This item is for a set of Cylinder Head Sleeve Nut Washers, of the thicker (1/4" depth) type fitted to most SOHC (and pre-Featherbed DOHC) Alloy and Bi-Metal cylinder heads (both International and Manx models).
These are CNC manufactured to fine tolerance and in stainless steel. Price is for matched set of 4 sleeve bolt washers.
Background and Fitting Information:
These Sleeve Nut Washers are listed in the 1948 Spare Parts Catalog as Norton Part Number 1015, and were shown fitted to both International (Mod30 and Mod40) and Manx models - and are of the thicker variety, being 1/4" in depth. However, these were normally only fitted on aluminium or bi-metal (i.e. aluminium with a bronze skull) cylinder heads - and were designed to fit into a bored out recess in the cylinder head vertical stud bores, to provide a hard and level surface for which the Sleeve bolts tighten down onto.
Although not immediately obvious - earlier SOHC Cast Iron cylinder heads were normally fitted with thinner (1/8" depth) sleeve nut washers in the same location, which we also offer - Item 1016.
If you are replacing the sleeve nut washers on an existing engine (which is often because originals become chewed over time) - then it is worth checking what thickness your original washers were - as previous owners may have changed the thickness of your washers and amending this depth will also affect your cambox height and therefore the oldham coupling thickness required.
It is very important that when fitting these washers, that a 'matched' set are used - i.e. they must all be the same thickness. Likewise, your sleevebolts should all be of the same batch and length - as the cambox is placed on top of these 4 supports, and if any of the 4 pillars are of a different length, it risks breaking the rear legs off the cambox casting (the worst issue to have with this engine design).
We CNC manufacture these Sleevebolt Washers to the standard Norton depth, but also ensure they are checked with a micrometer as a matched set of 4 before packing - they should all be within 1 - 2 thou tolerance of each other.
Final point on fitting. I have seen alloy or bi-metal cylinder heads where these spacers will (just) slide in and out, or other cylinder heads where the sleeve bolt wasehers are captive. We have machined them to the standard width - and as can be seen in the photographs - have been fitted to an original Manx Norton cylinder head from the late 1940's . . . where they slid in.
If you find when fitting these to your own cylinder head - they are a tight fit in, you can decide if you want to warm the head up and use a drift to push them in (ensuring they seat properly at the bottom of the recess) - in which case they will be held captive once the head has cooled, or linish the outside of the spacer washers (possibly with a flap wheel on an electric drill) - so they will fit in without heating (but may annoyingly drop out each time you remove the head to work on it!). Once fitted, you should double check they have all seated properly, by laying the cylinder head down on a flat surface, and using s a depth gauge to ensure each sleeve nut washer is the same height from the base of the cylinder head. If they are a tight fit on your head - you must satisfy yourself the tolerances are acceptable before pressing them in - as cylinder heads were made for many years, and tolerances could vary slightly from one head to another.
In the accompanying photographs is also a picture of an original pre-war Racing International (pre-war Manx) bi-metal cylinder head, and this particular cylinder head still has its original sleeve bolt washers held captive in-situ - so they may have originally been pressed in by the factory (and our spacers have the same dimensions)
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