Hello HT,


I recently installed a used z6 block on and I'm having issues starting the engine it up. I have all the essentials; air, spark and fuel. Compression is
Cyl 1 = 90, Cyl 2= 60, Cyl 3=150, and Cyl 4=90. It was out of timing but we figured it out and it isn't backfiring anymore. Currently, the pistons are flooded with gas and may be causing the spark plug tips to get drenched and not spark. I have an O2 sensor that is currently not connected only because the exhaust manifold I have on there now doesn't have a port for it. The previous one did but It was replaced because it cracked. Also, PVC breather box (oil separator) is not connected to air intake and box is open and is not plugged. I upgraded the air intake to the Skunk2 version. So not really sure what may be going on but any help is appreciated. Thanks.

 

Your motor isn't going to start with that compression, and if it did it will die right away.

Best bet is to find another z6 short block, and properly inspect it before purchasing.

 

ok. I got it on a 30 day warranty, so I'll take it back to the junkyard. How would I go about inspecting it though?

 

Use a bore scope on the cylinder walls, use your nail to pick up any scratches. If your nail picks it up its bad.

Check crank for warpage, rings, deck, clearances. And this is just things that come to my head, there's a lot more. If you have a experienced friend that can look it over that would be good too.