Camshafts

[Nick1973]

What’s everybody’s thoughts on the 731 camshaft, I am currently building up a 1300Gt Block and have chose to go with the 12G940 Head

I have got a 731 Camshaft that I am looking to use. Just wanted to see if this was a good camshaft for this application

[Thorp]

I think the accepted wisdom (rightly or wrongly), is that there are better cams. Swiftune SW5/8 would I suspect be a better starting point, but there are numerous options out there.

But, cam choice rather depends on the spec of everything else. Is the head standard or modified, what compression ratio are you running, what do you want it to Rev to (or what will the components stand), what type of driving will you be doing etc

Decide that, and then pick your cam. The only cam changes I’ve experienced are a Kent 286 and a Swiftune SW10; never used a 731 so I’m sure someone that has will impart their knowledge.

[Herbert]

The problem with a 731 cam is that you really need to time it in perfectly...There are better Cams and a 731 wont give you much more power than a standard engine. Kent cam 276 is good but a SW5/8 is a fabulous cam

[AndyPen]

Our 970 motor has the 731 in it still as it was out of an old racer. I had the distributor matched to it by the distributor doctor and it drives well. Bit flat at the bottom mind you, but soon picks up and in this motor, just wants to rev.

I got it like this, but would have tried to get the mg metro one if I had a choice. That's what's in my 1071.

[Daz1968]

I had a 731 in my 998 otherwise standard Cooper, just a little head work and lcb and it performed quite well,
I have since changed spec, but I never had any problems with the 731, but it does get bad reviews from some.

[winabbey]

Out of interest, in late 1970 the Cooper S pursuit cars supplied to New South Wales (Australia) Police were modified on the BMC production line to improve performance. Up to then they were stock standard showroom models from a mechanical perspective. The performance package was called Special Production Order 41 and comprised twin HS4 (1 1/2") SU's in place of the twin HS2's, mild head porting, Special Tuning valve springs and a modified distributor. Later the Special Tuning 731 camshaft was included in the package. By all accounts from those who drove them they went very well and met their target to reach and maintain 100 mph on the road.

More than 1,100 Cooper S and Clubman GT (Cooper S in a Clubman body) were supplied during the contract period.

In the ensuing fifty years it seems A Series camshaft technology has progressed so there are probably other options that may perform better. I don't have the technical knowledge to advise one way or the other.

I've maintained the 731 cam in my ex-NSW Police Cooper S more for originality and historical reasons.

[Exminiman]

Out of interest, in late 1970 the Cooper S pursuit cars supplied to New South Wales (Australia) Police were modified on the BMC production line to improve performance. Up to then they were stock standard showroom models from a mechanical perspective. The performance package was called Special Production Order 41 and comprised twin HS4 (1 1/2") SU's in place of the twin HS2's, mild head porting, Special Tuning valve springs and a modified distributor. Later the Special Tuning 731 camshaft was included in the package. By all accounts from those who drove them they went very well and met their target to reach and maintain 100 mph on the road.

More than 1,100 Cooper S and Clubman GT (Cooper S in a Clubman body) were supplied during the contract period.

In the ensuing fifty years it seems A Series camshaft technology has progressed so there are probably other options that may perform better. I don't have the technical knowledge to advise one way or the other.

I've maintained the 731 cam in my ex-NSW Police Cooper S more for originality and historical reasons.

So does it still "Reach and maintain 100 mph " ?