Part 1 of the Gasket and Seal Section lists:

Norton SOHC gaskets (or those common to all Norton singles)

Email us if you have a particular gasket or seal requirement and do not see it listed here: sales@racingvincent.co.uk

Copper/Asbestos Type Washer used to seal exhaust pipe where it screws into cylinder head (normally requires replacement each time Union Nut is refitted). Fits all SOHC, OHV and Side Valve Norton models.

This washer is of the original Copper/Asbestos 'crushable' type construction, originally used by Norton, but in these modern times - it is now a much safer mineral type filling (i.e. not asbestos).  These washers are manufactured for us by a high quality UK gasket manufacturer to the original pattern.

Note this washer should fit all Norton single cylinder models - SOHC, DOHC, OHV and SV type motors.  Email us for dimensions if you are not sure - at sales@racingvincent.co.uk.

These washers should be replaced each time the exhaust is removed.  From past experience - I have always used a large 'C' spanner on the finned exhaust nut - and tighten when cold, but then carefully retighten for the first couple of runs - with the engine hot.  This I have found ensures the nut is fully tight and helps prevent any backfiring or rough running

Update March 2024: Unfortunately the manufacturing cost of this copper/mineral washer has doubled since last ordered 2 years ago!! (partily the material cost).  We have only increased the retail price by a fraction of this amount.

High quality traditional paper gasket for all SOHC Norton timing chests.  Price is each

Specially manufactured for RacingVincent by top quality UK gasket manufacturer

High quality traditional paper gasket for all SOHC Cambox bevel covers, both Manx and International.  Price is each

Specially manufactured for RacingVincent by top quality UK gasket manufacturer

Paper gasket to fit all SOHC cambox back plate/cambox. This gasket is made specially for us and is virtually identical to the original Norton rear cambox washer listed in pre-war Spare Parts catalog.

SOHC Cambox rubber pad set, cut/planed from hard wearing oil resistent rubber (Nitrile), to the same width and thickness as originals, using a special jig for this purpose. These are fitted both above and below the rocker arm central boss in all SOHC cambox’s.

Along with the cork side washers, it is these being worn that normally results in these cambox’s leaking badly.

We use an original pre-war 'New Old Stock' Norton cambox rubber as the pattern to re-create these (bought many years ago from that great Norton exponent Phil Heath) to ensure the correct width.  Although they look very simple, they are not particularly easy to make . . . we buy slabs of the special oil resistent Nitrile rubber, cut them to approximate size blanks - but then have a special hardened jig (photos attached) to linish mill them to the correct dimensions (remembering that they may need further trimming to fit your own cambox).

Four rubbers are supplied, two for each rocker arm - one fits above (and is non adjustable) and the other fits below, and has some adjustment for wear - as it has a steel pad underneath it and an adjuster (both of which are manufactured by us in our Cambox section).  It would be nice if the top rubber had also been designed to be adjustable - but this would probably have meant the adjusters would foul the top tube of the frame.

The rubbers are slightly longer than required, which can be carefully trimmed to your required depth. They should be trimmed so they protrude just proud of the cambox slot, so the rocker arm has to be forced – carefully, into the cambox, as the originals were.  Take care not split or nick the rubber as you are pushing the rocker arms in place. The smooth end should be abutting the rocker boss and your trimmed end opposite.

Cambox Oil Tightness - Assembly Notes:

It is worth noting, it is never particularly easy to fit rockers after new rubbers and corks have been fitted - it is easy to think you are having to overly force everything together.  However, if everything is not a tight fit on first assembly - the cambox will quickly start to leak again once the engine has been ran a few miles. 

Therefore try and trim and assemble the rubbers so as much pressure as possible is being applied by the rubbers to the rocker surfaces.  As an indication - once the cambox is first assembled, the rocker arms should be very difficult to move by hand, feeling almost 'locked' up. 

The rocker arms should initially feel very stiff when first assembled, but they will soon loosen up in operation - but being like this should help ensure the cambox staying oil tight as long as possible.  This also applies to the rocker arm side washers (0062/0062b/0062c) - try and fit washers thick enough that some effort is required to fully tighten cambox rear cover (without damaging threads of course).  These will also compress a few thou in use - we sell different thicknesses for this purpose.

Final point on SOHC Cambox's leaking oil - after a period of time the top and bottom rubbing surfaces of the rocker arm centre hub (i.e. the area where the nitrile rubbers press against) get worn and sometimes scratched through dirt getting caught.  As long as smooth and reasonably evenly worn, the rubbers should still work.  However if scoring marks get excessive, even fitting new rubbers will only provide limited improvement.  If this is the case with your rocker arms, it may be necessary to have the rubbing areas of the rocker arms lightly milled.

