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Compression numbers - thoughts...

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Old 04-18-2011, 12:05 PM
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Default Compression numbers - thoughts...

Stock F20 with new 2mm gasket. Warm motor with throttle 100% and pulled fuel pump fuse. Dry and Wet (half cap of oil in cylinder). Cranking roughly 8 times. Average of three measurements for one reading.

Dry Wet
#1 - 170 - 195
#2 - 172 - 202
#3 - 182 - 220
#4 - 190 - 217

I think it's time to face the facts...
Old 04-18-2011, 03:00 PM
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sounds like scored walls or worn rings?
Old 04-19-2011, 02:01 PM
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leak down test shows 20% or less on all 4. im happy again.
Old 04-19-2011, 05:21 PM
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Originally Posted by hurtgen
leak down test shows 20% or less on all 4. im happy again.

Isn't it supposed to be 5% or less leakdown?

Why do you have a 2mm HG?
Old 04-19-2011, 09:10 PM
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looks like theirs too much variance between the cylinders, did you use the thick head gasket in plans to go turbo?

Old 10-12-2011, 07:37 AM
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sorry, back from dead. but thought i would update.

car is boosted with a 6265. had a 3m gasket on which blew of course. gave the cometic 2mil gasket a try. during install cyl wall damage was not evident. after the compression test/leakdown i brought the car in to get tuned again. has been running strong ever since. I think my rings are showing some wear. wont have the car running again until spring. sucks living in a state (WI) where you can only drive the car half the year.
Old 10-12-2011, 07:50 AM
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should crank 4times
Old 10-12-2011, 01:12 PM
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Originally Posted by jym89709
should crank 4times
WRONG!
Old 10-12-2011, 01:38 PM
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try cranking it for 8. But more importantly look at the gauge, see how quickly it shoots up after the first compression cycle. Did you do cyl#4 first in the test??
Old 10-14-2011, 12:36 PM
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at the time of performing the test, i was paying attention to the gauge. that's why i said roughly 8 cranks, was kinda counting in the back of my head but could be off a crank or two. i dont remember what cyl i started on. this was done early this year some time.


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