16 replies to this topic

[blakie]

Is there any difference between the MPI, SPI and Carbed Cooper Cylinder heads?

If so what are the differences?

[blackbelt1990]

I couldn't tell for definate but I know I have used an SPi head on my Carb'd mini. I think you can run a carb on an injection head but not the other way round?

Ryan

[RayBoogs]

I thought you can interchange carb and SPi heads, but not with MPi, but i may be completely off the mark.

Jack

[DAVEY_C]

my 1275 metro engine is fitted with an spi head (12G940B) and it doesn't have the temp sender tapped into the head because on spi's it is taken off the rad..... other than that it is the same as the standard 12G940 head....

i was told an mpi head is compatable with a carb'd engine but then again i could be wrong....

[blakie]

The thing is i need a new 1275 A+ head for my carbed engien and I may have the chance of one from a MPI cooper, I just wondered if this would go straight on?

blakie

[blackbelt1990]

The thing is i need a new 1275 A+ head for my carbed engien and I may have the chance of one from a MPI cooper, I just wondered if this would go straight on?

blakie

It probably will, but as said above, you'd probably need to get it tapped to take a temp sender in the front.

Someone reliable will be along soon... lol

[blakie]

HA HA lets hope so.

I think the SPI head just have a blank screwed into them for the temp sensor. I recall just undoing it and popping in a sensor when I converted an SPI car to carbs once.

[Asphalt]

Carb Cooper: thread for sensor, hole for heater take off
SPI head: no thread, no hole
MPI head: no thread, no hole - but some holes belo the thermostat for attachemnt of the alternator

You can use a SPI/MPI head on a carb engine, you just need to drill out the hole for the heater take-off (or water bypass on the RSP Coopers). The SPI heads allready have the threads for the heater take-off tapped, the MPI one doesn't (no biggie, I just want to mention it). And you need to drill & tap the sensor thread - or find an alternative way to mount the sensor.

The SPI hads do not have a blank! The openings are closed byt he cast...

[pikey7]

and you have the bypass hose to worry about. mpis and spis don't have them, but then some late carbs don't have them either. you'll need the sandwich plate to use one of those, plus a different hose routing, and you'll need to block the hole in the water pump, or get a new pump.

Edited by pikey7, 18 October 2010 - 05:51 PM.

[DAVEY_C]

Carb Cooper: thread for sensor, hole for heater take off
SPI head: no thread, no hole
MPI head: no thread, no hole - but some holes belo the thermostat for attachemnt of the alternator

You can use a SPI/MPI head on a carb engine, you just need to drill out the hole for the heater take-off (or water bypass on the RSP Coopers). The SPI heads allready have the threads for the heater take-off tapped, the MPI one doesn't (no biggie, I just want to mention it). And you need to drill & tap the sensor thread - or find an alternative way to mount the sensor.

The SPI hads do not have a blank! The openings are closed byt he cast...

so on my spi head do i have to drill and tap to put the heater sender onto it..... u say the spi already has the threads there, if so how do you open them up to use??

[Twincam]

my 1275 metro engine is fitted with an spi head (12G940B) and it doesn't have the temp sender tapped into the head because on spi's it is taken off the rad..... other than that it is the same as the standard 12G940 head....

The cam on the SPi heads still have the lobe for the mechanical fuel pump, but you're right where the temperature sender would be its not - its actually connected on the manifold (you have to basically take it out to change it)

The only thing connected to the rad is the fan switch (usually at the bottom front)

[Asphalt]

so on my spi head do i have to drill and tap to put the heater sender onto it..... u say the spi already has the threads there, if so how do you open them up to use??

The threads for the two screws which hold the heater valve or take-off lug. The red arrows in this picture:



Blue arrows indicate what has to be drilled to useon a carb engine.

1275cc A+ engines don't need to have anything plugged - drill the two holes, attach anything as it has been before and leave the cooling system untouched. And everything will be fine! A 1300 'carb Cooper' has the very best cooling system of them all - no need to touch anything or plug something up. Drill the two holes, tap one of them, put on the head & drive on

Cheers,
Jan

[blakie]

So..... If I can get this MPI head cheap its worth doing?

blakie

[DAVEY_C]

http://cgi.ebay.ie/w...e=STRK:MEWAX:IT

there's an aparent stage 2 mpi head you might be interested in.... i don't know if the valve sizes vary between a carb/mpi head...

[blakie]

http://cgi.ebay.ie/w...e=STRK:MEWAX:IT

there's an aparent stage 2 mpi head you might be interested in.... i don't know if the valve sizes vary between a carb/mpi head...

You say apparent??? Any reason wh you say this?? Looks good though