• Welcome to the forum website of the Vincent H.R.D. Owners Club.

    Should you have any questions relating to the Vincent H.R.D. Owners Club, or Vincent H.R.D. motorcycles in general, please contact Graham Smith, Online Forum Webmaster by calling 07977 001 025 or please CLICK HERE.

    You are unrecognised, and therefore, only have VERY restricted access to the many features of this forum website.

    If you have previously registered to use this forum website, you should log in now. CLICK HERE.

    If you have never registered to use this forum website before, please CLICK HERE.

Comet Oil Filter Woes

Martyn Goodwin

Well Known and Active Forum Website User
VOC Member
I have been chasing an elusive oil leak at the front of my Comet for some time – on reflection I recognise it started after I switched from the traditional “RAG” type oil filters over to the new metal/paper units. I use liberal amounts of non-setting sealant(Hylomar) on the oil filter cap and am in the habit (because of the pesky leak) of checking the filter cap after each run to ensure it is really snug and check for leaks. When I got home from a run today it was still feeling snug BUT still leaking so I pulled the oil filter out of my Comet and took the opportunity to perform some measurements.

The depth of the filter chamber from back to front edge is 3.678”
The diameter of the central spigot (at the base of the filter chamber) at its widest point adjacent to the base is 1.005”
The diameter of the central spigot (at the top of the spigot) at its narrowest point is 0.91”
The overall depth of the filter cap including the compressed spring and filter plate (how far it goes into the chamber to make a seal) is 0.41”

SO – with the cap and pressure plate in place, with the spring in the cap fully compressed there is 3.678 – 0.41 = 3.268” available to “house”the filter element; thus to allow for some wriggle room it seems that the absolute maximinum overall length of a metal/paper oil filter element, including seal rubbers must be no more than 3.258”

The “RAG” type element as supplied in the past by VOC Spares, uncompressed is 3.31” long, and with mild compression becomes 3.18” long; so it fits within the available space, allowing the end cover to be screwed downand sealed.
The VOC Paper Element filter metal body alone is 3.27” long and if you include the seal rubbers (which you must) it is then 3.40” long – so there is no way a seal can be achieved, the bugger is AT LEAST 0.133” too long!
Another Paper Filter element, obtained from another source, but stated to be for a “C” series Vincent Comet has a metal body length of 3.18”and if you include the seal rubbers (which you must) it is then 3.32” – so again there is no way a seal can be achieved as this filter is 0.053” to long!

I see that the VOC Spares Company no longer lists the RAG type of oil filter for Comets so I am asking my fellow Cometeers – is my problem unique to my Comet? I am wondering what sort of oil chamber dimensions can be found on other Comets and what are the external dimensions of the Metal Paper oil filters others have received from the VOC?

For now, I have reverted to the RAG type filter and am able to achieve an oil tight seal with the oil filter cap with thread sealant on the threads and Hylomar on the angled flange.


Martyn Goodwin,
 

Ken Tidswell

Well Known and Active Forum Website User
VOC Member
You are not the only sufferer from this problem, I at first thought it was the spring which had become coil bound because it was too long being a new one, there have been some cases. The woolen felt filter element is far more forgiving in the respect as it can be crushed easily as you screw in the brass cap. Iam building a bitsa Comet and have come across allsorts of 'interesting problems' , which must have consumed the factory fitters valuable time. i had considered slicing a section out of the filter to make it fit and applying silcone rubber to seal it up. Another idea was to fit a large inert object into the filter chamber, instead of the filter so that the chamber would quickly fill and circulate the oil where necessary and fit an external cartridge in the return line as others do. I think this is also a Royal Enfield dodge. The Spares Company have been persuaded to produce various oversize and under sizes of timing gears perhaps we could make special plea for Comet oil filter elements, which i imagine won't come cheap.
 

Martyn Goodwin

Well Known and Active Forum Website User
VOC Member
It strikes me that the "spring" within the oil filter chamber allows for a filter length variance of almost 1 inch. Given this, if future spares Co Comet oil filters were reduced in length, to say 3.10 inches, including sealing rubbers, then they would have a product that would work in any coneivable configuration of Comet oil filter chamber.

I wonder if our brothers with twins suffer from the same oil filter element longitudinal frustrations?
 

davidd

Well Known and Active Forum Website User
VOC Member
Martyn,

I have written about this before, but it must be over a decade. The casting at the base of the Comet oil filter is not as consistent as that of the twin. It varies quite a bit. On my racer the width of the circle that the paper element rests on is zero at one point, thus there is no seal. I considered a different paper element that could seal on a spindle and custom making the oil fitting, but it was too much work when I could simply use the original rag filter that seals on the floor of the oil chamber rather than the unreliable pad surrounding the oil fitting. I concluded that the paper element filters were not suitable for singles without some investigation.

Having never run the paper element I did not continue to investigate the width of the filter which you have done so well. I would argue that the best paper element filter should mimic the rag filter and seal on the floor of the oil chamber. This would allow the filter to always seal properly and would additionally resist crushing very well. This would in turn make the sealing at the cap much easier.

I presume that your leak might be caused by the lack of proper seating of the cap due to the excess length of the filter? I have never used sealer on the cap and I have no leaks so I see the cap as a reasonably reliable sealer in a stock application.

David
 

Martyn Goodwin

Well Known and Active Forum Website User
VOC Member
Exactly!! The VOC paper filter is simply too long for the intended application. The simple solution is the return of the original rag filter that has the accommidation to handle differing Comet Oil Filter chamber dimentions.

M
 

mercurycrest

Well Known and Active Forum Website User
VOC Member
I clean dirty felt filters by sliding them on a mandrel, putting them on my lathe set for the highest possible speed, sliding a big coffee can with both ends removed over the filter to catch the spray and feeding Stoddard solvent into the spinning filter. Works a treat.:eek:
Cheers, John
 
Last edited:

John Cone

Well Known and Active Forum Website User
VOC Member
I think if you check with Ian at the Spares Company the original RAG filters were manufactured by Crosland filters that have long gone down the drain. The filter that Vincent used was also used by Lister Engines and Petter Diesel engines in things such as Wingate and Twaites Dumpers. I seem to recall from my days as a plant fitter the Crosland No was 197. The company i worked for long before i'de heard of Vincents had a clear out and we threw hundreds of these older type filters away. Hind sight a wonderful thing.
 
Top