Thread: Adaptor shaft

Vern, do it for Lotza.

Forgot to mention. Marks adaptors do destruction test all their products per ISO4000(?), generally two from a batch...yay, cheers from the 'I won't buy till tested'...then they pass the cost on to the purchaser.

I think Lotza should pursue the straight adaptor with Marks, as Lotza has a better understanding of the proposed system than I do.

Originally Posted by workingonit

I'm sympathetic to what you are saying about prop shaft issues, that the prop shaft is there to take up any misalignment. But that is a very dynamic system, with suspension movement changing prop shaft angles significantly.

Take away suspension, weld axle casing to chassis, as near perfectly straight alignment as possible to gearbox output, would you need a prop shaft yolk? Sliding splines maybe. Must check out those trucks that use torque tunnels as the chassis to see if they incorporate a yolk.

Without suspension or other movement you dont need a uni or flex coupling, however think about what Land Rover did on the Range Rover when they went to independant front suspension and did away with the unis on the front diff pinion. There was sufficient flex in the system for the splines to fail and IIRC they killed a number of people in the US.

That is not the issue here, the adaptor should be rigid enough not to flex outside the tolerances of the spline. If you can't do that then we should be using a remote transfer and jack shaft.

I'll have to read back over the threads to understand what dougal and sitec are doing. However if you want to preserve the thread on the Isuzu mainshaft you could use a tube nut on the mainshaft thread and have a matching thread for the, socket headed cap screw inside the spud shaft to use as the draw bolt. Or even step the threads inside the tube nut and use a smaller draw bolt so you can have a smaller bore inside the spud shaft.

The compromise will be matching the draw bolt size and the preload required for the MSA against the bore inside the LT230 end of the shaft

So basically noel (AM) has gone about it all the wrong way😉

I still like Sitecs idea but with a bit of Mudmouse mixed in.

I still have the S3 drive on my desk and keep staring at it. Its the closest match to the Isuzu drive flange I have seen and probably with enough bell depth.

Don't know if you could find a propeller shaft small enough, but if you could then cut out the sliding yoke with a bit of length either side to play with.

Weld one half of the sliding yoke to the S3 flang and the other half to the input gear.

So bolt your S3 with welded fitment to the existing MSA output. Put on transfer box. Insert input gear with other half of welded fitment. Do away with oil seal and run wet adaptor case.

In more detail.

Mill out the centre of the oh so cheap Ashcroft input gear as large as you dare.

Make the yoke a full length press fit into the machined input gear. Weld where the shaft enters the gear and weld it also where it terminates near the pto cover. Alternatively look at something like vacuum brazing it in - there is one Oz place I saw that offers that service. May be particularly worth it if wanting to avoid welding - and may allow you to sweat them apart if ever damaged, for refurbishment. But it won't get damaged will it!

Similarly mill out the splines in the S3 - less wall thickness here to play with here.

The yolk for the S3 may need to be the diameter of the nose carrying the spline - 47mm. Then reduce in diameter to enter the area now machined free of spline - 31mm. So rather than having a 31mm shaft running up to your S3 flange so that it can enter the 31mm hole, you end up with a 47mm shaft running up to the S3, then only reducing as it enters the hole. Weld the 47mm to the nose and the 37mm at the rear.

Darn, another one liner...

If AM's has not failed after some use then he has executed correctly one of several options

I only query whether AM's can be fitted into 173mm of Outcast/Sheldon box. Which goes back to my complaint of needing some basic measurements when people post a proposal.

My main concern was that his MSA side of the shaft may have to be reduced in length to fit. I queried whether there would be sufficient spline length after shortening to be sufficient in strength, is all. I did post a diagram here!! His SAE10 or whatever into the input gear is pretty standard length.

Originally Posted by Vern

So basically noel (AM) has gone about it all the wrong way��

As the Budda is supposed to have said, "there are many paths to the top of the mountain, Ancient Mariner's is but one" !

All I know is back in the days of Moses and Noah, when we were doing gearbox conversions to series Landies and this was before McNamara's and Mark's were doing any conversions commercially, most particularly the C4 and NP conversions the only conversions that had any reliability were single piece spud shafts or complete mainshafts with the interface on the end.

The machinists doing this work were professionals, had access to gear cutters and and machines to cut most of the internal and external SAE and other standard splines. Sometimes the work were foreign orders at famous name airline maintenance facilities or at RAN Garden Island. So I have no doubt about the ability of the machinists involved.

Originally Posted by workingonit

Darn, another one liner...

If AM's has not failed after some use then he has executed correctly one of several options

I only query whether AM's can be fitted into 173mm of Outcast/Sheldon box. Which goes back to my complaint of needing some basic measurements when people post a proposal.

My main concern was that his MSA side of the shaft may have to be reduced in length to fit. I queried whether there would be sufficient spline length after shortening to be sufficient in strength, is all. I did post a diagram here!! His SAE10 or whatever into the input gear is pretty standard length.

Noels is 175mm, he also gets 50mm engagement at the msa end of his shaft.
His motor also is bigger and more powerful than ours.