Compression/Leakdown numbers at 2000 miles
07-17-2015, 10:55 AM
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Compression/Leakdown numbers at 2000 miles What's happened here?
429" LSX with ETP LSX 6 bolt heads @ 9.3:1 static compression. 18-19 psi boost at 10.85 AFR 16* timing on 110 fuel. Total Seal 1.5mm stainless top ring gapped at .024 and 1.5mm Napier 2nd gapped at .024. 3mm oil.
These are on a cold motor(sat overnight). Don't have any numbers from when build was fresh.
Comp:
1-192 re-tested the same on second round
2-165
3-170
4-155 first round, 165 after a squirt of oil
5-160
6-170
7-165
8-160
Leakdown
1- 20
2- 20
3- 12
4- 12
5- 18
6- 18
7- 15
8- 20
1-20____2-20
3-12____4-12
5-18____6-18
7-15____8-20
Some intake valve pics:
#1
#3
#5
#7
Some in cylinder pics (slideshow)
More in cylinder pics (slideshow)
429" LSX with ETP LSX 6 bolt heads @ 9.3:1 static compression. 18-19 psi boost at 10.85 AFR 16* timing on 110 fuel. Total Seal 1.5mm stainless top ring gapped at .024 and 1.5mm Napier 2nd gapped at .024. 3mm oil.
These are on a cold motor(sat overnight). Don't have any numbers from when build was fresh.
Comp:
1-192 re-tested the same on second round
2-165
3-170
4-155 first round, 165 after a squirt of oil
5-160
6-170
7-165
8-160
Leakdown
1- 20
2- 20
3- 12
4- 12
5- 18
6- 18
7- 15
8- 20
1-20____2-20
3-12____4-12
5-18____6-18
7-15____8-20
Some intake valve pics:
#1
#3
#5
#7
Some in cylinder pics (slideshow)
More in cylinder pics (slideshow)
Last edited by DrX; 07-25-2015 at 05:18 PM.
07-18-2015, 10:42 AM
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Oil source? Valve guides? Rings? Both?
I have been running a breather tank with GM LSX baffled valve covers for the last 1000 miles. Initially ran a catch can setup but the can would fill up in no time with non-baffled valve covers, resulting in a lot of oil getting into the intake.
I have been running a breather tank with GM LSX baffled valve covers for the last 1000 miles. Initially ran a catch can setup but the can would fill up in no time with non-baffled valve covers, resulting in a lot of oil getting into the intake.
07-21-2015, 01:22 PM
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Few more pics:
This piston is different. Lighter/more reflective deposits. Melted?
After scratching at it, I think it is just crud.
Looking through an injector boss into an intake port:
This piston is different. Lighter/more reflective deposits. Melted?
After scratching at it, I think it is just crud.
Looking through an injector boss into an intake port:
Last edited by DrX; 07-21-2015 at 08:55 PM.
07-22-2015, 07:10 PM
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Had the ID1000 injectors flow tested...looks like they didn't appreciate being cleaned. The automated test is a gradual ramp up.
So static(max) flow rates for the ID1000s were:
Initial/After 2 cleaning cycles
1. 864/888cc/min
2. 852/876cc/min
3. 864/888cc/min
4. 852/888cc/min
5. 852/876cc/min
6. 876/900cc/min
7. 852/888cc/min
8. 864/864cc/min
With 2 and 6 being erratic. Not sure why #3 was clean as a whistle(see pics) compared to all the rest. Wiring checks out good to all injectors.
What I had noticed was that bank 2 would tend to go way lean on a heat-soaked idle. Cold testing doesn't tell me how the injectors behave at higher temps.
So static(max) flow rates for the ID1000s were:
Initial/After 2 cleaning cycles
1. 864/888cc/min
2. 852/876cc/min
3. 864/888cc/min
4. 852/888cc/min
5. 852/876cc/min
6. 876/900cc/min
7. 852/888cc/min
8. 864/864cc/min
With 2 and 6 being erratic. Not sure why #3 was clean as a whistle(see pics) compared to all the rest. Wiring checks out good to all injectors.
What I had noticed was that bank 2 would tend to go way lean on a heat-soaked idle. Cold testing doesn't tell me how the injectors behave at higher temps.
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07-23-2015, 09:17 PM
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Didn't ask to have them cleaned, but I guess these guys were trying to see if they could get them up to the 1000cc/min spec. Not sure what their cleaning process is. Not looking at re-using them as they were maxed out when shifting at 6500 RPM.
One thing I noticed is that they have no inlet screens, so it is possible that something could get lodged in them and affect their operation. The ID site says it is not always possible to clean them out. I wonder if during ultrasonic cleaning internal corrosion/deposits could be loosened up and create a partial blockage or interference??
Last edited by DrX; 07-23-2015 at 09:22 PM.
07-23-2015, 09:38 PM
#10
Those leakdown numbers look okay. Not great, but considering the rings are gapped for boost and it's under 20% and the variance is under 10%... that's okay. Did you check to see if the valves were leaking? Did you hear the hiss out of the valve covers only or from the intake manifold or exhaust (indicating valve leak).
07-25-2015, 09:17 AM
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Only got the Bank 1 head off last night. Cylinders/pistons do not look as scary as the borescope pics, but..........
Album Link
Album Link
Last edited by DrX; 07-25-2015 at 10:31 AM.
07-27-2015, 09:32 PM
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Cleaned up #5 for closer inspection. Also noted that carbon buildup extends to different lands on different pistons.
Last edited by DrX; 07-28-2015 at 08:17 AM.
07-27-2015, 10:15 PM
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Detonation.
The scuffed and likely somewhat collapsed skirts, plus the loading of the upper rod bearing shell, plus the pocking of the piston crown indicates detonation.
The scuffed and likely somewhat collapsed skirts, plus the loading of the upper rod bearing shell, plus the pocking of the piston crown indicates detonation.
