This Flat Bottomed Rocker Adjuster and Tapered Locknut are to fit the first SOHC Walter Moore (i.e. Cricket Bat type) and 1930 - 1937 OHV Models. They were fitted to CS1 models from 1927-1930 (approximately) and OHV models from 1929 - 1937. This type of rocker adjuster were fitted to the rear rocker arms and acted directly on the valves. We have CNC manufactured this type using an original early 1930's Norton item as the pattern and includes the correct profile locknut, with tapered bottom face, the locknut being in stainless steel.
Price is for a single adjuster and locknut (i.e. 2 parts)
We have CNC manufactured this type of rocker adjuster using an original early 1930's Norton item as the pattern - and replicating all dimensions as per the original. They are made from case hardened EN32B, but like the Norton originals - the threads are 'painted off' before hardening, so the threads do not go brittle in the hardening process. The reverse end of the adjuster has a square head milled into it, for adjusting tappet clearance iwth a small spanner - again replicating the dimensions of the original Norton square. It should be noted that the thread of this type Rocker Adjusters (and the slightly earlier ball type adjusters we also offer - Item 1119) is actually 9/32" x 26tpi BSC thread - as per the original item.
As well as the actual hardened adjuster, we also include the correct profile locknut - which has a slight taper on one end - which should fit into the original Norton OHV Rocker recess. The other end has a minimum chamfer. This locknut is copied from an original period Item - but unlike the original, ours are CNC manufactured from stainless steel - to prevent rusting. It should be noted that on the original 1930's nut that we copied (which was still fitted to a flat bottomed adjuster) - we noted that the depth of this nut was fractionally deeper than the original 1920's nut fitted to the earlier 'Ball type' rocker adjuster (Item 1119) - but the difference is minimal, and I suspect either type could be used for either application.
Each Rocker Adjuster and Locknut is supplied assembled with high melting point grease applied - to prevent corrosion in storage.
Price is for a single adjuster and locknut (i.e. 2 parts) - Therefore 2 of these are required per engine.
Backgound:
This flat bottomed rocker adjuster is of the type that looks to have been fitted to most OHV models and also early SOHC models from approximately 1927 (in the case of Walter Moore CS1 Models) through to 1937 OHV motors.
This specific design - which has a flat foot, slightly wider than the thread shaft, is pictured in the 1933-34 Norton Spare Parts Catalog - and given the Norton part number 9163 - and was shown there as an adjuster and locknut, as we offer here - i.e. 2 parts.
As well as having this flat foot, the other distinguishing feature of this type of adjuster s that the thread is 9/32" x 26tpi BSC. And finally, the other feature is having a 'square' top at the other end of the adjuster - to allow tappet clearance to be adjusted, once the tapered locknut is looesened.
The reason these features are important - is that there does seem to have been some variations on this adjuster offered - particularly on earlier Walter Moore CS1 and OHV models in the late 1920's - for example, I have also seen early examples that look to have a pad which is closer to the diameter of the shaft, and other examples that have a Hex pad, rather than a round pad - Which I assume was to make adjustment possible from the lower end.
Therefore please satisfy yourself before ordering that your model of Norton has the correct 9/32" x 26 tpi thread in the rocker - and that you are comfortable to use this design with the wider flat pad - which seems to have been standardised on all OHV models by 1933 at the latest.
Wtih regard to the use of this type of Rocker Adjuster on SOHC Engines: It is difficult to be distinct about Walter Moore CS1 development between 1927-30 (and I am definitely not an expert on this model) - but they were definitely fitted with the 9/32" x 26 tpi adjuster - although early examples may have had a slimmer hardened head than the type shown here -this type should be interchangeable, but please satisfy yourself before ordering us, or email us on sales@racingvincent.co.uk before ordering.
Having consulted with some early SOHC experts- I gather that occasionally worn CS1 rocker arms were drilled out to a larger thread to take later 5/16" SOHC Adjusters (see our SOHC Cambox section for standard 3 part SOHC tappet adjuster sets) - but before ordering these adjusters - please satisfy yourself that your CS1 (Walter Moore) rocker arms still have a 9/32" thread.
Likewise - the earliest Arthur Carroll SOHC cambox's - i.e. 1931-33 era also had differnces to later SOHC cambox's. I cannot be certain, as I do not have a complete earliest type Arthur Carroll cambox in my collection - but there is also a good indication that the early versions of this type of cambox may also have used this type of adjuster (early Arthur Carroll Camboxs are often identified by a more curved front bevel cover casting thant the standard later version).
With all of this background - the key thing to remember is: It is very difficult to be definitive about types and sizes, as so few engines are totally original . .. and a high mieage engine may have had its consumable parts replaced many times over the years - often using whatever parts are available at the time.
However, with all these 1930's engines - up to the introduction of the adjustable pushrod on 1938 onwards OHV engines - these 9/32" rocker pads are manufactured to an original and well tested Norton design - hence why it is important to note that the thread diameter is the most important point to note if you have a Norton single model from late '20's to 1937 where the tappet adjuster sits directly over the valve stem.
You can email us on sales@racingvincent.co.uk if you need more information or need to check
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