250 engine locknut set

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Scottish888
Posts: 266
Joined: Wed Feb 07, 2018 1:47 am
Location: Edinburgh, Scotland UK

250 engine locknut set

Postby Scottish888 » Tue Dec 11, 2018 3:44 pm

Hi

Sourcing parts for my 250 mk3 engine, found these engine locknuts, what do you folks think?

Set of Engine nuts and spring lock washers.
Suitable for all Ducati narrow and wide case engines, now with spring washers (not tabs) proven to work better.

From classicducati.com in the UK, seems like a great site with fair prices but I am not sure if best to stay with locktabs or spring washers. Spring washers are much easier to install and never let me down on any other components but not sure I ever used spring washers inside a motor, have used locking tabs though.
Can anyone explain where the large cone shape part of the Ducati flywheel puller threads onto? Not stripped the engine yet so I can't tell.
Regards

ducwiz
Posts: 604
Joined: Tue May 22, 2012 12:52 pm
Location: near Frankfurt, Germany

Re: 250 engine locknut set

Postby ducwiz » Tue Dec 11, 2018 6:20 pm

I suppose both locking methods are OK, but more important is that one should apply some polymer thread locker like LOCTITE to the clean and oil-free threads. This results in a highly improved security against loosening. Up to now, I stayed with the tabs, as I still have a lot of them in stock.
The flywheel puller screws on a very short thread M60x1, on the flywheel's steel hub. Seems you do not have a user manual or never looked into it - here you otherwise could have found a photograph of flywheel and puller in action - as well as with other special tools.
A download of the manual is possible from ducatimeccanica.com or other places on the net.

cheers Hans

double diamond
Posts: 555
Joined: Thu Apr 28, 2011 1:20 am

Re: 250 engine locknut set

Postby double diamond » Tue Dec 11, 2018 7:21 pm

I've disassembled a number of engines with the stock lock tab washers where the nut had come loose but still held in place by the tab. By nature, lock tab washers have to be made of soft material so the tab doesn't crack when bent into position. Consequently, the washer can compress under the nut it is securing and the nut loosens. I've turned to using belleville washers and loctite on critical internal engine nuts.

Matt

ranton_rambler
Posts: 439
Joined: Sun Jun 04, 2017 11:33 am
Location: Stafford UK

Re: 250 engine locknut set

Postby ranton_rambler » Wed Dec 12, 2018 12:53 pm

I've built mine with Belleville washers, but no Loctite. Torqued to Nigel's recommended values. Early days yet - hope it will be OK.

Scottish888
Posts: 266
Joined: Wed Feb 07, 2018 1:47 am
Location: Edinburgh, Scotland UK

Re: 250 engine locknut set

Postby Scottish888 » Wed Dec 12, 2018 1:23 pm

Thanks all,

Spring washers with loctite seems to be the way to go.
After looking last night in the Haynes manual I have I can see the threaded section near the flywheel centre, puller makes sense now.
Used to the pullers that fit down the centre.
Does anyone know the average gasket paper thickness used in the cases?

Regards

ranton_rambler
Posts: 439
Joined: Sun Jun 04, 2017 11:33 am
Location: Stafford UK

Re: 250 engine locknut set

Postby ranton_rambler » Wed Dec 12, 2018 9:36 pm

Why do you need to know the gasket thickness? I think you'll need to check the endfloat and adjust the crank shimming if you split the cases.

LaceyDucati
Posts: 521
Joined: Sun Sep 19, 2010 10:30 pm
Location: Wales UK
Contact:

Re: 250 engine locknut set

Postby LaceyDucati » Wed Dec 12, 2018 9:46 pm

I use lock tabs and a small amount of 243 Loctite for good measure. Been doing it on my own and customer engines for 30 years now and not looking to solve a problem which doesn't exist. Lots of miles, Countless race finishes and wins, Manx GP and classic TT finishes/silver replicas, championships and no loose nuts....... Most nuts that come loose are caused by other issues. To start with old tired or poor quality nuts, worn spacers, etc.
Regards Nigel

LaceyDucati
Posts: 521
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Re: 250 engine locknut set

Postby LaceyDucati » Wed Dec 12, 2018 10:19 pm

Regarding Belleville washers, If the belleville washers do not have any serrations they are probably not really much use as lock washers, see extract from Wikipedia and link from where it was taken.

Belleville washers, without serrations which can harm the clamping surface, have no significant locking capability in bolted applications. [6]

https://en.wikipedia.org/wiki/Belleville_washer

You would be as well to use a plain washer with loctite.

Regards Nigel

Scottish888
Posts: 266
Joined: Wed Feb 07, 2018 1:47 am
Location: Edinburgh, Scotland UK

Re: 250 engine locknut set

Postby Scottish888 » Fri Dec 14, 2018 1:39 pm

Thanks everyone,

All very helpful, I will buy locknuts with tabs and follow Nigel's setup.
I ask about the gasket thickness as I usually make my own gaskets, I realise gasket thickness will affect shimming but just wanted clarification of original gasket thickness, 0.4 and 0.8mm gasket paper is what I have at the moment

Regards


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