SSSS headstamp

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Coolhands

Coolhands

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Good news or bad news? I was expecting a “C” under the head steady but mine is stamped “SSSS”.

The search told me this was related to cam profile? 1972 with 11000 miles. Any ideas?

TIA!
 

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I have never seen a head with this. Sometimes someone that has worked on it will stamp something with meaning only to them. Combat heads are pretty easy to identify by the much narrower distance between top cylinder fin and bottom head fin.
 
Found this under 1972 on the Norton Owners Club:

“There was also a new high lift camshaft, known as the SS. Norton distinguished later even faster ones though by calling them SSS and SSSS, Triple S and Four S, or 3S and 4S, but these were never fitted to a production road engine, except perhaps the Production Racers.”
 
Just looked at your photo. Looks like the original mark was ground off for what ever reason. Makes me wonder what modifications to the head have been done.
 
Looks like a private stamping with someone relating that it has or at least had a 4S cam.
My limited understanding on a 4S cam is it needs more lash/clearance. .012" ??
Someone else could confirm. You can check the exisitng lash to see where it's at.

The head may or may not be modified.
 
Coolhands said:
Found this under 1972 on the Norton Owners Club:

“There was also a new high lift camshaft, known as the SS. Norton distinguished later even faster ones though by calling them SSS and SSSS, Triple S and Four S, or 3S and 4S, but these were never fitted to a production road engine, except perhaps the Production Racers.”
Click to expand...

Why would someone stamp the head with identification for a cam shaft? A head can easily be fitted on an engine with different cam, or the cam changed out of the engine it came off of.
 
I can think of all kinds of things to do to a cylinder head based on cam profile. Just don’t know if that’s a thing with Commandos.

Runs like a scalded dog so I’m not going to worry too much about it.
 
MichaelB said:
Looks like a private stamping with someone relating that it has or at least had a 4S cam.
My limited understanding on a 4S cam is it needs more lash/clearance. .012" ??
Someone else could confirm. You can check the exisitng lash to see where it's at.

The head may or may not be modified.
Click to expand...
My understanding is .016 gives best power, .010/.012 gives quietest running for road use.
 
Norton didn't stamp it with those little S's. Never know what cam is in that motor until you pull the motor apart. With the carburetion off you might be able to see/tell if it has had some port work done on it. It's somebody's personal mark, and a mystery.

My gut feeling is (based on your video) that motor idles too well to have much of a cam in it, but I don't know Nortons that well having only owned 2. Maybe they idle nice with a 4S.
 
Schwany said:
Never know what cam is in that motor until you pull the motor apart.
Click to expand...
You can have a good idea by taking the rocker covers off, putting a degree disc on the crank on the primary side, removing the spark plugs and measuring the lift at the valves at various crank positions. You will also need the rocker ratio which will be 1.1:1 or thereabouts to calculate the lift of the cam. Then compare to the various cams available.
 
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