>The best way to test for compression loss- a leak down test.

Is a leak down test (that's where you put a little oil in the spark plug
hole and repeat the compression test, right?) any good on a Vanagon??
It's a flat four so how good a seal can you realistically get?  I've
also got low compression in no. 1 and 3 cylinders with a kind of tapping
sound from the engine.  Sounds almost like the tappets need adjusting.
I tried the leak down test and there was no change but then I'm not sure
how good a test it is with all the cylinders horizontal.

Rich
90 Westy
Vancouver BC