24 replies to this topic

[Cooperman]

What you need to do is to determine to what use your car will be used and how you will wish to drive it.

What sort of RPM's do you want to be using? Do you intend to use, for example, 6500 rpm on a regular basis? Or will you want to drive around the public roads, as most of us do, at between 3000 and 4500 rpm? What sort of rpm's would you like to be running at when cruising at 70 mph?

Once you have defined your driving profile you can note where you need your best torque and best power.

From there look at the cam graphs for all the cams you might wish to consider. The graphs give the best torque and power bands and then you can select the cam which best meets your needs.

No-one on here can say this cam, or that cam, is what you want because they will have different expectations from you. That is why engine builders use cam graphs after talking with their customers and agreeing where the best torque and power should happen.

The one thing you really don't want is anything over between 95 to 100 bhp for a road car. What you do want is the very best torque at between 3500 and 4700 rpm. That make for a really brisk road car with nice manners.

May I mention also that no cam will work well unless the engine also has a very well gas-flowed head, the right comp ratio, good induction & ex. system and a properly curved distributor..

One point is that whilst 1.5:1 rockers may give a couple more bhp, they tend to raise the rev range and take away some bottom end torque.

My suggestion is to look at the graphs for the Kent 266. the Evo001, and the SW5. You should find that one of these will meet your requirements, once you have arrived at a requirement to suit yourself.

[Reidbook]

What you need to do is to determine to what use your car will be used and how you will wish to drive it.
What sort of RPM's do you want to be using? Do you intend to use, for example, 6500 rpm on a regular basis? Or will you want to drive around the public roads, as most of us do, at between 3000 and 4500 rpm? What sort of rpm's would you like to be running at when cruising at 70 mph?
Once you have defined your driving profile you can note where you need your best torque and best power.
From there look at the cam graphs for all the cams you might wish to consider. The graphs give the best torque and power bands and then you can select the cam which best meets your needs.
No-one on here can say this cam, or that cam, is what you want because they will have different expectations from you. That is why engine builders use cam graphs after talking with their customers and agreeing where the best torque and power should happen.
The one thing you really don't want is anything over between 95 to 100 bhp for a road car. What you do want is the very best torque at between 3500 and 4700 rpm. That make for a really brisk road car with nice manners.
May I mention also that no cam will work well unless the engine also has a very well gas-flowed head, the right comp ratio, good induction & ex. system and a properly curved distributor..
One point is that whilst 1.5:1 rockers may give a couple more bhp, they tend to raise the rev range and take away some bottom end torque.
My suggestion is to look at the graphs for the Kent 266. the Evo001, and the SW5. You should find that one of these will meet your requirements, once you have arrived at a requirement to suit yourself.

Wouldn’t want to be doing high revs now that I think about it so 3500 - 4000 is fine.

[OzOAP]

Road car - Piper 255
Rally/Race Car- 649

I have never found anything inbetween worth using.

[DeadSquare]

I am disappointed that if you write "classic Mini" in Piper's 'cam finder', it comes up with bini cams.

[Cooperman]

I have used a Kent 286 in my historic FIA Gp 2 rally S for many years and consider it better than the 649's which I have previously used. With the SCCR gearbox and 3.9:1 fdr it is ideal so long as the revs are kept between 5000 and 7000 when being driven on a special stage.
I would certainly never consider a 286 in a road car - it would be horrible.

[fluffy23]

I have a 1293 with 649 and SU HIF44 or Weber45 and I just love this cam!!!

It's a bit rough at low RPM and starts to pull good at 3000 and up to 6000 (and it sounds fantastic at 6000).

 

With 3,44 diff you have a perfect cruising speed even outside town (around 100km/h (65mph) @ 4000).

 

You may not win at red lights race, but it soo fun to drive!
(SW5 is too linear for my taste, otherwise it is surely a good buy)

[Cooperman]

With a 649 if you only use 6000 rpm you are not getting the best from it. You need to rev to 7000 rpm with a 649 as peak power is at about 6500 rpm.

Of course, it will pull smoothly from 3000 rpm, but a softer cam will give better power and, more importantly, torque at 3000.

