Thread: Knocking noise

So i am getting the dreaded knocking noise coming from the motor. Motor is a VE. At idle the motor is quiet. under deceleration, the motor is almost quiet. under acceleration the motor is a little louder, but still kinda quiet. its when you are holding it steady it is a loud knocking noise. doesnt matter what gear or what rpm. Discovered this at a friends house and we took the vc off thinking i might have broke a lifter but all the lifters look perfect. I had no choice but to drive it home (bout 10-15 miles) and it did get worse but still same symptoms. If i put the clutch while driving, the noise completely goes away but im assuming this is because the rpms drop down to idle. I did go on about a 500 mile trip last weekend and before i left oil was about 3/4 full. didnt think to check it after i got back. checked it tonight and it was close to 2 quarts low. no idea where the oil went. so this is what im thinking.

1. spun bearing

2. early stages of rod knock

i know if the rod knock is bad you can pull the plugs at idle one at a time to figure out which cylinder is knocking. problem is, it is fine at idle. oh and as far as i can tell there isnt any power loss. i didnt get on it to really tell but just normal accelerating feels fine. Anything else it might be?

Check if the noise disappear at idle while pressing the clutch in, if it is most likely will be a bad throwout bearing

na i have the throw out bearing noise already cause i didnt put new clips in when i swapped the clutch. this noise is totally different.

sounds like knock to me, take one spark plug off an a time an rev the motor so it makes that noise when the noise goes away you've found the culprit

will try this tomorrow after work

The higher the engine RPM the more that is being pumped, doesn't necessarily mean that the level at hte pick up is ok though. Gradual high speed bank at high RPM can cause it. But if its light like that, STOP DRIVING IT. You can save the engine just replace that bearing that is bad and inspect the others. Did this and engine lasted another 8K miles until I sold the car and it never knocked even on cold start. Did it on my friends B16 honda as well, and he drove the piss out of it 8,500 RPM, held fine until he sold the car, never knocked. It's common place to just replace the bearings, not hard either on the VE. Leave engine in the car, seperate trans slightly put a thick washer between block and transmission, remove oil pans, and get to work. Go one size LARGER on the thickness of one bearing half, or just measure crankshaft and do it that way, no scaring on crankshaft, no wear, so size would be the same as the factory stamped the cranks and rods.

Oh also... You might have cracked some ringlands if you're losing oil that quickly. Check plugs, if they are gritty oily covered but chalky, your timing caused it. Takes a while to do, but I did it on my old B18B honda and same thing was happening, once I took the engine apart to upgrade it, sure enough all pistons had severely cracked ring lands on the major thrust side.

You dont have to separate the trans to pull the oil pans with the motor in the car. Just remove the bolts and dont forget the two 10mm nuts on the rear main seal housing thats holding the rear of the upper pan to the block. No need to separate or remove the trans to do the job. Its very simple and like they said if the knock is only slight and the bearing spun and returned into place and as long as the crank is not scored badly from the spun bearing you can replace the bearings and be just fine for a long long time of abuse.

Just inspect the crank for any deep scoring or scratches. If its too bad then you will need a new crank and the motor would have to be pulled. Again if its light scoring and light knocking you should be fine. Just order a set of good bearings like the ACL standard race bearings in standard size and you should be fine. Use a good oil and filter as well to keep it from happening.

Yeah I'm only gonna start it once more to do the plug test. After that I can push it to where I can work on it at. I'm hoping it is just a spun bearing and that the rods are still ok. And I use mobile 1 15w50 and oem Nissan filters. Thanks for the input so far.

mobile 1 is JUNK

never had one problem in 11 years with mobil 1. track days, daily beat downs, race cars whatever it was. never had one problem. cant be that much "JUNK" although i wouldnt use 15w 50 on your street car. try 0w 40 or 10w 40 at most.