Knocking Noise..oh god..

This isn't good :( I've just recently had my motor transplanted for the D15B and now the engine after only about 2 months developed a knocking noise. Never had low oil pressure, never had low oil either. It's really bad when the engine is cold and in the lower RPM and not bad in the high RPM, when the engine is warm you can kind of hear it but not that much at all. My old engine did the same thing for the 20k miles I drove it and I'm hoping that it's not a spun bearing. I changed the oil recently and didn't notice any shavings or metal parts. I ruled out the alternator bearing because I took it off the belt and it still made the noise. Could it be I need higher octane? I use 87. I never revved above the redline with this engine. The engine has actually been making a knocking noise for a good month now at least, would and engine with a rolled bearing last that long? Thanks.

is it coming from the valves?....try adding like an oil thickener or somthing....maybe that will help...

if its a spun bearing, oil pressure would be lower than spec.

the sound is actually coming from the timing belt area from what i can hear without a stethoscope. It makes the sound worse under load, but it does make it a bit when free-revving. Are there bearing somewhere in there? Maybe the tensioner?

the tensioner does have a bearing. its a possibility. ive never seen one that needed replacing, but its possible.

that is also the area where the water pump is located....never heard of one knocking before but I'm no expert

well i have a idea. it happens with the parts car i now posses. his crank was cracked in 2 causeing a knockin which over time turned into a clunking sound. this might be your problem. your crank could be broken.

well i have a idea. it happens with the parts car i now posses. his crank was cracked in 2 causeing a knockin which over time turned into a clunking sound. this might be your problem. your crank could be broken.
:eek7:

Could it be I need higher octane? I use 87.

My god man, spring for the extra 7 cents a gallon and get the good stuff. I mean you only live once you know.:)

My god man, spring for the extra 7 cents a gallon and get the good stuff. I mean you only live once you know.:)

u do realize higher octane is only to prevent detonation right?

as for u'r knockin noise: if it's a double knock, then it's a piston w/ too much clearance or a broken skirt; if it's just a single knock, then it's a rod or the crank itself. if it's a single knock, then it's just an easy bearing replacement and that should take care of it. double knock, could get costly. any kind of warrentee on the new engine u put in? by the way, a spun bearing usually makes a grinding noise too. and another thing. is it a knock, or a tick? tick would just be the valve clearance needing adjusted. if the sound is coming from the timing cover, then it could be the belt is loose and slapping something, but since u said it goes some after heating up, then prolly not it.