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Aug 24th, 2023
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Joined: May 2012
Posts: 1,790 Likes: 3
Talk Morgan Enthusiast
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Talk Morgan Enthusiast
Joined: May 2012
Posts: 1,790 Likes: 3 |
Hi Nippy, have a look at this.... https://youtu.be/Gtp3Tf8fYVE
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Joined: Mar 2011
Posts: 360 Likes: 8
Learner Plates Off!
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Learner Plates Off!
Joined: Mar 2011
Posts: 360 Likes: 8 |
This was from Morgan Ltd. ![[Linked Image]](https://www.tm-img.com/images/2022/12/05/crankNutTotque.jpeg) Great find - thanks for sharing.....
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Joined: Sep 2019
Posts: 284 Likes: 21
Learner Plates Off!
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Learner Plates Off!
Joined: Sep 2019
Posts: 284 Likes: 21 |
Just noticed by chance on PB website that Phil is no longer offering the full Centa conversion unless its hand fitted by himself to the engine at his Lancaster workshop....
Phil is now only offering the PB inner rotor upgrade option as a third party/non UK fit option (unless you ship the engine direct).
I have actually only been fitting our own modified inner rotor and not the full Centa for past 4 months due to the issues with the PB Centa/crankshaft fit.
So if you have a PB Centa kit waiting to be fitted by a third party then your choice but I for one would just go for changing the inner rotor and leaving the original outer Centa in place attached to the crankshaft.
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Joined: Feb 2019
Posts: 3,854 Likes: 2
Talk Morgan Addict
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Talk Morgan Addict
Joined: Feb 2019
Posts: 3,854 Likes: 2 |
Just noticed by chance on PB website that Phil is no longer offering the full Centa conversion unless its hand fitted by himself to the engine at his Lancaster workshop....
Phil is now only offering the PB inner rotor upgrade option as a third party/non UK fit option (unless you ship the engine direct).
I have actually only been fitting our own modified inner rotor and not the full Centa for past 4 months due to the issues with the PB Centa/crankshaft fit.
So if you have a PB Centa kit waiting to be fitted by a third party then your choice but I for one would just go for changing the inner rotor and leaving the original outer Centa in place attached to the crankshaft.
That is what I did, since the rear crank seal was not leaking oil I figured why mess with it.
The light at the end of the tunnel is actually a train. 2019 M3W
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Joined: Feb 2019
Posts: 1,876 Likes: 15
Talk Morgan Enthusiast
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Talk Morgan Enthusiast
Joined: Feb 2019
Posts: 1,876 Likes: 15 |
Just noticed by chance on PB website that Phil is no longer offering the full Centa conversion unless its hand fitted by himself to the engine at his Lancaster workshop....
Phil is now only offering the PB inner rotor upgrade option as a third party/non UK fit option (unless you ship the engine direct).
I have actually only been fitting our own modified inner rotor and not the full Centa for past 4 months due to the issues with the PB Centa/crankshaft fit.
So if you have a PB Centa kit waiting to be fitted by a third party then your choice but I for one would just go for changing the inner rotor and leaving the original outer Centa in place attached to the crankshaft.
That is what I did, since the rear crank seal was not leaking oil I figured why mess with it. wouldn't a step by step (with pictures) be great
Rodger
2018 M3W "Dreamers on the Rise"
2004 Plus 8 (wife's)
old Goldwings and a couple of Harleys
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Joined: May 2011
Posts: 1,613 Likes: 22
Talk Morgan Enthusiast
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Talk Morgan Enthusiast
Joined: May 2011
Posts: 1,613 Likes: 22 |
Just noticed by chance on PB website that Phil is no longer offering the full Centa conversion unless its hand fitted by himself to the engine at his Lancaster workshop....
Phil is now only offering the PB inner rotor upgrade option as a third party/non UK fit option (unless you ship the engine direct).
I have actually only been fitting our own modified inner rotor and not the full Centa for past 4 months due to the issues with the PB Centa/crankshaft fit.
So if you have a PB Centa kit waiting to be fitted by a third party then your choice but I for one would just go for changing the inner rotor and leaving the original outer Centa in place attached to the crankshaft.
That is what I did, since the rear crank seal was not leaking oil I figured why mess with it. wouldn't a step by step (with pictures) be great Phil has done a number of videos showing how it is done, https://www.youtube.com/@morganthreewheelerworkshop1189/videos
2021 M3W
2013 M3W - Sold
1971 4/4 2 Seater
1934 Sports
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Joined: Apr 2015
Posts: 450
Learner Plates Off!
