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 Post subject: Increasing power
PostPosted: Sun Dec 06, 2015 8:38 am 
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1098cc
1098cc

Joined: Fri Sep 10, 2004 6:39 pm
Posts: 1770
Location: Kaniva / Adelaide / Melbourne
Hi everyone,
I have a complete 998 standard engine with unleaded 12g202 head conversion done. Has been sitting 15 yrs, motor free , bores excellent, original mowing Pistons with no carbon build up. What suggestions are there for more power. Can do the non machining stuff myself. What would be my best bet with a budget of around 1000?
Cheers,
Steve


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 Post subject: Re: Increasing power
PostPosted: Sun Dec 06, 2015 9:23 am 
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998cc
998cc

Joined: Sat Nov 23, 2013 7:20 pm
Posts: 645
Location: Victoria
Firstly you could sell it to me and you won't have to spend a cracker.

Otherwise something similar to a Wade 104 cam, double valve springs, perhaps port
/polish the head, single 1 1/2 Su or twin 1 1/4's but would have to be jetted back quite a bit, that should give you some increase in performance.


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 Post subject: Re: Increasing power
PostPosted: Sun Dec 06, 2015 9:26 am 
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998cc
998cc

Joined: Sat Nov 23, 2013 7:20 pm
Posts: 645
Location: Victoria
Also how about lightened steel flywheel, cooper s dizzy, and extractors.


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 Post subject: Re: Increasing power
PostPosted: Sun Dec 06, 2015 9:48 am 
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1098cc
1098cc

Joined: Fri Sep 10, 2004 6:39 pm
Posts: 1770
Location: Kaniva / Adelaide / Melbourne
Lol, definately not for sale. I was thinking cam, beadwork, do you need double springs? Benefits?


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 Post subject: Re: Increasing power
PostPosted: Sun Dec 06, 2015 9:52 am 
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1098cc
1098cc

Joined: Fri Sep 10, 2004 6:39 pm
Posts: 1770
Location: Kaniva / Adelaide / Melbourne
Also, on a 68 deluxe the plate has car no. 34734, should this be on the car somewhere?


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 Post subject: Re: Increasing power
PostPosted: Sun Dec 06, 2015 10:10 am 
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1275cc
1275cc
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Joined: Fri May 02, 2008 3:07 pm
Posts: 5123
Location: The Internet
mooman10_0 wrote:
Also, on a 68 deluxe the plate has car no. 34734, should this be on the car somewhere?


Just under the ID plate and stamped into the firewall bulkhead.


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 Post subject: Re: Increasing power
PostPosted: Sun Dec 06, 2015 10:25 am 
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1275cc
1275cc

Joined: Wed Jan 19, 2005 1:52 pm
Posts: 2582
Location: Brisbane
If it will take a re-ring do that, with a light bore hone of course, get a warmer cam, 1.75 inch SU, extractor exhaust and that will do you. Save the dollars for some disc brakes.

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 Post subject: Re: Increasing power
PostPosted: Sun Dec 06, 2015 10:35 am 
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1098cc
1098cc

Joined: Fri Sep 10, 2004 6:39 pm
Posts: 1770
Location: Kaniva / Adelaide / Melbourne
I was thinking maybe a down draught weber set up from the guy in Brisbane who sells them on eBay. Anybody tried one?


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 Post subject: Re: Increasing power
PostPosted: Sun Dec 06, 2015 11:25 am 
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1098cc
1098cc

Joined: Fri Sep 10, 2004 6:39 pm
Posts: 1770
Location: Kaniva / Adelaide / Melbourne
anyone have some sugestions for a cam, just a road car wanting a bit more ooomph! Will most likely be standard boreand pistons.
Cheers,
Steve


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 Post subject: Re: Increasing power
PostPosted: Sun Dec 06, 2015 1:58 pm 
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1275cc
1275cc

Joined: Wed Jan 19, 2005 1:52 pm
Posts: 2582
Location: Brisbane
You won't need any fancy weber.

"single 1 1/2 Su or twin 1 1/4's but would have to be jetted back quite a bit," you might have an 1.5 on the 998 as in the seventies thats what the 998 were armed with. The twin 1,25s will work well, did so on the 998 Cooper but for bang for buck I'd get the 1.75 inch SU.

Regarding cam go for something mild not wild. In a small bore the choice is critical.
It was suggested a Wade104, go with that.

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 Post subject: Re: Increasing power
PostPosted: Sun Dec 06, 2015 2:03 pm 
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1275cc
1275cc
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Joined: Sun Apr 29, 2012 1:19 pm
Posts: 4504
Location: Wollongong, NSW
If the head is off check the combustion chamber volume. If you have standard pistons and a bigger chamber volume than a standard 998 head (which a standard 202 does) your compression ratio will be too low.

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 Post subject: Re: Increasing power
PostPosted: Sun Dec 06, 2015 2:15 pm 
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1098cc
1098cc

Joined: Fri Sep 10, 2004 6:39 pm
Posts: 1770
Location: Kaniva / Adelaide / Melbourne
What volume should it be? If we do open up chambers I gather machining the surface is needed to bring volume down?


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 Post subject: Re: Increasing power
PostPosted: Sun Dec 06, 2015 2:41 pm 
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1275cc
1275cc
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Joined: Sun Apr 29, 2012 1:19 pm
Posts: 4504
Location: Wollongong, NSW
The standard 998 head is ~24.5cc with C/R of 8.6:1
The standard 12G202 head is 26.1cc.

You'd need to skim the head or use some pistons with less dish in them.

I bought a "stage one kit" from minispares last year for about $500:
Exhaust manifold
Full exhaust
Intake manifold
KN filter
To go with a HS4 single carb.

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 Post subject: Re: Increasing power
PostPosted: Sun Dec 06, 2015 2:51 pm 
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1098cc
1098cc

Joined: Fri Sep 10, 2004 6:39 pm
Posts: 1770
Location: Kaniva / Adelaide / Melbourne
Cool,
Thanks for that :-)


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 Post subject: Re: Increasing power
PostPosted: Sun Dec 06, 2015 3:21 pm 
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998cc
998cc

Joined: Sat Nov 23, 2013 7:20 pm
Posts: 645
Location: Victoria
A Wade 104 or equivalent is an excellent cam for slightly warm 998's.

Really this what I would do due to the $1000 budget. If you want the motor to last, new Pistons, rings, bearings, hone bores if ok, double row timing chain and gears, balance the bottom end, lightened balanced steel flywheel, new oil pump, new water pump. Now you have a reliable short motor and nothing more needs to be done on the bottom end. All this should not cost you $1000 and you can do the reassembly. Have the head skimmed to square it up (machine shop), decoke and relap the valves and put back together, rejet the standard carby unless you have a 1 1/2 or 1 3/4 and you should be able to scrounge second hand extractors.

Later on when you have more folding stuff, a nice stage 3 head and twin SU's or a 40 Weber jetted back, and with one of those nice electronic dizzy's and you will have a nice jigger.


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