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998 with 1275 head
https://www.ausmini.com/forums/viewtopic.php?f=2&t=52826		 Page 1 of 1
Author:  blake12345 [ Sun May 03, 2009 11:40 am ]
Post subject:  998 with 1275 head
Hey,

I was wanting to know some information a standard 998cc with a 1275cc head? Im was looking at one and was wondering if it was worth doing?

Thanks Blake
Author:  drmini in aust [ Sun May 03, 2009 1:28 pm ]
Post subject: 
Graham Russell doesn't like doing this, Keith Calver (in UK) does. make of that what you will.
I think it's a bit big on a 998, but it worked great on my 1098 bored to 1220. But it had a big cam, twin HS4s, etc.
I would not bother unless you are trying to wring big HP out of it, and you will lose torque as the ports are much bigger.

Unless the exhaust valves have sunk in and you are using a stock cam, the block will need pockets cut in it to clear the exhaust valves (which hang over the bores). So it's hardly a `std 998' then.
Author:  blake12345 [ Sun May 03, 2009 4:18 pm ]
Post subject: 
Ok so really not worth it on small engine then?
And this is a novice question. What pocketing exactly?

This has nothing to do with this but what's the engine number for a clubman GT?

Thanks blake
Author:  drmini in aust [ Sun May 03, 2009 4:35 pm ]
Post subject: 
blake12345 wrote:
Ok so really not worth it on small engine then?
And this is a novice question. What pocketing exactly?

This has nothing to do with this but what's the engine number for a clubman GT?

Thanks blake

Pocketing is milling a semi-circular recess in the top of the block, below the exhaust valves. Usually around 2.5mm deep, and out to the gasket line of a 998 gasket.
But, you have to use a 1275 gasket on a motor with a 1275 head, or they leak.

1275 heads have the valves further apart then smallbore ones, and the valves are bigger too.
If the valves hit the head they will bend and/or break, and can trash your motor...

Early GT had 9F/XE/Y engine prefix same as Mk2 S. The Oz GTs all use a Cooper S spec motor, unlike the gutless UK ones. :lol:
Author:  blake12345 [ Sun May 03, 2009 7:36 pm ]
Post subject: 
Oh rite kool thankyou.

What kinda power and reliability could be expected from this combination?

I saw an engine with this combination and i was just wondering if this or a 1275 would be better choice for a daily driver and an occasional thrash around a track
Author:  drmini in aust [ Sun May 03, 2009 8:30 pm ]
Post subject: 
If you want good drivability on the road AND power for track work, I would build a 1275.
Sure you can get around 100HP at the crank from a 998 in race trim, but it'll be a pig on the road.
100HP from a 1275 is much easier to get reliably and you don't have to rev the nuts off it. :wink:
Author:  blake12345 [ Sun May 03, 2009 8:34 pm ]
Post subject: 
thanks drmini mmm yeh ive been looking for a 1275cc but finding something to suit what i want has been a hard task but yeh
Author:  simon k [ Sun May 03, 2009 11:24 pm ]
Post subject: 
blake12345 wrote:
thanks drmini mmm yeh ive been looking for a 1275cc but finding something to suit what i want has been a hard task but yeh


don't give up looking for a 1275, there are enough around for them to still be found cheaply.... ask in the ACT club etc. - you'll find one for a good price soon enough
Author:  drmini in aust [ Mon May 04, 2009 8:04 am ]
Post subject: 
simon k wrote:
blake12345 wrote:
thanks drmini mmm yeh ive been looking for a 1275cc but finding something to suit what i want has been a hard task but yeh


don't give up looking for a 1275, there are enough around for them to still be found cheaply.... ask in the ACT club etc. - you'll find one for a good price soon enough

Keep an eye out for 1275 parts- a block here, a crank there, a head, set of rods, etc. Sometimes bargains can be had this way. :wink:
If you are going to recondition it (and should, if it's all worn) it won't matter a hoot if the bits are from various motors.
My 1412 stroker was built up from a $50 1100S block, $50 big journal crank, 4 free S rods from a couple of people, and a 1275LS head I bought 15 years ago and did up with all new bits.
OK, prices have gone up now but you get the idea.
Author:  blake12345 [ Mon May 04, 2009 1:56 pm ]
Post subject: 
Thanks Simon i'll keep looking but yeh i had a great rebuilt engine lined up but havent heard anything for about 2months now which is ok but i just dont know whats ahppening with it.

I was thinking of buying it in parts but knowing my luck id forget something and go to build it and leave something critical out

THanks

Blake
Author:  blake12345 [ Tue May 05, 2009 2:24 pm ]
Post subject: 
This is kinda related to this but do people find it easier to put an engine into the car with the subframe in the car or pull the subframe out and put on the frame then into the car?
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