Bad valve seats?
06-09-2014, 10:50 PM
#1
Thread Starter
Bad valve seats?
TL
R - are my valve seats OK? See images here.
Background:
2005 F22C from wrecked car, ~50k when put in (2010) and now closer to 100k total mileage. AP1 ECU (2001). Entirely stock.
Since engine was in my car it has not been money shifted, although I do infrequently run it to 8800-9000 RPM in 1st - maybe once a month. No track days, very little aggressive driving, mostly just commuting to work and freeway driving.
Motor never idled *great* but was tolerable. Always had a bit of the exhaust poof at idle. Car otherwise ran very well. Valves adjusted shortly after the swap and again a year later, all in spec. Misfire potpourri started showing up maybe 10k ago, very infrequent, usually P0301, sometimes all 4 + 1399, depending on how soon I could pull the code. Started getting some stumbling when cold, power not great.
Did the usual swapping around of parts (I have a lot of known/probably good stuff from my F20):
- Plugs
- Coil packs
- Injectors
- MAP sensor (cleaned, swapped, swapped back)
- IAC (cleaned, swapped, swapped back)
No joy. ~1000 miles ago (coinciding with temperatures above 50 degrees) idle started getting REALLY bad, nearly stalling in heavy traffic + warm temps when pushing clutch in.
- Checked valve clearance, all good.
- Retainers all look good (F22C, yay)
- Ran compression: 90 215 185 215 Note that engine was not particularly warm, but the 90 PSI is obviously the problem. Reran several times and numbers were repeatable.
- Leakdown 80% 5% 7% 5% Engine was luke warm by this time. Listening with mechanic stethoscope seemed to indicate most of the leaking was going into other cylinders, especially #2 but some into #3 and #4. However when testing other cylinders none was indicated going into #1 (one way leakage). No bubbling in radiator, nothing backing out the intake, nothing coming out the dipstick tube, and as best I could tell very little coming out the exhaust.
- Removed head. Nothing jumps out at me. #1 exhaust were a bit pitted. Cylinders all looked good, #1 bit excess buildup, cylinder walls looked good.
Did a quick test of valve seals w/ water: all intakes were good. Exhaust, #4 and #2 held water, #3 leaked slowly, #1 did not retain water, correlating with leakdown.
- Head gasket was a bit mangled, but that may have been disassembly more than anything, although the warped area was the front of the #1. A check of the block indicates no warping (or rather, less than 0.005 inch).
- Pulled exhaust valves. I won't link all the pictures, here's the album:
https://imgur.com/a/P8yab
- #1 valves are trashed.
#2 thru 4 look OK even though #3 also was leaking a bit.
- I did a quick test using a drill to spin the valves, they *seem* straight, and no real indication on either pistons or valves of impact.
- Valve seats... I don't know. I can't get good pictures of them. They don't seem particularly pitted or galled, there's some corrosion and buildup on the perimeter but it seems pretty consistent across all 4 cylinders.
So, after that wall of text, I have two questions:
1) Sorta unrelated, but any idea why the intake valve spring keepers would absolutely not budge? Exhaust side were sticky, but intake side seems permanently mated. Lots of various lubricants and percussive encouragement and none of them will release.
2) At this point my only real question is whether to get the exhaust side valve seats machined. My visual check seems to think they're OK, but I don't know what a "good" 100k mile engine looks like vs a "bad" 100k mile engine. So, thoughts?
My game plan otherwise is replacing exhaust valves, head gastket, head studs, and various seals and gaskets. Hope for the best.
R - are my valve seats OK? See images here.Background:
2005 F22C from wrecked car, ~50k when put in (2010) and now closer to 100k total mileage. AP1 ECU (2001). Entirely stock.
Since engine was in my car it has not been money shifted, although I do infrequently run it to 8800-9000 RPM in 1st - maybe once a month. No track days, very little aggressive driving, mostly just commuting to work and freeway driving.
Motor never idled *great* but was tolerable. Always had a bit of the exhaust poof at idle. Car otherwise ran very well. Valves adjusted shortly after the swap and again a year later, all in spec. Misfire potpourri started showing up maybe 10k ago, very infrequent, usually P0301, sometimes all 4 + 1399, depending on how soon I could pull the code. Started getting some stumbling when cold, power not great.
