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lucittm lucittm is offline
Manassas, VA
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Join Date: Apr 2007
Posts: 1,211
Leakdown tester, $15 in parts:

#6 piston ring failure from PO overboost, blow-by diagnosed by leakdown tester:

Broken rings on #5 cylinder and #6 cylinder:

New rings, gaskets, seals - priceless:

The car has been running great since this I did this rebuild back in July, 2008. The engine went from using a quart every 500 miles to maybe a cup in 1000 miles. The plugs (Bosch WR6 DP0) looked good then because the synthetic oil doesn't burn like regular dino oil. The plugs are a perfect tan color now. Never thought to crank the engine over with the plugs out, it would have spit oil, but I had no idea there was any oil in the cylinder anyway.

In hindsight, the oil in the cylinder confirmed the compression and leakdown tests I had done the week before I opened up the engine. It was amazing how well the car ran with about 2 tablespoons of oil in the #6 cylinder.

Other than rings, nothing fell off the engine or suffered any damage. It is easy to look at pictures and say, "Of course, look at what is wrong there." The higher skill is to diagnose what is wrong before the engine is disassembled, buy the parts ahead of time to have on hand, and get the car back on the road in the shortest possible time. We old guys would call this intelligence. BTW, this car is a daily driver, not a garage queen. Today, compression test on all cylinders within 10psi, leakdown on all cylinders 5% or less.

One question, have you ever actually used a leakdown tester?

1991 964 Polar Silver Metallic Turbo Coupe

Last edited by lucittm; 08-14-2010 at 04:36 PM..
Old 08-14-2010, 04:32 PM
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