Compression results
04-02-2013, 07:53 PM
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Compression results
As for compression..
Cylinder 1 dry/wet: 195/210
Cylinder 2 dry/wet: 200/210
Cylinder 3 dry/wet: 200/210
Cylinder 4 dry/wet: 195/210
I'm assuming the high compression is due to oil burning for so long creating alot of carbon in the combustion chamber? Question is will that buildup affect my actual data? From these numbers it seems that my rings are in good condition and that my valve stem seals are leaking but if I end up cleaning out my combustion chamber when I have my head removed; my compression should go back down within spec, correct? I should have the same ratio of dry to wet? Or will it completely change my dry to wet numbers?
Cylinder 1 dry/wet: 195/210
Cylinder 2 dry/wet: 200/210
Cylinder 3 dry/wet: 200/210
Cylinder 4 dry/wet: 195/210
I'm assuming the high compression is due to oil burning for so long creating alot of carbon in the combustion chamber? Question is will that buildup affect my actual data? From these numbers it seems that my rings are in good condition and that my valve stem seals are leaking but if I end up cleaning out my combustion chamber when I have my head removed; my compression should go back down within spec, correct? I should have the same ratio of dry to wet? Or will it completely change my dry to wet numbers?
04-04-2013, 05:23 PM
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First off are you having any problems that caused you to do a compression test?
Actually the compression looks good, as far as being a little high, many things including accuracy of the guage can be a contributing factor. Other factors such as prior machine work to the heads can cause higher compression because of reduced chamber volume. Most of the time you are looking for consistency between cylinders.
How the compression test was done, and consistent battery voltage can also affect a compression test.
Compression testing should be done with a battery charger on the batter. All spark plugs removed from the engine. Fuel and spark should be disabled. The throttle should be opened to wide open throttle. The reading should be taken on the 4th compression stroke on the test cylinder.
Usually carbon in the combustion chamber will not reach enough mass to cause a compression change. At least not with most modern gasoline blends, but it is possible. Most blends contain enough detergents to not allow carbon buildup with enough mass in the cylinders. This is especially true with "Top Tier" fuels.
There are some fuel system services that most shops can do that actually slowly break apart carbon deposits. It will help with carbon deposits on the valves and the combustion chamber. Several companies such as Everwear, Wynn's, PMI, Gumout make systems that do this. They usually run from about $60-$90 dollars.
Actually the compression looks good, as far as being a little high, many things including accuracy of the guage can be a contributing factor. Other factors such as prior machine work to the heads can cause higher compression because of reduced chamber volume. Most of the time you are looking for consistency between cylinders.
How the compression test was done, and consistent battery voltage can also affect a compression test.
Compression testing should be done with a battery charger on the batter. All spark plugs removed from the engine. Fuel and spark should be disabled. The throttle should be opened to wide open throttle. The reading should be taken on the 4th compression stroke on the test cylinder.
Usually carbon in the combustion chamber will not reach enough mass to cause a compression change. At least not with most modern gasoline blends, but it is possible. Most blends contain enough detergents to not allow carbon buildup with enough mass in the cylinders. This is especially true with "Top Tier" fuels.
There are some fuel system services that most shops can do that actually slowly break apart carbon deposits. It will help with carbon deposits on the valves and the combustion chamber. Several companies such as Everwear, Wynn's, PMI, Gumout make systems that do this. They usually run from about $60-$90 dollars.
04-05-2013, 08:34 AM
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As for compression..
Cylinder 1 dry/wet: 195/210
Cylinder 2 dry/wet: 200/210
Cylinder 3 dry/wet: 200/210
Cylinder 4 dry/wet: 195/210
I'm assuming the high compression is due to oil burning for so long creating alot of carbon in the combustion chamber? Question is will that buildup affect my actual data? From these numbers it seems that my rings are in good condition and that my valve stem seals are leaking but if I end up cleaning out my combustion chamber when I have my head removed; my compression should go back down within spec, correct? I should have the same ratio of dry to wet? Or will it completely change my dry to wet numbers?
Cylinder 1 dry/wet: 195/210
Cylinder 2 dry/wet: 200/210
Cylinder 3 dry/wet: 200/210
Cylinder 4 dry/wet: 195/210
I'm assuming the high compression is due to oil burning for so long creating alot of carbon in the combustion chamber? Question is will that buildup affect my actual data? From these numbers it seems that my rings are in good condition and that my valve stem seals are leaking but if I end up cleaning out my combustion chamber when I have my head removed; my compression should go back down within spec, correct? I should have the same ratio of dry to wet? Or will it completely change my dry to wet numbers?
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