Did the usual swapping around of parts (I have a lot of known/probably good stuff from my F20):
- Plugs
- Coil packs
- Injectors
- MAP sensor (cleaned, swapped, swapped back)
- IAC (cleaned, swapped, swapped back)
No joy. ~1000 miles ago (coinciding with temperatures above 50 degrees) idle started getting REALLY bad, nearly stalling in heavy traffic + warm temps when pushing clutch in.
- Checked valve clearance, all good.
- Retainers all look good (F22C, yay)
- Ran compression: 90 215 185 215 Note that engine was not particularly warm, but the 90 PSI is obviously the problem. Reran several times and numbers were repeatable.
- Leakdown 80% 5% 7% 5% Engine was luke warm by this time. Listening with mechanic stethoscope seemed to indicate most of the leaking was going into other cylinders, especially #2 but some into #3 and #4. However when testing other cylinders none was indicated going into #1 (one way leakage). No bubbling in radiator, nothing backing out the intake, nothing coming out the dipstick tube, and as best I could tell very little coming out the exhaust.
- Removed head. Nothing jumps out at me. #1 exhaust were a bit pitted. Cylinders all looked good, #1 bit excess buildup, cylinder walls looked good.
Did a quick test of valve seals w/ water: all intakes were good. Exhaust, #4 and #2 held water, #3 leaked slowly, #1 did not retain water, correlating with leakdown.
- Head gasket was a bit mangled, but that may have been disassembly more than anything, although the warped area was the front of the #1. A check of the block indicates no warping (or rather, less than 0.005 inch).
- Pulled exhaust valves. I won't link all the pictures, here's the album:
https://imgur.com/a/P8yab
- #1 valves are trashed.
#2 thru 4 look OK even though #3 also was leaking a bit. - I did a quick test using a drill to spin the valves, they *seem* straight, and no real indication on either pistons or valves of impact.
- Valve seats... I don't know. I can't get good pictures of them. They don't seem particularly pitted or galled, there's some corrosion and buildup on the perimeter but it seems pretty consistent across all 4 cylinders.
So, after that wall of text, I have two questions:
1) Sorta unrelated, but any idea why the intake valve spring keepers would absolutely not budge? Exhaust side were sticky, but intake side seems permanently mated. Lots of various lubricants and percussive encouragement and none of them will release.
2) At this point my only real question is whether to get the exhaust side valve seats machined. My visual check seems to think they're OK, but I don't know what a "good" 100k mile engine looks like vs a "bad" 100k mile engine. So, thoughts?
My game plan otherwise is replacing exhaust valves, head gastket, head studs, and various seals and gaskets. Hope for the best.
06-11-2014, 12:55 PM
#4
Thread Starter
The only obvious symptoms earlier were slightly rough idle (engine would shake/shimmy a bit) and occasional misfire codes. My original F20 had an occasional misfire which was traced to a bad injector (after several weeks of diagnosis from the dealer), which is why I went through the process the way I did.
06-16-2014, 07:00 PM
#5
Thread Starter
06-17-2014, 04:12 AM
#6
Looks like you have a couple burnt valves and seats. The seats can be re-ground by any automotive machine shop. May as well go through and have them do the whole head. The burnt valves may or may not be able to be re-ground as well, worst case scenario you have to source a couple replacement valves.
06-17-2014, 08:58 AM
#7
Thread Starter
I'm not worried about replacing the valves, I just don't want to go through the process and discover the seats don't seal. Thanks for the insight.
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06-17-2014, 09:29 AM
#9
Thread Starter
The cylinder walls look flawless. 
As I mentioned, I don't rev it that high very often and the valves don't appear to be bent/damaged, just pitted. Though I guess I don't have a really good understanding of how that comes to be in the first place (poor combustion?).
As I mentioned, I don't rev it that high very often and the valves don't appear to be bent/damaged, just pitted. Though I guess I don't have a really good understanding of how that comes to be in the first place (poor combustion?).
06-18-2014, 07:02 AM
#10
In our engines, generally burnt valves and seats are caused by the valve clearance being out of spec. The valve isn't fully closing 100% during combustion thus burning and pitting the valve and seat. Other things can cause burnt valves as well such as improper timing and poor air/fuel ratio.