There are some specialist Norton engine restorers who will sometimes perform this task, Email us at sales@racingvincent.co.uk if you think want more information on this.

I was asked for more information recently on fitting these by a customer . . . as it is indeed a fiddly and time consuming operation to trim them to fit your own cambox . . . and each time you try and push the rocker arms in . . . it requires some effort (unless you have over trimmed them . .. in which case it is quite easy to assemble!!) - so took some pictures of one of my own (magnesium) cambox shells and then overwrote the general sequence of trimming.  I know it is not particularly easy to read my writing - but look closely, follow the arrows and hope this helps.  It is important to note that there is 3 'planes' of the rubber - the Width, the Depth and the Breadth.

Oil Resistent Cork Washer, fits on either side of the rocker arm bearing - Fitting new cork washers helps keep the cambox oiltight - Cork thickness = These are 2.0mm (std) thickness.

Manufactured for RacingVincent by UK based specialist gasket manufacturer.

SOHC Norton Rocker Arms, side plates and cork washer information:  

For the duration that the Arthur Carroll SOHC engine was manufactured by Norton's (i.e. approx 1930 - 1957) there were at least 3 different rocker arm variations - possibly more.  The initial cambox rockers arms (I think approx 1930 - 33) had a smaller diameter central boss for the rocker arm.  The cork washers we sell here are a larger diameter than that earlier diameter - but it is easily possible to trim the cork with sharp scissors to fit the cambox shell recess.  The second type of rocker arm had the 'normal' larger diameter, which is the same diameter as these cork washers.  This second type of rocker arm used flat shims between the rocker/bearing sides and the cork.  We sell that (non lipped) flat shim - item 0288.  Not sure of exact periods for this type - but most pre-war cambox's I have seen have this flat shim (non lipped) type. 

The final rocker arm type I am aware of is the type that require a 'Lipped' side washer - Item 0287 in our catalog.  This type seems the most common. The rocker arm for this type is identifiable by each end of the central rocker arm boss having a lip machined around it, to fit the lipped washer.  The diameter of the cork washer for both non-lipped and lipped type rocker arms is the same.  Although I cannot be sure - I always assumed the 'lipped' type side washers were introduced because they put side pressure (of the cork) on the rocker arm boss itself, not the bronze bearing inside, as well as helping prevent leakage of oil from the central bearing/rollers.

Because restorers of these engines often end up acquiring mismatched rocker arms and cambox shells, we provide oil resistent cork side washers in three different widths.  In the past, I have found the side play of rocker arms to vary by cambox - and therefore a thicker cork washer on some being desirable.  A simple way of confirming this is to remove all traces of old cork washer, fit Blu-Tac or plasticine into the cork washer recesses of the cambox shell/rear cover, and then trial assemble the cambox with rockers.  Then strip and carefully remove rockers and use a depth gauge to carefully press into the soft plasticine to estimate the ideal thickness of washers required.  Dont forget to level out the differences between both sides, and allow a small additional amount for the cork compressing - it is this that stops the leaking!

Cambox Oil Tightness - Assembly Notes:

It is worth noting, it is never particularly easy to fit rockers after new rubbers and corks have been fitted - it is easy to think you are having to overly force everything together.  However, if everything is not a tight fit on first assembly - the cambox will quickly start to leak again once the engine has been ran a few miles.  Therefore try and trim and assemble the rubbers so it as much pressure as possible is being applied by the rubbers to the rocker surfaces.  As an indication - once the cambox is first assembled, the rocker arms should be very difficult to move by hand, feeling almost 'locked' up.  If the rocker arms are very still, they will soon loosen up in operation - but this should help ensure the cambox staying oil tight as long as possible.  This also applies to the rocker arm side washers (0062/0062b/0062c) - try and fit washers thick enough that some effort is required to fully tighten cambox rear cover (without damaging threads of course).  These will also compress a few thou in use - we sell different thicknesses for this purpose.

Final point on SOHC Cambox's leaking oil - after a period of time the top and bottom rubbing surfaces of the rocker arm centre hub (i.e. the area where the nitrile rubbers press against) get worn and sometimes scratched through dirt getting caught.  As long as smooth and reasonably evenly worn, the rubbers should still work.  However if scoring marks get excessive, even fitting new rubbers will only provide limited improvement.  If this is the case with your rocker arms, it may be necessary to have the rubbing areas of the rocker arms lightly milled. There are some specialist Norton engine restorers who will sometimes perform this task, Email us at sales@racingvincent.co.uk if you think want more information on this.

