Crossflow opinion please guys.

[Oldskoolbaby]

There seems to be all manner of different crossflow heads out there these days. From typical 7 and 8 ports to the twin cam 8 and 16 valve variants. