glen242

Did a leakdown test using a tester that is calibrated in %. Gauge says 10-40% is low leakage, 40-70% is moderate and >70% is high. My results were between 35 and 45% on a warm to hot engine with all indications being that the leakage was past the rings not the valves. During the tests, I noticed that turning the crank a little had a noticable effect on the leakdown. I guess I was not exactly @TDC on several cylinders because turning the crank would decrease the leakage by 10-15%. How do my numbers look?

I am chasing an excessive oil consumption problem, thus the test. On occasion, when the engine is hot, I can get a puff of smoke when I floor it from idle and then close the throttle. No smoke on startup after sitting, so I ruled out valve train problems. Also, the heads are almost brand new. Plugs show no sign of oil, are light tan to white. Engine has about 46,000 original miles on it. Is it possible my oil control rings are frozen or hanging up? The car is stored over the winter and I first noticed the problem when I started it up this past spring. If the oil rings are indeed the culprit, is there anything I can do, short of a ring job, to free them up? Compression is ok and uniform. Any ideas?

redvetracr

glen,
From what i have been told (i just rebuild mine all the time) LESS than 10% is OK and any more than that is not so good and one leaking alot more than the others is very bad. ...redvetracr

glen242

10%!!! The initial air pressure setting on this gauge runs between 0 and 10%.

Are different gauges from different manufacturers calibrated differently?

redvetracr

glen,
The way i have read the directions you put 100lbs in the cylinder and read the difference on the second gauge. where 100 in and 98 out means 2% leakage which is good.I think 30-40% leakage is bad. ...redvetracr

norvalwilhelm

I like a leakdown test. With a healthy motor and no plugs in the motor will turn over by itself, You can not leave it at TDC and expect it to stay. I often just set my pressure at 125 and plug it to the spark plug adaptor and listen to the leak. This is not a accurate way but after doing it for years you can hear a good cylinder and one that leaks alot. Worn older motor really leak bad. My leak down tester has a flow meter on it. You set the pressure with a regulator right on the meter , plug it into the cylinder with the adaptor and then read the flow required to keep the cylinder at 100psi. This is a very accurate guage.
I know this doesn't help you but if moderate is 40-70 I feel that is way too much. The 10-40 you can live with.
With a new motor torque plate honed you can get 4% leakdown.

glen242

I talked with a tech. from Eastwood (where I purchased the tester) and he seems to think the tester is bad. They are shipping me another one tomorrow.

Will post results after I try the new unit.