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Tuning A 998Cc Engine..novice In Need Of Help

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Poll: Tuning A 998Cc Engine..novice In Need Of Help (20 member(s) have cast votes)

Is it worth changing to a 12G940 head?

  1. yes (13 votes [61.90%])

    Percentage of vote: 61.90%

  2. no (8 votes [38.10%])

    Percentage of vote: 38.10%

Is it worth changing to twin HS2's carbs?

  1. yes (9 votes [42.86%])

    Percentage of vote: 42.86%

  2. no (12 votes [57.14%])

    Percentage of vote: 57.14%

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#1 olliewiltshire

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Posted 12 May 2014 - 10:34 PM

hello guys

 

I currently have a 1982 998 cc HLE with a standard engine with a standard carb. i have put a stage 1 kit on when i first brought the mini two years ago and have now decided i would like a bit more power out of it. i have recently brought a pair of twin HS2's  with a cooper manifold and also just brought a 12G940 head but i am not sure when i fit them both on what else i will need to change, if anything?  i have tried to have a look into whats needed to do when changing the head but there seem to be alot of different ideas of what is involved and i was wondering what you guy thought about this? also i want to see if anyone had done this change and know if it will make much of a power increase? any help would be much appreciated

 

thanks  

 


Edited by olliewiltshire, 12 May 2014 - 10:36 PM.


#2 Anthony30

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Posted 12 May 2014 - 10:49 PM

I would sell the 12G940 and buy a 12G295. You should also consider converting to electronic ignition. Depend how much power you want really to be honest. I was converting my 998 to twin 12g295/HS2 carbs, but now going turbo.



#3 olliewiltshire

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Posted 12 May 2014 - 10:54 PM

really, what would be the reason you would get a 12g295 ? i also forgot to say i have electric ignition, i have also converted to ap disc brakes making sure i will be able to come to a stop as well ahah! i would like to gain more power with out making it horrible to drive as its my daily driver aha



#4 Anthony30

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Posted 12 May 2014 - 10:58 PM

Just my personal opinion really, the 12g295 was designed for the 998 engine. :tumble:



#5 Anthony30

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Posted 12 May 2014 - 11:05 PM

My car will be my daily driver again soon, I've just started a new job. Still need to get my Megasquirt 2 ECU kit built for electronic ignition. :ermm:  :ohno:



#6 olliewiltshire

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Posted 12 May 2014 - 11:15 PM

Oh reall, I didn't know that! That's the thing when it comes to modifying, knowledge is key! I bet it will turn into a beast once you turbo it aha

#7 Anthony30

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Posted 12 May 2014 - 11:29 PM

Hopefully. :highfive:  It's got a very firm grip on my money ATM. O_O  :lol:

 

Looking for 80-100 BHP.



#8 Anthony30

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Posted 12 May 2014 - 11:44 PM

I've just been searching TMF, turbominis.co.uk, and reading Mini World for the last 4-5 years roughly, building up knowledge and reading about other builds. If you have any questions just ask on the forum, loads of helpful/knowledgeable people willing to help.

 

:highfive:



#9 olliewiltshire

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Posted 13 May 2014 - 10:59 AM

that will fly aha  :mrcool:  thanks alot for your help mate



#10 coopdog

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Posted 13 May 2014 - 12:38 PM

998 turbo is the way to go :L



#11 olliewiltshire

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Posted 13 May 2014 - 04:01 PM

it isbut also quiet expensive aha 



#12 coopdog

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Posted 13 May 2014 - 04:19 PM

it isbut also quiet expensive aha 

 

very expensive :L



#13 Stiggytoo

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Posted 13 May 2014 - 04:26 PM

If you want to fit the 12G940, you will ideally need to pocket the block and plug/redrill one or two waterways in the block (although you can get away without doing this) If the engine's coming out to do this, you might as well fit a slightly better cam to go with it. The MG metro cam is quite good for this.

 

Other minor things you will need to think about are the lack of bypass hose, unless you have a head with a plug there which will allow you to screw in a bypass pipe. Otherwise you can just use a non bypass water pump, and use a metro or similar setup. You will also need a 1275 top radiator bracket.    



#14 olliewiltshire

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Posted 15 May 2014 - 10:19 AM

thanks alot stiggytoo. i had a look at the head last night and realized it doesn't have a bypass hose, will this be a problem? do you know how much larger i will need to make a couple of the water ways?

 

Also how much does it cost to get someone to pocket the block or is this something i can do my self ? 

 

thanks alot mate



#15 Outofthegame

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Posted 15 May 2014 - 11:28 AM

You will probably need to modify your water pump at the top to allow clearance for the 12g940 head, if you would like I can put up a photo of what I did with mine and what I did to block the water pump bypass. 

 

Pockets. 

Best to be done by an engine pro, however there are people, some of whom are on here, that have made their own pockets with a dremel. I can't give you too much advice on this, the only thing I will say is you will have to make the pockets as equal as possible otherwise your compression ratio will be uneven. 







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