This item is for a pair of 2 original Norton New Old Stock (NOS) 1948 to 1956 type OHV or Side Valve timing cover phospher bronze camshaft bearings.
These original Norton camshaft bearing came from one of our older customers who remembers buying them from an old dealership many years ago - he thinks in the 1960's! I have sorted them into complete sets and checked dimensions to ensure there is a matching set of 4 bearings in each set - the two bearings that fit into the crankcase are the same - so there are two of those, but the two that fit into the inner timing cover are each different and packed in a seperate bag.
As well as having enough bearings in the old stock to make up full sets of 4 bearings (see Item 0937) - there were also a number of additional outer timing case bearings. Ideally, if replacing camshaft bearings, it is better to replace all 4 bearings - but if you do not wish to strip the whole engine (which is required to fit and ream the crankcase bearings), and if your original timing cover bearings look worn (often it is the thrust face on the timing cover bearings that looks badly worn - leading to excess fore and aft movement of the cams in the timing case) - then just replacing these timing cover camshaft bearings will still be beneficial.
These camshaft bearings are in good unused condition, and have the correct oil scrolls - they just have slight surface corrosion from having sat in a drawer for many years - but are still just as usable as when first made.
It is worth noting that the 1948/56 OHV/SV camshaft diameter was 0.625", but these bearings are machined approximately 10 thousandth of an inch undersize. Therefore when you try them loose - you will find they will not fit onto the cam shafts. This was clearly a purposeful feature of the Norton spare parts department - the idea being that the bearings are pressed into the crankcase/timing cover first, then should be final reamered with a 0.625" reamer once fitted - ensure they are the correct bearing tolerance after pressing. Please take this into account when purchasing these bearings - they will need to be final reamered once pressed in, but this is how Norton's intended them to be fitted.
Additionally - ensure you check the original crankcase and bearing oil drain holes - dependent on year, there is sometimes a hole drilled into at least one of the camshaft bearings after fitting to feed oil - this to can only be done once the new bearings are fitted, and ideally should be done just before reamering.
I only have a few sets of these original Norton bearings . . . so if your own camshaft bearings are worn (and often it is the side thrust area of these bearings which wear worst), this is a great opportunity to fit original 1950's Norton items!.
ps- if you own a 1938/47 OHV/SV engine - I cannot guarantee these bearings will fit that earlier model so cannot recommend them for that model, I have only measured dimensions against original 48-56 type engines (although I believe the 57-59 camshaft bearings were also the same as 48-56 engines).
Removal of old camshaft bearings from the timing case: Obviously, removing crankcase camshaft bearings and the inlet timing cover camshaft bearing is relatively simple - as a drift can be used to tap them out from the non-lipped side. However, removal of the bearing from the blind hole in the timing case is much more difficult. There is no easy and safe way of doing this (that I know) without using a special tool. However, one way to do this is to obtain some kind of expanding pin that can be placed into the old timing case cam bearing, then tightened so that the expanding pin tightens against the bore of the bearing. Then the timing cover can be placed in an oven to heat the alloy and a puller then used on the expanding pin to pull out the old bearing out, when hot (you may find that some building suppliers can provide suitable wall fixing bolts with expanding steel rawplugs which are usable for this job with some fettling)
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