Z24 engine shakes and smokes from the oil cap.

[RafaelSagrero]

Good evening friends, yesterday I was driving my Nissan 720 at 40mph, suddenly on an inclined straightaway it began to choke for a few seconds (it hasn't done it again) and released a couple of explosions from the exhaust. After 5 minutes smoke started coming out of the hood and I thought it was overheating but the coolant was ok in the radiator and the temperature was 80°C. I saw that smoke was coming out of the oil dipstick and when I removed the cap more smoke came out.

 

I checked the compression and cylinder 1-2-3 has more than 160psi and cylinder 4 has 110psi, what could be the fault, my engine was running perfectly and suddenly it fails like this. It shakes at low revs but above 1200-1500 it runs almost perfect. A month ago they changed the complete distribution and valve seals. What could it be, my mechanic says it needs to be ringed?

[datzenmike]

Try the compression again on #4 then a second time with a few teaspoons full of engine oil. If not much change it not the rings. If it goes up 5 -10 PSI then the rings are nor sealing. See what you get.