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MG MGB Technical - Rx for 130 hp

Hi!

I already have a crossflow head with twin 45dcoe
Iam looking to achieve 130hp from my engine.
I need to buy a cam and i was thinking piper 285 degree (I dont know how it is going to react with more duration)

Anu suggestion is welcome
luis

If you are looking for 130 at the flywheel I would guess it's there already. With B series engines in MGs head work alone seems to have more effect than you would think. I think this is because the cheap to make with "tolerable" performance in line valve arrangement is the one high investment thing the Abingdon engineers could not change. Is the car for road use? If so I think you will be unable to cam it to take full advantage of the twin Webers while keeping it usable below 3000rpm.
Stan Best

Have you had this head ported and the valves reshaped to 3 angles? What compression does this engine run?

The Piper 285/2 is a very good grid, if your engine can be run bith the extreme lift of this cam. As i do not know enough details of the HGR head, you should compare all critical dimensions with the std cars iron one before.

You can reach your estimated 130 hp (and even more) and a boost of midrange torque and high reeving with this setup, so be careful with selecting other items that might reach critical limits!

RAlph

Don't be afraid to put a good cam in it. I had a B years ago with a crossflow and 42mm webers and a factory 770 cam It didn't run at all rough at idle (well just a little bit) I think that having a seperate carburettor throat for each cylinder and no balance tube really evens the idle out. It used to pull like a train down low from about 2000rpm even with this cam. Really easy to drive'you could lend it to your grandmother if you had to
130 HP easy. With that Piper cam that Ralph suggests and what you have already I would reckon more like 140+
Gary.
Gary

The modern crossflow heads (and several of the original HRG models) benefot from some port work. They also like more compression - I suggest around 10:1.

With that combination the cam you mention should work very well. A 770 may be a bit tiresome on the road for driving in traffic as there is little bottom end.

Make sure that the Webers use appropriately small main venturis. In my experience people tend to set them up as if they were going to be racing, with an attendant loss of power below 4000.
Bill Spohn

Luis,

I agree with the gentlemen who posted before me.

The engine in my car was bored to 1950cc, has a CR of +11:1, a ported HRG crossflow head (work done by Peter Burgess), an appropriate Aldon dizzy and two sidedraught Dell'Orto 40 DHLA carbs (+- equivalent of Weber DCOE 40 carbs). It was built by Chris Betson of Octarine Services. http://www.octarine-services.co.uk/alex1950.htm

It makes approx. 150 bhp at the engine (124 at the wheels, set up and measured at Peter Burgess' rolling road). It pulls like a train from 2000 rpm and has a very steady idle. Basically, it's very flexible and powerful.

So yes, what you want is achievable! If you want more info, don't hesitate to shout (But I'd presume the two gentlemen I mentioned above could be more useful to you ;-) )

Make sure your brakes, gearbox and rear axle are up to it.
Alexander M

This thread was discussed on 27/05/2008

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