Now back to the camshafts. The opening and closing don't tell the whole story. It's what is between that is important and it can't be described in numbers.

The other number question is: The identification numbers (and colours) on the camshaft.

I have this mysterious one:
71981552 GNK 1599
lift: 7,3 m.m. 0,287 inc.
blue colour patches

Anyone who knows???

Firstly, if you had posted this in my thread I might have had a chance of seeing it as I'm watching the thread by email.
By opening a new topic you sidestepped this quite neatly and unecessarily.
Also I'd like to say that neither me or Chris are walking parts manuals.
Although you say you have a camshaft you divulge nothing else of any importance in the way of helping us to identify it.

Those numbers mean absolutely nothing to anyone except perhaps the company that made it.

Is it a Rootes camshaft ? Who knows or even cares ?
The only thing we can agree on is that going by the numbers on a camshaft mean absolutely nothing to how an engine performs and if you'd read the thread properly that is exactly my conclusion.
Yet if you go to buy a " hot " camshaft from any of the performance suppliers you will be bombarded by those self same numbers. Unfortunately a lot of people think that this will produce rocket like performance and go for the hottest grind they can get. Big, big mistake.
The end result is usually pathetic, after spending a king's ransom.
You just cannot treat this subject like cooking a meal. I'll have this and that and one of those, cos it's the biggest.

All I am trying to do is help people understand what those numbers mean.
What they won't tell you is how it will affect the way your engine runs.
Only your engine can tell you that.
But think about this. The car manufacturer usually get's it right because they have more R & D budget for testing than anybody else.
And the fastest Alpines I've ever driven have all had standard cams.
But of course you may know things I don't. I'm not the world expert, but I am willing to share my experiences with other members. If you can enlighten us please feel free to use this thread.

Best Regards Eddie

I apologies if I did open a new thread in Camshafts and Understanding the numbers. I thought that I was supposed to open a new thread in Camshafts and Understanding the numbers. if I had a camshaft question. Obviously I was wrong.

I did buy a box with Rootes parts and there where 3 unused camshaft in this "box". One standard Hunter, a Holbay, and this unidentified one that I first did mistaken as a Alpine one until I saw these numbers.
It looks like profiles between Holbay and Alpine.
The person who sold the parts was involved in Rootes-Chrysler in some way so it can be a one-off cam.

I don't expect anyone to know about any performance figures or whatever. I was just curious if someone did recognize the numbers.

Aha, a little more meat on the bones here, well it seems you may have a little rocking horse poo there, and the unidentified cam could possibly be the special Le Mans one. ( halfway between Holbay and Alpine would be about right )
The only way to be sure is to measure the Lobe centre angles and work out by degrees the inlet, exhaust and overlap durations.
We know this from McGovern's book.

If it is you have one hell of a good cam there and a good commercial opportunity to produce copies.
I'd be inclined to take it to Piper's and see what they make of it.
Let us know what occurs.

Best Regards Eddie

Just for fun I have investigated my pile of new camshafts!
The only thing I can measure is the lift, and it doesn't say much.
However, what can you do a rainy Saturday afternoon in the garage!

Camshaft lift. Alloy head engines:
1600 (twin-port Solex) 6,4 m.m.
Hunter 1725 6,7 m.m.
Holbay 8,0 m.m.
Harrington LeMans 1600 7,4 m.m.

unknown (for 5 bearing eng.) 7,4m.m.

If I look at the "unknown" cam lobes they look much like the LeMans lobes. But that is a very subjective impression, but an interesting thought!
I would like to imagine it has the LeMans profile because it's a nice camshaft.
Don't understand why they didn't put it in other cars.

Call it a gut feeling, or whatever you like but it looks like that unidentified cam is the Le Mans profile which was sadly never developed beyond there being something very similar, briefly available for the Factory stage 2 tuning kit.

This was the cam that helped Rootes win the coveted Index of Thermal Efficiency at the Le Mans 24 hour race in 1961. The cars reached speeds of 120 mph on the Mulsanne straight ( using the Twin Zeniths and the small 1494cc block no less ).
So I feel it must be a great profile for the bigger engines like the 1725.
Less cammy than the Holbay and probably quieter too.

Hope it gets put to good use one day.
Best Regards Eddie

Going from the lift that you have measured I would say you have a cam from one of the twin carb arrows 1725 engines. Either the 79 BHP .298" cam or the 82 BHP .295 lift cams, The .320 is the Holbay and the 5 series Holbay.
Pete

Info for the metric people

inc. to m.m.

0,298 = 7,57
0,295 = 7,49
0,320 = 8,1

The British has some "things" to take care of :
Change to metric (going to slow)
Change to "drive on the right side of the road" (right is right)
Change to Euro (and drop the Pound forever!)

The last is the hard part

If we outside UK help to take care of the british cars, you in UK can change the things I mentioned above.