Leak Down Test ?

Hi,could anyone explain how to do a Leak Down Test on a 78SC. And what the ideal results should be for a compression/leak test.The car is a European one.THanks,Guy.

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I do not have an answer, but, I too would like to know if it is possible to do a leak-down test, using fabricated or easy to aquire tools

Leland Pate

____79 SC targa

Any advice please.Guy

In a leakdown test, the test device is screwed in in place of the sparkplug. The cyl is then pressurized, and the amount of pressure drop over a set period of time is measured. It measures the amount of air escaping either through the rings or the valves.

Thanks for your info Brian,could you do a leak down test with a compression tester?and do you know what the compressions should be for a 78SC Euro.Thanks for your help,Guy.

I don't think you could do a leakdown test with a standard compression tester, but I'm not sure.

I don't think there is really a set number that compression "should" be, because there is somje variance between gauges. What most people seem to look for is something in the ballpark, but most importantly, consistency between cylinders.

For a point of reference, though, my 78 SC was serviced at Andial exclusively for a period of about 13 years. They take a compression test at just about every service, and mark it down on the invoice. During those 13 years (starting from when the car was new), it always tested at 150 lbs in each cylinder.

I think other gauges may read a little higer or a little lower, but should be in that ballpark, and consistent between the cyls.

Brian