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changing back to a std head and hif38....


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#1 Prawn

Prawn

    One Carb Or Two?

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Posted 07 May 2005 - 05:09 PM

hey guys.

im currently in the process of geting parts together to build my new engine.
ive decided to go with a 1399 semi long stroke engine.
ive got a 1380 short engine which needs a new crank, and ive also got a set of cooper s rods, so im having a crank stroked to 82.3mm to give me 1399cc.

ive already got a steage 3 unleaded head on my current knackered 1275, but this is going to be skimmed and cleaned up with new guides and things before being fitted to my new engine.

the little problem i have, is that im currently doing a lot of miles, and a reduced aount of work due to my exams in the next few months, so im driving more, and making less money!!!!

my mini is VERY uneconomical though!!!!
the spec is a 1275 metro engine, with 3.44fd, all standard other than the stage 3 head and an hif44 carb, and of course an lcb with a twin box maniflow exhaust.

driving normally im only getting 24mpg!!!! i went for a week driving as carefully and economically as possible, yet still only returned 26mpg!!!! typically its between 20-24 for any given week.

so, to get to the point.

my carb is going to need rebuilding to go on the new engine, and the head is due some work and a spray to make it look good again.

so, i was thinkin of fitting a standard 12g940 metro head for a few months and downgrading to an hif38 carb too.

would this help with fuel economy much? and am i going to notice a huge loss of power?
ive also got a set of 1.5:1 rockers to fit, would fitting these while ive got the head off act against my economy saving head change?

i was thinking that if i were to fit the hif38 carb and standard head with the 1.5:1 roller rockers id improve my fuel economy with the rockers helping to still keep it 'nippy'

when it was rolling roaded a year ago it made 79bhp at the flywheel, how is this figure likely to change with the downgrade in head and carb?

sorry to ask so many questions, i know my new engine wont be economical at all, but by the time it goes in ill be at uni and the mini will then be a weekend car! not the 50 mile a day car it is now.

for all those people who dont want to read all my rambling:

if i fit a std head and hif38 carb instead of my stage 3head and hif44, what power losses/economy increases am i likely to get? and is fitting 1.5:1 roller rockers going to take away the economy benefits of the head?

thanks

nick




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