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Learner Plates Off!
Joined: Apr 2015
Posts: 450 |
I wonder where he got that torque figure? I just looked at several charts for graded fasteners, and for bare (unplated and un lubricated) the torque for Grade 5 is about 475lbs/ft. For plated and lubricated bolts the torque is more like 350. For Grade 2 it's about half that, and for grade 8 about 40% more. Bolts all have rolled thread which are generally stronger than the machined threads as found on the crankshaft. So to come up with a suitable torque for a 7/8" machined thread in an unspecified steel would be a non S swag, IMO. Perhaps Phil was able to determine the type and hardness of the crankshaft and extrapolated from there?
The thickness of the nut may or may not have an impact on the torque figure. I was taught you need at least 1 diameter (of the male thread) of thread engagement to achieve full strength in a bolted joint, with 1.5 diameters preferred in order to provide a margin of safety. So if the 'thin' nut is roughly 7/8" tall then there is little to be gained by a deeper nut. Sorry for the delayed comment - I haven't been on here for a bit. Figures from here will give a rough guide https://www.norbar.com/Portals/0/downloads/TorqueValueGuide.pdf one should read the notes at the top of the page and realise that torque wrench settings are very much dependant on surface finish of the thread - plating - lubrication - washers and a lot of other things which can be controlled in a production line environment but not when we are doing a one off installation in a small workshop. I have made assumptions in the absence of information from manufacturers. I assume the material to have an ultimate tensile strength round about 50 tons / sq in (S grade) and you can see the reading recommended for 7/8 UNF S grade threads is 433 Lbf ft. The reason for getting this right is that the assembly forms a compound bar to withstand the sideways thrust of the centa rollers - something the original crankshaft was not designed for. I don't recall telling anyone to discard the flat washer - you should discard the spring /star washer - there is no point in locking the nut to a flat washer which is not locked to the shaft. Hope this helps folks to understand what is going on inside that bell housing - feel free to contact me if you want further clarification of my ramblings. Phil
2013 M3W 1960 Velocette Venom and the Landrovardo!
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Joined: Apr 2015
Posts: 450
Learner Plates Off!
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Learner Plates Off!
Joined: Apr 2015
Posts: 450 |
Just noticed by chance on PB website that Phil is no longer offering the full Centa conversion unless its hand fitted by himself to the engine at his Lancaster workshop....
Phil is now only offering the PB inner rotor upgrade option as a third party/non UK fit option (unless you ship the engine direct).
I have actually only been fitting our own modified inner rotor and not the full Centa for past 4 months due to the issues with the PB Centa/crankshaft fit.
So if you have a PB Centa kit waiting to be fitted by a third party then your choice but I for one would just go for changing the inner rotor and leaving the original outer Centa in place attached to the crankshaft.
Sorry again for the delayed reply. As a result of a small percentage of failures due my assumption that a well made item would fit on every crankshaft - which turns out not to be the case - I have had to re think the job. I recommend that, If you have one of my kits waiting to be fitted, then you should bring it to me or find a properly skilled mechanical fitter to install it for you - that person may find that the fit is not good enough in which case you should contact me for a solution in the form of an undersized hub to fit your shaft. whoever is fitting the hub to your shaft should look here for a description of the process https://www.youtube.com/watch?v=UAnLJGKJDsM Please do not make the assumption that if it feels tight going on that it will be OK - you must inspect the splines carefully to see marks where it fits tightly especially on the flanks of the splines - this will require pulling it on and off several times - tedious but there is no safe alternative. As always I am here for advice please feel free to get in touch although I don't spend much time on these pages so a mail or phone call would be better. Phil
2013 M3W 1960 Velocette Venom and the Landrovardo!
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Joined: Jan 2022
Posts: 62
Just Getting Started
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Just Getting Started
Joined: Jan 2022
Posts: 62 |
That is the recommended MAXIMUM torque load in the chart, a bit close to the wire in my view
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Joined: Jun 2012
Posts: 2,141 Likes: 43
Talk Morgan Expert
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Talk Morgan Expert
Joined: Jun 2012
Posts: 2,141 Likes: 43 |
I don't think any crankshafts have broken under excessive torque on the nut. The problem seems to relate to poor spline fit due to crankshaft machining variations that have caused some play, even with the high torque. I cannot see that reducing the torque of the crank nut would help anything.
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