This is a complete crankcase and timing chest cheesehead screw set for 1930's to 1947 type OHV and Side Valve Norton single cylinder models - i.e. Model 18, ES2, Mod 19, 16H and Big 4. It consists of full timing case inner and outer cheeseheads, Inner timing case countersink screws and crankcase sump cheesehead screw - all of these being CNC bar-turned in stainless steel to the original period Norton dimensions and head pattern. See detail listing for more information.
As you can see from the photographs, this cheeseheaad set is shown fitted in the photographs to a 1938 OHV Model 18 engine, but the timing case and crankcase screws are the same for the corresponding Side Valve (SV) crankcase.
This particular model of crankcase was used on both OHV and SV models between 1937 and 1947, and we have faithfully replicated all cheesehead and countersink screw dimensions from that type of engine. However, the earlier design of OHV and SV crankcase (late 1930-37) is also very similar to this type, sharing the same main timing cover cheeshead screws, crankcase screw and countersunk screws - but the earlier design of OHV and SV design only used two cheesehead screws for the outer magneto chain cover, while this design used 3 screws.
Please email us on firstname.lastname@example.org if you require the similar cheesehead set for the earlier 30-37 design, we may be able to make that set up as well.
This set consists for following:
7 x Main timing chest cover screws
2 x Countersunk screws that fit into the magneto chain cavity (also available seperately as Item 1004)
3 x Outer magneto chain cover screws: 2 x long ones (into main cover) 1 x short (top left)
1 x Very long crankcase sump screw
12 x High quality red fibre washers to fit behind cheesehead screws (11 screws + 1 spare washer1)
All screws are bar turned stainless steel which we CNC manufacture in-house. For every screw, dimensions are faithfully replicated from original screws. We also ensure the cheesehead head pattern is faithfully replicated from the original Norton screw, and these are actually slightly wider diameter heads than most commerically available 1/4" diameter cheesehead and allen screws.
The set also includes 12 high quality red fibre washers (we always include an extra fibre washer - in case you lose one under the bench!).
Sorry, not as cheap as some of the mass produced type available – but these are CNC turned from stainless steel bar with milled head slots to the original dimensions in small batches.
Final assembly points:
All engine timing covers and rockerbox covers of this period were originally fitted with red fibre washers behind them, which often get omitted. We recommend always fitting these and supply a high quality example (which are much better quality than most commercially available).
This type of OHV and SV engine design also used countersunk screws in the magneto chain cavity - which normally get badly chewed on original examples. If you look closely at original timing covers, you will find that these screws were normally stopped from coming loose by centre punching the surrounding aluminium cover, alongside the scredriver slot. We will leave it to customers to decide on the best way to secure these screws - but the original method seems to work well, and in modern times there is also stud lock fluid available.
Final point: We sell this as a separate set - but for OHV engines, we also sell a corresponding Rockerbox Cheeshead Set (Item 1001). Those two sets bought together provide a full cheesehead set for OHV models. (they are sold separately as the crankcase set will fit both Overhead valve and sidevalve models).