G80 CS cams - identification

g80csp11 · Post by **g80csp11** » Mon Dec 24, 2007 7:48 pm

How do you identify the correct cams for a 1961 G80CS
Roy Bacon book lists several over the years
6 inlets and 6 exhausts all fitted at different times for different applications

Other than the SH marking how can I tell the correct ones for a 61 CS running with monoblock carb

010837 Inlet and 010836 Exh (1951-1953)
012695 Inlet and 012694 Exh (1951-1953 option)
018833 Inlet and 018834 Exh (1953 Longstroke racing )
018833 Inlet and 018834 Exh (Long stroke)
018833 Inlet and 022567 Exh (Monoblock-Short stroke)
024534 Inlet and 022567 Exh (GP carb-Short stroke)
02191 Inlet and 02193 Exh (1962-1963)
030202 Inlet and 030205 Exh (1964 Norton pump)

I've found a pair that are marked SH but don't want to get the wrong ones , is there a differnce between dot and number timing marks etc.. I don't think they have part no on them do they ?
Obviously I can tell once they are fitted by checking the actual timing . but that's a bit late

The other option is to purchase new from the club or AMC classic , but Circ 170 pound

itma · Post by **itma** » Mon Dec 24, 2007 9:05 pm

SH cams are leary scrambles cams
And if they are early ones they will not fit your bike.
Do you have the Norton oil pump?Magneto or coil ignition?
The carb is irrelevant.

g80csp11 · Post by **g80csp11** » Mon Dec 24, 2007 9:13 pm

Magneto , and standard Matchless oil pump. Ideally I'd like to build to standard , but don't know how to tell the diffrent SH cams apart . The only reason I listed the GP carb option is thats what AMC classic list it for in their spares list . I guess extended period ?

Don Madden · Post by **Don Madden** » Mon Dec 24, 2007 9:18 pm

Forget Bacon when it comes to specific equipment, & use the spares lists. Short stroke cramblers were not fitted with touring cams.

SH cams were used on short stroke scramblers, (16CS, 18CS, G3LCS, G80CS) from 1956 through 1963, pre-Norton gear pump. They will not fit 64-up.

From 1960 to 1963 CI, (Cooper Inlet), & CE, (Cooper Exhaust), were also used. The SH & Cooper cams were often mixed to provide the power required for different use, with SH/SH giving the widest power band, & CI/CE the greatest output with noticible loss of low end.

CI inlet with SH exhaust was popular in our deserts for good power with little loss of low end grunt.

Merry Christmas! Don. Edited by - Don Madden on 24 Dec 2007 9:23:09 PM

itma · Post by **itma** » Mon Dec 24, 2007 9:23 pm

As far as I know all the SH cams were the same for the early stuff pre norton pump.
The norton pump ones had bigger wheels and differences on the shafts [memory getting feeble here]
Unless you are building it as a scrambles machine I'd say that the SH cams will be wasted.
They make a lovely racket, but unless matched to carb, compression, etc they do not make a great deal of difference.
The can also be mixed, say for instanceSH inlet and a std type on exh.
There are others here better informed on that than me.
You may have to wait till all the bottles are empty for a reply on that.

g80csp11 · Post by **g80csp11** » Mon Dec 24, 2007 9:26 pm

So , If I have SH cams avaialble for both inlet and exhaust they should fit and run OK . I was worried that I didn't want to buy cams and find them unsuitable for the bike

thanks for your input

Don Madden · Post by **Don Madden** » Mon Dec 24, 2007 11:38 pm

I have experamented with the various combinations in my 1956 & 1960 scramblers. As I am not a professional racer, & at age 73 do not want to be a wild kid anymore, I find the SH/SH combination my favorite. Good, but not race winning power & a tractable engine.

I have combined them with touring ratios in the gearbox & tallish final drive to give a useful machine on easy to medium off-road, unpaved & paved roads.

Merry Christmas! Don.