2.0 engine questions

[CaptDon]

Please help, all you 2.0 motor guru's.

How do I tell if I have euro pistons? I thought I had flat top euro pistons until I cleaned my engine parts. Now I see there is a concave dished section that is about .041mm deep. To further assist in figuring if I have euro or low compression pistons the following castings are on the underside.

GER 1275
KS

and opposite that

094091
1

I am rebuilding the motor and would like the higher compression afforded by the euro pistons. However, the ones I have are in excellent condition, in fact the hatch marks from the cylinder wall honing are still visible in the barrels.

Incidentally the motor is a 76 2.0, case code GC.

Secondly, are the heads on these later engines the same as the 73-74 vintage with the addition of the air injection ports? If so, is there a kit to plug the ports since I will not need air injection on this motor, or is it better to have a machine shop weld the ports closed and smooth out the exhaust port?

Thanks in advance for your assistance.

Don

[Dave at Pelican Parts]

Some of the European pistons have dishes on top. The original ones have a very curved edge to the dish (seen in profile) while the US-spec dish has more beveled sides. The factory manual has a cut-away drawing that shows the difference, but I can't post it.

The only real way to know what the final compression ratio is going to be, though, is to mock it all up and measure everything yourself, then calculate the pertinent volumes. When the heads get fly-cut, that throws off the numbers. So do a lot of different procedures that often get done to engines...

The real difference between the 75-76 2.0 heads and the 73-74 is the air injection ports. Getting them welded up is the "best" solution (assuming you find someone who can deal with the heads correctly, pre-heating and post-cooling and all of that). But you can get screw-in plugs that will plug up the holes. Someone once mentioned Bug valve adjusting lugs? (Not sure on that.) Make sure you do something to keep them screwed in, though, whatever you use!

--DD

[Bleyseng]

The US spec dished pistons have a obvious dish while the Euro pistons have a very slight dish thats barely noticeable unless you flat edge the top of the piston.

[CaptDon]

Thanks Dave and Bleyseng.

These must be the euro pistons because to determine the depth of the concave I placed a steel rule over the edges of the piston and slid a feeler gauge under it at the deepest point. That's where I came up with the .041mm reading.

Don

[Bleyseng]

a pic of the US and the Euro's I have