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LeakDown Test

01/06/03*

                 Checking Side Clearance of Top Ring

     This is all you have to do, to check if the Piston & Cylinders need replacing.

 With the top ring compressed in it's grove, place the thickest feeler gage that will fit in the grove along side the ring.  VW lists maximum side clearance of the top ring as .0495"   
We tell  our customers if the ring side clearance is over .005/.006"  then it's a waste of time and money installing new rings. The VW Cylinders are very hard and if you see a ring grove in  the cylinder then it's most certain past time to replace the Pistons.

Note: The rings not only seal the hot gases but also transfer the largest amount of heat from the piston to the cylinders. If the rings can not transfer the heat away from the aluminum piston, they will either start to melt (get soft) and stick or seize to the cylinder wall. When  rings overheat they will collapse and flutter and will most likely break if the piston doesn't stick first. Rings also break when the side clearance is to great.

 Wide rings transfer more heat but only work efficiently at low RPM's because of there weight. 
The higher the engine speed the narrower the ring you should be using. 
Never use chrome rings when re-ringing an engine as they will not seat properly.

If you want to check the rings before you tear it down, here is the way -> LeakDown Test

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