Engine Knock - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

syrupninja · 01-14-2004, 04:16 PM

I was driving to work this morning, and just as I pulled into the parking lot, the slight tapping, which I attributed to nosiy valves turned into a serious knock. A metal on metal knock. Absolutely the most horrid sound any car I've ever driven has made. It's been tapping slightly since I bought it, and I've put less than 2k on it. It's a 92 with 120k on the odo.

The only recent changes I've made were changing my oil from 20W-50 to 10W-30, and removing the lower upper timing chain guide. It was running fine until today, so I have no reason to think that I messed up the timing, but possibly I didn't use enough rtv when putting the timing cover back on.

It idles very rough, surging in rpm's and after a minute or two dropping to 500. The whole car shakes while it's running, and the sound damn near breaks my heart.

I find it strange for it to run fine for a week and then just start out of nowhere. It's parked at work right now, as I'm afraid to drive it.

Is it time to scrap the motor or is there a possible solution I'm possibly overlooking?

s13Steve · 01-14-2004, 09:50 PM

Its funny how i had the same problem... New cam and lifters helped that....

BoroFabulous · 01-14-2004, 09:59 PM

Sounds like your not firing on all four cylinders. The first thing your going to want to do is make sure all cylinders have spark by pulling a plug wire, putting a spare spark plug into it and holding the plug's threads against any non painted grounded part of the vehicle. Crank the engine and if there is a blue spark than no worries for that cylinder, repeat the proccess for all 4. If you have orange or no spark for any cylinder, then there is a cylinder getting no spark.

Also don't drive the car around when the engine isn't running on all four like this.

uiuc240 · 01-14-2004, 10:26 PM

Check your oil.

Does the sound remain steady? I mean, does it click/clunk rhythmically? Misfires are frequently haphazard, so if it's more random, it might be that. But, a rhythmic clunk that increases with engine speed is likely a spun bearing. You need to find out what's going on before you continue driving the car. If you do in fact have enough oil, the next step would be to hook up a temporary connector/hose/pressure tester to the oil pressure sender (take the sender out, screw in connector/hose, and crank engine to check pressure).

If you don't have enough pressure, you have a bad oil pump, and now you have a bad motor.

Eric

syrupninja · 01-14-2004, 10:56 PM

The oil is full, that was the first thing I checked as soon as I killed it. And I'm not driving it, it's sitting in the parking lot at work, so I'll be hoofing it tomorrow. Thanks for the suggestions, I'll check them out tomorrow.

At least it's tax season, maybe I can manage enough for an SR.

01-14-2004, 04:16 PM	#1
syrupninja Leaky Injector Join Date: May 2003 Location: Dallas, TX Age: 44 Posts: 79 Trader Rating: (0) Feedback Score: 0 reviews	Engine Knock I was driving to work this morning, and just as I pulled into the parking lot, the slight tapping, which I attributed to nosiy valves turned into a serious knock. A metal on metal knock. Absolutely the most horrid sound any car I've ever driven has made. It's been tapping slightly since I bought it, and I've put less than 2k on it. It's a 92 with 120k on the odo. The only recent changes I've made were changing my oil from 20W-50 to 10W-30, and removing the lower upper timing chain guide. It was running fine until today, so I have no reason to think that I messed up the timing, but possibly I didn't use enough rtv when putting the timing cover back on. It idles very rough, surging in rpm's and after a minute or two dropping to 500. The whole car shakes while it's running, and the sound damn near breaks my heart. I find it strange for it to run fine for a week and then just start out of nowhere. It's parked at work right now, as I'm afraid to drive it. Is it time to scrap the motor or is there a possible solution I'm possibly overlooking? __________________ The Syrup is strong with this one.

01-14-2004, 09:59 PM	#3
BoroFabulous Join Date: Oct 2003 Location: Sausalito, Marin County, Cally Posts: 33 Trader Rating: (0) Feedback Score: 0 reviews	spark Sounds like your not firing on all four cylinders. The first thing your going to want to do is make sure all cylinders have spark by pulling a plug wire, putting a spare spark plug into it and holding the plug's threads against any non painted grounded part of the vehicle. Crank the engine and if there is a blue spark than no worries for that cylinder, repeat the proccess for all 4. If you have orange or no spark for any cylinder, then there is a cylinder getting no spark. Also don't drive the car around when the engine isn't running on all four like this. __________________ '89 SE coupe - Black Eibach Sportline springs KA24de swapped in ya, its a pos

01-14-2004, 10:26 PM	#4
uiuc240 Nissanaholic! Join Date: Apr 2002 Location: Naperville, IL Age: 46 Posts: 2,093 Trader Rating: (0) Feedback Score: 0 reviews	Check your oil. Does the sound remain steady? I mean, does it click/clunk rhythmically? Misfires are frequently haphazard, so if it's more random, it might be that. But, a rhythmic clunk that increases with engine speed is likely a spun bearing. You need to find out what's going on before you continue driving the car. If you do in fact have enough oil, the next step would be to hook up a temporary connector/hose/pressure tester to the oil pressure sender (take the sender out, screw in connector/hose, and crank engine to check pressure). If you don't have enough pressure, you have a bad oil pump, and now you have a bad motor. Eric __________________ 2002 Mazda Protege5 1989 S13 w/SR20DET (sold)

01-14-2004, 10:56 PM	#5
syrupninja Leaky Injector Join Date: May 2003 Location: Dallas, TX Age: 44 Posts: 79 Trader Rating: (0) Feedback Score: 0 reviews	The oil is full, that was the first thing I checked as soon as I killed it. And I'm not driving it, it's sitting in the parking lot at work, so I'll be hoofing it tomorrow. Thanks for the suggestions, I'll check them out tomorrow. At least it's tax season, maybe I can manage enough for an SR. __________________ The Syrup is strong with this one.

01-14-2004, 09:50 PM	#2
s13Steve Leaky Injector Join Date: Feb 2003 Location: Annapolis, Maryland Age: 41 Posts: 88 Trader Rating: (0) Feedback Score: 0 reviews	Its funny how i had the same problem... New cam and lifters helped that....