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Discussion Starter · #1 ·
How can i tell visually if i have a spun rod bearing? The engine is disassenbled. Its a 454. All the rod bearings have lines running around the area that makes contact with the crank and some of the lines are grooved. They are starting to show copper. Is this a sign of oil starvation? Thanks
 

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Probably high mileage and not enough oil changes.
 

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Discussion Starter · #3 ·
I aquired this engine as a long block. 1973 circa. Prolly out of a motorhome. All stock. Standard bore. Forged crank, 049 heads, truck rods, flat top pistons. Im thinking wear also. I understand the concept of spinning a rod bearing. But want to know how the machine shop determines a spun rod by sight?
 

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when the bearing welds itself to the crank and spins in the rod it makes a mess. usually the big end of the rod is all burnt looking, caked burnt oil, etc. the crank journal is trashed, needs re-ground, etc, etc. Pretty much a disaster.

That's a great engine to start a hi-perf BB with.
 

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Doesn't sound too bad to me, I've pulled apart running motors with small grooves in the bearings from stuff.

You would notice if the bearing was spun. Lots of discoloring on the rod and/or crank journals. The little locating tab on the bearing is typically pushed flat from spinning in the rod.

-Daniel
 

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Discussion Starter · #6 ·
Reason i asked was i took a set of 350 rods to the machine shop to be resized, balanced, magnafluxed ect and the shop foreman said one of the rods had been spun and he would sell me a new one. i agreed. But when i think about it all the rods looked the same when i took them in. This is a machine shop w/ a "good" reputation. Car Craft magazine has used them. Also many racers in So Cal. But i got some bad advice from them once and it cost me 23 hours labor and at least $200 because they were wrong. I had a rocker stud pull and had water in the oil. They told me that this wouldnt do it. So i suspected a cracked block and disassembled the engine and had them pressure test the cylinders. Turned out it was a pulled rocker stud. Motherf****ers! Could have repaired it in the truck. In fact the name of the shop is Dougans. All the other machine work theyve done for me was good including rebuilding 049 heads and a 383 short block. Beware of machine shop "experts".
 

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Many years ago i spun a bearing in my 454, which was not an uncommon problem. believe me you could HEAR it. it squealed like a banshee. just wearing off the surface and exposing some copper is not in my opinion indicative of spinning a bearing. it is probably just normal wear. if you spin a bearing you will really tear up the journal on the crank. again, this is just my personal experience. i'm sure one of the several engine builders on here can give you a much better definition/description but to a novice...spun bearing equals major noise and severe metal removal of a crank journal.
 

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Pull the caps off the rods, if a bearing was spun, the little locating tang would be sheared off of the bearing. Another sign of the bearing losing it's crush and getting close to spinning is if you pull the bearings then clean the bearing housing of the rods and their caps, if you were close to trouble, the housings would be somewhat polished. For that matter, the outside of the bearing shells would have a similar appearance.
 

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I'd give 'em the benefit of the doubt, if a rod has had a bearing spin in it, the heat treat's way off and it'll be way out of round - trash it and get a new one.
 

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If you do indeed have a spun bearing, it will be very obvious. When a bearing spins, it self-destructs very quickly. The bearing itself will be totally ruined, almost beyond recognition and the housing bore as well as the crank journal will be visually damaged too.
 

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Discussion Starter · #11 ·
The rods were given to me and didnt have bearings in them. Machine shop told me one had been spun so...?
 

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IF the machine shop says Spun a bearing ,and you aren't sure(should be obvious) .Take the safe out and get a rod .1 rod doesn't cost didly...JMO.
 

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The rods were given to me and didnt have bearings in them. Machine shop told me one had been spun so...?
Doesn't make sense. Your first post said that the bearings had lines in them, now you state that the rods didn't have bearings in them. Then in another post you were bashing a machine shop, for some reason that has nothing to do with your original post (as far as I can tell, anyway).
 

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Doesn't make sense. Your first post said that the bearings had lines in them, now you state that the rods didn't have bearings in them. Then in another post you were bashing a machine shop, for some reason that has nothing to do with your original post (as far as I can tell, anyway).
You should have read his follow up posts, he had problems with a set of 350 rods in the past!
 

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You should have read his follow up posts, he had problems with a set of 350 rods in the past!
Yes, I did read all of his posts. The one about the 350 rods is where he was bashing the machine shop and has nothing to do with his original post, concerning rods in a 454 Motorhome engine (IMO).

In summary, if a person has any doubt about the abilities of a machine shop to take care of his needs, then the incident in question should be taken up with said machine shop until he (the customer) is satisfied and has erased any doubts. If this cannot be done, then the customer should seek another shop that he can be comfortable with.
 
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