1.1 engine compressions

[n81641]

I have a 1971 Kadett with a 1.1 engine. The number stamped on the block starts out 11us-

After reading this thread: http://www.opelgt.com/forums/kadett-...-question.html
and looking at the pictures in this thread: http://www.opelgt.com/forums/kadett-...ere-we-go.html
and reading the 1971 factory manual, I figure I should have a 7.6:1 compression engine with dual carbs.

In fact, The engine has single carb, and the linkage has been modified to accommodate. I also looked through the spark plug hole, and spotted 2 notches for the valves, and no dish in the top of the pistons. Does this mean the engine might have 8.2:1 compression ratio, and be from an older car? Or did the 1971 7.6:1 engines have flat top pistons, and some other method of lower compression, like different heads?

I know with the 1900 engines, if you have flat top pistons, it's not a 7.6:1 engine, no matter what (stock) head you put on. Are things similar with the 1.1?

--Karl

[tekenaar]

Originally Posted by n81641 I have a 1971 Kadett with a 1.1 engine. The number stamped on the block starts out 11us- After reading this thread: http://www.opelgt.com/forums/kadett-...-question.html and looking at the pictures in this thread: http://www.opelgt.com/forums/kadett-...ere-we-go.html and reading the 1971 factory manual, I figure I should have a 7.6:1 compression engine with dual carbs. In fact, The engine has single carb, and the linkage has been modified to accommodate. I also looked through the spark plug hole, and spotted 2 notches for the valves, and no dish in the top of the pistons. Does this mean the engine might have 8.2:1 compression ratio, and be from an older car? Or did the 1971 7.6:1 engines have flat top pistons, and some other method of lower compression, like different heads? I know with the 1900 engines, if you have flat top pistons, it's not a 7.6:1 engine, no matter what (stock) head you put on. Are things similar with the 1.1? --Karl

Karl, first you'd have to give the rest of the engine's S/N to determine the year it was built and more accurately guess what the specs might be. Still, even that, doesn't take a rebuild, always a possibility with an engine that old, into consideration.

That said, maybe this US Opel engine chart will help

[n81641]

Thanks for the chart. Very helpful, since with the few clues I have, the engine matches a '69 11us. I need to get more agresive with scraping and cleaning to read the rest of the numbers.

And yes, I'm aware that with a car this old, and no known history, and obvious engine changes, This could be literally mix and match of anything.

The engine runs on regular fuel w/o pinging, so i'm guessing it's not 9.2:1 compression. I suppose that fuel economy will be a tell, once I've run a few tanks of gas through it and have some numbers --Karl