DFL dynamos.

[Alan]

Has anyone replaced the felt oil seals in a DFL with modern lip seals? Or maybe sealed bearings?

[Robert Foreman]

I usually fit a 2rs ball race and a lip seal.

[Alan]

Do you need to machine the casing to fit the seal?

[Robert Foreman]

No you don't.

[Dennis Nicholas]

When I fit sealed bearings (several on my Reliant Scimitar) I carefully pop off the seal, remove some of the grease and add some special anti friction metal treatment which is longer lasting than grease and stays put on metal surface  (remember modern parts are usually only expected to have a short life).
Before someone points out that bearings have to have some friction to work just google bearing friction and read up about research into reducing bearing friction etc....very very technical and most is far beyond what my brain can (wants to) cope with.
My alternator belt tensioning arm pulley bearing is an example of a high rotating use where I have done this.
That stuff good for reducing friction/wear on any metal to metal.......now looking forward to the next century wear free celebrations 

Dennis

[Tony Griffiths]

...and the anti-friction material used is?

[Dennis Nicholas]

https://silverline-uk.com/?product=synio...-treatment
Hi Tony.  It was good to at last put a face to a name when we met at Centenary.
Hope the above link works as it gives a (more simplified) description of the complex chemistry involved.

You will have heard of MIRA. the independent UK LAB and there is also SCINTEFfull ...The Norwegian Lab who first confirmed to the USA government the claims of the manufacturing companie's patent.  MIRA also show interesting reduced wear.  Surface breakdown pressure of it is also rather impressive and it is not destroyed by high heat so great for turbos (really!? you don"t have a turbo on your 7!!!!  )

For my Local Reliant Scimitar club I have volunteered to co-ordinate orders so we can buy in BULK saving in cost and cost of courier.  For my use I keep a 5 litre container (AFMT - Anti Friction Metal Treatment).  Add 10% by vol to first application then 5% thereafter at engine etc. oil change.  There is also a ready treated grease cartridge..(quite a thinish consistency)...great for King pins, steering box etc. 
I used to use the original Molybdenum-disulphide in oils/grease (on advice from a research engineer in our club) When I changed to AFMT, just the simple recording of fuel consumption showed reduced consumption and paid for itself in few hundred miles.....then so much extra money saving and more important less wear.

You may remember I was rather hobbling around at Centeenary...well things developed and I now have a new polypropylene vein and artery in length of one leg replacing worn out ones.......surgeon refused to add grease nipples.......but then bone/blood is non metallic 

Hope this helps

Dennis

[Alan]

MIRA isn’t an independent body. You pay them to do research work for you. If you want to prove the efficacy of something they will do tests to do that. It isn’t in their interests to disprove what you have asked. So, my question is always is this stuff works why isn’t it being used already?

[Dennis Nicholas]

It is in use. 
MIRA are not going to damage their reputation by falsifying tests.
USA government advertising more strict than ours and satisfied with patent claims.  Ditto SCINTEF not falsifying results.  
I have been using it many many thousand miles now in my Scimitars.
Many examples of before and after rolling road tests have been posted shown the improvements.  I really don't believe they are all false.
Some modern race teams using it to good effect (including longer time between new parts being required during seasons strip down inspections)

I have nothing to do with the makers or marketers other than being a very satisfied user.  I am a big sceptic at heart and like to research things before use. (Yes Ido have a copy of SCINTEF lab report).  

Dennis

[Tony Press]

When I fit sealed bearings (several on my Reliant Scimitar) I carefully pop off the seal, remove some of the grease and add some special anti friction metal treatment which is longer lasting than grease and stays put on metal surface  (remember modern parts are usually only expected to have a short life).
Before someone points out that bearings have to have some friction to work just google bearing friction and read up about research into reducing bearing friction etc....very very technical and most is far beyond what my brain can (wants to) cope with.
My alternator belt tensioning arm pulley bearing is an example of a high rotating use where I have done this.
That stuff good for reducing friction/wear on any metal to metal.......now looking forward to the next century wear free celebrations 

Dennis

(remember modern parts are usually only expected to have a short life).

Not anti-friction bearings- newer bearings from a known provider will last a very long time ! 

Because they are rolling ball bearings  there is very little friction to overcome (which is why they are called anti-friction) so why do this? 

Plain bush bearings are another matter altogether.