SR20DET knocking noise - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

dreimers · 10-02-2015, 11:42 AM

i just rebuilt my SR. Black top. New ACL rod and main bearings, new rings and cylinder hone. Stock pistons, rods, and crankshaft. No scoring or gouges. I have not driven the car more than a mile. Back and forth in the drive way and down the block. When I rev it to 2k and up the noise can be heard. Im pretty sure it is rod knock, but why would it happen with all new bearings? I changed the oil after I started it up a few times and let idle. The oil was pretty dirty. Put new oil in and same noise same rpm. I tried to pin point it to a cylinder by pulling the plug wire one at a time. Didnt really hear a difference, 4 might have made a slight change. I pulled the oil pans and found no brass pieces. A little bit of silver flake, but no big chunks of any thing. My oil pressure is about .5 bar after the motor is warmed, 4 bar when first started. When I had the pans removed i could wiggle the rods slightly forward and back. 1-3 made a slight click forward and back, 4 did not, but it moved just as much as the others. No up and down movement from any of them.
Any one have any insight? I have searched and searched. Found some good threads, but nothing like what I have. They all have put some milage on there engines.

AzS13hatch · 10-02-2015, 09:33 PM

Are all the pistons, rods, and the crank new? Did you have the block line honed? Did you check to make sure you were buying the correct size main and rod bearings? That is the main thing that is coming to mind when you say that the rods move and click. How much is slightly? Only other thing I can think is if you may have put the valve shims in the wrong spots on assembly, it may have ill effects on how far your valves are opening.

dreimers · 10-02-2015, 10:02 PM

Quote:

Originally Posted by AzS13hatch

Are all the pistons, rods, and the crank new? Did you have the block line honed? Did you check to make sure you were buying the correct size main and rod bearings? That is the main thing that is coming to mind when you say that the rods move and click. How much is slightly? Only other thing I can think is if you may have put the valve shims in the wrong spots on assembly, it may have ill effects on how far your valves are opening.

No reused what I had.
No. Engine ran before the rebuild happened. It was low on compression.
I put in ACL bearings. They only come in one size. I got the standard ones.
I'm not sure how far the movement is...maybe a half mm or so. Didn't touch the head except for removal of the cams and a new head gasket. Never touched the rocker arms or anything.

zombiewolf513 · 10-02-2015, 10:49 PM

.5 bar shitty idle oil pressure, you want to be at 1.1 at least. Im usually between 1.6-1.8 bar.

ACL bearings also come in sizes for cranks that have been reground.

Take a video.

My preliminary thoughts are a worn wrist pin maybe or an oil deprived system creating large clearances, but its almost impossible to tell without being there or at least seeing it.

dreimers · 10-03-2015, 08:08 AM

Quote:

Originally Posted by zombiewolf513

.5 bar shitty idle oil pressure, you want to be at 1.1 at least. Im usually between 1.6-1.8 bar.

ACL bearings also come in sizes for cranks that have been reground.

Take a video.

My preliminary thoughts are a worn wrist pin maybe or an oil deprived system creating large clearances, but its almost impossible to tell without being there or at least seeing it.

I will see if can get the vid i took up. I have the STD. ACL
Are you there when the engine is warmed? It goes up with the rpm.
So possibly it only needs a new front cover and pump if thats bad?
Any way to test the pump? I have the lower oil pan off right now.

zombiewolf513 · 10-03-2015, 06:37 PM

The oil pressure is a test somewhat, you could have a leak somewhere else. Or low oil level

Should be in the range i gave you hot or cold

dreimers · 10-03-2015, 07:58 PM

I double checked the level on the dip stick just above the cross hatches. I can not visually see any leaks. I'm going to replace the oil pump and see what happens...

zombiewolf513 · 10-03-2015, 10:45 PM

You might as well pull the whole motor to do that, its probably not just gonna come right off. Ive found that out the hard way several times. I always end up saying, "shoulda just pulled the damn motor" over and over

Kingtal0n · 10-03-2015, 11:37 PM

new bearing but used an old oil pump? What gives?

Your bearing clearance needs to be a known. you should have measured properly as it defines the kind of oil you will be using. OEM Clearances of .0008" rod bearing for example will be best suited here in Florida for example to 10W-30 motor oil. If I was using a .002" clearance I would certainly want to be using a 20W-50 on the other hand. FSM idle oil pressure as a guideline is 11psi hot. You must be using a high quality mechanical gauge to get this reading; electric senders are prone to reading inaccuracies due to voltage/grounding and design issues (some will read +/- 10psi, many will even show some 5psi with the engine off or adjust as you provide electrical load).

