Block groove above main bearing?

[Kevin Johnson]

First of all, the phrase you keep using "solution looking for a problem" wasn't mine.

I am well aware of that. No offense to you intended. It is just a measure of my exasperation.

Second, I already stated my views, and it is to free up oiling architecture in different combinations. Be it main oiling or accessory oiling such as piston oilers ect. Maybe it is driven by cost saving along with the oiling deal, as that would be a great place to save some material over a couple million pieces. As I said earlier, RWtech would probably know exactly why in the case of the LS engine.

Ok, that is kind of a generic catch-all which has been addressed in several instances already. So that cannot be the source of your complaint.

I'm still waiting to hear a clear explanation as to why the varying oil feed grooves in the main bearings?

Emissions and excess oil loading is my opinion. Additional oil loading from the centermain will put more stress on oil control rings in the center two bays. Mains two and four already evenly oil bay pairs 1-2 and 3-4 so the additional oil from the center makes the load on 2-3 disproportionate. Not only the groove is varied but also the aim and size of the slots on the thrust bearings and that is variance within the LS engine series.

This has also already been mentioned.

If you look at oil witness marks in the full length Corvette trapezoidal windage tray, chaotic flow over the third main is indicated. This means that the situation is even worse since chaotic flow could force most the oil from one bay pair to another versus evenly divided. I have had an explanation of the chaotic center flow in the LS up on my website for three or four years now and a suggestion on how to address it as well.

[Walter R. Malik]

So, if you HAVE experienced a main bearing oiling problem in a certain application and you do this main saddle groove with multiple holes through the bearing ... and, then those engine(s) show no more symptoms; you have either cured the problem or put a good bad aid on it.

It is nice to know the why's however, to me it is not absolutely imperative when that problem no longer appears.

[Warp Speed]

The groove above the main bearing is purely for oiling architecture as I stated earlier. The LS main bearings are fed with 2 holes. The hole in the leading portion of the groove (relative to crank rotation) is there to provide a better quality of feed to that portion of the groove, and subsequently the rod bearing.

The grooves in 1,2,4,5 main bearings stop well short of the parting line to reduce the bleed off caused by the large clearances in that area, thus increasing pressure in the groove to better feed the rod bearings. This bearing groove architecture, along with the added feed hole greatly increases the efficiency of the system. Even though with the shorter groove you are reducing the time the rod gets oiled, it is getting a higher pressure/quality shot. All with the reduction in losses spilling into the crankcase, increasing power, mileage and longevity.

The reason #5 main has a full half groove going to the parting lines, is to allow more bleed off to feed the thrust.

How's that?!?

[af2]

The groove above the main bearing is purely for oiling architecture as I stated earlier. The LS main bearings are fed with 2 holes. The hole in the leading portion of the groove (relative to crank rotation) is there to provide a better quality of feed to that portion of the groove, and subsequently the rod bearing.

The grooves in 1,2,4,5 main bearings stop well short of the parting line to reduce the bleed off caused by the large clearances in that area, and to increase pressure in the groove to better feed the rod bearings. This bearing groove architecture, along with the added feed hole greatly increases the efficiency of the system. Even though with the shorter groove you are reducing the time the rod gets oiled, it is getting a higher pressure/quality shot. All with the reduction in losses spilling into the crankcase, increasing power, mileage and longevity.

The reason #5 main has a full half groove going to the parting lines, is to allow more bleed off to feed the thrust.

How's that?!?

UMMMM it didn't say that on the patent papers I read through 1000 flippen times!!

[Warp Speed]

With some similar oiling architecture work, Jon may not have to run 18gal/minute through an engine?!?


BTW.................where did he go????????

[Barry_R]

I'll take the blame for the "solution looking for a problem" comment.

I use that line pretty often when I see people doing something just because they saw it used someplace else - even though it may have absolutely nothing to do with their application or engine. Or when they optimize an engine around some testing parameter or computer model number rather than around power or performance - ie dynamic compression ratio or internet camshaft calculators or leakdown tester numbers.

