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I change diapers now
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Discussion Starter #1
After a questionable compression test last week, I wanted to try it once more with and without some oil in the cylinders.

2003 2.3 175,000 abused miles

Going to go by cylinder, with and without 1/2 cap of oil in a row;

Cylinder 1





Cylinder 2





Cylinder 3





Cylinder 4





Going to perform a leak down test this weekend. I'll take opinions on this for now.

- Drew
 

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I change diapers now
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Discussion Starter #3
The change with oil is the odd thing for me.

Cylinder two is low. But it improved the exact same amount as the other cylinders with a half cap of oil.

So. Is it a ring issue with 2? Is it a ring issue with any of them?

Do I have worn valve seats? Worn cams? Burnt valves?

They all improved the exact same amount via the same amount of oil. So why is that when one cylinder is noticeably lower than the other but shows the same improvement?

I'm not good with engine work so please. I need ideas on what to look for.

Doing a leak down test shortly.

- Drew
 

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You have around a 30 psi change from dry to wet test on all cylinders..that tells me all cylinders have an even amount of ring/bore wear. Your low # 2 could be from bad valves seats etc.
 

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You have around a 30 psi change from dry to wet test on all cylinders..that tells me all cylinders have an even amount of ring/bore wear. Your low # 2 could be from bad valves seats etc.
That's kinda how I see it too
 

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Look at exhaust seats first. Even with all the improvements in metallurgy the exhausts still go through hell since they took out the lead. I see the earlier zetec motors needing exhaust seat work at 100K miles to bring them back up to snuff, the intakes merely polish in and fine. The exhausts will be eroded from heat and carbon particle impacting dents the seats. The engines will seem to run fine but reseat the exhausts and you get back the easiest 10 HP you ever saw.
 

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Sounds like a valve seat or two alright... you can verify that with a vacuum gauge (extremely valuable instrument for diagnosing engine internal failings), it will tell you much more than a leak down test, since you already did a compression test. Hook the gauge to a vacuum port on the IM and look for irregularities.

Check this site to help interpret: http://www.secondchancegarage.com/public/186.cfm
 

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I change diapers now
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Discussion Starter #9
Well. Finally did a proper leak down test.



Every cylinder was within 3% of this reading(this being cyl. 1).

Opinions?

- Drew
 

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Over 10% leakdown isn't horrible but it's not good. I don't like to see anything over 10%. The last time I leakdown tested my Focus, it was 4-6% leakdown on all cylinders with 170-175psi compression (my cams are the reason for lower compression). That's with nearly 70k turbo miles.
 

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Drew did you drop a dowel through the spark plug holes to verify the piston was at TDC for each cylinder?

Also did your leak down tester have it's own regulator or were you relying on the compressor's? If it has it's own, you'll want to set the compressor regulator a bit above 100 psi......say 110 -120. If it doesn't have it's own, you need to block the leak tester outlet and adjust the compressor regulator to 100 psi on the leak tester's gauge before proceeding.

Be sure to warm the engine slightly before testing. By that I mean fire it up and let it idle for about 30 seconds if it's dead cold. Avoid removing spark plugs from a hot engine if you can.

Finally grab a mechanic's stethoscope and listen to each cylinder as it's leaking. Place the probe on the intake port, the exhaust port, the oil pan (up high) and the thermostat housing. You can usually hear where most of the leak is coming from. Obviously the intake and exhaust ports indicate valves, the oil pan for rings, and the stat housing for a head gasket.
 

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I have a 2001 Zetec DOHC engine and my compression numbers are...
1-200
2-200
3-190
4-190

Numbers are high but is that 10 difference bad?

Thanks
 
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