ok this is going to be a long post but please bear with me because im lost and need help from someone that knows these engines

1986 nissan 720 king cab 2.4 motor 5 speed 4x4 130,000 miles

i bought the truck with it pushing oil into the radiator pretty bad, pulled it all apart and found that the head bolts where not very tight, then found that someone installed the head gasket cocked and literly took a hammer and beat the head bolts through the gasket.

what i have done so far

i had the head all worked over, milled flat, valve job, pressure tested... done....

checked the deck of the block with a machinest straight edge, and its with in tolerence according to my machine shop...

new oil pump installed

at this point i put the motor all back together, started it, still doing the same thing, i figured from what i found tearing it down that someone worked on it that didnt know what they where doing and i figured a head job and proper headgasket install would fix this problem, i mean the truck runs fine except its pushing oil into the rad.


so i tore it back down again and really started digging.

i have small hairline cracks in the front cover on the inside from where someone over torqued the water pump, i cleaned the inside like crazy, they do not come all the way through

i have a very very small hairline crack betweeen cylinder 3 valves in the head, (passed pressure test)

i have looked all over the oil passage way between block and head, no signs of cracking or abnormal passage. then i got to thinking if that reducer in that hole is supposed to be sticking up out of the block and go into the head a little bit, tried that theory, fail with the dowel alighment pins in the block and that sticking up, everything does not line up...

ive dug all over google cant find crap on this. id really like to save this truck i think its cool, but im out of ideas..... any help and thanks in advance.

idk is wrong with this thing.

Bump bump. Anyone?

I would suspect front cover would be the culprit. Could just source another napz. Or do kae swap. Both motors are easy to find and relatively cheap.

It was a while ago but I bought a front timing cover off eBay for pretty cheap.

Change timing cover. Or as suggestted above swap to KA.

I am not saying this is the issue, but the 210 head on the L16 had this issue, not all of them, the ones that cracked.
What happened was the oil port in the head would get a crack, and when you drove it after it was warmed up it would push oil in the water jacket, all the testing they could do to the head did not shine any light on the issue, a guy named Dan Hart bought a new head for the guy he was dealing with and all was well, he then had the head sliced open like a loaf of bread till he found the crack in the oil port in the head.
I had this issue and asked him about it later(couple years) and that is how I found out what the issue was, mine only pushed oil in the water jacket if I drove on the freeway for an extended period of time with the oil pressure being steadily high, around town when the oil pressure went up and down it didn't push oil into the water jacket, only on long trips for me, but I do have to say on the freeway I was pretty close to being floored as it was an L16, I fixed my issue by upgrading to an L20b with a super head.
You are talking about a Z24, they are built for torque, they do very well starting out when properly set up.