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PostPosted: Thu Mar 31, 2011 9:55 pm 
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998cc
998cc
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Posts: 631
So Ive got myself a new mini, excellent body but it has a smokey 998 engine.

So I'm looking for advice on whats the best way to get a daily 998 built. Cheaply and quickly, doing as much work myself as possible for fun and education.

I already have a few bits:
Pulsar Dizzy
Twin 1-1/4 SUs
Single 1.5 SU
ARP Head studs
Cooper S Head
1100 Crank
998 blocks standard bore
Standard pistons.

I am thinking Ill keep the standard bore, and use the 998 crank over the allegedly weak 1100.
Would the second hand pistons surfice or should I look at some flat top hypatects for a nice high compression.

Ill be going with an RE13 or Kent equivalent cam which ever is cheaper.
Is a duplex timing chain recommended?
I can deck a block myself but is crank wedging and balancing required?
Ill be looking at a lightened flywheel, worth it on such an engine?
What rockers would be best, ratio and brand?

I have a cooper head but I want to try my hand at porting so I will probably use a standard 998 head, are oversize valves needed and what size?

I will probably use the twin carbs as they are just cooler, is a single 1.5 really so much better in performance and fuel economy?

Yes I do have a copy of vizards book on the way but any opinions would appreciated.


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PostPosted: Fri Apr 01, 2011 12:23 am 
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848cc
848cc

Joined: Mon May 22, 2006 12:33 am
Posts: 276
Location: Western Australia
Firstly, if this is for a daily driver USE THE 1100 CRANK! I really get sick of hearing how it's only as strong as a bent bit of wire and should be avoided. Get it crack tested - if it's all good get it balanced and it will run strongly to 6000rpm in every gear all day long (for a ROAD motor) and the extra power and torque over the 998 will make you smile everyday.

Using the 1100 crank you will need new pistons.

I wouldn't trust a 'Standard' bore unless it was carefully measured and inspected before use. Most of the time a standard bore these days requires a rebore due to wear (which will be uneven over the length of the bore). Best idea - measure the bore and go to the oversize required to get the bore spot on. In your case probably +20thou but measure.

There are many good cams out there and everyone has their views/opinions/preferences. Pick your cam grinder and ask them what they recommend.

Twins or single carb??? A well setup 1.5"SU on a good manifold will be more than a match for twin 1.25"SUs. But I too like the look of twin 1.25"SUs. At the end of the day - It's your car, if you want to use the twins (for this spec of engine, you're not going to really notice anything either way) USE THEM. Just make sure they are setup correctly (much easier to achieve with a single carb).

Have fun :)


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PostPosted: Fri Apr 01, 2011 6:03 am 
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Mods rock!
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miniobsessed wrote:
Firstly, if this is for a daily driver USE THE 1100 CRANK! I really get sick of hearing how it's only as strong as a bent bit of wire and should be avoided. Get it crack tested - if it's all good get it balanced and it will run strongly to 6000rpm in every gear all day long (for a ROAD motor) and the extra power and torque over the 998 will make you smile everyday.

Using the 1100 crank you will need new pistons.

I wouldn't trust a 'Standard' bore unless it was carefully measured and inspected before use. Most of the time a standard bore these days requires a rebore due to wear (which will be uneven over the length of the bore). Best idea - measure the bore and go to the oversize required to get the bore spot on. In your case probably +20thou but measure.

There are many good cams out there and everyone has their views/opinions/preferences. Pick your cam grinder and ask them what they recommend.

Twins or single carb??? A well setup 1.5"SU on a good manifold will be more than a match for twin 1.25"SUs. But I too like the look of twin 1.25"SUs. At the end of the day - It's your car, if you want to use the twins (for this spec of engine, you're not going to really notice anything either way) USE THEM. Just make sure they are setup correctly (much easier to achieve with a single carb).

Have fun :)


Some very good advice there.

I would agree that the 1100 cranks are good, just not the 'ultimate'. Will last quite well if you're not looking for huge HP (or use huge HP) or insane revs.

You can also read Phat Kat's ( & others) tips and hints here

http://www.ausmini.com/forums/viewtopic.php?t=67980

On the Carb(s), again as miniobsessed says, the look of the twins is sexy, but stick with a single. You'll get very repectable results with a single 1 1/2", which is good up to about 80 flywheel HP!

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PostPosted: Fri Apr 01, 2011 12:58 pm 
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998cc
998cc
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Joined: Sat Mar 13, 2010 4:19 pm
Posts: 840
Location: Ridin' the rails somewhere
Pretty good advice already...

You've asked lots of specific questions, personally I would start out with more general questions like :

- how much $$ can I spend? (the real limit on modifications)
- What am I gonna use the car for? (road only? some race?)
- What sort of motor do I want - a tame road-going torque master or a fire-breathing monster from the pits of hell?

Once you've got those worked out, a lot of questions almost answer themselves ;)

cheers,

_________________
'72 Clubman Van - 1022cc, 295 head, 731 cam - Daily Driver :D
'69 Morris 1100 S - Dinged by a bus, in shed under repair
'64 Morris 1100 - Early 1100, long term project



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PostPosted: Fri Apr 01, 2011 9:46 pm 
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Yay For Hay!
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Joined: Wed Sep 08, 2004 9:27 pm
Posts: 15912
Location: Wodonga - Vic/NSW border
project small bore: http://www.minimania.com/ArticleV.cfm?DisplayID=1881


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PostPosted: Sat Apr 02, 2011 4:28 pm 
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998cc
998cc
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Joined: Thu Aug 20, 2009 12:31 pm
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Just read half of the last night Simon.
If anyone has issue 6 of the mini experience for sale let me know, mines gone awol.

What should I pay for an average over bore?


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