I recently replaced the bottom half of the engine with a JDM block. installed my VTEC cylinder head. I have low compression <30psi in Cylinders 1 and 2 and almost zero in 3 and 4. Someone mentioned a possible reason is the "camshaft is 180 degrees out of phase" does anyone have any information on this and how to go about correcting it?

 

If you rotate the crankshaft to the TDC position (and the crank pulley mark aligns to the TDC mark on the lower timing cover), and the cam gear points UP and the TDC level marks align with the pointers on the upper inner cover... you are IN mechanical time. If the cam is 180' upside down when you move the crank pulley to TDC, simply rotate the crank one full rotation back to TDC (360') and you will be correct again. Being "180' out" relates to the distributor timing. Placing the crank and camshaft at TDC, remove the distributor cap and visually check to see if the rotor button contact points at the #1 plug wire position... if it does, you are all good. IF it points toward the #3 plug wire position, then electronically you are 180' out. To fix this, you remove the distributor from the end of the cylinder head, remove the cir-clip from the back side of the distributor shaft, gently drop out the pin, rotate the offset tangs 180', re-insert the pin and re-install the cir-clip. Now you will be in proper time.

You likely have another problem... don't listen to that "someone" who suggested this 180' out silliness... the fact is that this electronic issue would have absolutely nothing to do with low compression.

 

Low compression in your engine could be one of a few things.

1. Bad rings in the bottom end that you just installed.
2. Improper valve seating or a tight valve adjustment.
3. Improperly installed head gasket allowing compression to bleed over between cylinders.

A leak down test will help reveal if your problem is #1, #2, or #3.