 

It seems as though you are 'over-cammed' for your application and a Kent 266 or 276 would work better for you if you don't want to be using much over 6000 rpm and like to cruise at c.4000 rpm. The 649 really is a very high-revving full race cam. We don't even use them much in rally cars, except for full-on tarmac spec cars.

[fluffy23]

With a 649 if you only use 6000 rpm you are not getting the best from it. You need to rev to 7000 rpm with a 649 as peak power is at about 6500 rpm.

Of course, it will pull smoothly from 3000 rpm, but a softer cam will give better power and, more importantly, torque at 3000.

 

It seems as though you are 'over-cammed' for your application and a Kent 266 or 276 would work better for you if you don't want to be using much over 6000 rpm and like to cruise at c.4000 rpm. The 649 really is a very high-revving full race cam. We don't even use them much in rally cars, except for full-on tarmac spec cars.

 

 

 

My post was mostly to tell that 649 is not totally useless outside racetrack  (unless you are going to tow a caravan).

And you are right, it does not fit everyone. But I like it just as it is. 

In my other mini, which is more standard, I run with 276 and it does not have at all the character that 649 has and which makes me so happy.

 

And in my setup the 649 peaks about 6000. 

 rollingroad.jpg   56.47K   5 downloads

 

Many cams have one for me for the linear power curve which can be practical, but not so fun to drive and then I can take a practical car as well = maybe not a mini.

But it's the best thing about our cars, we all to find our own style and things that we like. 

Lets hope Reidbook finds one that suits his needs =)

[Spider]

 

With a 649 if you only use 6000 rpm you are not getting the best from it. You need to rev to 7000 rpm with a 649 as peak power is at about 6500 rpm.

Of course, it will pull smoothly from 3000 rpm, but a softer cam will give better power and, more importantly, torque at 3000.

 

It seems as though you are 'over-cammed' for your application and a Kent 266 or 276 would work better for you if you don't want to be using much over 6000 rpm and like to cruise at c.4000 rpm. The 649 really is a very high-revving full race cam. We don't even use them much in rally cars, except for full-on tarmac spec cars.

 

 

 

My post was mostly to tell that 649 is not totally useless outside racetrack  (unless you are going to tow a caravan).

And you are right, it does not fit everyone. But I like it just as it is. 

In my other mini, which is more standard, I run with 276 and it does not have at all the character that 649 has and which makes me so happy.

 

And in my setup the 649 peaks about 6000. 

rollingroad.jpg

 

Many cams have one for me for the linear power curve which can be practical, but not so fun to drive and then I can take a practical car as well = maybe not a mini.

But it's the best thing about our cars, we all to find our own style and things that we like. 

Lets hope Reidbook finds one that suits his needs =)

 

 

Given all the data you've supplied here, I'd say your 649 has been dialed in with about 8 - 10 degrees of advance. When set up with the right head, induction and exhaust, they 'come on' at around 4000 and will go all the way to orbit from there. Below 4000 they are quite undrivable, even the idle needs to be set at 1200 - 1500. Your Power and Torque Curve also suggest that it's quite advanced. I had one in my Race Car and that produced 118 HP on the rollers.

[Cooperman]

I built a 1071 'S' historic rally car in 1989 - 90 and did some tarmac special stage rallies in it. It was a very 'full-on' engine with 11:1 CR, very big valves, light-weight flywheel, twin H4's, 649 cam, etc.

 

It got a class win on the Belgian Historic International Rally and a couple of good results on other tarmac stage events. However, I decided to change to a 286 cam and that was a bit better at the lower end of the rev range, although it still needed almost 4000 rpm to make it think about really going well.

 

For rallying I do like the 286, although if it is slippery or very twisty the lack of mid-range torque can be an issue, despite my running a 3.9:1 FDR and a SCCR 'box with twin H4's. To make it go at its best I do change up at around 6600 rpm. As Chris says, it looks like your engine has altered cam timing to move peak power revs down, but this will be at the expense of maximum power, although it is unlikely that mid-range torque would be improved by doing this. That would have the effect of making the 649 perform about the same as a 276 at the top end, with peak power at around 6100 rpm but without the lower end torque of the 276.

 

It's all there on the cam graphs.