Which compression tester should I get?

[stopintime]

My engine guy asked me to do a compression test to help our diagnostic work.

Fuel prices makes it cheaper to buy a kit and do it myself, rather than travel two hours t/r to my dealer (after just one use).

The cheapest kit has 14 and 18 mm thread mounting pieces, but also a coned rubber thingy. https://www.biltema.no/en-no/car---mc/workshop-equipment/test-instruments/compression-testers/compression-tester-2000016979

The other has more stuff  https://www.biltema.no/en-no/car---mc/workshop-equipment/test-instruments/compression-testers/compression-tester-petrol-2000022140

[ducpainter]

If the cheaper one has the threaded adapters, it will be fine. It doesn't show any in the photos. 

The rubber cones work, but can be a PITA.

[stopintime]

If the cheaper one has the threaded adapters, it will be fine. It doesn't show any in the photos. 

The rubber cones work, but can be a PITA.

The cheaper one has a 14mm adapter. Our plugs are 12, I believe. Rubber PITA because?

[ducpainter]

The cheaper one has a 14mm adapter. Our plugs are 12, I believe. Rubber PITA because?

Sometimes it's a pain to hold it in place and operate the starter switch.

[stopintime]

For a more specific piston to cylinder test, they recommend pouring a teaspoon of oil in the spark plug hole. That should spread out nicely in the vertical combustion chamber, but what about the horizontal? Spray another liquid in the hole? WD40? Silicone spray? Chain lube?

[Howie]

For a more specific piston to cylinder test, they recommend pouring a teaspoon of oil in the spark plug hole. That should spread out nicely in the vertical combustion chamber, but what about the horizontal? Spray another liquid in the hole? WD40? Silicone spray? Chain lube?

Good question.  My best guess would be fogging oil.
https://www.bing.com/shop/productpage?q=engine+fogging+oil&filters=scenario%3a%2217%22+gType%3a%2212%22+gId%3a%22156673970157%22+gIdHash%3a%220%22+gGlobalOfferIds%3a%22156673970157%22+AucContextGuid%3a%220%22+GroupEntityId%3a%22156673970157%22+NonSponsoredOffer%3a%22True%22&productpage=true&FORM=SHPPDP&browse=true 

A more conclusive test would be a cylinder leak down test.



The tool is awfully expensive for a one time use, but any competent local shop should be able to perform this test.

[stopintime]

Adapter is fitted finger tight?

[ducpainter]

Adapter is fitted finger tight?

Yes. The o-ring should seal it.