Piston rings not sealing

[klipzedgsx]

hey guys im just trying to figure out what is wrong with my car and the next thing i could think of is burnt pistion rings. could someone tell me what i would know if i have burnt pistion rings with out getting a compression check, if that is the only way ill go and get it done or do it my self but is there any other way i could find out thanks

 

[turboholic]

-You can get a compression gauge at Pep-boys for $20. I would prefer the one from Sears for better hose and seal. Or do a leak down test.

 

[klipzedgsx]

ya i seen that tester at pep boys but how do they work they look cheap and hard to use, could someone tell me how they work, and could somone tell me if ther is any other way to tell

 

[me612]

its so simple, all you do is disconnect the fuel pump, restart the car, it'll run for a split second and then die. Once u do that, just unplug the plug wires, take out one spark plug leaving the other 3 still screwed in, screw in the compression tester in the well u just took that one plug outta. Have sumone get in the car and turn the key, when the engine cranks the needle will rise on the gauge, keep cranking until the needle doesn't rise anymore, and there is the compression for that cylinder. Take out the tester, put the spark plug back in that hole, then go on and do the same for the other 3. Takes like 5 minutes.

 

[Floridabird]

1. Make sure the battery is fully charged. A battery with a low charge will give low compression readings because of reduced cranking speeds.

2. Warm the engine to operating temperature to produce metal expansion and to reduce oil drag. A cold engine will give low readings.

3. After the engine is warm shut it off and loosen the spark plugs one turn. Restart the engine at a fast idle for about 5 seconds. This removes carbon debris from around the spark plug. This will keep small particles of carbon from being blown into the compression gauge.

4. Shut the engine off and remove the spark plugs noting which came from which cylinder.

5. Block the throttle open.

6. In turn, carefully insert the compression gauge in each cylinder and with the starter, turn the engine over through five compression strokes.

7. Make a note of the readings from each cylinder. What was the pattern? Does the gauge pump up fast? Is the max reading obtained after five strokes? (Very important)

8. On all low readings, retake and if it is still low, inject about two teaspoons of 30 weight oil into the combustion chamber and retest.

9. Check the spark plugs from the cylinders with abnormally low or high readings. look for carbon buildup or oil deposits.

10. Replace the spark plugs and torque them to the recommended specs.

Once you've got the readings, it's time to evaluate them to determine just what the future of your engine is going to be.

If the gauge pumps up slowly, such as 30, 50, 70, 90, etc. to an almost normal reading, you probably have ring problems. A general rule is that a maximum reading should occur after two strokes. If oil is added to a low reading and the pressure improves, this will confirm worn rings. A persistent low reading generally indicates valve problems.

Oil lost through worn valve guides will not be determined through compression testing. Low readings can also be caused by a warped head and occasionally, two cylinders will have very low compression which can be the result of a blown head gasket. It is important to remember that the addition of oil to the combustion chamber will not improve the compression readings if your engine has burned, warped or stuck valves. High compression readings can be the result of carbon buildup or head surfacing.

Generally, if the variation between the cylinders is 10 to 15 lbs., this is acceptable, but always check the specs in the manual. It would seem that equal pressure is necessary to have smooth running engine, but it's been found that with only 70% of normal pressure is enough for running smoothly. Also, manufacturers specs usually list a bottom line acceptable pressure and a good engine will usually read 20 to 30 psi over the acceptable readings.

If you find that your engine has good compression, it may be time to go back over your tune-up steps. On the other hand, if you've found low compression readings, it's probably time to have that 200,000 mile engine rebuilt

 

[turboholic]

Originally posted by klipzedgsx
ya i seen that tester at pep boys but how do they work they look cheap and hard to use, could someone tell me how they work, and could somone tell me if ther is any other way to tell

http://www.dsmgrrrl.com/FAQs/compression.htm
http://www.dsmgrrrl.com/FAQs/leakdown.htm