Ive been listening like crazy for a week or 2 and there is some sort of faint knocking going on in my car at idle. The best way to describe it is there is an angry little monkey with a tiny hammer inside my motor that doesnt like me very much and enjoys driving me crazy. Nothing going on at any rpm exept idle...sometimes. Its a slow da da da da as if its only happening in one cylinder. It doesn't seem to be coming from any specific place in the motor, and Ive had no luck with my fancy mechanics stethoscope.

It comes and goes whenever it wants to and it isnt at all affected by engine temperature or oil pressure, its just there slowly driving me mad

In my short time with these motors I have experienced two #2 rod bearings go, so naturally I'm extremely paranoid having bought a used motor from a "professional" Porsche dismantler. I really wish I wouldn't have skipped torquing down the knock sensor, Id say its about wrist tight right now, would that have any affect?
Any input would help, thanks

 

What's your oil pressure at idle and what type of oil are you using? Is the knock frequency the same as engine RPM?

Also, you may want to check the oil for any contamination (i.e. metal).

 

When its warm its around 2.5 bars. Im using Mobil 1 10w-40. I guess ill look through the oil but Im a little scared to haha

 

Sounds like a sticking lifter. Buy an automotive stethothscope from Sears or similar and see if you can isolate the noise. If its a lifter an oil change may improve the situation. There are also oil additives that assist/improve in stopping the noise.

If its a sticking lifter then it could get better by itself, if its dirt that's doing it. Otherwise you will have to change one or more than one. Lifter noise is annoying but not damaging.

It's unlikely to be a bottom end knock as that noise just build utill something fails.

 

In what circumstances have you spun 2 rod bearings? Very unusual for a road car. If it's track....dare I mention the oil.....

 

Samluke, thanks for the good news im not sure if ive ever heard a bad lifter myself but it seems to be a bigger knock than that. Ive had Marvels Mystery oil in the car for almost a week now which doesnt seem to do much and I have a cheap stethoscope that hasent given me any clues on any part of the motor.

333pg333, Its an intresting story. As a new owner, I didnt do my homework or read any of the horror stories before tracking the car, and the typical oil starvation around the turns happened and that was the end of that. The crankshaft was so badly scored that it ate through a second rod bearing within a matter of about 50 miles, i was hoping id get lucky but i guess not.

New motor has the Lindsey Racing baffle kit in the pan so eventually ill be able to sleep at night

 

For these engines 10w would be more of a winter weight then a summer. I was always told 20w since i live in AL. If i was you i would step up the weight of the oil your using and get rid of that snake oil in the engine.

 

The way i was taught, high school small engines class, the 10w it just when its cold right? The noise is no diffrent when the car is warm

 

I fear a rod or main bearing, change the oil, look for metal. I don't like 10W in the summer.

 

From wiser people on the board the conclusion is having a heavier weight usually helps prevent rod bearing trouble and using a zddp additive or zddp heavy oil is ideal. there was talk of using a scale in the owners manual to determine what weight of oil to your location would be ideal. Having that posted would be great because im sure most of the owners manuals are absent from the car.

 

Can you post a video with sound, so we can hear it. Have you checked your belt tension to make sure it's not the belt slapping on the timing cover?

 

I checked the belts when i put the motor in there not going anywhere. I could try to make a video but theres a small exhaust leak that would cover up the sound so you wouldnt hear much else, and with my luck the car is camera shy and wont knock for you guys anyway.

I fear one of the main bearings too it sure sounds like it but not nearly as severe as the knocks i heard before the old motor spun the bearings. There are a few things that need to be done to the car before i get around to fixing the exhaust but when its all quiet ill see what my camera can hear

 

Oh and btw i am one of the lucky ones who was gifted the owners manual with the purchase of the car. i'll scan the engine oil section and post it on here when i get the chance, but im within its specifications.