Bearing tangs

[modok]

Funny you mention aviation......that's exactly the kind of situation where I would be against it.
I have seen quite a few cases where there was zero crush on a pair of bearing shells and it still run hundreds of hours like that.
I am sure some of you know what that looks like, on teardown. You can tell from what the inside of the housing looks like if it was slightly loose, sometimes looks polished, sometimes more dull, but you can see the bearing shell wasn't totally stationary.
Sometimes from damage, sometimes it was never right in the first place, or caps mixed up.
Not supposed to happen but, RARELy indeed it does happen.
Runs long enough to know what it looks like, sometimes a LONG time.
But if the oil feed gets blocked on a main bearing then it won't live minutes. This makes it more difficult to see what went wrong.
I'm just opposed to it AS A DESIGN practice. I would be just fine having NO locating feature on something I personally built custom.
Even did that a few times before it was cool, and it was fine.
Look closely at the main bearing tangs on a small block chevy.....tiny. only half overlaped, no strength at all, it's not really doing anything, so how does that work? No shortage of quality bearings, all specifications standardized long ago and well known. Some of these NEW more obscure engines, plus grey market/chinese bearings then lets see how it goes.

[BCjohnny]

In a freshly assembled, correctly clearanced engine, I doubt there's much need for tangs

However we've all pulled engines apart, core or for rebuild, where without the presence of tangs the bearings would likely have spun and the whole thing relegated to scrap ....... most evidenced by the tang slots being a bit beaten up

So I'm often happy they're there, but not so fussed in more modern designs if not

[Warp Speed]

5 years ago I would have said tangs are stupid.
Still think so on rods, but I have changed my mind on main bearings.
It may be wise to have some locating feature on main bearings to assure the oiling holes cannot drift out of alignment.
Maybe tangs, or a stepped hollow dowel at the oil feed, or a stepped dowel next to the oil feed, something like that.

Again, according to the Clevite engineer, when crush is correct, there is no way the bearing will shift.

Surprised no one has mentioned aluminum connecting rods are a whole different deal.

jack vines

I have seen winning race engines that went through distress come back with the tangs in the rod bearings heavily damaged. If it wasn't for the tang, the bearing would have spun amd the engine failed.
It is common to see marks from tangs working in the cap and main web from of high hp billet engines. Again, according to theory and design they are purely for assembly. In the real world they can save you.

[Truckedup]

5 years ago I would have said tangs are stupid.
Still think so on rods, but I have changed my mind on main bearings.
It may be wise to have some locating feature on main bearings to assure the oiling holes cannot drift out of alignment.
Maybe tangs, or a stepped hollow dowel at the oil feed, or a stepped dowel next to the oil feed, something like that.

Again, according to the Clevite engineer, when crush is correct, there is no way the bearing will shift.

Surprised no one has mentioned aluminum connecting rods are a whole different deal.

jack vines

Somehow Jack knew the engines I work on would have alloy rods, lol.....This engine does have aluminum rods..It's a vintage British bike lump ,oddball Ariel square four. The rods are new production high quality forged billet, the original rods were also aluminum.The bearing crush is correct. I suppose it's really no big deal to hand cut the notches. the engine is not for racing or sustained high high rpm

[mag2555]

So here's a question for all of you rod Bearing tang promoters.
With a Aluminum rod and its locating dowl do you folks still think tangs are needed?

[Warp Speed]

So here's a question for all of you rod Bearing tang promoters.
With a Aluminum rod and its locating dowl do you folks still think tangs are needed?

Yep!
It will help keep the upper half aligned side to side, reducing the chance of the bearing moving into the filet radius.
As I said before, tangs aren't needed in a perfect world. High performance, let alone max performance rarely sees a perfect world!

[modok]

The bearings already have tangs and the rods are aluminum.
I think we all agree, notch the rods.

Thanks for the fun anyway.

[bentvalves]

if you decide to notch the rod and the cap, is the right diameter end mill the way to get it done?

how do you sweep the radius into this operation?

[BCjohnny]

I'd use a woodruff key cutter ......

[Warp Speed]

This may cause a stir, but a Dremel with a cut off wheel works surprisingly well if your handy at things like that.

[mag2555]

Yes a cut off disc works fine in a steel or powered metal rod, but is a good bit of a pain in a Aluminum rod if you can't access a slow enough speed.