1986 Nissan 720 King Cab with 2.4 Naps Z engine (Carb based) running rough (suddenly)

[Lockleaf]

Pull the Piston as far as you can down into the boar and then clean. If it leaves any pitting you can feel with your fingernail that will allow some oil consumption or compression loss. That being said as long as you're willing to check the oil and deal with it being slightly underpowered I see no reason you couldn't just move forward. I've reassembled some serious garbage with the z24s and while they were not impressive they did just keep on running. So if all you need is a motor that moves the vehicle and you're willing to deal with the compromises you should be fine.

[datzenmike]

Have a care!!! The timing chain tensioner MUST be blocked from falling out. Once blocked you cannot turn the engine. Head gasket is $25 so swap in a new one and try it. If it's fucked.... it's fucked and cleaning the rust up won't help... and you're only out a gasket.

 

 

Check the oil. If milky dump it out and refill with the cheapest oil you can find by the gallon and throw a $2.99 filter on. Get a couple of hours on it and change the oil for one with high ZDDP level like Shell Rotella T4 10w30 and a new GOOD filter like NAPA gold..