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Old 05-29-2005, 05:13 PM   #1
BlackoutWRX
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Default how accurate are compession/leakdown tests

i would think that most of the cylinder scratches from wear/ dirt would be masked by the oil left on the cylinder walls. is this true? is there a more accurate way to tell the health of a block?
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Old 05-30-2005, 12:37 PM   #2
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anyone?
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Old 05-30-2005, 01:01 PM   #3
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a boroscope is what you are looking for.

accuracy is dependant on equipment, but no matter how good your gauge is, a compression or leakdown test wont tell you if your cylinders are scored, unless some major damage has been done. they are more helpfull in determining if you have bad rings, bent valves, and other sealing issues.
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Old 05-31-2005, 02:21 AM   #4
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Quote:
Originally Posted by BlackoutWRX
i would think that most of the cylinder scratches from wear/ dirt would be masked by the oil left on the cylinder walls. is this true? is there a more accurate way to tell the health of a block?
how did it get dirt in it.
the most accurate way is to pull it apart and look. Otherwise, externally you can do the leakdown and comp tests, or as ^^ said put the scope in for a closer look. Do you thyink you have this problem, or are you running like crap or something, or just a general query?
If they are scored bad it will show ona comp test.
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Old 06-01-2005, 10:34 PM   #5
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Quote:
Originally Posted by ncarn8
how did it get dirt in it.
the most accurate way is to pull it apart and look. Otherwise, externally you can do the leakdown and comp tests, or as ^^ said put the scope in for a closer look. Do you thyink you have this problem, or are you running like crap or something, or just a general query?
If they are scored bad it will show ona comp test.
eh, i had the dreaded back clips on the airbox not secured correctly, so i want to know how to check for unfiltered air damage. is this the way to do it? and i guess monitor my oil comsumption very carefully.
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Old 06-01-2005, 10:58 PM   #6
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unfilitered air damage will show up in an oil analysis as high silicone (sp).

blackstone labs if you can't sleep at night.
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Old 06-01-2005, 11:15 PM   #7
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Quote:
Originally Posted by hondaeater69
unfilitered air damage will show up in an oil analysis as high silicone (sp).

blackstone labs if you can't sleep at night.
the presence of Silicon in your oil means there is sand/dirt in the oil, but it doesnt tell you that you have actual damage. if he has done multiple oil changes since he found and corrected the airbox problem, oil analysis wont tell him anything. (except if he is having wear issues causing other parts to wear and leave stuff in the oil, i.e. bearings etc)
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Old 06-01-2005, 11:23 PM   #8
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You're assuming he's changed his oil multiple times.
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Old 06-01-2005, 11:50 PM   #9
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Quote:
Originally Posted by hondaeater69
You're assuming he's changed his oil multiple times.
you're assuming he hasn't.

my point was that DAMAGE will not show up in an oil analysis as high Silicon.

the presence of engine metals, and bearing materials is an indicator of damage.

high silicon levels can be a clue, but they are not an indicator of damage itself, merely an indicator of possible damage.

also, i used the word damage a lot.
IBOT-carbonfiber is hard to damage hard to damage

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Old 06-02-2005, 12:03 AM   #10
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Did i EVER say silicon = engine damage. NO i did not dickbag.

I said unfiltered air will show up in an oil anlysis, excuse me if i assumed he hadn't just changed his oil yesterday.
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Old 06-02-2005, 12:05 AM   #11
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Dude, you're anal'yizing (anal) a little too much. How about a simple NO! when done correctly!
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Old 06-02-2005, 12:16 AM   #12
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the oil has been changed probably 4 times since the problem occured.
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Old 06-02-2005, 12:19 AM   #13
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how long has the current oil been in since you found the problem?
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Old 06-02-2005, 12:24 AM   #14
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Quote:
Originally Posted by hondaeater69
how long has the current oil been in since you found the problem?
well the problem happeded a while ago i changed the oil soon after the problem, then regular 3k oil changes since then, the reason im worrying about it now is because im getting ready to go for aome big power, and dont want to start out with a crap block.

now, say the damage wasnt large enough to show up in a compression/ leakdown tests, would the damage be visible with a bore scope?
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Old 06-02-2005, 12:27 AM   #15
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So how long were you running with the latches unlatched?
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Old 06-02-2005, 12:32 AM   #16
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ANd also how big was the gap in the seal? And did you notice a differnce in PSi or power?
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Old 06-02-2005, 12:36 AM   #17
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Quote:
Originally Posted by hondaeater69
So how long were you running with the latches unlatched?
oh, about 1,200 miles. it was one of those deals where it "looked right" and fitted right but then after reading a few post from people here about it happening to them, i decided to check, and then i saw it


but all im trying to figure out is if theres a definate way to tell the condition of the walls sealing ability without ripping the engine apart.
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Old 06-02-2005, 12:39 AM   #18
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Quote:
Originally Posted by hondaeater69
ANd also how big was the gap in the seal? And did you notice a differnce in PSi or power?
it wasnt very big. No possibitly of rock or pebbles,just dust / pollen. thats why i dont think the damage would be picked up by compression/ leakdown tests.
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Old 06-02-2005, 02:31 AM   #19
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Quote:
Originally Posted by BlackoutWRX
it wasnt very big. No possibitly of rock or pebbles,just dust / pollen. thats why i dont think the damage would be picked up by compression/ leakdown tests.
do a comp test and a leak down test if your paranoid. Other wise, theres not much else. If anything showsa up on either test, then you have an answer. If its fine, then its fine. What mods/power are you chasing?
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Old 06-02-2005, 03:52 AM   #20
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Ok, do you live in a particularly dusty area? Did you spend a lot of time driving for extended periods of time on dirt roads during this 1200 miles?

if not, dont worry about it. you MAY have shortened your engines life span by .05%.

seriously, its ok.
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