It is my understanding that the integrated web/pin design is cheaper to build. I have no idea why the clearances are what they are, but I can look into it.
I'll see if I can get someone to post, but not sure how sucessful I'll be.
Crankshaft Failures
QUOTE
Originally posted by cannondale27
My point is I am trying to understand WHY Cannondale did the crank this way.It must have been more difficult and probably more costly to go with the integrated pin.That and also the huge side clearances must have been done for a reason.I believe it was done to compensate for other deficencies.Mainly the case.It would be nice for one of the crank builders to come on and explain why the Winky cranks AND to a lesser degree the stock cranks fail.That would give them a lot of credibility in my book.
My point is I am trying to understand WHY Cannondale did the crank this way.It must have been more difficult and probably more costly to go with the integrated pin.That and also the huge side clearances must have been done for a reason.I believe it was done to compensate for other deficencies.Mainly the case.It would be nice for one of the crank builders to come on and explain why the Winky cranks AND to a lesser degree the stock cranks fail.That would give them a lot of credibility in my book.
The cranks are cheaper to produce and to assemble. I have ran & rebuilt Banshee cranks for years. I have also used and associated with Falicon for over 20 years. I don't think, I know they are the best in the business. They are not crank rebuilders, they design, create, manufacture and rebuild both stock and exotic cranks. To state that they have never seen our motors is incorrect. They were the original choice for manufacture of the Cannondale cranks. They have the original design plans to the crank, and were passed over for a lower cost vendor. Aren't we complaining about how they are made and rebuilt now? Those who don't want to try the Falicon- FINE. Sit back and watch. I have had no crank problems (mostly due to lack of seat time), and I will be buying one for the future. My opinion on the crank failures has changed to "I am not sure what the problem is". LOL
I hope that you guys will give Falicon a chance.
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cannondale27
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- Joined: Wed Mar 10, 2021 10:41 pm
Ok they are cheaper.Why are the Dale cranks put together at such tight pin/web tolerance?So what if Falicon had original plans and motor.Do you realize how many changes and problems have come up since then?Everyone was convinced that Winky had solved problem of stock cranks failing also.If you guys can convince me that Falicon has solved the reason why STOCK cranks fail then I will buy one right away.Jay is trying that so I will wait for that.Oh and I never said they didnt see a motor like ours.I said they never dealt with a motor such as ours.Until now.
ok, cannondale27, i have measured three cranks that i have had and all of them the side clearence on the big rod end were at .015", the winky crank that i got was at .007" the pic that haydug posted about the wrist pin being scored, possibly could be contributed, half of the clearence=less oil for the wrist pin, hopefully mine stays running. just a thought,
Blaze, I'm not sure I agree with your theory of less oil. less clearance theoretically means increased pressure. Since the only way oil is getting to the wristpin is from splashing out of the crank, the higher pressure should be better because the oil will spray better. Think of it like when you put your thumb over the garden hose, it sprays alot further.
Now, the thing we don't know is exactly how much volume will flow through the gap at various clearances vs how much flow through the crank journal. It could be that at a .007 gap oil pressure is maintaned, and anything more than that pressure is decreased and oil just drips out.
Now, the thing we don't know is exactly how much volume will flow through the gap at various clearances vs how much flow through the crank journal. It could be that at a .007 gap oil pressure is maintaned, and anything more than that pressure is decreased and oil just drips out.
Excellent thoughts Jay. My experience with cranks & crank rebuilding involve two stroke cranks. In this scenario the oil is premixed with gas and the whole crank is in an environment of sorts. I do not have any small engine (vs V8 race motors) experience with dry sump oiling. The pics Haydug supplied of the wrist pin failures after only a few hours have me a little confused. My first thoughts were not of lack of oiling but of vibration caused by extreme side play. But this damage could also be caused by the lower end bearing failing first, then putting extreme side force pressures on the rod small end. Truth, I just don't know. I have never seen this much damage in such a short period of run time. I've seen more damage, but on motors with hundreds of hours, not after a fresh rebuild. I think the high pressures involved with the assembly and dis assembly may have something to do with this.
BPHillman: I think it would be wise to put in new press in pins in your test cranks. My only thoughts to the tight clearances used, are that the crank maybe made out of different materials than other cranks?? or they were a little worried about them coming apart at the higher RPMs that the Cdale motors run. I wish you luck, and I DO hope it works. I don't have any blown cranks, but I will help in any way possible.
BPHillman: I think it would be wise to put in new press in pins in your test cranks. My only thoughts to the tight clearances used, are that the crank maybe made out of different materials than other cranks?? or they were a little worried about them coming apart at the higher RPMs that the Cdale motors run. I wish you luck, and I DO hope it works. I don't have any blown cranks, but I will help in any way possible.