Connecting Rod Oiler Hole

[JeepFamily]

I've noticed a notch in the thrust side of both 258 and 4.0L connecting rods. The notch appears to be an oil passage seemingly to splash oil either on the camshaft and or cylinder wall? Interestingly, the factory bearings have a notch cut in the bearing allowing oil flow but aftermarket bearings such as Clevite do not have the notch. Can anyone confirm the function of this passage? and is it a problem that the aftermarket bearings don't have a mating slot?

[SilverXJ]

I don't know if it is a problem or not. Some people, including myself, have put a notch in the bearing to allow it to operate. It doesn't need to be very big. I used a Dremel with a small burr to make the notch. I would recommend using a bur of some sort and nothing abrasive like a grinding stone or a cartridge roll. You don't want abrasive to be come embedded in the bearing.

[JeepFamily]

The engine has about 1500 miles on it without the bearing mods. Whats the risk?

[SilverXJ]

Someone though it was necessary, but it could have been a just in case thing. Since it is already together and running I would let it go. I don't think its a big deal.

[Cheromaniac]

The notch appears to be an oil passage seemingly to splash oil either on the camshaft and or cylinder wall?

I suspect it's for the latter 'cause the oil spray path isn't aligned with the cam lobes. I don't think it's necessary though 'cause the cylinder walls already get plenty of splash lubrication from the crankshaft counterweights.

[Muad'Dib]

I am not convinced its necessary either. It may give some piece of mind.. but in my case I ran with bearings that did not have the notch and I don't have any issues. Others are in the same boat.

Its really up to you on what makes you feel warm and fuzzy about your build.

[woodjeep]

Take a good look at your middle picture...how much oil do you think is going to spray past that giant connecting rod bolt...with no hole in it...and then reconverge back into that slot