This shaft has been drilled to allow pressure oiling from the rear main bearing (if you have pressure oiling).
Also it has been "nitrided" so it is about 50-51 Rc for about .004-.005" thick. This will improve wear resistance when run with bushings and will also make using needle roller bearings worth considering
I ran across pictures of your 2009 version and meant to ask how these are holding up on the long term. Getting any feedback on the originals?
They are doing fine
What is the purpose of having the shaft float?
Paul Vitko did extensive research into the deflection that occurs at the back end of the engine during various operating conditions. The floating shaft isolates these strains from the crankshaft
Les, tell us more......Jerry.
Until Les says more, here's some background:
The nitriding I have done usually leaves a surface hardness of 68/70 Rc. How are you getting 50/51?
Over the years I have had both gas and liquid Nitriding done and never got near to what you have on 4140 type materials
Maybe you have had tool steel or something similar done?
It would be interesting to find out how many broken crankshafts or other wear problems occur with the floating shaft as compared with the standard shaft. I also wonder if the benefit changes with engine speed. Example, a floating pin in the front of the crankshaft makes a knock at idle, but centrifugal force holds it in one position and the knock stops with speed. So I wonder if the benefits of the floating shaft would also be lost or even possibly cause damage if the shaft were to be held in an off center position while driving?
This is not intended to be a criticism, but would be a proof that the shaft either does or does not do what it is intended to do.
That makes sense then. I'm talking about H-13.
1.Fortunately so far no crank failures attached to this shaft
2. I don't represent that it will prevent crank failures
3. With 5 years of use ZERO problems
When a new product like this, a crank, a cam, an aux. transmission, a 2 speed diff, an OHV, a timer etc. come out; I make a decision on whether to buy based on three things:
1. Who's the designer, why did they design it and what's their track record.
2. Has it been tested; what are the results.
3. Is it worth the price in my eyes and can I afford it.
Point no. 1 is the most important, just like it is when choosing an engine rebuilder.
Guys like Les, Joe Bell and many other guys on this forum, do what they do because they love the hobby and want to contribute. They're not in it for an ego trip or a quick buck, nor is money a major factor behind what they do. Other guys contribute in different ways; some rebuild carbs, others coils, some study production history, the late Bob McDonald was a snowmobile/sandmobile expert, others remind us (constantly!) we don't need expensive add-ons that do very little. Many are along for the ride and make the trip more fun for everyone. And yes, there are a few wise guys like me that apart from crazy ideas and smart remarks do very little...they're just into Ts for themselves as a way to meet women...which rarely pays off.
So if I had the cash I'd buy this based on point no. 1.
The other thing is, say one of the test cars gets a two piece crack...what will that mean? It will be hard to know whether it was the shaft that caused it or another factor or multiple factors.
(Message edited by m2m on August 05, 2015)
Like Constantine, I'm watching Les's innovation with a lot of interest.
Several people have asked or wondered whether there have been any broken cranks during the testing of the floating shaft. I would posit that one (or even more) broken cranks during testing isn't very meaningful. Here is my reasoning:
From the pictures of the crank breaks that I have seen, I firmly believe that they are fatigue failures, as opposed to single-event overloads. What exactly is a fatigue failure?
Fatigue failures occur when a part is stressed to less than its breaking point, but many times in repetition. Maybe you could tie a crank in a knot one time without having it break, but could you untie it and re-tie it over and over without having it eventually break ? I think not. Think of flattening and then bending a beer can back and forth. Didn't break the first time you bent it ? No. Second time you bent it ? Probably not. But if you bend it back and forth enough times, it will break. That's fatigue. Here are a few fundamental facts about fatigue:
1. The closer you stress a part to its breaking point, the fewer cycles it takes to finally break.
2. For most materials, if you keep the stress low enough the cycles can go on pretty much forever without breakage.
3. Some materials are more subject to fatigue. Aluminum, for instance, is pretty safe as long as you never stress it to no more than 1/3 of it's breaking point. Wood, on the other hand, can be stressed to nearly 100% of it's breaking point without causing fatigue. Steel lies somewhere in between.
4. A part like a crankshaft may or may not have experienced fatigue causing stresses over its lifetime. But the old crank remembers every time it has been stressed above the memory point, and when you put it back into service you are adding to whatever is already in memory. Just because you clean and inspect an old shaft, including magnaflux, there is no way to know if its memory has been filled to 10% or 50% or even 90% of its fatigue life. Magnaflux, which is about the best test we can do, only tells us if the part has reached the end of its life and begun to break.
I may not have my numbers exactly right, but I was told once that the nosewheel axle on a Navy F-4 Phantom has a safe life of 100 cycles. After 100 launches/landings, the axle is removed and thrown away. Would they always break at 101 landings ? No. If you kept using the same axles, you would just begin to notice an increased rate of breakage. Maybe the first one would break at 150 cycles, then the next one at 170 cycles. But no doubt the last one would be broken by 300 cycles or so. That would be the axle with the nicest machine finish, the softest landings, the best metallurgy, etc.
My point is that there is a lot of variability in the quality of crankshafts, the magnitude of stress they have experienced, and the number of times that they have been stressed. That's why we're all playing a bit of Russian Roulette every time we drive our cars.
So to get back to my original point, I suspect that Les's floating shaft is a great innovation in stress reduction. If Ford had incorporated Les's innovation, perhaps broken crankshafts would be much less common today. But some shafts are so close to their ultimate life that they are due to break fairly soon anyway. And some are in such good shape that, given good bearing alignment, they will outlast their owners.
One way or the other, the floating shaft seems like a good way to reduce stresses caused by 4th main misalignment. Even if your crank is near its fatigue limit, the floating shaft will probably buy you quite a bit of time.
But don't draw any hasty conclusions if ONE of the crankshafts with the floating shaft does break. It's all a statistical game and it will take a fairly large sample size before we can draw any conclusions.
Les, if you have one of your improved tail shafts available, shoot me an email....Jerry.
Les, I am going to have a 1915 engine rebuilt soon and would like to install one of your new improved floating shafts. Let me know when one comes available. Thanks!