I am desperately trying to get my 1980 Mini 1000 back on the road and need your help. To cut a long story short, a so called 'friend' offered to fit a 1275 engine, I bought the exhaust system to use with it, but my 'friend' then disappears leaving me with a half completed job - and as it turns out an engine which is completely seized.
We have now reverted back to the 998 engine (which worked perfectly well before removal) but struggling to get it set up correctly. Whatever we do it seems to be running very rich, and although it will start, it dies again once its warm leaving all the spark plugs soaked in fuel.
I have the following kit:
Exhaust bits from Mini Spares:
Manifold Std bore exhaust long centre branch
Large inlet manifold for HS6 drilled + plug for servo
S/Steel side exit DTM twinpipe
S/Steel downpipe LCB to rear box
Plus
K & N cone filter & HIF 44 carb
Pipercross cone filter & HS4 carb (currently in the car)
Someone suggested I just ditch the cone filter and re-fit the big air box filter, but others run their cars using a cone filter so I am sure its not impossible.
My last resort is to pop it into the garage, but he advised me none of it will work and I would have to get the head bored out at a cost of £400 - definitely out of my price range.
Thanks
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Firstly you need to decide which carb to use.The HIF is better,but,presumably came off the 1275,in which case you will need to get the correct needle and jet.If you use the HS4 it is probably worn,which will cause rich running, and will need a new needle and jet.These come in different sizes (red spring,3mm jet,ADE needle).You would be best to visit a Mini or SU specialist(Moss,if there is one near you), and tell them you are using the K&N or P/Cross filter,this allows more airflow,resulting in a weaker mixture,so may require a different jet from standard.If you use the HIF do not forget that the mixture screw works the opposite way to other carbs,i.e.screwing in gives a richer mixture(it pushes the jet down).Also ensure the 'choke'is going fully off(either carb)as this works by lowering the jet.Also you need to check that the float is not leaking(shake it and listen for fuel inside),that float level is correct and,most importantly,that the needle and seat under the float are not worn.Better still,just replace it as they usually are.
I do not know what your man means by boring the head,is this to match the manifold?If you are using your original engine which ran before I do not understand why he should say'none of it will work'.Not very helpful and possibly BS.
Good luck.
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Sierraman you are a star. Think you have hit the nail on the head about the jet. Both carbs were rebuilt to the original standard, we replaced the needle on the HS4 which is currently in the car but never thought about changing the jet for a different one. Definately off to the mini shop at the weekend.
As for the guy suggested boring out the head, he said he would need to do so to increase the capacity?? No adjustments have got to be made to fit the manifold. However, I know of many people who have a similar set up to mine and never went to such extremes so think it was a case of "charge you for a full set of tyres when you only need a new spare wheel" type of service!!
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As for the guy suggested boring out the head, he said he would need to do so to increase the capacity??
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Ignore utterly ignore him as he does not know what he is taking about. However, it may be that an 1000 head has a lower capacity than a 1275 head, but the latter is displacing more capacity within the block. So it would probably be necessary if you were marrying a 1000 head to a 1275 block. However I'm not a A series specialist.
If you increase the capacity of a chambered head (a la mini) without changing the displacement you do increase the capacity, but you also reduce the compression ratio. In the interests of power and fuel econonmy you want this as high as you can get, without making it knock.
Do be aware that you may actually reqire more fuel than a standard engine installation but obviously not as much as you have. Usually however the idle mixture wont alter much and a needle which slims down faster is all that is needed. I think this age of SU will have a waxstat jet, and these do fail to a rich mixture. Take it out before you go to the carb specialist as they will be able to check if is the correct one for the age and capacity of the engine.
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As far as I know the main difference between the heads is valve size,also the 1275 has a higher CR.The HS4 does use the Capstat jet,the HIF a bi-metallic arrangement,as you are replacing the jet there is no need to worry about it.Don't forget to centralise the jet before making adjustments and doing up the locknut.
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