SS cam

I realise this, and the content of my last thread re: oil pickup mod has been covered but I am struggling with the search function these days, whilst searching for the oil mod info, I found a post by Grandpaul that looked like it would have a load of pics for the mod, but all the links were broken, there are a lot of broken links just now. Also a search for SS cam replacement states that as SS and cam are common words they have been omitted. Anyway that is the reason for asking questions that have probably been answered before.

What would be a good replacement for a SS cam, ideally another SS cam would be good but are there any proven new ones out there? I have read about soft cams and followers.

It is for the Combat motor we have recently pulled apart and one of the lobes has a small amount of wear and once started I guess the wear could accelerate so I feel it need addressing now.

I see RGM offer a Stellite build and regrind service, has anybody had this done? and would this be a better option for known quality?

Thanks

Speak to Jim Comstock. He supplied me with a Webcam 312b (I think). Excellent torque and power.

If you’re keeping the Combat as a Combat, then I’d keep the Combat cam.

If you’re planning on castrating the poor beast with low compression, single carb, vase of daisies on the handle bars, etc, then fit a softer cam. Ok, tongue in check a bit there, but IMHO Combats are Combats, and I think de-tuning one is a shame, and if that’s what you want, don’t buy a Combat (I feel the same when folk put B33 pistons and cams into Gold Star’s FFS) !

Have you seen this site, great for cross referencing: http://atlanticgreen.com/camsurvey.htm

Megacycle do a SS cam, the 560-SS. And a tweaked version, the 560-20 SSS, see page 15 here: https://www.megacyclecams.com/catalog/catalog_optimized.pdf

Then there’s the Maney cam, not quite a 2S but close, and well proven, and would work well in a Combat I think.

Ref RGM welding service, I’m aware of the dissimilar metals argument against welded up cams (stelite on stelite) but perhaps they are different types / grades of stelite? I don’t understand the metallurgy fully, but I know I used to run welded up cams all the time in Triumphs and Nourish engines just fine.

On balance, if the cam you have is otherwise good (journals etc) then I’d definitely consider using it as a donor for hard welding.

storm42 said:

I realise this, and the content of my last thread re: oil pickup mod has been covered but I am struggling with the search function these days, whilst searching for the oil mod info, I found a post by Grandpaul that looked like it would have a load of pics for the mod, but all the links were broken, there are a lot of broken links just now. Also a search for SS cam replacement states that as SS and cam are common words they have been omitted. Anyway that is the reason for asking questions that have probably been answered before.

What would be a good replacement for a SS cam, ideally another SS cam would be good but are there any proven new ones out there? I have read about soft cams and followers.

It is for the Combat motor we have recently pulled apart and one of the lobes has a small amount of wear and once started I guess the wear could accelerate so I feel it need addressing now.

I see RGM offer a Stellite build and regrind service, has anybody had this done? and would this be a better option for known quality?

Thanks

Click to expand...

Yes! fitted it ages ago after a new chilled white iron Norvil cam cracked (DynoDave will remember when) and I needed a quick cheap fix. It's still in the motor no wear at all and working fine.
Dave

Webcam 312a is what I fit into my hotter street motor, and love it.

Check out this thread - there are many 2s references scattered throughout.


BTW - it is the followers you have to watch are soft.

The unfortunate fact is that the sloppiness of language is more infectious then C-19.
SS cam is for NHT from 1961-1970 twin chain engines, stopping with 20M3 commando.
1S cam is identical profile as SS, but the core is for single chain NHT engines 20M3S+.
2S cam is originally for the 200000 Series NHT combat, which again is for a single chain engine.

seperate issue:

cash said:

Yes! fitted it ages ago after a new chilled white iron Norvil cam cracked (DynoDave will remember when) and I needed a quick cheap fix

Click to expand...

Highly confused about the truth of this statement. The cam I was involved with was new chilled iron 1S from AN maybe BSA Regal/pre Seifert

AFAIK Les Emery "norvil" only sells "steel" cams. Iron cams, if from "norvil", it is unknown by me.

+1 on the Webcam 312 (a or b), bonus is that you can order a set of Jim's new lifters to go along with it

Fullauto said:

Speak to Jim Comstock. He supplied me with a Webcam 312b (I think). Excellent torque and power.

Click to expand...

I have read through the thread that gortnipper has linked to and I would agree that looks a good choice. The owner has sourced a cam from RGM though, thanks for the advice.

Fast Eddie said:

If you’re keeping the Combat as a Combat, then I’d keep the Combat cam.

If you’re planning on castrating the poor beast with low compression, single carb, vase of daisies on the handle bars, etc, then fit a softer cam. Ok, tongue in check a bit there, but IMHO Combats are Combats, and I think de-tuning one is a shame, and if that’s what you want, don’t buy a Combat (I feel the same when folk put B33 pistons and cams into Gold Star’s FFS) !

