Chevy 350

BURRBRIAN

MECHANIC
1935 GMC

Hi, I have a sb 350 that I just put new cam and lifters in because I had a tap-knock when I would hit about 2000 rpm, thought it took care of problem as a cam lobe was wore down almost round and lifter was dished on the bottom. But now it runs lot better and I still have the knock after warming up,
anybody think that I might have some bad rod bearings? I hit the throttle and it starts in, let up and eases up, feather the gas and it comes and goes.
Motor is nothing complicated, carb, headers, no cat. Converter or any of that stuff. Old fashioned and easy to work on. Any old gearheads have any ideas? :Shock:

2 Replies

LOSONE

MECHANIC
1,616 POSTS

Sounds right. It is easy to drop the pan and replace the rod bearings. Replace the oil pump with a high volume while you are at it. Good luck

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Wednesday, April 12th, 2006 AT 1:05 PM

BURRBRIAN

MECHANIC
158 POSTS

Thanks, Lee. That is pretty much what I thought I had but when I had the motor out and found the cam and lifters I thought that was it and like a dumb#&*#&* didn't keep digging and put motor back in. Never knocked during cam break-in and sounded good but by the next day-well you know the story. Think I'm gonna pull it again as I tried to check the bearings by just dropping pan, got a little uncomfortable. Has been knocking long enough that it might have got to crank, not sure which rod it is, eithier. So might have to put new crank in, can get recon one for 82.00-40$core. Looks like another fun weekend as I have to have truck mon. Morn for work.
YEE-HAW! :Twisted: Okay, all is sais and DONE on this problem- we can delete this now, somehow I can't seem to manage it this time so if a moderator wishes to go ahead and get rid of it. Oh, btw-Lee thanks for confirmation, nailed it and put melling high volume pump in and are running 65 lbs. At start-up and 25-30 lbs. At hot idle, better than I have since rebuild 2 years ago, thanks again and catch you around the site later :twisted: