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Discussion Starter #1
I know this is a common problem with racing motors as I have lost two motors to this now and other friends have also lost motors to rod failures and it is always this number two rod that fails on the big end. I have been told a reason for this is because the way KW oil supply is ran. Most everything is ran off the left side which causes oil starvation of the number two rod? What if anything can be done about this. I am just about ready to throw in the towel with KW motors.
 

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Not sure it's really all that common, but you've certainly had a bad run it sounds like. But if the supply is of the left side, then you'd expect the #4 cylinder to have the problem as it would be the last one to get the oil. So I'm not sure that theory is really sound. But whatever.

Have you tried a different pressure regulator? Or crushed your stock one a bit to increase the pressure? If you're spinning bearings, it's due to worn or low oil pressure.
 

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I am gathering from your other posts that you are using a Gen 3 zx10r engine in a 4-wheeled application, which will result in a much different fluid level situation in the oil pan. In hard cornering, oil will slosh to the side of the engine, which does not happen to any meaningful significance in the original (motorcycle) application.

I'm not aware of zx10r engines of any generation having a reputation for blowing up any more (or less) frequently than anything else. Using them in a kart or sidecar application could be a different matter.
 
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I am gathering from your other posts that you are using a Gen 3 zx10r engine in a 4-wheeled application, which will result in a much different fluid level situation in the oil pan. In hard cornering, oil will slosh to the side of the engine, which does not happen to any meaningful significance in the original (motorcycle) application.



I'm not aware of zx10r engines of any generation having a reputation for blowing up any more (or less) frequently than anything else. Using them in a kart or sidecar application could be a different matter.

Absolutely true. I was missing that key piece of info about use in a non-moto application.
 

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The stock rods of all gens are as far as i know very good many motors running well over 200HP without stretch or failure.
 

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Discussion Starter #6
Yes this is in a 4 wheel car. It is always #2 rods. Have done extensive oil baffling and windage tray in aftermarket pan along with crankcase venting. It for whatever reason is always the #2 rods that fails??? I know we are taxing these motors in the environment we are using them for but other manufactures don't seem to have this issue. I looked over the oil flow path in the OEM manual but don't see a obvious answer to why this happens. I am not ruling out some type of oil starvation but when the motors are disassembled no other bearings show sign of lack of lub. I have seen on other forums (drag racing) that some offer increased oil flow to the bearings? Is this just a case of opening up the oil feed holes to the bearings in the crank? These motors are fast but delicate it seems.
 

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Delicate? No. At least not in what they're designed for.
 

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Quantrill, if you send me a PM we can work together on these oil pressure problems.

I'm using a 2009 ZX10R in an SCCA road race car and have been working on baffling in the stock pan. The data acquisition shows the oil pressure drops only 4 psi on right hand corners and as low as 7psi with braking AND a left hand corner. I'll get some screen shots of the data in a day or so.


The stock smog control system causes the engine to pump oil up into the sealed chamber above the transmission and depending on the engine this can be a significant loss of oil volume in the pan.

This is the baffle that by itself showed the left hand turn oil pressure loss seen in the above data.


This is a picture which shows the sealed chamber without the cover.


This is what the stock cover looks like in place.


This the cover with the 3 corners cut off.


This is the breather oil that goes to the bottom of the oil pan.


This breather hole is behind the flywheel.


These are pictures of the oil baffles that I'll be trying at Sears Point in early September. I'm very hopeful and confident that this will solve the problem. The engine in these pictures is the #2, #1 from the above data is coming out and getting a full bearing replacement.



 

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If your oil pressure is doping at all i would think you could suck air in the system and that will make the oil foam and kill a rod bearing in a hurry. Why not just dry sump them?
 

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Likely at low oil pressure there is some air sucking and at low rpm the load may not cause a bearing failure. For me personally the extra cost and complexity is not worth the HP gain. Certainly I'm using up my time and some $'s pulling an engine and replacing bearings if they are damaged. I have gotten feedback from a number of bike guys that just fixing the oil breather problem has improved their bike performance.
If the oil pressure can be maintained above 50psi then I'm good.
David
 
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