Have you seen this site, great for cross referencing: http://atlanticgreen.com/camsurvey.htm

Megacycle do a SS cam, the 560-SS. And a tweaked version, the 560-20 SSS, see page 15 here: https://www.megacyclecams.com/catalog/catalog_optimized.pdf

Then there’s the Maney cam, not quite a 2S but close, and well proven, and would work well in a Combat I think.

Ref RGM welding service, I’m aware of the dissimilar metals argument against welded up cams (stelite on stelite) but perhaps they are different types / grades of stelite? I don’t understand the metallurgy fully, but I know used to run welded up cams all the time in Triumphs and Nourish engines just fine.

On balance, if the cam you have is otherwise good (journals etc) then I’d definitely consider using it as a donor for hard welding.

Click to expand...

Thanks Nigel, The original cam may be sent for welding and put on the shelf. Pete has sourced another from RGM so we can get it back together quicker. (you met Pete at Mallory, we came across to look at your bike.)
Agree with you about keeping it a Combat as well, would be a shame to cut it's balls off.

cash said:

Yes! fitted it ages ago after a new chilled white iron Norvil cam cracked (DynoDave will remember when) and I needed a quick cheap fix. It's still in the motor no wear at all and working fine.
Dave

Click to expand...

Good to know, I have a cam that will be sent for welding now, thanks.

gortnipper said:

Webcam 312a is what I fit into my hotter street motor, and love it.

Check out this thread - there are many 2s references scattered throughout.

Cams (2012)

Here is some of the more popular cam graphs I have compiled. First is the PW3 vs Js2 , they are nearly the same. The pw3 has a little more lift and the js2 has a little more overlap. I would expect similar performance. Next is the Norris D+ vs the Megacycle 560N480 Here is the Megacycle...

www.accessnorton.com

BTW - it is the followers you have to watch are soft.

Cam and follower tests.

I have been experimenting with alternative cam followers for my engine. Here is some cuts from the spintron testing. Over the past 2 days the hardweld followers have ~ 16 hours of runtime.

www.accessnorton.com

Cam followers - Andover to the rescue?

This just popped into my inbox, kudos to Andover for the investment in time and research: "With metallurgists on both sides of the Atlantic looking at this, a new material was formulated that would allow casting but was a little under the required hardness we needed. This was spotted by the...

www.accessnorton.com

Click to expand...

Thanks for those links, very useful, just the sort of info I was searching for and failed, thanks.

dynodave said:

The unfortunate fact is that the sloppiness of language is more infectious then C-19.
SS cam is for NHT from 1961-1970 twin chain engines, stopping with 20M3 commando.
1S cam is identical profile as SS, but the core is for single chain NHT engines 20M3S+.
2S cam is originally for the 200000 Series NHT combat, which again is for a single chain engine.

seperate issue:


Highly confused about the truth of this statement. The cam I was involved with was new chilled iron 1S from AN maybe BSA Regal/pre Seifert

AFAIK Les Emery "norvil" only sells "steel" cams. Iron cams, if from "norvil", it is unknown by me.

Click to expand...

I guess it didn't matter to the factory back in the day, but the way the cams are marked up does seem a bit confusing without a good deal of background knowledge.

The cam has SS on the shaft and is out of a freshly rebuilt 200000 series Combat motor, but we are not sure what the previous owner has changed in there, hence the question about sourcing a known quality cam, preferably a Combat one.
The cam is in very good condition and could have been new, apart from one lobe (drive side exhaust) which has a slight lip round the edge of the lobe which looks like wear, could it be a lip left by a poor grinder? The followers look new with no visible wear and the owner thinks the engine has probably only done 100 miles, if that, from the rebuild.

The Webcams recommended by others look a good alternative but it would be a shame to not build the motor as it was intended, possibly.

storm42 said:

I guess it didn't matter to the factory back in the day, but the way the cams are marked up does seem a bit confusing without a good deal of background knowledge.

The cam has SS on the shaft and is out of a freshly rebuilt 200000 series Combat motor, but we are not sure what the previous owner has changed in there, hence the question about sourcing a known quality cam, preferably a Combat one.
The cam is in very good condition and could have been new, apart from one lobe (drive side exhaust) which has a slight lip round the edge of the lobe which looks like wear, could it be a lip left by a poor grinder? The followers look new with no visible wear and the owner thinks the engine has probably only done 100 miles, if that, from the rebuild.

The Webcams recommended by others look a good alternative but it would be a shame to not build the motor as it was intended, possibly.

Click to expand...

I'd agree about the lack of clarity and consistency of cam identification . I do a slightly more complete description on my cam page in my library.
http://atlanticgreen.com/camsurvey.htm
However with some that lack of general NHT evolution knowledge , items like twin chain VS later single chain or dynamo VS alternator engines, the distinctions are lost.
My combat cam at 9000 miles was bent, probably from the defective spring perches that forced coil bind on the intakes. I bought a new replacement from Norton/Shenstone in about 1988. Back then even Les Emery(norvil) was getting them from norton. There seemed to still be plenty NOS factory 2S cams
Granted there are cam profiles galore like in a candy store to chose from. I'm glad to own one as a combat out of all my other nortons.
good luck

The Superbike shootout 12.69 sec 1/4 mile was done with the standard profile cam in a standard pre- combat 750.
Did any Combat ever go this quickly thru the 1/4?
Maybe they did, I just haven't found any Combat tests that equalled that time.
Norman White went faster, but I believe that was also with a standard 1s or SS profile.


