Cam followers

Hello Peter. I have an old cam here marked "QR", probably the same one you have. This was the standard cam for 1959 and later Dominators. In one book I have it says it was used with radius lifters in 1959, and in 1960 Norton switched to flat tappets which made the valves open and close a bit more quickly for some added power.

This would be a hotter cam than your 54' came with, so of course when you are mixing and matching parts you will have to check everything carefully to make sure that nothing is binding up in the valve-train and the valves are clear of your pistons etc.. As long as the valves, springs, lifters, pushrods and rockers all have enough clearance throughout their range of movement I think you will be fine running whatever tappets you can get your hands on.

Norton did put the "Daytona" cam into production racing bikes at least as early as 1953, which was basically the same timing and lift as the "QR" cam minus the quietening ramps. But those Daytona Beach racers had pre-production aluminum heads, which may have had better clearance than the iron heads used on the early 88 production bikes, which again begs for a close inspection of running clearances when mixing parts at this late date when parts of various years might be all that is available to keep a bike running at a reasonable cost.....

According to Norton's Maintenance Manual P106/P (Page 60), dated around 1965, they fitted the Daytona cam to all Model 99s and to all 88s from 1956. They added QR on all 1959 and later models. Flat-based tappets were used with the same cam from 1960 on, as Benjamin says.

Interestingly they list the various piston options showing that the 99 didn't have 9:1 "high comp" pistons until 1960. Before then H/C was only 8.2:1. All academic of course, unless you have a bike with standard bores, as a rebore will change the compression ratio. (Something I mentioned on another thread about how to calculate your own bike's ACTUAL C/R.)

My 1959 Dommie was fitted with the Daytona QR camshaft with radiussedtappets ex-works so I would stick with that, especially on an older engine where you don't really want anything "hot"! Of course I AM just an old fuddy duddy! Not really though as I'm an old rock'n'roller and have been invited as aguest guitarist in a Punk Rock covers band! How does it go? "You're only as old as......".

I had my original radiussed tappets ground flat to go with an SS "X1" cam but may go back to a QR with those. A local engineering firm happily did the tappetsfor me as "the usual suspects" wouldn't do it! (They also did the rebore as Norman White recommended them to me) There is no problem with the case-hardened sections as they are now an equal thickness all the way across whereas their normal state on a radiussed tappet is thicker in the middle.

Cheers, Lionel