Its time for crank updates
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cannibalq8
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- Joined: Wed Mar 10, 2021 10:41 pm
... u still think that z400 bearing and pin r the best solution ?-
cannondale27
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- Joined: Wed Mar 10, 2021 10:41 pm
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Brad Oakley
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- Joined: Wed Mar 10, 2021 10:41 pm
Hey 27, have you touched a magnet to both bearing cages? The Z400 cage looks like copper, but is there steel underneath?
Wistech - what you cleaned out of your crank was carbon. There is an oil sprayer located on the crank cartridge plate that squirts oil up onto the wrist pin and the bottom of the piston. It is VERY hot right there and this heat causes the breakdown of some of the components in the oil. This is the main reason that synthetic oil is needed - to minimize (you can't eliminate it completely) the breakdown - known as Coking - of the oil. Oil is made up of long chains of carbon and hydrogen molecules. When they break down under heat the hydrogen goes away, leaving only the carbon. That's why used oil is black! However, carbon is also a solid. When I worked in the refinery lab, we had one tried and true method for seperating solids from liquids. All you have to do is spin the liquid very fast and the solids will be "thrown" out of the liquid by centrifugal force. In the lab we used a centrifuge. In our motors, that oil passage inside the crank is a perfect centrifuge. In the lab, our centrifuge ran at about 1500 to 2000 rpm. Guess how effective a centrifuge would be if we spun it at 10,000 rpm? We do this every time we open the throttle. Any solid material passing through that channel while the motor is running will be thrown to the outside of the passage by centrifugal force. That's why any overhaul work on our motors should involve the careful cleaning of that passageway inside the crank.
Wistech - what you cleaned out of your crank was carbon. There is an oil sprayer located on the crank cartridge plate that squirts oil up onto the wrist pin and the bottom of the piston. It is VERY hot right there and this heat causes the breakdown of some of the components in the oil. This is the main reason that synthetic oil is needed - to minimize (you can't eliminate it completely) the breakdown - known as Coking - of the oil. Oil is made up of long chains of carbon and hydrogen molecules. When they break down under heat the hydrogen goes away, leaving only the carbon. That's why used oil is black! However, carbon is also a solid. When I worked in the refinery lab, we had one tried and true method for seperating solids from liquids. All you have to do is spin the liquid very fast and the solids will be "thrown" out of the liquid by centrifugal force. In the lab we used a centrifuge. In our motors, that oil passage inside the crank is a perfect centrifuge. In the lab, our centrifuge ran at about 1500 to 2000 rpm. Guess how effective a centrifuge would be if we spun it at 10,000 rpm? We do this every time we open the throttle. Any solid material passing through that channel while the motor is running will be thrown to the outside of the passage by centrifugal force. That's why any overhaul work on our motors should involve the careful cleaning of that passageway inside the crank.
27
You are pressing them apart at home but how are you putting them back together? I thought that when you pressed them apart you used a machine that would hold them exact for putting them back together.
brad
Man, thanks for sending 27 that crank and please keep spitting out the obvious for us. Its kindof funny how this is all working out. Our motors have been open-sourced. Now everyone can give a little input to on what to do to fix it and the smarties can take the best ideas and put them together.
Way to go 27,timbo,wistech,brad,jay,and others :clap:
You are pressing them apart at home but how are you putting them back together? I thought that when you pressed them apart you used a machine that would hold them exact for putting them back together.
brad
Man, thanks for sending 27 that crank and please keep spitting out the obvious for us. Its kindof funny how this is all working out. Our motors have been open-sourced. Now everyone can give a little input to on what to do to fix it and the smarties can take the best ideas and put them together.
Way to go 27,timbo,wistech,brad,jay,and others :clap:
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cannondale27
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- Joined: Wed Mar 10, 2021 10:41 pm
I am not putting them back together.I take them to a local crankbuilder to put them together and sync them.I may attempt doing this sometime but those guys are really experienced at that and for $30 it isnt worth the risk of me doing it.Taking the crank apart saves them time and I get to see what is going on in there.Brad the cages of Z400 and Dale bearings are steel seems some dale bearings have a coating some dont.All the z400 bearings have a copper coating.
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Canniboomer
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- Joined: Wed Mar 10, 2021 10:41 pm
I have to agree that the material in the crank pins is acumulating there as an effect of centrfugal forces. Its just too unlikely to be there from the building process. Im not so sure its all carbon but a mixture of heavy particles(steel,aluminum,carbon) to small for any filter . I dont think it a serious threat to the engine other than throwing it out of balance and possibly breakin loose and clogging the oil passage. From all the cranks Ive pulled apart the only one that had a salvagable rod was a one that the most sludge in it.
Another thing I would like to add is the idea that the early billet cranks are somehow immune to this problem. Yesterday I pulled a fairly low mileage fx400 crank apart and it was in the final stages of failure. Cage grooves .008" deep and the center surface just starting to lift off material from fatigue.
Athough the suzuki bearing may not be the perfect bearing for this update so far its the best we have. It has proven to be very durable in the suzuki engines and although our test engines are just getting to a 100 hours acumulated run time , the results look very promising.
My whole reason for starting this thread is to make everyone aware that the crank issue is out there and needs to be addressed. I dont think it matters if you just spent thousands of $ on the biggest baddest big bore kit and other reliabilty enhancements. If you have the stock bearing its only a matter of time before the damage is done and you have a crank failure. The good news is that we have a group of guys here that are doing what it takes to get this problem solved. If caught early it can be fairly inexpensive too.
Another thing I would like to add is the idea that the early billet cranks are somehow immune to this problem. Yesterday I pulled a fairly low mileage fx400 crank apart and it was in the final stages of failure. Cage grooves .008" deep and the center surface just starting to lift off material from fatigue.
Athough the suzuki bearing may not be the perfect bearing for this update so far its the best we have. It has proven to be very durable in the suzuki engines and although our test engines are just getting to a 100 hours acumulated run time , the results look very promising.
My whole reason for starting this thread is to make everyone aware that the crank issue is out there and needs to be addressed. I dont think it matters if you just spent thousands of $ on the biggest baddest big bore kit and other reliabilty enhancements. If you have the stock bearing its only a matter of time before the damage is done and you have a crank failure. The good news is that we have a group of guys here that are doing what it takes to get this problem solved. If caught early it can be fairly inexpensive too.