I'm having an engine built. In fact it's darn near complete but I need to decide which cam. The engine build is speced for very fast road use and in fact he has already fitted the cam I ordered, which is a BP 300. But he generously offered to replace it if I want but I need to decide pretty quickly between a BP 300 vs a BP 285. The basics of the engine is a 1430 with ground cooper S rods, a race head, duplex timing chain, pre-verto clutch, orange diaphragm, lightened flywheel, complete balancing, center strap, SC drops and SC gears, twin 1.5 SU carbs. To tell you the truth I don't really understand most of the intricacies of the build, but I have read about how the choice of cam can affect the lumpiness of the idle and make it less pleasant to drive around town, light to light.

Any input would be appreciated.

 

Although I'm no expert, I chose a 266 cam for my 1330 build so that it was very streetable. The 266 cam combined with the lightweight flywheel does cause some annoyances when driving it on the road - specifically it exhibits run-on and reasonably high idle. I would imagine that with a 300 cam your car will be _very_ unpleasant to drive at or near idle, and will have a very lopey idle. I have a friend with an engine very similar to yours and it is not fun to drive in town. Mine is built to be used both as a daily driver and used occasionally on the track, and has a 266 cam, lightweight flywheel, GT7 longman head, and single 1.75" SU carb - it idles at around 1500 and nearly always exhibits run-on. According to the engine builder, the combination of the cam and lightweight flywheel will result in run-on. Yours will be worse with a longer-duration cam.

Is this car going to be driven on the street or just the track? For the street I would choose the 285 cam.

Jeff

 

Great reply. I'll probably ask him to switch it out to the 285. Can you explaint what run-on is?

thanks

 

Run-on is when the engine tries to stay running after the ignition is shut off. It doesn't sound like a big deal but the Mini shop that built my engine was careful to explain to me that it's hard on the engine and that when it happens I need to put the transmission in 2nd gear and let out the clutch to stop the run-on. Is this engine builder a Mini specialist? If so, I would get their advise on which cam to use based on how you plan on driving the Mini.

It sounds like the engine is going to be quite a monster. Good luck and let us know how it turns out when you get it running!

Jeff

 

Get yourself a Swiftune SW5 or SW10 cam there the best on the market ........