"Wet Compression Test" ?
#1
05-30-2017, 06:38 PM
Join Date: Mar 2017
Location: Tulsa, OK
Posts: 220
"Wet Compression Test" ?
OK, there's spark from the coil...
I read an article about a "wet compression test" I should perform after the first test readings from those 2 cylinder's. Look :
From article - "The results you obtain from this second ‘Wet’ compression test will help you determine if the low compression you recorded in the ‘Dry’ compression test are caused by worn piston rings or worn cylinder head valves."
CASE 1: The compression value shot up.. This tells you that the piston compression rings are worn out and thus the problem is in the bottom end (block) of the engine in your GM 4.3L, 5.0L, or 5.7L equipped vehicle.
Here's why: The engine oil helped the piston rings seal better, thus bringing up the compression value almost back to normal. If the problem were in the cylinder head valves... the engine oil you just added wouldn't make a difference at all (on the compression value).
CASE 2: The compression value stayed the same.. This confirms that the problem is in the cylinder head valves.
Here's why: If the cylinder head valves and their seats are worn out (or maybe even bent from a broken timing belt), no amount of engine oil is gonna help seal the compression in, in the cylinder. So, if the compression value, for the specific cylinder you're testing did not go up (after you added oil to it)... then this is a dead giveaway that you've got cylinder head valve damage.
OK now my question is, where can I add oil to these cylinders besides the spark plug holes ? Oil leaks back out when I add it there.
I read an article about a "wet compression test" I should perform after the first test readings from those 2 cylinder's. Look :
From article - "The results you obtain from this second ‘Wet’ compression test will help you determine if the low compression you recorded in the ‘Dry’ compression test are caused by worn piston rings or worn cylinder head valves."
CASE 1: The compression value shot up.. This tells you that the piston compression rings are worn out and thus the problem is in the bottom end (block) of the engine in your GM 4.3L, 5.0L, or 5.7L equipped vehicle.
Here's why: The engine oil helped the piston rings seal better, thus bringing up the compression value almost back to normal. If the problem were in the cylinder head valves... the engine oil you just added wouldn't make a difference at all (on the compression value).
CASE 2: The compression value stayed the same.. This confirms that the problem is in the cylinder head valves.
Here's why: If the cylinder head valves and their seats are worn out (or maybe even bent from a broken timing belt), no amount of engine oil is gonna help seal the compression in, in the cylinder. So, if the compression value, for the specific cylinder you're testing did not go up (after you added oil to it)... then this is a dead giveaway that you've got cylinder head valve damage.
OK now my question is, where can I add oil to these cylinders besides the spark plug holes ? Oil leaks back out when I add it there.
#2
05-30-2017, 10:27 PM
Spark plug hole is your option. It helps to have a oil can similar to this Powerbuilt 500cc 16 oz. Pint Capacity Oil Can-648751 - The Home Depot to get the oil in the hole. Also sometimes you may need to turn the motor by hand a bit too lower the piston in the cylinder so that the oil has somewhere to go rather than just running off the piston and back out the hole.
#3
05-30-2017, 10:52 PM
Join Date: Mar 2017
Location: Tulsa, OK
Posts: 220
OK thats what I thought and makes sense. Thanks man !
#4
06-01-2017, 07:37 AM
OK, there's spark from the coil...
I read an article about a "wet compression test" I should perform after the first test readings from those 2 cylinder's. Look :
From article - "The results you obtain from this second ‘Wet’ compression test will help you determine if the low compression you recorded in the ‘Dry’ compression test are caused by worn piston rings or worn cylinder head valves."
CASE 1: The compression value shot up.. This tells you that the piston compression rings are worn out and thus the problem is in the bottom end (block) of the engine in your GM 4.3L, 5.0L, or 5.7L equipped vehicle.
Here's why: The engine oil helped the piston rings seal better, thus bringing up the compression value almost back to normal. If the problem were in the cylinder head valves... the engine oil you just added wouldn't make a difference at all (on the compression value).
CASE 2: The compression value stayed the same.. This confirms that the problem is in the cylinder head valves.
Here's why: If the cylinder head valves and their seats are worn out (or maybe even bent from a broken timing belt), no amount of engine oil is gonna help seal the compression in, in the cylinder. So, if the compression value, for the specific cylinder you're testing did not go up (after you added oil to it)... then this is a dead giveaway that you've got cylinder head valve damage.
OK now my question is, where can I add oil to these cylinders besides the spark plug holes ? Oil leaks back out when I add it there.
I read an article about a "wet compression test" I should perform after the first test readings from those 2 cylinder's. Look :
From article - "The results you obtain from this second ‘Wet’ compression test will help you determine if the low compression you recorded in the ‘Dry’ compression test are caused by worn piston rings or worn cylinder head valves."
CASE 1: The compression value shot up.. This tells you that the piston compression rings are worn out and thus the problem is in the bottom end (block) of the engine in your GM 4.3L, 5.0L, or 5.7L equipped vehicle.
Here's why: The engine oil helped the piston rings seal better, thus bringing up the compression value almost back to normal. If the problem were in the cylinder head valves... the engine oil you just added wouldn't make a difference at all (on the compression value).
CASE 2: The compression value stayed the same.. This confirms that the problem is in the cylinder head valves.
Here's why: If the cylinder head valves and their seats are worn out (or maybe even bent from a broken timing belt), no amount of engine oil is gonna help seal the compression in, in the cylinder. So, if the compression value, for the specific cylinder you're testing did not go up (after you added oil to it)... then this is a dead giveaway that you've got cylinder head valve damage.
OK now my question is, where can I add oil to these cylinders besides the spark plug holes ? Oil leaks back out when I add it there.
Last edited by LesMyer; 06-01-2017 at 07:40 AM.
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