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[Dan_Lockwood]

I hope this is not a double post, but just asking a question in the Twin Cam forum.  I'm not sure the engine builders that frequent this CVO forum browse in other CVO forums.  So I'll pose a slightly different question here in hopes of having more motor experienced people give their thoughts.

I probably know the answer, but what does the Timken bearings do to support the crank better than currently used?

My thought is that it controls end play better and stops the crank from walking.  But in normal Harley setups, there really isn't any end load on the crank.

"IF" the Timken bearings work like the twin apposing tappered bearings in the old style front hubs and spindles of cars, the Timken upgrade allows for side/end force as well as radial loads on the crank like on the hub/spindle assembly of a car.

The answer I'm looking for is this, would the Timken upgrade allow a "certain" amount of direct end load on a Harley crank be supported better than without the Timken upgrade?

The "certain" load would be the amount of force required to push in a pressure plate similar to a 200mm VW clutch setup.  The crank end load would be limited to only when the clutch pedal is pushed in to disengage the clutch for shifting or an extended red light in traffic.

Thoughts on the better Timken bearing upgrade would be greatly appreciated.

Also in the EVO style motors, did all of them through a certain year have the Timken bearings?  Also do the EVO clone motors like a S&S, Ultima etc have Timken bearing?

Thanks.

[GMR-PERFORMANCE]

roller bearings work with a preset play based on the comp asy. You tq it that is the end play what ever it is. As well the roller is a slip fit thus it can move back and forth and up and down. Pop a cam plate and gab ahold on the pinion and you can move it around. Where as the timken is a  pair pressed on tapered bearing so the shim sets the end play ( you choose shim thickenss)  and comp tq again is used to keep it tight but you will get much less up and down play and you know what the end play is as well can set it.


For the most part a stock roller set up works very well for the avg builds. If you are building a engine crank work it is a nice upgrade. as you are there. I would not go into a engine just to add a timken..  Tons of 120R engines out there running stronger than ever with a non timken lower end. 

[S E Road King]

   Actually, it is two 'taper roller bearing sets' and the fact that they are assembled opposed to each other, with the cones locked to the sprocket shaft and the cups enclosed in the left case half that make the flywheel assembly more secure in its house(cases). With the proper running clearances these two bearing set are were the about the longest lived components in the big twin design.
   I have had my hands in to engines made from 1949 until my current 2002(last offering) and never seen one fail on it own devices.
Other than money, there was absolutely no reason to move away from that design. Most believe that if you want real power out of your twin cam you need this setup on the left side of your engine. I will agree.

[kcbike]

correct me if i'm wrong timken left side started 1955. 48-54 did not use timken left

[S E Road King]

correct me if i'm wrong timken left side started 1955. 48-54 did not use timken left

Timken manufactures lots of bearings, opposed taper roller bearings have been used successfully for a very long time, If your date is correct then, I stand corrected and thank you.    
However I still have never seen them fail in a regular big twin use on their own. In my experience they were usually taken out from contamination of another component polluting the oil supply

[Dan_Lockwood]

Thanks to all for the comments.

So going back to the example of the older front car hub/spindle assembly, the two apposing tapered bearings in the hub when set correctly, handle all the side loads from turning that a car can provide as well as support the weight of the car.

In my case and why I asked the question above, if I were to move forward at some point with this new project, my motor would have no radial load, i.e. belt or chain drive, only the rotational torque to drive an input shaft on a car 5 speed transmission.  Without the Timken bearings on the crank I would be afraid that the force when the clutch is pushed in that it would eventually put too much crank end load and wear something out in motor.

Thanks again for the input and comments.

[GMR-PERFORMANCE]

Your money but really the roller bearings work very well. 

[Dan_Lockwood]

But what about the pushing force that would be directly on the end of the crank?  With the roller bearings as currenlty used, what is used for the side thrust?

Thanks.

[GMR-PERFORMANCE]

PM sent

[S E Road King]

But what about the pushing force that would be directly on the end of the crank?  With the roller bearings as currenlty used, what is used for the side thrust?

Thanks.

They are set up with a thrust washer now and they may have moved it to the right side for accessability reasons. My issue is that when thrust washers are used then we now have components in much larger diameters that are bearing loads. Larger diameters mean higher surface speeds, that, combined wit holding the load on the opposite flywheel that delivers the torque thru the sprocket shaft sits ill with me. Now you have good folks out there that believe in the change and it's robust ability for reliability. Listen to all of them and draw your own conclusion. One thing that they are certainly right about is that millions of those stock configured engines run. I am not yet convinced.

[HILLSIDECYCLE.COM]

A dual tapered Timken bearing, LOCKS the flywheel assembly/sprocket shaft, into the left side case half.
Extremely rugged set-up.
Scott

[Thermodyne]

The simple answer is that for a street twin cam, it doesn't.

For a street motor the only benefit would be if you had a trued crank and were going to gear drive the cams.  Stabilizing the crank would also stabilize the cam timing.  But you're really talking about going after that last bit of power for that to pay off.  Most folks don't even verify that the cam timing is as advertised.

For the MoCo, leaving the opposed Timken set was a win win win situation.  Less expensive bearing, less install time/skill, eliminated a problem area with case manufacture, and allowed for the use of a less expensive flywheel asm.  Add to that, they work just fine.  As said above, they are not a failure point.   One of the few places where that setup is still used is front wheel drive hubs.  And for the most part they are well beyond the standard off the shelf tapered roller bearing.  Back in the day, it was a big step forward over the poured babit, bronze bushings and ball bearings that they replaced.  But even then it was about service life, not performance.   

They also don't hurt anything, so long as you set the motor up to close tolerances on the line bore and crank.  If people wanted to actually make an improvement to the twin cam, they should work out a way to put some larger tappet rollers in there.   

[HD Street Performance]

For the MoCo, leaving the opposed Timken set was a win win win situation.

Well one more item
The case halves could be machined independently not as a matched pair.

[HILLSIDECYCLE.COM]

In regards to perhaps using a degree wheel to verify cam timing on a T/C engine....how would one go about moving that around, if in fact the manufacturer did have them out of phase?
Used to degree cams back in the Shovel/Evo days and some were off, but much more than some would suspect.
Scott

[Thermodyne]

In regards to perhaps using a degree wheel to verify cam timing on a T/C engine....how would one go about moving that around, if in fact the manufacturer did have them out of phase?
Used to degree cams back in the Shovel/Evo days and some were off, but much more than some would suspect.
Scott

If the cams are off, then I'm thinking you send them back for another set.  As for advancing or retarding the set, then a sprocket cut to the desired offset would be needed.

From what I see out there today, the grinders would rather sell cam sets, not offset drive sprockets.