Block groove above main bearing?

[Barry_R]

I've looked at a few bearings with the extra holes in them. Always figured it was a solution looking for a problem.

[wyrmrider]

With top oil feed you are introducing oil at the largest clearance hence most oil lost.
There is also no pocket or diagonal or X in most bearings to spread the oil across the face
by shifting to 3 o'clock oil is introduced into the pocket at the parting line - some bearings or easy to create one with a scraper-
just trying to get a better hydrodynamic wedge with less oiling loss
I use squirters often

[Warp Speed]

With top oil feed you are introducing oil at the largest clearance hence most oil lost.
There is also no pocket or diagonal or X in most bearings to spread the oil across the face
by shifting to 3 o'clock oil is introduced into the pocket at the parting line - some bearings or easy to create one with a scraper-
just trying to get a better hydrodynamic wedge with less oiling loss
I use squirters often

Introducing the oil at the parting line is about as inefficient as you can get. The parting line is by far the largest clearance until enough distortion is encountered to close this up. By this time, this bore is so distorted the bearing shells become scrapers and your all but done anyway.

[coolchevy]

GM ís using it on all LS7 blocks, but groove stops way before the parting line and is very shallow there. Why are they doing it there but not on other LS blocks?

[wyrmrider]

Only More clearance in the center of the bearing they are standard size on the edges
For your analysis oil inserted at the top would run out at mid point anyway-

[robert1]

With top oil feed you are introducing oil at the largest clearance hence most oil lost.
There is also no pocket or diagonal or X in most bearings to spread the oil across the face
by shifting to 3 o'clock oil is introduced into the pocket at the parting line - some bearings or easy to create one with a scraper-
just trying to get a better hydrodynamic wedge with less oiling loss
I use squirters often

Introducing the oil at the parting line is about as inefficient as you can get. The parting line is by far the largest clearance until enough distortion is encountered to close this up. By this time, this bore is so distorted the bearing shells become scrapers and your all but done anyway.

Well Warp I figure if anybody could answer the whys about this groove you could. Otherwise I'll' stand by my first first post about responses worth looking at.

[Kevin Johnson]

With top oil feed you are introducing oil at the largest clearance hence most oil lost.
There is also no pocket or diagonal or X in most bearings to spread the oil across the face
by shifting to 3 o'clock oil is introduced into the pocket at the parting line - some bearings or easy to create one with a scraper-
just trying to get a better hydrodynamic wedge with less oiling loss
I use squirters often

Introducing the oil at the parting line is about as inefficient as you can get. The parting line is by far the largest clearance until enough distortion is encountered to close this up. By this time, this bore is so distorted the bearing shells become scrapers and your all but done anyway.

Well Warp I figure if anybody could answer the whys about this groove you could. Otherwise I'll' stand by my first first post about responses worth looking at.

For some reason I had Malik in my head. It was Meernik at GM Research in 1986: http://papers.sae.org/860229/ It is a variation on his reasoning.

[Kevin Johnson]

GM ís using it on all LS7 blocks, but groove stops way before the parting line and is very shallow there. Why are they doing it there but not on other LS blocks?

http://wot.motortrend.com/qa-with-corve ... z2PEuI5yGp

[Warp Speed]

So why do they use a partial groove on 1 2 4 5 mains, but use a full half groove on 3?

Sorry, full article not coming up on my phone........

[n5ifi]

Something I'm wondering... Some new blocks are coming with a big groove above the main bearing. I know it's to feed extra oil holes to be drilled in the upper main bearing. But why? In 45 years fo assembling race engines, I've never drilled 1 hole in a main bearing. Even in a big 825" boss hemi, with 3" mains, 8600 RPM and 18 gallons a minute of oil rushing through it, we never drill or enlarge the oil slot in a main bearing. But a new Motorsport Mod motor 5.4 aluminum block comes with a huge groove, about 1/3 of the main surface is taken away with the groove. Now we have an RHS aluminum LS Chevy block, same thing, huge groove. Apparently, whoever thought the groove was a good idea has never played the Chess Game of line honing an aluminum block with steel caps, and 1/3 of the aluminum surface missing. The housing will get real big real fast, going toward the groove, because it cuts so easy there with no surface area.

Does anyone think the groove is important? Jon

I'm a lifelong Ford guy and I've always done this on the Ford blocks I've built. I never modify the bearing though.
I take the used bearing inserted in the block and spray some bluing on it and die grind a groove in the blued area only about 3/16 deep.
I look at it as a sump for oil and that area isn't used for support anyway. It may not be a necessary procedure but it doesn't seem to hurt anything either.
I've never seen anyone else do it but it just seemed like it would help ensure an unrestricted path of oil to the 3" mains.
I've done it on all the 3" main Fords motors I've built and the 2.25 302"s also. Never had a problem with mains oiling either.
Of course you obviously don't either so it's probably not necessary.
I just figured everyone did it on 3" mains Fords.

[flyingwedge]

Something I'm wondering... Some new blocks are coming with a big groove above the main bearing. I know it's to feed extra oil holes to be drilled in the upper main bearing. But why? In 45 years fo assembling race engines, I've never drilled 1 hole in a main bearing. Even in a big 825" boss hemi, with 3" mains, 8600 RPM and 18 gallons a minute of oil rushing through it, we never drill or enlarge the oil slot in a main bearing. But a new Motorsport Mod motor 5.4 aluminum block comes with a huge groove, about 1/3 of the main surface is taken away with the groove. Now we have an RHS aluminum LS Chevy block, same thing, huge groove. Apparently, whoever thought the groove was a good idea has never played the Chess Game of line honing an aluminum block with steel caps, and 1/3 of the aluminum surface missing. The housing will get real big real fast, going toward the groove, because it cuts so easy there with no surface area.

Does anyone think the groove is important? Jon

>>Jon, Is it possible you didn't have bearing problems, with said 825" boss hemi, because it was flowing 18 gal./min. of oil ? Is it possible these large oil "slots"provide a pressurized minurature resovoir, and additional cooling, to the bearings ? What about the potential of rotating the main bearing, in its bore approximately 5 deg. ? The tang reliefs in the block and cap would need remachining, to accomodate and the oil feed hole, likewise. I suspect because bearing shells are no longer aligned with main cap part lines, there should be reduced lateral movement of mating parts, under higher loads ? Cheers, flyingwedge.

[n5ifi]

So why do they use a partial groove on 1 2 4 5 mains, but use a full half groove on 3?

Sorry, full article not coming up on my phone........

I've only seen that done on cross drilled cranks.
Who does that on a stock or aftermarlet cranks that aren't cross drilled?
I'm not taking into account FE stuff?

[Warp Speed]

So why do they use a partial groove on 1 2 4 5 mains, but use a full half groove on 3?

Sorry, full article not coming up on my phone........

I've only seen that done on cross drilled cranks.
Who does that on a stock or aftermarlet cranks that aren't cross drilled?
I'm not taking into account FE stuff?

HUH???

[robert1]

27 responses 900 views and not one reason as to why this groove is there!!!

[tsanchez]

I questioned it last year.

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