Update Autumn 2019:  New batch of cork washers just manufactured.  Apologies for price rise, but I am told that the price of cork has risen considerably since our last batch were made

Oil Resistent Cork Washer, fits on either side of the rocker arm bearing - Fitting new cork washers helps keep the cambox oiltight - Cork thickness = These are 2.4mm (med) thickness.

Manufactured for RacingVincent by UK based specialist gasket manufacturer.

SOHC Norton Rocker Arms, side plates and cork washer information:  

For the duration that the Arthur Carroll SOHC engine was manufactured by Norton's (i.e. approx 1930 - 1957) there were at least 3 different rocker arm variations - possibly more.  The initial cambox rockers arms (I think approx 1930 - 33) had a smaller diameter central boss for the rocker arm.  The cork washers we sell here are a larger diameter than that earlier diameter - but it is easily possible to trim the cork with sharp scissors to fit the cambox shell recess.  The second type of rocker arm had the 'normal' larger diameter, which is the same diameter as these cork washers.  This second type of rocker arm used flat shims between the rocker/bearing sides and the cork.  We sell that (non lipped) flat shim - item 0288.  Not sure of exact periods for this type - but most pre-war cambox's I have seen have this flat shim (non lipped) type. 

The final rocker arm type I am aware of is the type that require a 'Lipped' side washer - Item 0287 in our catalog.  This type seems the most common. The rocker arm for this type is identifiable by each end of the central rocker arm boss having a lip machined around it, to fit the lipped washer.  The diameter of the cork washer for both non-lipped and lipped type rocker arms is the same.  Although I cannot be sure - I always assumed the 'lipped' type side washers were introduced because they put side pressure (of the cork) on the rocker arm boss itself, not the bronze bearing inside, as well as helping prevent leakage of oil from the central bearing/rollers.

Because restorers of these engines often end up acquiring mismatched rocker arms and cambox shells, we provide oil resistent cork side washers in three different widths.  In the past, I have found the side play of rocker arms to vary by cambox - and therefore a thicker cork washer on some being desirable.  A simple way of confirming this is to remove all traces of old cork washer, fit Blu-Tac or plasticine into the cork washer recesses of the cambox shell/rear cover, and then trial assemble the cambox with rockers.  Then strip and carefully remove rockers and use a depth gauge to carefully press into the soft plasticine to estimate the ideal thickness of washers required.  Dont forget to level out the differences between both sides, and allow a small additional amount for the cork compressing - it is this that stops the leaking!  I normally keep a few of each type handy when assembling for this reason.

Cambox Oil Tightness - Assembly Notes:

It is worth noting, it is never particularly easy to fit rockers after new rubbers and corks have been fitted - it is easy to think you are having to overly force everything together.  However, if everything is not a tight fit on first assembly - the cambox will quickly start to leak again once the engine has been ran a few miles.  Therefore try and trim and assemble the rubbers so it as much pressure as possible is being applied by the rubbers to the rocker surfaces.  As an indication - once the cambox is first assembled, the rocker arms should be very difficult to move by hand, feeling almost 'locked' up.  If the rocker arms are very still, they will soon loosen up in operation - but this should help ensure the cambox staying oil tight as long as possible.  This also applies to the rocker arm side washers (0062/0062b/0062c) - try and fit washers thick enough that some effort is required to fully tighten cambox rear cover (without damaging threads of course).  These will also compress a few thou in use - we sell different thicknesses for this purpose.

Final point on SOHC Cambox's leaking oil - after a period of time the top and bottom rubbing surfaces of the rocker arm centre hub (i.e. the area where the nitrile rubbers press against) get worn and sometimes scratched through dirt getting caught.  As long as smooth and reasonably evenly worn, the rubbers should still work.  However if scoring marks get excessive, even fitting new rubbers will only provide limited improvement.  If this is the case with your rocker arms, it may be necessary to have the rubbing areas of the rocker arms lightly milled. There are some specialist Norton engine restorers who will sometimes perform this task, Email us at sales@racingvincent.co.uk if you think want more information on this.

Update Autumn 2019:  New batch of cork washers just manufactured.  Apologies for price rise, but I am told that the price of cork has risen considerably since our last batch were made

Oil Resistent Cork Washer, fits on either side of the rocker arm bearing - Fitting new cork washers helps keep the cambox oiltight - Cork thickness = These are 3.0mm (thick) thickness.

Manufactured for RacingVincent by UK based specialist gasket manufacturer.

