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PostPosted: Fri Jul 04, 2014 3:25 pm 
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998cc
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Location: Close to Maitland NSW
Hi all, so I'm rebuilding my 1098 motor that came with my current mini k project. My thoughts are that it will be a Sunday driver and my wife will also drive it.
I want to fit say a 1 1/2 su, lcb extractors. Bigger valves etc.
It has to idle pretty smoothly but still a little sporty. Should I port the head mildly or leave it alone? My engine builder suggested he could throat the area under the valves and I could mildly match the ports with the exhaust and intake.
Any thoughts on valve sizes, cam etc.
cheers, Richard .


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PostPosted: Fri Jul 04, 2014 4:08 pm 
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Get the head done to 998 cooper specs as in the same as a 12g295 head and then put a nice cam in like a Kent 266 I had this on an 1100 of mine and it went really well. Make sure you get the motor fully balanced as well. My brother had a similar setup except had a re13 cam from graeme Russell and it also went well. The 731 cam is also great one of these three cams would be my recommendation.

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PostPosted: Fri Jul 04, 2014 4:30 pm 
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I've used all 3 of those cams in various motors, my pick for a 1098 motor would be an RE13.
You don't need to make the 202's chambers as big as a 295 has, they are too big to get decent C/R.

Here's a 202 I prepared earlier- pic taken before polishing.
The chambers were routed to shape using a carbide burr in a bench drill.
Image

Image

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PostPosted: Fri Jul 04, 2014 5:59 pm 
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I had same motor as my brother -1100 I had a 295 head he had a worked 202 and I had a 266 cam he had re13 and my mini went harder then his..... My preference 266

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PostPosted: Fri Jul 04, 2014 6:55 pm 
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998cc
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I've seen one 1100 running an RE13 and it's one lumpy beast, it idles like a fully worked group n spec car and that's with standard rockers.
It has a ported 202 on it and it beats most of the mild 1275s in our club.
It's a great engine.

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PostPosted: Fri Jul 04, 2014 7:47 pm 
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998cc
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drmini in aust wrote:
I've used all 3 of those cams in various motors, my pick for a 1098 motor would be an RE13.
You don't need to make the 202's chambers as big as a 295 has, they are too big to get decent C/R.

Here's a 202 I prepared earlier- pic taken before polishing.
The chambers were routed to shape using a carbide burr in a bench drill.
Image

Image

Would this setup suit the brief Kevin? The missus would be driving it and she wouldn't be happy if she having to rev 3000rpm to get it off the line :)
Also what order would you do the work, cut the seats first or modify the chambers?
Richard.


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PostPosted: Sat Jul 05, 2014 7:17 am 
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Yes it would be fine.
Always cut the chambers first, and do the seats last. This head got unleaded exhaust seats in, and is running on a 1220cc Sprite motor in a Morris Minor woody. Twin HS2 carbs. Cam is a Cooper 997 one (16-56/51-21).

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R. :mrgreen:


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PostPosted: Sat Jul 05, 2014 7:30 am 
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998cc
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drmini in aust wrote:
Yes it would be fine.
Always cut the chambers first, and do the seats last. This head got unleaded exhaust seats in, and is running on a 1220cc Sprite motor in a Morris Minor woody. Twin HS2 carbs. Cam is a Cooper 997 one (16-56/51-21).

Ok thanks Doc, did you need to cc the chambers after and make up the lost compression somewhere else? Also what valves are they, part numbers would be great! Thanks


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PostPosted: Sat Jul 05, 2014 7:42 am 
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Yes the chambers got cc'd, I can't remember what the volume was. Pistons were 68mm flat tops (Hillman Imp). C/R was around 9.5:1.

[edit] for those wondering, I don't do heads anymore, my eyesight now isn't good enough.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R. :mrgreen:


Last edited by drmini in aust on Mon Jul 07, 2014 8:08 am, edited 1 time in total.

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PostPosted: Sat Jul 05, 2014 9:35 pm 
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Location: North of the Harbour planning my next mini project
266 cam with a mildly worked 202 head, 1 1/2" carby and extractors works well. Check out one of David Vizards books on how to modify the A series engine for further info.

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PostPosted: Mon Jul 07, 2014 5:49 am 
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alternatively see Graham Russell's work on the subject
http://russellengineering.com.au/perfor ... der-heads/
or this chap has an interesting blog for those looking to learn more about porting mini cylinder heads
http://aseriesmodifications.wordpress.com/


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PostPosted: Mon Jul 07, 2014 12:22 pm 
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998cc
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Lots of good resources in these posts, thanks for the replies, I will need to do some research and defiantly not rush into anything yet.


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