Talk Morgan Forums Morgan Sports Cars Morgan Three Wheeler & Super 3 A reason why M3Ws leak oil…

Nippy, I'm not sure what you don't get about this, but this may help.

Here's a picture of JV's original Harley compensator setup as it has just been removed from the original S&S rotor. You can see that when the inner hub spline was worn due to lack of lube, it when in and rubbed against the rotor.



This is with the rotor off and that shows the stub hub that made up the difference from the rotor into the inner main crank bearing so it could all then be torqued down.



This shows the short hub that Harley and S&S uses to seal off the oil from the crank and oiling pressure system. The seal can clearly be seen inside the stator inner crankcase hub.



This short spacer hub is then replaced with the Centa stub hub on the end of the Centa housing assembly. (The part that has the jaw marks on it and shown below)



You can see that Centa kit now has a new rotor that has to be bolted to the Centa support drive hub via the six flathead bolts. This also clearly shows how the new Centa kit has a stub hub that is now going to be used in lieu of the original short spacer hub shown a few pictures above.



The Centa support drive hub is slightly larger than the original Harley / S&S spacer hub and will require a larger seal.



The final picture shows the new Centa drive side support being installed onto the S&S crank. Next is the outer housing adapter from the motor to the trans.



If anyone wants to see JV's entire pictorial of his conversion to the Centa, go to my signature and click my Picture Trail link and the album is called CENTA Install.

Nippy, I hope that this clears up your questions.

Hopefully now you can see that the outer surface of the black Centa drive hub with the jaw marks, dimples, can be a problem when it randomly aligns with the seal lips when installed.

Some sell manufacturers make seals to replace O.E.M. seals with just a very slightly different sealing contact dimension that when installed allows them to be on CLEAN smooth metal on a specific hub. Like a new part again a new seal.

Thanks Dan , I am with it now.
Another example of the immaturity of the drive train design.

pictures are always really helpful. While I have worked on V-twins (and old gold wings) trying to make sense out the M3W drivetrain has been perplexing. I know see how the Centa is very similar to the compensator my wife's softail has between the rotor and the sprocket for the main chain drive.

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@ Phil Bleasey
Morgan will never aknowledge there are different crankshaft sizes. The first Centa that was installed as replacement to the standard compensator destroyed the splines of the crankshaft in less than 4000 miles. Morgan never accepted any responsability in this matter and i was left to replace both crankshaft and Centa at a cost of around 10.000€.

That's quite the cost to brunt @nadvys and not surprised that Morgan's reaction was dismissive! The two different crankshaft sizes is a new one to me. Is there a way of forecasting time frames of the different sizes and if extra examination is in order prior to assembly? i.e. late 2013 motor and latest Centa version?

I'll guess that the early batches of Centas were silver without the jaw marks, this batch may have sealed oil better since the seal partially developed after installation; like Bleasey noted. Then came the black (hardened?) version with jaw marks; and most recently, after ~October 2018, another back version without jaw marks and a turned finish on the Centa journal's sealing surface.

Looking back at all the oil leak /oil seal failure threads on TM is seems like many could be attributed to the Centa version in black before October 2018.

Forecasting crank sizes would best be done with communication with S&S and engine serial numbers when they changed.

wow.... mine was made right during that change over period.... fingers crossed!

I am waiting for a response from S&S but this is the second time of asking, so I am not hopeful. I have gauges made up so anyone in doubt about which shaft they have can check before getting me to carry out a repair with one of my inserts. Fingrers crossed in the hope that there are only two versions. My machine was built in 2013 with the smaller shaft.

I really don't understand the need for change as the difference is minimal - in the region of 0.2 mm on diameters. It is, however vital that the right choice is made, failure will be quick to follow a mistake.

This last week I have had to do the Pinion bolt upgrade, due to the customery extrusion out through the timing cover.
I have a 2012 but the motor was rebuilt in 2014/15 with a new crankshaft due to original compensator issues.
Also had a Centa installed at that time

When removing the timing belt etc to do upgrade, the pinion sprocket literally fell off
It was a very loose fit with almost one tooth of rotation!
I thought this was strange?
The replacement pinion sprocket was a good interferance fit with no slop!

Could this be to do with the crank size variation? or was it damage with bolt failure?

When loctite used on the new sprocket it was a good tight fit and as I feel it should be/have been.

Its raining so havent been on a run since upgrade, but the motor seems? to be quieter with regard to tappets etc!

+1 this was regular practic in the Machine Shop, we also used to have roller heads, small hardened rollers in a cage set at ~1000' smaller to bring the finished OD to size with a smooth polished surface.