Well, my motor has decided to grace me with a knock, from about 2500 to 3500 rpm, then it goes away. I doesn't do it at idle, or above 3500. It sounds like a bottom end problem, but I have never heard a rod or main bearing that didn't knock all the time, or increase with rpm. I have had clutch problem, and that made a similar sound, but this is different. Maybe somebody has some help.

 

Locate the noise with a stethoscope and post your findings.

 

Does your CEL light come on when you hear the knock? THe knock sensor (youre running one, right?) should throw a code if it detects knock. What CR are you running, gas, ETC. Lets get all the easy questions out of the way.

Are you running forged pistons? could be slap.

 

The problem has just started, I don't think that it is from compression or fuel. No cel, (no knock sensor) Yes, they are forged, but I never noticed it before, It only does it from 2500 to 3000 or so weather the motor has a load on it or not, I doesn't do it when I rev it, just at a steady speed. My first idea was a rod bearing, but It doesn't do It at any other rpm. Oh well, It was fixing to come down for boost worthy compression anyway.

 

Well, I cut apart my oil filter for closer examination. Only to find a vast array of metallic pieces, and bearing particles. I really don't understand why the motor didn't last longer, I have about 3000 miles on it, about 2500 have been wide open, but I still thought it would have lasted a little longer, I used acl bearings, and plastigauged everything on assembly, any suggestions?

 

main bearing maybe?

 

definitly the mains or rod bearings, I just hope nothing else, crank, or rods are screwed. guess I will find out this week. Haven't drove it but about 2 miles so hopefully they will be ok.

 

i thought you used honda rod bearings?

 

Did you use ARP rod bolts? If I had to specualte, it sounds like the rod bolts stretched from 8k+ causing a bearing to spin. Just rebuild, but this time with honda bearings and ARP bolts.

 

actually I did use honda rod bearings all greens, now that I think about, just acl mains. I have eagle rods with arp bolts, a couple nights ago I raced a s-10 with a nasty 327 from a roll on and I twisted first and second gear way way to hard, I would say that is when it happened. I am definitly going to have my rev limiter brought down, I will further asses the damage this week.

 

yep i will not plug you up at anything over 8400 on your next motor

 

Thanks "my enginge tuner"

 

sweet...I was right. Booya. What do you think you spun it to?

BTW, you said you didnt have a knock sensor...you may want to get one of those buggers.

 

i thought that a knock sensor only worked at low rpms

 

never heard that one. Even if it does only work at low RPM, its still a damn good investment. Im only running 10.5:1, but I have one. But then, I get crappy gas around here.

 

You need to be more thorough with the clearances besides plastiguaging. When you rebuild inspect the bearings and you should be able to get a good idea of where the problem is coming from.

 

I've always found the stock knock sensor to be useless added weight.

Sorry to hear about your wipeout.