right mate has had some issues with his cossies engine smoking abit and missfiring. Also the 2 middle plugs no 2 and 3 and are filling up with black soot and 1 and 2 seem fine.


He had a compression test done on the engine and it read

140/130/120/140

The engine was recently rebuilt about 10k approx its a 200 block had .5 oversized pistons etc fitted and new oil pump new bearing, crank ground etc.

Would it be possible to just change the rings on the pistons all the way across? would this remedy it? Why else could the compression be low ?


Whats should the compression ratio be for a healthy 200 blocked cossie engine?

cheers in advance guys