20 replies to this topic

[Davetom]

Hi folks, I bought a Mini recently, 1340 with a ‘ stage 3 head ‘ (36/31) . It’s not been used for a while, the carb (hif44) is off and there’s no LCB & exhaust. Elderly seller couldn’t remember much . It’s got a ‘fast road’ cam but I don’t have any info on it except it probably came from Minisport around 1995.
I have a good MG Metro cam that I was thinking of using, mainly so that I know what I’m dealing with. I’m presuming it’ll work well with the head ? If so , should I use an MG Metro dizzy , or something more bespoke like an Aldon matched to the cam ?
Thanks in advance

[DeadSquare]

The answer depends a lot, on how you intend to drive it.  Round town, touring, motor sport etc:.

 

At 1340, in its mildest tune, there is adequate power, but with a hottish cam, If the engine is all in one bit, and in the car, just drive it.

 

If you want to strip and rebuild a bespoke engine, buy another engine and swap it in a couple of years time.

 

[Davetom]

The answer depends a lot, on how you intend to drive it. Round town, touring, motor sport etc:.


At 1340, in its mildest tune, there is adequate power, but with a hottish cam, If the engine is all in one bit, and in the car, just drive it.

If you want to strip and rebuild a bespoke engine, buy another engine and swap it in a couple of years time.

Thanks, I suppose my question is that I wonder if the MG cam would work with a big valve ported head ? Apparently in its current form it was 78hp at the wheels in ‘95 but I’d like to increase that without making it too antisocial. It’ll be a Sunday car for the lanes but I don’t want it too lumpy . I might just pull the engine out to look at the cam as that’s the only unknown in the equation.

[slidehammer]

The MG Metro is a good cam, but an old design, what about a Swiftune SW5 they get good reviews.

[Davetom]

Just trying to keep costs down. I’ve had the MG cam knocking around for a while, be nice to try it out really

Edited by Davetom, 17 January 2025 - 11:25 AM.

[Cooperman]

The MG Metro cam is the best production cam ever made by BMC/BLMC/or whatever they were calling themselves that week.

I have one in my 1990 historic road-rally 1330 with a big-valve head and LCB exhaust manifold/RC40 twin box system. I run a comp ratio of 10.3:1. The cam pulls well from around 2200 rpm with peak power at 5700 rpm.

By the way, I believe your car is actually 1330 cc, which is the +60 thou bore size. 1340 would be an odd size.

[Davetom]

The MG Metro cam is the best production cam ever made by BMC/BLMC/or whatever they were calling themselves that week.
I have one in my 1990 historic road-rally 1330 with a big-valve head and LCB exhaust manifold/RC40 twin box system. I run a comp ratio of 10.3:1. The cam pulls well from around 2200 rpm with peak power at 5700 rpm.
By the way, I believe your car is actually 1330 cc, which is the +60 thou bore size. 1340 would be an odd size.

Thanks Cooperman, I’ve read a few of your posts re the MG cam and it’s part of the reason that I’d like to give it a try in my ( as you rightly say 1330 !) engine . What dizzy would you recommend ? What sort of HP do you reckon yours is putting out, mine was 78 at the wheels when built but I don’t know the current cam spec . Not sure if that’s a good figure and I know dyno readings vary place to place. ( If I swap to MG I’ll find out the current cam info obviously)

Edited by Davetom, 17 January 2025 - 01:05 PM.

[Lplus]

The MG metro cam has a longer exhaust timing than the inlet, since it uses the inlet timing from the 997 cooper cam and the exhaust timing from the "731" rally cam.  The lift isn't any more than the usual lift for BMC engines.  The MG metro still used the smaller exhaust valve so with your larger exhaust valve the benefit of the exxtended exhaust timing may not be as great.  Your cam may also be a high lift cam and even high lift rockers.

 

Best to at least try to measure the cam lift (valve depression) and have a look at the rockers to see if they're anything special.  Even valve timing can be measured without removing it, so that might give you a better idea of what your cam is. 

 

Having a good cam sitting there doing nothing is certainly an itch waiting to be scratched, but I'd find out what you have first, since it may be effectively better than the MG cam.  Changing the cam is a lot of work unless you know it's going to make a significant improvement.

 

by the way, Kent cams produce a copy of the MG Metro cam.

[Davetom]

The MG metro cam has a longer exhaust timing than the inlet, since it uses the inlet timing from the 997 cooper cam and the exhaust timing from the "731" rally cam. The lift isn't any more than the usual lift for BMC engines. The MG metro still used the smaller exhaust valve so with your larger exhaust valve the benefit of the exxtended exhaust timing may not be as great. Your cam may also be a high lift cam and even high lift rockers.

Best to at least try to measure the cam lift (valve depression) and have a look at the rockers to see if they're anything special. Even valve timing can be measured without removing it, so that might give you a better idea of what your cam is.

Having a good cam sitting there doing nothing is certainly an itch waiting to be scratched, but I'd find out what you have first, since it may be effectively better than the MG cam. Changing the cam is a lot of work unless you know it's going to make a significant improvement.

by the way, Kent cams produce a copy of the MG Metro cam.

Food for thought, thanks

[DeadSquare]

If your block is early enough to have the removable cam covers, by removing the radiator, the cam can be change in situ in a morning.

[StefanMini]

For the dizzy you can fit an 123 ignition unit, or the CSI unit. Then you have multiple curves to choose for your engine.

[Lplus]

If your block is early enough to have the removable cam covers, by removing the radiator, the cam can be change in situ in a morning.

If it has cam follower covers it would be an S block.  It seems unlikely, but possible I guess.

[gazza82]

... by the way, Kent cams produce a copy of the MG Metro cam.

MD266 ;)

[Davetom]

If your block is early enough to have the removable cam covers, by removing the radiator, the cam can be change in situ in a morning.

If it has cam follower covers it would be an S block. It seems unlikely, but possible I guess.

No it’s a late 1275 GT lump.
I think you were onto something re the existing cam, I’ve just done a rough check of lift. ( car is under tarps in a lock up). Using a dti sat on the block , I got roughly 315thou of lift IN and EX directly off the pushrods but things weren’t exactly laboratory conditions! Looks like the cam is a bit more lumpy than Mg Metro

Edited by Davetom, 18 January 2025 - 02:49 PM.

[Midas Mk1]

... by the way, Kent cams produce a copy of the MG Metro cam.

MD266 ;)

kc500 is the mg cam, 266 slightly hotter