ronniek said:Finally I sorted out why My car had low compression.I bought a compressor and did a leakdown test and found air leaked from all intake ports and 3 of exhaust ports.I also removed a rivet from one of the titan head-gasket.
Hopefully by next week,the supra will be back on the road.
thank you very much man... I'm going to have to do that when I change my timing belt b\c I get a little bit of blow by that comes out my exhaust and it's starting to dull my freshly painted white car...cjsupra90 said:You need a leakdown tester and a air compressor. The leakdown tester can be picked up at any Napa or Snap-on dealer. They are not to badly priced. If I recall, mine was around $60 at Napa....
They are fairly simple to use. They are a unit that is a block with 2 gauges on it. One is the in or test pressure. the other is a precentage gauge representing the lose of pressure within the tested cylinder. The unit has 2 hook-ups on it. one is the compressor hook up and the other is just like a compression tester hook-up and threads into the spark plug hole just as the compression tester. To use, you turn the motor over to TDC compression stroke for the cylinder that you are testing. hook the unit up to that cylinder and hook up your shop air. Most units have an adjuster knob to set the test pressure. I usually use 100 to 120 PSI as the test pressure. If it seams like the motor is turning over, make sure that the motor is perfectly at TDC, and or lower the pressure slightly. Once hooked-up and pressurized, look at the percentage gauge and see what it is at. O to 5% is typicaly a good cylinder, 5 to 10% could use attension. Anything over 10% needs attension. If you find a cylinder that has a high % of leakdown, listen in the intake, exhaust, oil cap opening and remove the radiator cap.
Air heard from intake = leaking intake valve
Air heard from exhaust = Leaking exhaust valve
Air heard from oil cap oplening = bad rings and or problem with cylinder wall also possibly a crack in the block.
bubbles seen in radiator = leaking headgasket and or possibly a crack in the head or block
here ya go, from the reference section:7M-GTE said:how exactly do you perform a leak down test... I've been told to do this with my car but don't know how to do it...