S14/S15 SR20DET vvt issue

[redline19]

It seems that the S14 and S15 sr's that have vvt has a problem with a rattling upon starting up the motor and only hear it when you step on the throttle.

I found the diagnosis on a site(http://www.200sx.org/faq_4.html):

The car needs to have been sitting, engine off for an extended period (30+ minutes). The first time you try and move off ( or just put the car in gear, hold the clutch in and blip the throttle), you will hear a sharp "metallic" rattling sound from somewhere in the front of the engine.

Always consult your dealer, but we have found on several cars, there is a problem in the variable valve timing actuator and inlet cam sprocket, that causes this noise. Nissan have a fix for it, and the job is done within a day.

So what causes it? It's the variable valve timing actuator. This is a hydraulic piston which moves the inlet cam sprocket slightly. The problem is that when you start the engine, oil pressure does not come up fast enough to hold the actuator firmly in place, so it rattles. Because this assembly is mounted on the cylinder head, it seems to reverberate and amplify the noise.

just to let people know when they buy a S14 or S15 engine, its a pretty common problem. 3 of them at my shop including mine has this problem and you have to redo the whole timing chain with all the components to fix this problem, which involves taking apart the head which is a good amount of labor not including parts. not sure how many other people experience this with their vvt sr's - let me know

[sean350z]

i have the problem...it's annoying. the only way i get around it is to ever so slightly ease the gas at first startup and it doesn't seem to sound as bad. o btw i have an s15 sr20.

if it sits near the inlet cam sprocket i wouldn't imagine you'd have to replace all timing chain components...i thought you'd just have to replace the plunger for the vvt which is located (see page 173 in S15 fsm)

the thing just screws into the head...i wonder if anyone has just replaced the solenoid and it fixes the problem?!?!?

KEEP ME POSTED!!!!

[r1jlewis]

Man, i though i was the only one that had the problem. I was always just like o well. I have another VVT dohickee but haven't installed it yet. I will find out very soon though. S15 also, but new VVT is from S14

[sean350z]

yea tell me how it went...it's just an easy screw out old screw in new.

oh by the way...did you send that recirculation hose yet justin?

[r1jlewis]

Yep, hose was sent out last week, should probably get it by today or tomorrow!

[ArcherV20]

Wow yeah, I have the problem too! Our North American mechanics will be able to deal with the problem? I'd love to find a proper fix for that. Keep us updated.

[redline19]

ok, got got my whole timing chain done... not the route to take with this. I bought every single timing chain part possible except the intake sprocket because that thing is non existant in the US. Put everything back together and the problem was still there. After narrowing it down to the intake sprocket and the vvt actuator solenoid, it was actually a missing spring in the solenoid that cause the oil pressure not to build up. Once you pop the hood the solenoid is on the left side of the engine between the intake manifold and valve cover by the front of the engine, like right around where it bulges out for the timing chain. Don't have the schematics for the spring or where to put it, but its basically narrowed down to that portion of the engine. Let me know if that helps out.

[sean350z]

I took out my solenoid the other night, cleaned it up, tested to see if it worked with 12v and it moved. I haven't started the car yet though to check but i'll be doing that a little later. After some research on the web I've seen things stating that the solenoid basically stops working correctly and needs more and more oil pressure to function correctly. I've also found that the intake cam sprocket maybe needs replacing as well. There are used sprockets on yahoo japan and some say the sprockets (big part on the end) does not work anymore which leads me to believe that this maybe the part that's malfunctioning.

[sean350z]

oh and here's a schematic of the solenoid and cam gear

[img=http://img253.imageshack.us/img253/98/ecaw6.th.jpg]

[Sabot]

So if you eliminate the vvt and change to s13 sprockets Would it fix the problem?

[sean350z]

i just started up my car and attempted to get that rattle and it wasn't there, i did let it warm up a little (2-3 minutes before hitting the gas) but not hot. all i did to the solenoid was take it out, clean it, tested the piston with a 12v source, cleaned out the opening with some q-tips, and moved the bearing in the left of the opening with my finger then cleaned it off with a q-tip. the car has been sitting for two days.

granted this my be a one time only thing but it didn't do it which makes me happy

[redline19]

yea its really nice not having that rattling sound everytime you fired up you engine. but for anyone else that has it, the solenoid is probably the first place to look to get rid of the rattle.

if you change out it out for s13 sprockets then you wouldn't need the vvt solenoid so most likely that would elimate it since it would work like a normal s13 SR with no vvt. i think unpluging the solenoid would disable it when you run s13 sprockets.

[ArcherV20]

So even with the rattle, does this mean VVT is functional?

[redline19]

yes, its just that the oil pressure doesn't build up upon start up, but once the rattle goes away in a few seconds the vvt functions normally

[da40]

yes, its just that the oil pressure doesn't build up upon start up, but once the rattle goes away in a few seconds the vvt functions normally

right on!!!

[FAST-DATSUN]

You also need to make sure that the netural saftey swt is hook up so it doesn't cycle just sitting there..