10-02-2015, 11:42 AM	#1
dreimers Zilvia Member Join Date: May 2009 Location: Naperville, IL Posts: 280 Trader Rating: (3) Feedback Score: 3 reviews	SR20DET knocking noise i just rebuilt my SR. Black top. New ACL rod and main bearings, new rings and cylinder hone. Stock pistons, rods, and crankshaft. No scoring or gouges. I have not driven the car more than a mile. Back and forth in the drive way and down the block. When I rev it to 2k and up the noise can be heard. Im pretty sure it is rod knock, but why would it happen with all new bearings? I changed the oil after I started it up a few times and let idle. The oil was pretty dirty. Put new oil in and same noise same rpm. I tried to pin point it to a cylinder by pulling the plug wire one at a time. Didnt really hear a difference, 4 might have made a slight change. I pulled the oil pans and found no brass pieces. A little bit of silver flake, but no big chunks of any thing. My oil pressure is about .5 bar after the motor is warmed, 4 bar when first started. When I had the pans removed i could wiggle the rods slightly forward and back. 1-3 made a slight click forward and back, 4 did not, but it moved just as much as the others. No up and down movement from any of them. Any one have any insight? I have searched and searched. Found some good threads, but nothing like what I have. They all have put some milage on there engines. __________________ This is a site ran by the US government, not some crazy biased organization

10-03-2015, 07:58 PM	#7
dreimers Zilvia Member Join Date: May 2009 Location: Naperville, IL Posts: 280 Trader Rating: (3) Feedback Score: 3 reviews	I double checked the level on the dip stick just above the cross hatches. I can not visually see any leaks. I'm going to replace the oil pump and see what happens... __________________ This is a site ran by the US government, not some crazy biased organization

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10-02-2015, 09:33 PM	#2
AzS13hatch Leaky Injector Join Date: Oct 2014 Location: AZ/ South Korea Age: 33 Posts: 121 Trader Rating: (0) Feedback Score: 0 reviews	Are all the pistons, rods, and the crank new? Did you have the block line honed? Did you check to make sure you were buying the correct size main and rod bearings? That is the main thing that is coming to mind when you say that the rods move and click. How much is slightly? Only other thing I can think is if you may have put the valve shims in the wrong spots on assembly, it may have ill effects on how far your valves are opening.

10-02-2015, 10:49 PM	#4
zombiewolf513 BANNED Join Date: Mar 2011 Location: AZ Age: 33 Posts: 1,682 Trader Rating: (6) Rides Gallery: zombiewolf513 Feedback Score: 6 reviews	.5 bar shitty idle oil pressure, you want to be at 1.1 at least. Im usually between 1.6-1.8 bar. ACL bearings also come in sizes for cranks that have been reground. Take a video. My preliminary thoughts are a worn wrist pin maybe or an oil deprived system creating large clearances, but its almost impossible to tell without being there or at least seeing it.

10-03-2015, 06:37 PM	#6
zombiewolf513 BANNED Join Date: Mar 2011 Location: AZ Age: 33 Posts: 1,682 Trader Rating: (6) Rides Gallery: zombiewolf513 Feedback Score: 6 reviews	The oil pressure is a test somewhat, you could have a leak somewhere else. Or low oil level Should be in the range i gave you hot or cold

10-03-2015, 10:45 PM	#8
zombiewolf513 BANNED Join Date: Mar 2011 Location: AZ Age: 33 Posts: 1,682 Trader Rating: (6) Rides Gallery: zombiewolf513 Feedback Score: 6 reviews	You might as well pull the whole motor to do that, its probably not just gonna come right off. Ive found that out the hard way several times. I always end up saying, "shoulda just pulled the damn motor" over and over

10-03-2015, 11:37 PM	#9
Kingtal0n Post Whore! Join Date: Jul 2005 Location: South Florida Age: 38 Posts: 4,649 Trader Rating: (17) Feedback Score: 17 reviews	new bearing but used an old oil pump? What gives? Your bearing clearance needs to be a known. you should have measured properly as it defines the kind of oil you will be using. OEM Clearances of .0008" rod bearing for example will be best suited here in Florida for example to 10W-30 motor oil. If I was using a .002" clearance I would certainly want to be using a 20W-50 on the other hand. FSM idle oil pressure as a guideline is 11psi hot. You must be using a high quality mechanical gauge to get this reading; electric senders are prone to reading inaccuracies due to voltage/grounding and design issues (some will read +/- 10psi, many will even show some 5psi with the engine off or adjust as you provide electrical load).