The extra hole might be a great way to address a problem in certain OE or racing applications. I don't know. OE guys work within a range of conflicting parameters that sometimes do not apply to performance at all - cost, manufacturability, speed of assembly, long term high mileage durability, emissions, mileage. Only guys I ever talked to about the extra holes simply said it "seemed like a good idea to put some extra oil in there..."

[Warp Speed]

Crickets?????????????????????????

I figured Kevin would be all over this by now! LOL

[Barry_R]

The groove above the main bearing is purely for oiling architecture as I stated earlier. The LS main bearings are fed with 2 holes. The hole in the leading portion of the groove (relative to crank rotation) is there to provide a better quality of feed to that portion of the groove, and subsequently the rod bearing.

The grooves in 1,2,4,5 main bearings stop well short of the parting line to reduce the bleed off caused by the large clearances in that area, thus increasing pressure in the groove to better feed the rod bearings. This bearing groove architecture, along with the added feed hole greatly increases the efficiency of the system. Even though with the shorter groove you are reducing the time the rod gets oiled, it is getting a higher pressure/quality shot. All with the reduction in losses spilling into the crankcase, increasing power, mileage and longevity.

The reason #5 main has a full half groove going to the parting lines, is to allow more bleed off to feed the thrust.

How's that?!?

Sounds pretty convincing to me....

[Kevin Johnson]

Crickets?????????????????????????

I figured Kevin would be all over this by now! LOL

I figured you needed a chance to look at some examples of main bearings spanning a few decades, keeping in mind the upper rpm regimes at hundreds of hours: LS bearings (LS1 versus LS7, for example), BMW S62 bearings, Porsche 928 bearings and Mercedes M100. Google image searches will pull all of them up, including shots of the grooved upper bearing saddles in the block.

The dyno studies on the Porsche 928 were publicly documented in the book, Project 928, that was written in 1977.

[Warp Speed]

Crickets?????????????????????????

I figured Kevin would be all over this by now! LOL

I figured you needed a chance to look at some examples of main bearings spanning a few decades, keeping in mind the upper rpm regimes at hundreds of hours: LS bearings (LS1 versus LS7, for example), BMW S62 bearings, Porsche 928 bearings and Mercedes M100. Google image searches will pull all of them up, including shots of the grooved upper bearing saddles in the block.

The dyno studies on the Porsche 928 were publicly documented in the book, Project 928, that was written in 1977.

HAHAHA............I don't need to become a historian to figure out whats up!!!

I live it every day!

[Kevin Johnson]

HAHAHA............I don't need to become a historian to figure out whats up!!!

I live it every day!

So, go over that again, why did they change the grooves for the LS7?

[Barry_R]

By extension - should we be putting the primary oil feed hole for the main bearings on the lead side of the groove and not having it in the center at all?

[Warp Speed]

HAHAHA............I don't need to become a historian to figure out whats up!!!

I live it every day!

So, go over that again, why did they change the grooves for the LS7?

Which grooves???

You have mentioned both the feed groove in the bearing, and also the slots/grooves in the thrust surface.

[Warp Speed]

By extension - should we be putting the primary oil feed hole for the main bearings on the lead side of the groove and not having it in the center at all?

You could, but I think with groove not extending into the parting line area, we are able to feed more oil to this area, without the negative of additional wasted flow out the higher clearances at the parting line, or having to raise system pressure.
When a crank is spinning with some good bearing to journal surface speed, does this action inhibit flow in the groove toward the leading edge from the main feed hole?
The oil pressure isn't that high in these engines, so they may require both to be effective. You may be able to use just one feed hole on the leading side, but with a higher system pressure?

[Barry_R]

Don't know - that's why I am asking...
Seems like having multiple feeds from a lower pressure area into a load area where we are trying to develop a higher pressure wedge gets us back into the cross drilled crank problem - where the oil just migrates away from the wedge back toward the lowest pressure feed.

If we have the big feed hole at the beginning of a partial groove that starts in the upper main, could we reduce the size/area of that groove as it goes around - something of a trailing teardrop shape that wraps into the lower - to induce a fully loaded pressure fed wedge?