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,
