Kansas
First Name
Lonnie
Vehicle(s)
2017 mustang gt
What scared me alittle more was the cylinder wall on number 3 and 4. How worried should I be about this?

20240107_180013.webp


20240107_175848.jpg


20240107_180108.webp
 

Sponsored

OP
OP
Lonniesgt

Lonniesgt

Well-Known Member
Joined
Jun 27, 2023
Threads
18
Messages
174
Reaction score
73
Location
Kansas
First Name
Lonnie
Vehicle(s)
2017 mustang gt
GEN2 correct ?
Cylinders look good,
LED borescopes make things look worse than they are. Add magnification and things can start looking sketchy when they’re not.

Yes gen 2. 60k miles. 35k on boost
I feel alittle better. That one scratch worries me alittle like it's down pretty deep in the middle vertically but doesn't go all the way up or down. I parked car for winter and was gonna do all new timing and opg and support and other mods. Just wasn't sure if I should pull to rebuild or just send it. Car seems to run good.
 

GregO

Well-Known Member
Joined
Mar 5, 2018
Threads
41
Messages
3,342
Reaction score
2,482
Location
Illinois
Vehicle(s)
S550 GTPP
Yes gen 2. 60k miles. 35k on boost
I feel alittle better. That one scratch worries me alittle like it's down pretty deep in the middle vertically but doesn't go all the way up or down. I parked car for winter and was gonna do all new timing and opg and support and other mods. Just wasn't sure if I should pull to rebuild or just send it. Car seems to run good.
Yeah man those borescopes can highlight the most minor surface imperfections and turn nothing into an OMG moment.
Next thing you know the heads are pulled off and the naked eye inspection takes a peek then the finger nail surface scratch test is done only to find the borescope fooled the viewer.
 
OP
OP
Lonniesgt

Lonniesgt

Well-Known Member
Joined
Jun 27, 2023
Threads
18
Messages
174
Reaction score
73
Location
Kansas
First Name
Lonnie
Vehicle(s)
2017 mustang gt
Hello; I see what you are concerned about in the image. like others have said likely not too much scoring. The cross hatch is still good.
You say

Last thing I noticed is this set of valves, seems like there knife edging. But I'm kinda thinking of just not even tearing into it over the winter and just drive it and build a forged shortblock over the summer while I'm enjoying the car for one more season
Thanks for all the help guys.

Screenshot_20240107_200553_Messages.webp
 

Sponsored
OP
OP
Lonniesgt

Lonniesgt

Well-Known Member
Joined
Jun 27, 2023
Threads
18
Messages
174
Reaction score
73
Location
Kansas
First Name
Lonnie
Vehicle(s)
2017 mustang gt
Same thing, that borescopes high powered LED is creating shadows that are being magnified.
I think there’s a bit of Boostane deposits building up.

Good enough for me. I'll send it. Doesn't use oil. Hot idle pressure is 30lbs.
 

GregO

Well-Known Member
Joined
Mar 5, 2018
Threads
41
Messages
3,342
Reaction score
2,482
Location
Illinois
Vehicle(s)
S550 GTPP
Good enough for me. I'll send it. Doesn't use oil. Hot idle pressure is 30lbs.
Compression test was 200 psi across all 8 cylinders ?
Typical spec. is 10% of highest reading, call it good then send it and sleep well at night.
Leak down should pass as well being you have 200 psi on all holes.
 
Last edited:

ice445

Well-Known Member
Joined
Apr 13, 2020
Threads
40
Messages
6,798
Reaction score
8,247
Location
Salt Lake City, UT
First Name
Ryan
Vehicle(s)
2020 Mustang GT 6MT
What scared me alittle more was the cylinder wall on number 3 and 4. How worried should I be about this?

20240107_180013.jpg


20240107_175848.jpg


20240107_180108.jpg
I've seen those same black lines on my stock car, it's just carbon streaks after it flakes off the piston and gets stuck in the rings. Harmless. Everything looks pretty good.
 

Oakley

Well-Known Member
Joined
Nov 10, 2022
Threads
25
Messages
1,310
Reaction score
1,761
Location
Texas
First Name
Lee
Vehicle(s)
2022 Mustang
all of that looks like a normal healthy engine to me. the lines on the bore are crosshatch if i'm lookin at that right. its good to see that. its getting stripes of vertical lines when ya should be worried lol
 

sk47

Well-Known Member
Joined
Nov 12, 2020
Threads
32
Messages
6,858
Reaction score
3,191
Location
North Eastern TN
First Name
Jeff
Vehicle(s)
Chevy Silverado & Nissan Sentra SE
Hello; I would not tear down an engine based on the visual evidence shown. Especially if it is not using excess oil. I guess some 60,000 mile engines might look better but the cross hatch being intact seems good to me. Some of those miles under boost to boot.
This may be over kill. Have you done the compression test both wet and dry. By wet I mean adding a small amount of engine oil into the cylinder before the compression test. Dry is a compression test without adding oil. Do it dry first. (also be careful to not add too much oil so as to risk hydro lock. You should have all the spark plugs out anyway.)

I figure the wet compression will be some better than dry regardless but if it is a lot better in one or more cylinders, that might be a clue.
Sponsored

 
 








Top