So here goes.....

I cooked my ecotec two months ago. Just finished getting the motor back in today. Wiseco forged pistons, eagle forged rods, head ported and polished, ferrea valves, dual valve springs, and ti retainers.

So the question is... I have no compression on cylinders 2 and 4. ZERO. On 1 and 3 I vahe about 175 pounds. Who can tell me why. The timing seems to be dead on, we checked it 3 times now. Therer were no banging or clanking noises. Just sounds like an inline twin. I don't think you can put the cam gears onto the cams wrong. And once you line up all of the marks on the timing gears and the chain, you should be good to go..... Right? Anyhow the manual is no help.

Any suggestions? Thanks for the help in advance.

Try removing the plugs for those cylinders and unplug the coil, put some oil in the cylinder, and let it sit for 10 mins or so. Then crank the engine for 10 seconds and recheck for compression.

When you had the head ported, did you have the machine shop check the compression on it?

Did you change out the pushrods?

Sometimes you can get the wrg pushrod mixed in, if it's a bit too long the valve will never seat and you will have zero compression.

Um, no push rods in the eco. It is DOHC, I would definetely be checking the head too.

That is correct... No pushrods in the ecotecs. Just to add. When an ecotec is "cooked" as you describe it.
The head tends to be the first thing that is messed up. The heads either warp, and blow a head gasket, or crack inside the water jacket where it is not noticed. If it was warped the gasket will not seal the cylinder and cause no compression. Majority of overheated ecotec we diagnose ends up being the head is warp and the valve train has become bad. That is why the head should have been compression tested at a machine shop. Which could be done usually for about $30-$50.

Last but not least the piston rings. When you rebuilt your motor, did you have the cylinders honed so the piston rings seat right to the cylinder? That could be another issue if that was not done. Especially if your cylinder sleeves were a color other than silverish grey. If the sleeves were black or burnt looking... you need new cylinder sleeves. If the sleeves were subjected to heat to cause them to discolor. More than likely they have been exposed to heat that will cause them to expand dramatically and when finally cooled are slightly to small for the jacket that holds them in place.

When we get a overheated ecotec and there is no compression. We tend to just replace the whole engine with a used one from a salvage yard. If you wondering why, because it costs more in parts and labor to either get a new head and replace it or re-machine the old head and replace the valve train.

Do a leakdown test make sure that when you check each cylinder the valves are closed to find where compression loss is( or just remove cams if you can easily)

OOps...

My bad 'bout the pushrods, had a senile moment there!

i guess...


yes, run a leakdown test, but id bet xian is right...

Go aluminum cylinder heads!!!! Also, did you make sure your rings were correct? Surefire way to lose compression.


God made turbo lag so V8's can catch up!

ya know the eco comes with aluminium heads

i think you just messed up on puting the cam gears on, those marking system sucks. Worst case those piston rings went out of staggar.