SOHC Norton Rocker Arms, side plates and cork washer information:  

For the duration that the Arthur Carroll SOHC engine was manufactured by Norton's (i.e. approx 1930 - 1957) there were at least 3 different rocker arm variations - possibly more.  The initial cambox rockers arms (I think approx 1930 - 33) had a smaller diameter central boss for the rocker arm.  The cork washers we sell here are a larger diameter than that earlier diameter - but it is easily possible to trim the cork with sharp scissors to fit the cambox shell recess.  The second type of rocker arm had the 'normal' larger diameter, which is the same diameter as these cork washers.  This second type of rocker arm used flat shims between the rocker/bearing sides and the cork.  We sell that (non lipped) flat shim - item 0288.  Not sure of exact periods for this type - but most pre-war cambox's I have seen have this flat shim (non lipped) type. 

The final rocker arm type I am aware of is the type that require a 'Lipped' side washer - Item 0287 in our catalog.  This type seems the most common. The rocker arm for this type is identifiable by each end of the central rocker arm boss having a lip machined around it, to fit the lipped washer.  The diameter of the cork washer for both non-lipped and lipped type rocker arms is the same.  Although I cannot be sure - I always assumed the 'lipped' type side washers were introduced because they put side pressure (of the cork) on the rocker arm boss itself, not the bronze bearing inside, as well as helping prevent leakage of oil from the central bearing/rollers.

Because restorers of these engines often end up acquiring mismatched rocker arms and cambox shells, we provide oil resistent cork side washers in three different widths.  In the past, I have found the side play of rocker arms to vary by cambox - and therefore a thicker cork washer on some being desirable.  A simple way of confirming this is to remove all traces of old cork washer, fit Blu-Tac or plasticine into the cork washer recesses of the cambox shell/rear cover, and then trial assemble the cambox with rockers.  Then strip and carefully remove rockers and use a depth gauge to carefully press into the soft plasticine to estimate the ideal thickness of washers required.  Dont forget to level out the differences between both sides, and allow a small additional amount for the cork compressing - it is this that stops the leaking!  I normally keep a few of each type handy when assembling for this reason.

Cambox Oil Tightness - Assembly Notes:

It is worth noting, it is never particularly easy to fit rockers after new rubbers and corks have been fitted - it is easy to think you are having to overly force everything together.  However, if everything is not a tight fit on first assembly - the cambox will quickly start to leak again once the engine has been ran a few miles.  Therefore try and trim and assemble the rubbers so it as much pressure as possible is being applied by the rubbers to the rocker surfaces.  As an indication - once the cambox is first assembled, the rocker arms should be very difficult to move by hand, feeling almost 'locked' up.  If the rocker arms are very still, they will soon loosen up in operation - but this should help ensure the cambox staying oil tight as long as possible.  This also applies to the rocker arm side washers (0062/0062b/0062c) - try and fit washers thick enough that some effort is required to fully tighten cambox rear cover (without damaging threads of course).  These will also compress a few thou in use - we sell different thicknesses for this purpose.

Final point on SOHC Cambox's leaking oil - after a period of time the top and bottom rubbing surfaces of the rocker arm centre hub (i.e. the area where the nitrile rubbers press against) get worn and sometimes scratched through dirt getting caught.  As long as smooth and reasonably evenly worn, the rubbers should still work.  However if scoring marks get excessive, even fitting new rubbers will only provide limited improvement.  If this is the case with your rocker arms, it may be necessary to have the rubbing areas of the rocker arms lightly milled. There are some specialist Norton engine restorers who will sometimes perform this task, Email us at sales@racingvincent.co.uk if you think want more information on this.

Update Autumn 2019:  New batch of cork washers just manufactured.  Apologies for price rise, but I am told that the price of cork has risen considerably since our last batch were made

47 thou (1.2mm) thickness Stainless Steel Compression Plate. This really is a useful item andwill save you an awful lot of time with a fretsaw and file.  Used to amend compression ratio, fitted to base of barrel.

It is not uncommon to have to make these up when fitting new pistons and trying to get the engine to a particular compression ratio. These plates are laser cut from stainless steel (they do not deform or damage as easily as aluminium) and are 1.2mm/0.047 thou), which for a STD bore 79mm barrel equates to an approximate reduction in compression ratio of 1.2:1 per compression ring fitted.

Should you require it, Some years ago I created a utility for my own use availabe from our RacingVincent website to work out compression ratios and spacers required.  As always in the modern world - we take no responsibility for you using this, but if it helps, it can be found here: Compression Ratio Utility

Note: Do not forget that when fitting or removing compression plates, it is necessary to check the clearances on the vertical shaft assembly, and if necessary fit a different width top Oldham Coupling. Should you need to change couplings - we also sell these in different thicknesses - see our SOHC Vertical Coupling Section.

Final point - always check the oil holes on your barrel match up with holes on the compression plate - as there were some variations over the years. If so - just open holes up to match with a small file

These can also be used on the base of most OHV Norton Model 18 and ES2 Barrels, if wanting to change compression ratio - but again, check oil holes match up, as they can also be different