aliveagain
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posted November 05, 2008 07:23 AM
journal groove
My neighbor stopped by yesterday and happened to mention something that caught my attention.He was talking about in his old drag car, they use to groove the journals to enhance oil flow all the way around the bearing.I know ours is fluted by the hole but never heard of nor seen in the crank machine shops about doing this.Why not anymore?I respect the knowledge on this board so I ask.He said it helped a lot during idle and other low pressure times.
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VincentHill
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posted November 05, 2008 08:46 AM
My guess would be that they turn a LOT less RPMS and the Groove would be an un supported part of the bearing and leave "2" More edges to deal with.
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osti33
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posted November 05, 2008 01:57 PM
AA,
Are you talking about grooves like this??
Mr. Hill,
This is a bone stock 2008 hayabusa crank. So I would think the RPM's are close to the same.
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NINJA12
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posted November 05, 2008 02:12 PM
My guess would because the car engines are not as concerned about the length of the crankshaft. they have wider journals and bearings for more support, The groove could be to increase oil volume in the bearing area as a cushion during low oil pressure.
They don't have to make consessions between space and better oiling system.
Now lets see what the pros have to say.
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aliveagain
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posted November 05, 2008 02:14 PM
quote:
AA,
Are you talking about grooves like this??
Mr. Hill,
This is a bone stock 2008 hayabusa crank. So I would think the RPM's are close to the same.
Yes,interesting how they are only on the mains.
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I wondered why the baseball kept getting bigger. Then it hit me.
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VincentHill
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posted November 06, 2008 07:52 AM
AA Exactly what I noticed! No rod bearings and on the Driven side the second bearing does not look like there are grooves
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aliveagain
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posted November 06, 2008 08:06 AM
I asked Marine Crank about that while I had him on the phone.He said it was too hard to set it up to do the rod journals.Porsche also does it on their cranks but only half way around the journals. There was no engineering reason why they don't do this on more cranks.
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I wondered why the baseball kept getting bigger. Then it hit me.
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TRNorBRN6001
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posted November 06, 2008 08:40 AM
Nice Spacer Plate!!!!!
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TRNorBRN6001
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posted November 06, 2008 08:51 AM
Yep, I'd guess it would be to retain oil for start up and maybe low oil pressure. It looks like Harry's machine shop likes to whittle out a little on the cases under the bearings. I'd asume for the same reason, keep a little extra hanging around for start up.........................but I don't know much!
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aliveagain
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posted November 07, 2008 12:46 PM
I just noticed in my other post how two of the main bearings have grooves in them.
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I wondered why the baseball kept getting bigger. Then it hit me.
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dougmeyer
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posted November 08, 2008 07:29 AM
Follow the oil
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KZScott
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posted November 08, 2008 03:41 PM
ill take a stab at this one. someone can correct me if im wrong.
oil is coming from the cases to the crank where the groves are. it has to have the groove to keep constant oil pressure to the inside of the crank or the bearings without grooves would only get bursts of oil since they are pressurized by oil coming from inside the crank.
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00 ZX-12R 8.62 @ 165.2 no bars, slicks, Pump Gas, 55 shot.... turbo 8.32 @173
00 ZX-12R Fastest NA Kawasaki in the world 1: 222.046 1.5: 226.390 Loring AFB
00 ZX-12R street turbo 1: 227.9 1.5: 234.1 Loring AFB
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ninja12
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posted November 08, 2008 06:56 PM
I agree !
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dougmeyer
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posted November 09, 2008 05:36 PM
Very good Mr. KZ. You may go to the head of the class.
The rod bearings are fed from the case galleries via the mains through the cross drilling in the crank. The groove provides a constant rather than intermittnt flow.
That's not the only reason you ever see it though. "Back in the day" it was common to groove the mains in small block Chevy's simply to (it was thought) increase oil flow across the whole bearing surface. Better oil pumps negated the need for this mod.
Conside this- You've got to assume that Kawasaki could provide a perfect alignment of the hole in the bearings with the drilled hole in the case, but they don't always do that (didn't on the ZX-11's). I used to carefully match these by grinding away the case a bit to enhance the oil flow through the crank. After there was no effort on KHI's part to "fix" this apparent mismatch, I got to thinking they might be doing it on purpose. To meter the oil flow perhaps?
What do you think?
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2000redrocket
Pro
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posted November 09, 2008 05:47 PM
on the bigblock mopar of mine they recomend fully grouved mains. i do not know if it was for the mains them selves or more oil to the rods.
doug my friend had a zx11d that had #4 rod go all the time and semed fixing the mis matched oil feed hole on the crank feeding that journel was the fix. usually it was #3 rod on zx11 wasen't it doug???
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dougmeyer
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posted November 09, 2008 08:51 PM
Nope, The only thing that you need to do to keep ZX-11's from toasting the #3 rod is keep enough oil in it. Major myth. I've written endlessly on it. The engine was particularly oil level critical because of poor drainback from the head.
The deal on the grooved rod journals is that in order to keep the pins from galling the rods were gun drilled up the beam into the small end and the groove fed the pin oilers.
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ZXLNT
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posted November 09, 2008 10:57 PM
quote:
Very good Mr. KZ. You may go to the head of the class.
The rod bearings are fed from the case galleries via the mains through the cross drilling in the crank. The groove provides a constant rather than intermittnt flow.
That's not the only reason you ever see it though. "Back in the day" it was common to groove the mains in small block Chevy's simply to (it was thought) increase oil flow across the whole bearing surface. Better oil pumps negated the need for this mod.
Conside this- You've got to assume that Kawasaki could provide a perfect alignment of the hole in the bearings with the drilled hole in the case, but they don't always do that (didn't on the ZX-11's). I used to carefully match these by grinding away the case a bit to enhance the oil flow through the crank. After there was no effort on KHI's part to "fix" this apparent mismatch, I got to thinking they might be doing it on purpose. To meter the oil flow perhaps?
What do you think?
Heh you weren't the only one that dremeled out the mismatched oiling hole.
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ninja12
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posted November 10, 2008 03:20 PM
since we got that one fixed.
What is your thoughts on tapering the oil hole in the bearings?
Primary the rods
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dougmeyer
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posted November 10, 2008 08:36 PM
If you mean chamfering the edges of the hole in the crank, yes but not across the journal, only in line with the circumferance.
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NINJA12
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posted November 11, 2008 08:19 AM
Are you saying it ok to make the hole an oval , but not to chamfer the entire bearing and crank into a slightly larger opening?
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KZScott
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posted November 11, 2008 09:20 AM
i think a picture would help clarify the situation 
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01 ZX-12R 8.84 @ 156.3 no bars, DOT tires. Pump Gas, NA.... turbo 8.47 @ 164.
00 ZX-12R 8.62 @ 165.2 no bars, slicks, Pump Gas, 55 shot.... turbo 8.32 @173
00 ZX-12R Fastest NA Kawasaki in the world 1: 222.046 1.5: 226.390 Loring AFB
00 ZX-12R street turbo 1: 227.9 1.5: 234.1 Loring AFB
00 ZX-12R LSR turbo 1: 263.1 1.5: 266.5 Loring AFB Worlds fastest ZX-12R
CMG Racing RCC Turbos
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dougmeyer
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posted November 11, 2008 11:46 AM
Pretty much. I'll see if I can come up with a picture.
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