Need advice on a bad rod bearing

Need advice on a bad rod bearing

Joined: November 15th, 2008, 5:31 pm

June 16th, 2011, 2:12 am #1

My friends Cleveland lost #6 rod bearing just recently; it is down to the copper and it will no longer fit back into the rod after it was removed. It is spread out so far that it cannot be bent back into the rod.

The engine is a 71 with CC heads, forged pistons and a new hydro roller; I don't have the cam spec's, it is street driven only, doesn't see anything past 6k; and no matter how hard I tried to talk him into it, doesn't have any oil system modifications whatsoever. Not even restrictors!! I suspect that the oil system gremlin has bitten him, what do you guys think????
Quote
Like
Share

Joined: February 3rd, 2003, 5:22 pm

June 16th, 2011, 2:25 am #2

#8 & # 7 look? For that matter, all the other rods. Gotta' remember that Fords, due to the front mounted oil pump give priority oiling to the front rods and mains. In other words, an oil starvation issue (pump, pump drive, etc.) in SBF's occurs with the rear-most bearings getting toasted first unlike an SBC which will toast the front-most rods and mains first. If 7 and 8 look great as well at #5 main bearing, it's not an oiling issue
Quote
Like
Share

Joined: December 11th, 2008, 10:11 pm

June 16th, 2011, 3:06 am #3

I would have the rods checked for roundness, and bearing clearance to the crank.
Quote
Like
Share

Joined: February 13th, 2006, 4:59 am

June 16th, 2011, 4:11 am #4

My friends Cleveland lost #6 rod bearing just recently; it is down to the copper and it will no longer fit back into the rod after it was removed. It is spread out so far that it cannot be bent back into the rod.

The engine is a 71 with CC heads, forged pistons and a new hydro roller; I don't have the cam spec's, it is street driven only, doesn't see anything past 6k; and no matter how hard I tried to talk him into it, doesn't have any oil system modifications whatsoever. Not even restrictors!! I suspect that the oil system gremlin has bitten him, what do you guys think????
I see he has closed chamber heads?Maybe his fuel wasn't up to snuff and he had some detonation issues?Premium fuel would be iffy for even a stock comp.cc engine.If he was using Race gas then I doubt thats it.6k is no problem I would think for stock oiling?
Quote
Like
Share

Joined: May 7th, 2005, 1:24 am

June 16th, 2011, 2:35 pm #5

My friends Cleveland lost #6 rod bearing just recently; it is down to the copper and it will no longer fit back into the rod after it was removed. It is spread out so far that it cannot be bent back into the rod.

The engine is a 71 with CC heads, forged pistons and a new hydro roller; I don't have the cam spec's, it is street driven only, doesn't see anything past 6k; and no matter how hard I tried to talk him into it, doesn't have any oil system modifications whatsoever. Not even restrictors!! I suspect that the oil system gremlin has bitten him, what do you guys think????
Before I started using Lifter bore bushings in the early 1980's, I lost at least 3 engines due to oiling problems. Each time it was usually either number 2 or 7 rod bearing that failed. Number 6 is fed by number 3 main, so it stands to reason it could also fail there. If it is equipped with a cam with a lot of lift it is possible that the oil might have leaked past the lifters even though it was not reved past 6000 rpm's.

www.lifterboretools.com
Quote
Like
Share

Joined: November 15th, 2008, 5:31 pm

June 17th, 2011, 4:11 am #6

that the rod was undersize; and he neglected to tell me the correct rod. It was not #6 it was #5. The rest of them look like new, so I think that the rod is the culprit.
Quote
Like
Share