Low compression test help

[Wet0willy01]

Recently got my car running again after my waterpump went out in June. New tbelt, tensioner, water pump etc. Then I replaced my leaking VC gasket and cam tensioner gasket. I had been running low vacuum at idle.(18-19") and my spool was pushed back to ~5k rpm. My DV was also fluttering so I suspected the vac line was leaking. I serviced my DV, and reattached the vacuum line and then did a boost leak test. I immediately found my MAP sensor was leaking. I pulled it out and the O ring was tore in two spots on the O.D. Replaced the O ring, still leaked. Then I noticed the hole in my map sensor flange was burnt back on inside of the hole from the welder that tig'd the flanged to my IC piping. The two spots were in same orientation as the tears in my O ring. So I was able to seal it by using a spare oil return gasket ( @ oil pan) to face seal the sensor. Then I tested again... no more MAP sensor leak but I immediately heard the oil gurgling in the oil pan and my boost gauge was only reading 2psi

Car has 50k, 71R elim 630 uni file running 21 on the N75. I have the pcv system removed and have the VC and block breather vented to atmosphere. If I plug the end of my vent tube, it builds pressure in the crankcase. The car now has low vacuum at idle 16-18 varying. But when I lift the throttle when moving and in gear I finally see 23-24" where before June I would only see 22". But then if I push in the clutch, or come to a stop in neutral it stubbles, almost stalls, kicks the idle up and the vacuum comes up to 16-18" vacuum and ~10-11:1 AF. Now today when it warmed up a bit I would occasionally get 20" and it would run extremely smooth at idle, AF, seemed okay. But shortly if I touch the throttle it will stumble and drop to 17-18" and the idle is a bit rough.

So I did a compression test, 180,180,155,180. (cold)
I am planning on a leak down test tomorrow or wed. I am going to log miss fires and I suspect to see cyl 3, and also compare my VEI vacuum gauge to what the ecu is reading.

When the water pump went out I did overheat, temp gauge pegged, coolant bubbling out of the reservoir. The car does not smoke, no bubbling in the coolant. I doubt my rings failed at 50k, and I was thinking the head warped or cracked, or head gasket isn’t sealing from the overheating. I will also try a warm compression test, and a cold with a bit of oil in cyl 3.

Any other thoughts before I pull the head? I have acess to a AEB head I may have rebuild and put on if it comes to that. But idk if it’s worth it on a stock motor @ 21psi with an eliminator.

Thanks in advance for the help!

[dougyfresh]

When the water pump went out I did overheat, temp gauge pegged, coolant bubbling out of the reservoir. The car does not smoke, no bubbling in the coolant. I doubt my rings failed at 50k, and I was thinking the head warped or cracked, or head gasket isn’t sealing from the overheating. I will also try a warm compression test, and a cold with a bit of oil in cyl 3.

Most likely blew the head gasket due to the overheating condition. It is very common on this motor if you run the motor very hot (ie: overheat).

[Wet0willy01]

Is it worth rebuilding the AEB head? Or is going to larger runners and loosing the VVT going to move my power range too high for my setup?

[diagnosticator]

With the larger intake runners there will be reduced low RPM torque and throttle responsiveness. Drivability problems with 1.8Ts already, that get worse with the larger manifold runner/intake ports. Running with no VVT does not help with this.