Connecting rods and which way they are installed

[Kern Dog]

Aren't the oil squirters on the connecting rods and caps supposed to face INward or toward the outside? I thought they were inward to throw oil against the camshaft.
The reason that I ask: A buddy with a 340 Dart is having a strange knock/rattle in the bottom end and I wonder if his engine builder made a mistake. It is a fresh build with very low miles, maybe less than 100. Oil pressure was 50 at cold idle. Oil is clean. He pulled the RH valve cover and watched the rocker arms and pushrods move at idle. No problems there. The flexplate is not cracked, the torque converter bolts are tight, the shield isn't hitting anything.
This noise is intermittent. It can start at idle or be silent. Once the engine is revved, the noise sort of "flares" then quiets down to about half as loud.
I tried to pull the oil pan but he didn't have a pickle fork for the steering linkage. I should be able to get the pan and windage tray off tomorrow to get a look at the rod caps. If any are loose, that is obviously trouble but I was curious about the oil squirters.
Thanks!

 

[69Bee]

Mopar/Chevy: Driver side 1,3,5,7 (Locks out), Pass side 2,4,6,8 (Locks out) Forget about the oil squirt holes (bearings are not notched anymore). With the locks out, the large chamfer goes towards the crank radius and if you look closely, you will see the bearing sits more to one side for radius clearance. If a rod was installed backwards, it would lock up the crank when the bearing is pushed into the radius.

 

[Lionized]

Aren't the oil squirters on the connecting rods and caps supposed to face INward or toward the outside? I thought they were inward to throw oil against the camshaft.
The reason that I ask: A buddy with a 340 Dart is having a strange knock/rattle in the bottom end and I wonder if his engine builder made a mistake. It is a fresh build with very low miles, maybe less than 100. Oil pressure was 50 at cold idle. Oil is clean. He pulled the RH valve cover and watched the rocker arms and pushrods move at idle. No problems there. The flexplate is not cracked, the torque converter bolts are tight, the shield isn't hitting anything.
This noise is intermittent. It can start at idle or be silent. Once the engine is revved, the noise sort of "flares" then quiets down to about half as loud.
I tried to pull the oil pan but he didn't have a pickle fork for the steering linkage. I should be able to get the pan and windage tray off tomorrow to get a look at the rod caps. If any are loose, that is obviously trouble but I was curious about the oil squirters.
Thanks!

My first guess would be one of the rod bearings is mis-aligned.

 

[WP29440SE]

I had a rattle / light knock coming on about 2,000 ish and above rpm , turned out to be 2 rod bearings going south. had great oil pressure. as mentioned, bearings aren't cut for squirting anymore, though some file the hole out for preference

 

[Kern Dog]

Mopar/Chevy: Driver side 1,3,5,7 (Locks out), Pass side 2,4,6,8 (Locks out)

I'm not sure what you mean by "Locks out".

 

[Lefty71]

I'm not sure what you mean by "Locks out".

He means the little tabs on the bearing, that keep it from spinning. If the rods are original, and not aftermarket, then the stamped rod numbers 1-2-3-4-5-6-7-8 should be visible, or "out" as well.

 

[Kern Dog]

Oh yeah, the bearing tabs. I have not heard them referred to as "locks" but that makes sense. Thank you!

 

[miller]

Here's one someone will probably dis-agree with me.
My 440, rod inserts, got the squirter notches cut, by me! Heard nonsense they weren't needed anymore...bs...on mine, yeah.
And the squirters aim for the cylinders. How else do the cylinders get oil, especially if a windage tray is installed. Oil mist?? Gimme shelter...

From the pan side, rod numbers face down, and together, for each rod.

 

[69Bee]

Yes, locks/tangs, same thing. Bearing tangs and factory numbers or symbols face out. Just a little trivia, the bearing tangs do NOT prevent the bearing from spinning, the bearing "crush" does. Crush locks the bearing in place. All the tangs do is locate the bearing half into place and maintain its alignment until the crush, when torqued together, locks it into place. As bearings wear, they will eventually lose crush, and will eventually spin in the bore. Also, the oil squirt holes are not an absolute necessity, hence their removal from bearing shells. Oil that escapes from the rods STILL gets flung all over the place, so there is a lot of oil and mist in there. There are a lot of motors that do not use any kind of oil squirt, and have been working just fine for decades. An exception to this is diesel piston cooling jets. They squirt oil onto the underside of the piston head to cool it. You can notch the bearings if you like, there is no harm in doing so, but is completely not necessary.

 

[fbs63]

It being a small block I would suggest checking the oil pump and pickup clearance. Also make sure the bottom two long water pump bolts aren't TOO long. They will brush the timing chain and make some odd noises.

 

[Derwud]

The stories I could tell about saving 24 cents and eliminating oil holes from Connecting rods.

 

[Kern Dog]

SPUN bearing!
Son of a gun. I got the center link off and pulled the pan. The windage tray was okay. The oil pan had chunks and grit in a metallic paste. It feels like brake rotor shavings. I pulled #s 5 and 6 rod caps off. # 6 was heavily grooved and to copper. # 5 was spun. The ends were worn to a taper. I suspect the bearing halves were sliding in and out of each other since the rattle was not consistent. The pistons are new, they looked fine from what I could see. He is going to strip the accessories off and I'll help him pull and transport the engine.
Thanks for the help!

 

[miller]

Rod bearing bore out of whack, not enough bearing crush, just one of a few gory details...gives you...

A good handful of motors, never have spun a bearing.

 

[69Bee]

The rods probably weren't resized, or done incorrectly. It would amaze you how many people I have to explain why they need to have the rods resized when rebuilding a motor, especially when putting in ARP rod bolts.

 

[miller]

Half one, half the other. Re-sizing, only when needed. Except in certain cases, like using rod bolts that don't fit the holes. They align the rod hole. They can distort the holes, making it a must to re-size, or at least hone til right.

If the hole is round, and straight, it's good to use. I've got my own tolerance numbers I go by, but that's beside the point.
Split bearing inserts fall into place, with the hole they go into. Bearing pinch, crush, however you want to call it, can be too little, too much. Assembled by hand, I go for slightly less than .001 crush, the gap between the rod/cap, just hand tightened. Mix and match bearing halves, to fit each rod set. I even put a 'light wipe' of lube between the rod and bearing halves. Just to help things to slip into place. But, that's for the final go together.

Bearing crush, and clearance at the crank journals, is the key, at least to me. Same thing on the mains.

 

[Challenger340]

Oh boy.....
so much general knowledge has been lost around resizing connecting rods these days, bearing eccentricities, WHY it's done.... and what you are trying to accomplish... what's acceptable... what's NOT acceptable...
lord help north america if we ever have to do things for ourselves again !