ka24e high idle, loose timing chain
 

Hey guys, havn't posted here in a while but I just got another 240 this time a single cam one, and have a few questions. I need this engine to run right while I'm rebuilding my FC's wankel. right now it's got a ~1500 rpm idle, sometimes it settles back down to 1200, but usually sits at 1500 once its warmed up. Second question, the timing chain is tense on the passenger side of the car, and so loose that it slaps against the guide on the drivers side. I searched for both of these but didn't find a definate answer/suggestion.

Greetings,

I have a 92 Stanza that has the 2.4l KA24 engine. I recently experienced the same problem. I didn't fix mine in time and it cost me dearly! For all you Nissan owners with this engine ... this is very important!

The original timing chain guide in these engines are made of harden plastic. This guides wear out and allow the chain to go slack. Not only does this throw your timing off, the chain slaps against the guides wearing them down faster. If the guides are replaced (along with chain and spockets since your in there) the guides are eventually destroyed, the chain flys off (which in my case broke the oil pump cover), the cam stops rotating but the crank doesn't. Since this is an interference motor, the pistons then ping which ever valves were open at the time (in my case 4 intake valves) and bend them and possibly bust/crack the piston (my pistons didn't crack).

DO NOT let a loose timing chain go unfixed for an extended period.

Now... changing it out.. that's the fun part. For my vehicle, chaning the timing chain took me about 16 hours! You have to remove the oil pan which requires the removal of the motor supports, cross bracing, all the front engine components, etc. It's easier to change the head than the timing chain but that's still a job in itself if you get bent valves like happened to me.

The moral of the story, don't let the rattle become a grenade!

Good luck and I hope this helps.