18 replies to this topic

[biggav]

Blew the 1000 engine today, managed to get a 1275 complete unit with subframe and uprated discs and calipers from a mid 90's spi cooper. I take it i can remove the injection unit and bolt a carb on without any bother??? im going to take the head off to check the engine condition, and will obviously do gaskets at the same time, may get head skimmed and polish the ports a bit... is it worth getting a new cam? i would like to give her a bit more poke. if so, which cam is best for fast road? someone told me to get a 731 but i can't find one in any mag, website or ebay.... should i do roller tip rockers too? budget ain't an issue but im looking for good performance without spending too much.... im planning on a zcars job next winter.

[RacingGreen]

injection heads are different to carb'd heads i believe

[Sprocket]

Not that much at all. The MPI heads have extra fixings for the alternator. You will have to drill and tap the temperature sender hole though on the SPI head. valve sizes are a bit poo unless you get lucky and have an early 92 ish Cooper with 35.7mm inlets.

[biggav]

should i leave the cam as it is just get the head sorted or a stage 3 head? already have a straight through exhaust

[miniboo]

as the engine is out i would say get a cam put in now as it will be a nightmare to do after you have put the engine back in and got it running.

Headwork is easier to get done at a later date i reckon.

[stormduck]

A 731 cam is exactly what i wanted for my 1275 based on David Vizard's book. But as that book is quite old the AEG731 doesn't seem to be sold any more. Or at least that code isn't used. A close match as far as duration and lift goes is the Kent 276 which is what i now intend to get instead. I believe the 276 gives about 9mm valve lift with the standard ratio rockers, which is quite a lot of lift so it's unlikely you would want to put 1.5:1 ratio rockers in, as it may get dangerously close to hitting the pistons, but it would have to be worked out based on how much metal is on the head and block and therefore how much clearance there is from valve seating position to piston face at TDC.

[supermotolee]

the switune sw5 cams seem to be getting good reviews might be a good bet they do roller rockers too

[neil_g]

youll struggle to get an injection engine through an emmisions test with a carb on it.

replace the lump entirely for a carb lump and have the paperwork to hand proving its an original (older) carb engine when it comes to MOT time.

[biggav]

oh dear... bit late now, ive already got the engine. are 1.3 roller rockers worth doing? ive just reads that threat about 1.5 roller rockers that goes on and on and on but im no engineer... more of a tinkerer come bodger.... will i not be able to blag it through the MOT?

[Jammy]

I think the general outcome of the thread that you read was that the cam and the rockers are kind of like a matched pair, to get the best performance you should have a cam and a set of rockers that work well together. Getting a 'rocker kit' is the best idea as it'll give you the springs, etc that the manufacturer has found to work best.

To find out what rockers will suit your needs best, again its a good idea to phone the suppliers and see what they recommend, no one will have a better knowledge of their own rockers.

[stormduck]

full roller rockers that cost £300ish will last a long time because of the rollers that allow movement where metal meets. Roller tip rockers cost £170ish and just teh tips that hit the valve tops are moveable - these are ideal for fast road and are good value for money. The 1.3 versions of these would be perfect with a 276 cam without worrying about complicated measurements.

[Jammy]

....without worrying about complicated measurements.

If only mini1071s was around to see you say that!! lol

[Sprocket]

youll struggle to get an injection engine through an emmisions test with a carb on it.

replace the lump entirely for a carb lump and have the paperwork to hand proving its an original (older) carb engine when it comes to MOT time.

Hows that work then when the injection emissions levels are way lower than that of a carb

731 cams are still available from here http://www.kentcams.com/

[biggav]

trying to order 276 cam and 1.3:1 from mini spares, it asks what drive type spider, peg or slot what the hell does that mean... out of my depth me thinks... luckily i now have a bloke who build stock cars doing all the work for me, he told me to get whatever stuff i wanted and he'd fit it.... for a small cash reward of course... which drive type then people? and should i be getting some hefty engine steady's on order too????

[miniboo]

probably slot drive. it is the type of drive for the oil pump.