Wet compression testing is an old school trick, originally adapted on V8 engines. 1-2 teaspoons will almost always guarantee oil on the cylinder wall because the cylinders are not vertical. On straight four, low compression 4G63 engine you have to full the “dish” on top of the piston before you get oil on the cylinder wall! At that point, you have taken up at least 30% of your combustion chamber. How do you NOT get a higher reading in this case?
The only method that I found somewhat acceptable is to use a long straw and spray few squirts of aerosol oil. It tends spray around and deposit itself on the cylinder walls without greatly affecting the volume. But even that method is not very reliable.
Take a head off, have a good shop rebuild it, they will tell you if it was bad. You have to do this no matter what, so why not start with it? You can save yourself a MAJOR headache if you end-up avoiding short block rebuild!
Remember – NO ONE BUILDS THESE ENGINES BETTER THAN MITSU!
Timing belts are definitely easier to change on the engine stand, than in the engine bay, but it can definitely can be done inside the car!
BTW, the nicks on the pistons indicate previously bent valves, so this head was already rebuilt once (or replaced by a remanufactured head). And if it wasn’t done right, that could explain why you valves could be leaking
I just bought this tool http://www.ebay.com.au/itm/121173625211?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649 and I will be lapping the valves and doing the seals myself.
