Spun rod bearing?

[keithbaker]

Engine ran great in hot laps. Tried to crank to go out and motor was locked down. Took the motor apart and spun rod bearing on #2. Bearings were overlapped on bottom side of rod. All other bearings looked brand new, the #1 bearing also looked good except for a couple small spots prob caused by #2. Only 6 races on motor. Stock cranked turned .10 rods and mains, eagle i beam rods, arp bolts, acl bearings p series. Turning motor max 7k probably less most of the time. Always have good oil pressure. Always use good oil and filter.

What would cause this?

[raceman17]

The same thing happened to me a few months ago.

Lack of oil to the rod bearing caused the bearing to melt.

What type of filter are you using? I used the ACdelco oil filter until I had the inside of the filter colapse and restrict the flow of oil throught the engine. Now im using the system 1 resuable filter.

[keithbaker]

HP4 filter, wouldn't the other rod bearing have the same issue if oil flow was restricted?

[parrot69777]

#1 & #2 rod bearings and #1 main are the last bearings to get oil.

[raceman17]

Have you looked at the filter and see if it looks ok on the inside? Did you happen to look at the oil pump as well and see if the internals looked good?

[keithbaker]

Filter looks normal, oil pump looks good. #1 main and #1 rod bearings looks brand new, only a ring on #1 rod brg on inside near #2.

[beer30]

the fram hp4 filters are junk. they will colapse. as will any fram filter. put a WIX racing filter on . i ran hp4 for awile then 2 filters in a row colapse. put a WIX on and no problems since. you can get them at napa. that may have not been your problem but you keep running the hp4 and it will be one. good luck

[CNC BLOCKS]

Stock cranked turned .10 rods and mains, eagle i beam rods

What bearings are you running with a crank that is truned 100 thousands!!!! And if those are the eagle sir rods we have seen more guys drag them into the my shops and after breaking them down and retourquing them they will not maintain there original size when retorqued!!!

You may want to go to a better rod like the scat I beam with 7/16 bolts if you going to go cheap.

[keithbaker]

Ok, going to go with wix oil filters for now on.

Sorry, typo .010. They are the eagle sir rods with 3/8 bolts. Thanks for the info cnc.

[parrot69777]

Agree 100% with CNC.....those SIR rods are junk. Stock gm rods are better than those.

[Racingtech]

I have had good luck with the sir rods in lower hp motors

I'm not disagreeing with anyone here but I have a 355 that has sir rods in it and it has seen 7600 plenty of times and it was built in 2007, still going. from what you are saying it doesn't sound like it was a oiling problem. I would guess that either that journal was to tight, or the crank was nicked when the rods where installed. If those rods distort after being taken apart and retorqued that could be it. Something else I would look at is the head on that cylinder, and make sure you aren't getting water in there causing it to beat the bearing out. Good luck

[latemodel21m]

screw all paper filters buy a real oil filter System One