Low compression in cylinder one and two

When two adjacent cylinders have low compression, a leaking head gasket is the best suspect. The compression test showed the compression was low. A cylinder leakage test will show why it is low. That involves pumping compressed air, through the tester, into the cylinder, then you observe where it is sneaking out.

For a leaking exhaust valve, you will hear hissing at the tail pipe. For a leaking intake valve, you will hear hissing at the throttle body. For leaking piston rings, the hissing will be heard at the "oil" cap or dip stick tube. The most common head gasket leak will cause a steady stream of tiny bubbles in the radiator.

It is possible to incorrectly blame a leaking valve when you hear hissing at the tail pipe or throttle body when the air leaks into the adjacent cylinder, then out its open valve. (This test requires each piston to be at top dead center on the compression stroke when that cylinder is being tested). To avoid that, have the spark plugs removed from adjacent cylinders. That way you will hear the air at those spark plug holes.

You might find a cylinder leakage tester at an auto parts store that rents or borrows tools. You can also ask at a community college that has an Automotive program. An instructor might borrow the tester to you or offer to have the students do the test if they are currently studying engine repair.

From what I can tell, you might be over-thinking this. Exhaust gas is corrosive and can attack the head gasket. Once a path forms through the gasket, the flow of additional hot gas can burn the metal ring and push it out. There really is not any defect that led to that.

Do not panic if you find small cracks between the two valve seats in the head. Those are common and harmless. Proper surface finish is most important for good sealing of the new gasket. I do not like the Scotch pads on rotary air tools because they can gouge into aluminum heads too easily. You will have better luck with the discs with plastic fingers. It is also a good idea to take the head to an engine machine shop to have it checked for flatness. They will use a precision straight-edge to measure the warpage. You can have up to.005" warpage on a cast iron head, and.002" on an aluminum head.

If this helps, I use Microsoft Word a lot for my pictures. It is a typing program but I use it for the shapes and drawing objects that can be added, including arrows. Copy and paste the picture to a new document. Go up to "view", drop down to "tool bars", then check "drawing". That will put the drawing objects menu on the screen. Click on the circle, then click on your picture where you want it to go. You can drag it around and resize it. If the circle covers what you want me to see, go back to that tool bar with the circle highlighted, and there is a place to select the circle "fill" color. Select "no fill".

You can add arrows the same way, and there are places to make them bigger and change the color.

When you have everything added that you want, click the picture, then hold the "shift" key down and click the arrow and then the circle. You will keep adding things as long as the "shift" key is held down. Once everything is selected, you can release the "shift" key. Click "draw" on the left of the drawing tool bar, then at the top, click, "group". That turns all the items into a single picture. Copy that into MS Paint, then save it as a j-peg file. That file can be uploaded here.