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Rod and Main bearing ?

1K views 8 replies 6 participants last post by  6426yy 
#1 ·
I tore down the old 305 yesterday and all of the rod and main bearings were
showing copper bad! But only on the block and rod side of the bearings. the other half look near new. What would cause this? I've usually found them to be evenly worn on both sides of the bearings. Just wondering.
 
#2 ·
Doc here, :pimp:

Wow..That's special... :D

About the only thing I could think of is reduced oil pressure through the crank??

The lower ends are getting oil from oil dipping in the pan and upward spray..

Never seen one do that.. :pain:

Doc :pimp:
 
#4 ·
Thanks Doc,

That's what I was thinking but according to the cheapo oil pressure gauge It had plenty of oil, was always above 20psi when fully warm at idle. And it gradually climbed with rpm. Just made me curious. Would a dry start condition do this? It was supposed to have been "rebuild". But shortly after I got it I had to reset all the lifters, replace new starte (wasn't shimmed properly), fuel pump, carb and now the timing chain went out!! The best part is that all the reciepts are in the glovebox form the shop that did all the work!!
 
#5 ·
Doc here , :pimp:

I defer to Poncho, since he's seen the malady before..and I haven't , But I should think a dry start would score Both halfs of the bearings..

With all the failures you are having, it sounds like the block wasn't cleaned of machine dust before it was assembled though.. did you wash the block down (assuming you assembled it) ? You may have a plugged gallery.

Doc :pimp:
 
#6 ·
6426yy said:
Thanks Doc,

That's what I was thinking but according to the cheapo oil pressure gauge It had plenty of oil, was always above 20psi when fully warm at idle. And it gradually climbed with rpm. Just made me curious. Would a dry start condition do this? It was supposed to have been "rebuild". But shortly after I got it I had to reset all the lifters, replace new starte (wasn't shimmed properly), fuel pump, carb and now the timing chain went out!! The best part is that all the reciepts are in the glovebox form the shop that did all the work!!


Or, Did they.?
 
#7 ·
I wonder if a little long term, mild detonation or short term severe detonation coulda helped that irregular bearing wear along? I'd measure the width of the bearing (across the face) to determine if it has smashed and spread a little from the hammering effects of detonation. Are all of the bearings worn the same?
 
#8 ·
56Maynard said:
I wonder if a little long term, mild detonation or short term severe detonation coulda helped that irregular bearing wear along? I'd measure the width of the bearing (across the face) to determine if it has smashed and spread a little from the hammering effects of detonation. Are all of the bearings worn the same?
I would agree with that
 
#9 ·
Sorry guys I've been in the garage all day. I suppose detonation could have helped them along as I said the timing chain was going out of it, for quite some time I suspect. I kept thinking that I was having carb and distributor problems (which I was) but mostly it was the timing chain.

All of the bearings were were pretty much worn the same: top bearing half, copper showing through the whole width of the bearing. I didn't think to measure them and there in the trash now. I'm throwing a 350 together and hope to have it done tomorrow but since I quite so early tonight I doubt that will happen. The wife's kinda been on me! Well thanks for all the replies. I'll try and post some photos of the "new" 350.
 
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