HELP! - might be a lifter tap, wanted some real advice

[Jok3r1552]

New to the forums, hello peeps. have a video for you guys to check out. been doing my own self diagnosis on the car. im happy to announce that it might be a lifter tap just wanted some real advice from real gear heads; first TT ive owned. i layed into her today for about an hour and a half on the road and the worst you are gonna hear from this motor is from the video im linking on this thread. thanks

[seagull369]

I'm no expert, but that sounds a little like a bad rod bearing to me.

[nissanfreak12]

It doesn't sound like rod knock. A light rod knock will knock on start up and hitting the gas, when there is a "load" on the engine. Sometimes its also can be heard when you just let go of the throttle, but just fro the second when the rpm's are going down.

Personally it sounds like a bearing is bad in one of the accessories, alternator, water pump, sterring pump, pulleys, etc. It also may be a collapsed lifter. Was it not running for any amount of time before that video? Reason I say this, I believe you took the camera to under the car and noise lightened up. If it was rod knock, it would have been more pronounced. Lifter issues make more noise on the top of the engine.

[Jok3r1552]

That video was of her sitting for an eight hour shift at my job. She only started making that tap when it got closer to the winter nights and cold warm ups. Only for a solid minute or 30 seconds total she makes the noise. I was leaning towards collapsed lifter, its coming from right under the plenum. Just did the maintenance to her after 60k miles she is at 78k now. I changed the oil to 10-30 too (synthetic). It quieted it down for awhile and that's about it. Yea, that was the reason I put the camera under the wheel well. I've Ben searching for step by steps for taking the heads off. I really want to fix the problem asap, if possibleft clean all the lifters.

[MarkerZ32]

My motor sounds like that in open loop. If your engine is not up to full warm fuel/ignition mapping temp (I believe 171F and normal operating temp is 185F) the motor is too cold and the ECU will run rich. A faulty O2 can cause this without a MIL or CEL on the earlier models. However, if your hearing this all the time in closed loop and normal operating temp, I would start looking for another long block assembly.

[Jok3r1552]

Nah, only in open loop but I wont lie though, sometimes I "think" I hear it sometimes when shes warmed up in synced with the cams when the viscosity of the oil gets thin from doing brutal third gear pulls. shes not your average VG30DETT, she is completely modded in the sense that her (normal build) intake, exhaust, injectors, turbos (which scream for some unknown reason) just your basic entry level street mods for a Z32. There was a time in the cars life that it felt like I flooded the right bank on her when I didn't let her warm up and (dumb of me) first gear pulled her, guy in a Camaro was talking trash. last time I let my brains get the best of my car; black smoke pluuummmed from the exhaust and a sudden *POP* came soon after, she only smoked out on he right exhaust port. immediately after the car had THE nastiest idle I have ever witnessed in any of my cars. It almost felt like a dead cylinder, she shut off twice turned her back over and everything was back to normal. Which made me indicate that it might be my valves are running a course of a short life. I would really like to know your insight of why I should be searching for the my next long block.

[MarkerZ32]

A loud rapping that is consistent with engine speed during normal operation is usually indicative of worn rotating assembly parts. Unfortunately, the older Nissan fuel injection systems (long vacuum lines, multiple air bypass controls, long intake runners between the MAF and throttle bodies, lack of a MAP sensor, and just plain antiquated technology) causes most engines running on stock base mapping to run slightly rich. This causes the oil to degrade faster, especially if you have a heavy foot. Unless you're religious about oil changes and quality of said oil from the start of the engine's life (every 3000mi or less) that degraded oil will allow the rotating assembly to wear out the tolerances of all rotating parts (big ends, wrist pins, main journals, cam journals, etc.) When a tolerance is out of spec it will result in metal striking or grinding on metal which will only get worse no matter what you add to your oil. You could have an engine shop machine everything but it will end up costing you about as much as a ~stage 2 long block assembly.

But I'm more sure that your issue is between a rich condition (mostly attributed to the cold weather) or worn VTC gears/spring/piston.

[Jok3r1552]

Rich conditions I can totally agree, be it that VTC is now being mentioned in this thread you have got me curious. Only because that I'm thinking about it. It sounds like it does come from the camshafts housing area cause the "tappet/tick" sounds within the immediate area under the intake manifold. When you mentioned "worn VTC gears/spring/piston" I'm assuming you're referring to the VTC pistons themselves. Is there anything I can troubleshoot as far as a plug I can disconnect to check the same way you can tell with a rod knock by disconnecting a spark plug?

[MarkerZ32]

Well I've read on this forum that if you have worn VTC components you can unplug both VTC connectors and the noise should go away. I've never done this diag myself so I can't really put my word on it =/

[Jok3r1552]

Alright, before I leave my job I'm gonna try it out. My management team let me park my car inside our warehouse from the snow so I'm pret-t-y freaking lucky to have people who care haha. If anything, I would appreciate if there were a diagram for the VTC plugs and locations so I can take test it out while I let her warm up thanks, I hope I get more people on this thread.

[Jok3r1552]

Alright, before I leave my job I'm gonna try it out. My management team let me park my car inside our warehouse from the snow so I'm pret-t-y freaking lucky to have people who care haha. If anything, I would appreciate if there were a diagram for the VTC plugs and locations so I can take test it out while I let her warm up thanks, I hope I get more people on this thread.

Update: she sat for the two days it snowed here. I started up and the noise was gone. Not a slight tap or anything... strange. It's like 22 degrees outside

[Jok3r1552]

https://www.youtube.com/watch?v=h7MhTFMZF0Y

[spiffy]

could be a lifter that's ticking, it's pretty common on old VG's. I had it, revved the engine and it disappeared and has since been quiet. It's winter here now so the car hasn't been started since october, wouldn't surprise me if the lifter tick came back when I fire it up again in spring.

[Jok3r1552]

could be a lifter that's ticking, it's pretty common on old VG's. I had it, revved the engine and it disappeared and has since been quiet. It's winter here now so the car hasn't been started since october, wouldn't surprise me if the lifter tick came back when I fire it up again in spring.

Just a heads up, this thread is also continued on another forum. Message me for more info.

[Jok3r1552]

could be a lifter that's ticking, it's pretty common on old VG's. I had it, revved the engine and it disappeared and has since been quiet. It's winter here now so the car hasn't been started since october, wouldn't surprise me if the lifter tick came back when I fire it up again in spring.

Just a heads up, this thread is also continued on another forum. Message me for more info.

https://www.youtube.com/watch?v=mAcZF9BegH4