Glen

worntorn said:

The Superbike shootout 12.69 sec 1/4 mile was done with the standard profile cam in a standard pre- combat 750.
Did any Combat ever go this quickly thru the 1/4?
Maybe they did, I just haven't found any Combat tests that equalled that time.
Norman White went faster, but I believe that was also with a standard 1s or SS profile.


Glen

Click to expand...

Yes combats did a bit faster helped by the lower gearing 19T counter sprocket. Do you know the terminal speed of the 12.69 sec run?

I'll look it up. Like all serious Commando owners I paid way too much on eBay for a tattered March 1970 Cycle mag.
Also have the Commando gold portfolio of period road tests, will have another look at pre Combat and Combat acceleration results.
I guess the standard 750 lacks a top endpowerband such as the Combat has but more or less makes up for it with extra oomph in the midrange.

Glen

103.68 mph achieved with the Cycle March 1970 test.
I checked the Commando Gold portfolio. There are 3 Combat 1/4 mile tests done, all low 13 s
Same for most regular 750.
There are a couple of high 12 second 850 tests and then the one 12.69.
I think some of that was Cook Nielson, who had the knack.
Norton did beat the other six tho.
So stock cam profile or extra bumpy, it probably doesn't change overall acceleration much.



Glen

dynodave said:

I'd agree about the lack of clarity and consistency of cam identification . I do a slightly more complete description on my cam page in my library.
http://atlanticgreen.com/camsurvey.htm
However with some that lack of general NHT evolution knowledge , items like twin chain VS later single chain or dynamo VS alternator engines, the distinctions are lost.
My combat cam at 9000 miles was bent, probably from the defective spring perches that forced coil bind on the intakes. I bought a new replacement from Norton/Shenstone in about 1988. Back then even Les Emery(norvil) was getting them from norton. There seemed to still be plenty NOS factory 2S cams
Granted there are cam profiles galore like in a candy store to chose from. I'm glad to own one as a combat out of all my other nortons.
good luck

Click to expand...

Dave's info (here and on his website) is spot-on correct. John Hudson sat me down the week that my Combat Commando was delivered at Andover and talked me through the entire history. In his description, the original (early 60s) "SS" cam was the Sports Special racing cam especially developed for the Domi/Manxman 650 twin carb engine. That grind was the standard Atlas grind (at least, I'm sure it was the standard Atlas grind for the US "export" models, I think, but not certain, for all). It was carried over (the cam profile grind - not the part number) to the 20M3 and 20M3S engines on the Commando and became called the "standard Commando cam". The "Combat" cam had a different grind profile and was designated by being stamped with "SS". I think that the Combat cams could be used on rebuild on any Commando from the 20M3S engine (early 1969) - the "strengthened 750 cases" and then 850 cases and finally MkIII crankcases at "The End".
He was a strong believer in that early cam, both from the power delivery standpoint and what he considered the harshness that the "SS/Combat" supplied to the valve train, leading to early wear and impact-load damage.
When John Baker and I were building up my 850 engine, I remembered that and again asked John H for his opinion. He gave me an earful (*surprise*!!! to all who knew John) about that standard cam being an excellent cam - it's mid-range strong power characteristics matching the larger-bore 850 engine's inherent torque - and he recommended it highly even for a motor intended for production racing. We fitted it to my engine (which may have been John Baker's first hopped-up 850) and it has proven to be an excellent cam, giving great acceleration and good topend speeds (racing) due to the strong "drive" out of corners onto a straightaway.
As Dave says about the candy store of Commando cams, most with updated, computer-derived valve opening take up and lifting angles which are way more gentle on valve trains than 50 or more year old cams, being available -- there are lots of choices out there now.
I loved my 750 Combat motor. I had never seen anything like the rush from the top end of that motor but I suspect that John H was correct about the "standard" cam for the 850. I know that John Baker continued to use the std cam for many of his 850 hop-up builds before he went on to the wild tuning on the Dave Rawlings bikes in 1974 and 75.

(Be careful about part numbers, single vs. dual timing chains, cam bush scrolling variations, tach drive, etc.)

worntorn said:

103.68 mph achieved with the Cycle March 1970 test.
I checked the Commando Gold portfolio. There are 3 Combat 1/4 mile tests done, all low 13 s
Same for most regular 750.
There are a couple of high 12 second 850 tests and then the one 12.69.
I think some of that was Cook Nielson, who had the knack.
Norton did beat the other six tho.
So stock cam profile or extra bumpy, it probably doesn't change overall acceleration much.



Glen

Click to expand...

Only way to know is put an as supplied combat up against the same for an 850 at the 1/4 mile night run what you got.

True. You would think that would have occurred and be recorded some where by now!

Glen