Rod knock or just wiped cam lobe - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

Bkahl · 11-07-2016, 10:56 PM

A story summed up quick. I was taking my sr20det out and having some fun. After one strong pull it felt like the car lost power, like I was building boost but not moving anywhere, like a clutch slipping. . Looked down engine was super hot, I pulled over let the car cool down and limped it home. Car has a knocking sound but isn't heard at all times. I pulled the valve cover off and noticed my cams seem to be wiped. But I'm unsure if this is the only issue. I found copper like shavings in the oil and I'm unsure if that's from the cam lobe or a bearing of some sort. What's the best way to check for rod knock without tearing the motor down.

KAT-PWR · 11-07-2016, 11:42 PM

Does it make a knocking sound?
When you rev it does the knocking frequency increase?

Cams aren't made of copper.

Rod Knock.

Bkahl · 11-08-2016, 06:32 AM

Yes the car knocks. When I got the car home I took up and down the road once so I could listen to the sound again. It didn't seem to increase with speed. But just would make the sound for a couple seconds and stop. Then start for a couple seconds and stop. At idle the knock didn't seem apparent at all.

jedi03 · 11-08-2016, 07:50 AM

yup thats the bearings in your pan...

Bkahl · 11-08-2016, 08:05 AM

What're my options? Complete tear down and rebuild??

Bkahl · 11-08-2016, 08:57 AM

Couldn't it also be a cam bearing that went bad, and that's why I'm seeing the shavings.

hanzbrady · 11-08-2016, 09:01 AM

Quote:

Originally Posted by Bkahl

Couldn't it also be a cam bearing that went bad, and that's why I'm seeing the shavings.

If it where an LS1 yeah sure. But you have one of them der fancy nissin engines with da overhead cams

KAT-PWR · 11-08-2016, 10:44 AM

No cam bearings dude.

Bkahl · 11-08-2016, 11:02 AM

New to 240's and dual overhead cams. So basically I probably have (most likely) a rod knock, am I better off to buy a new motor or just rebuild. By better off I mean cheapest route

KAT-PWR · 11-08-2016, 11:59 AM

We don't live where you do. Weigh the costs, call around, get quotes.

Kingtal0n · 11-08-2016, 02:45 PM

a next engine is almost always going to be the cheaper/reliable option, once you start seeing debris.

SR20 have tiny orifices which even the slightest bit of grit will cause you a never ending stream of frustration.
If you want to rebuild one, do it to an engine which is already running good/in known great condition with clean oil.

Koukiii · 11-12-2016, 04:40 AM

Quote:

Originally Posted by Kingtal0n

a next engine is almost always going to be the cheaper/reliable option, once you start seeing debris.

SR20 have tiny orifices which even the slightest bit of grit will cause you a never ending stream of frustration.
If you want to rebuild one, do it to an engine which is already running good/in known great condition with clean oil.

I agree. Peace of mind is a beautiful thing.

11-07-2016, 10:56 PM	#1
Bkahl Join Date: Oct 2016 Location: Arkansas Age: 25 Posts: 8 Trader Rating: (0) Feedback Score: 0 reviews	Rod knock or just wiped cam lobe A story summed up quick. I was taking my sr20det out and having some fun. After one strong pull it felt like the car lost power, like I was building boost but not moving anywhere, like a clutch slipping. . Looked down engine was super hot, I pulled over let the car cool down and limped it home. Car has a knocking sound but isn't heard at all times. I pulled the valve cover off and noticed my cams seem to be wiped. But I'm unsure if this is the only issue. I found copper like shavings in the oil and I'm unsure if that's from the cam lobe or a bearing of some sort. What's the best way to check for rod knock without tearing the motor down.

11-07-2016, 11:42 PM	#2
KAT-PWR Nissanaholic! Join Date: Dec 2011 Location: US Posts: 2,040 Trader Rating: (11) Rides Gallery: KAT-PWR Feedback Score: 11 reviews	Does it make a knocking sound? When you rev it does the knocking frequency increase? Cams aren't made of copper. Rod Knock. __________________ MRP Manufacturing

11-08-2016, 10:44 AM	#8
KAT-PWR Nissanaholic! Join Date: Dec 2011 Location: US Posts: 2,040 Trader Rating: (11) Rides Gallery: KAT-PWR Feedback Score: 11 reviews	No cam bearings dude. __________________ MRP Manufacturing

11-08-2016, 11:59 AM	#10
KAT-PWR Nissanaholic! Join Date: Dec 2011 Location: US Posts: 2,040 Trader Rating: (11) Rides Gallery: KAT-PWR Feedback Score: 11 reviews	We don't live where you do. Weigh the costs, call around, get quotes. __________________ MRP Manufacturing

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11-08-2016, 06:32 AM	#3
Bkahl Join Date: Oct 2016 Location: Arkansas Age: 25 Posts: 8 Trader Rating: (0) Feedback Score: 0 reviews	Yes the car knocks. When I got the car home I took up and down the road once so I could listen to the sound again. It didn't seem to increase with speed. But just would make the sound for a couple seconds and stop. Then start for a couple seconds and stop. At idle the knock didn't seem apparent at all.

11-08-2016, 07:50 AM	#4
jedi03 Nissanaholic! Join Date: Jul 2008 Location: albuquerque Posts: 1,786 Trader Rating: (8) Feedback Score: 8 reviews	yup thats the bearings in your pan...

11-08-2016, 08:05 AM	#5
Bkahl Join Date: Oct 2016 Location: Arkansas Age: 25 Posts: 8 Trader Rating: (0) Feedback Score: 0 reviews	What're my options? Complete tear down and rebuild??

11-08-2016, 08:57 AM	#6
Bkahl Join Date: Oct 2016 Location: Arkansas Age: 25 Posts: 8 Trader Rating: (0) Feedback Score: 0 reviews	Couldn't it also be a cam bearing that went bad, and that's why I'm seeing the shavings.

11-08-2016, 11:02 AM	#9
Bkahl Join Date: Oct 2016 Location: Arkansas Age: 25 Posts: 8 Trader Rating: (0) Feedback Score: 0 reviews	New to 240's and dual overhead cams. So basically I probably have (most likely) a rod knock, am I better off to buy a new motor or just rebuild. By better off I mean cheapest route

11-08-2016, 02:45 PM	#11
Kingtal0n Post Whore! Join Date: Jul 2005 Location: South Florida Age: 38 Posts: 4,649 Trader Rating: (17) Feedback Score: 17 reviews	a next engine is almost always going to be the cheaper/reliable option, once you start seeing debris. SR20 have tiny orifices which even the slightest bit of grit will cause you a never ending stream of frustration. If you want to rebuild one, do it to an engine which is already running good/in known great condition with clean oil.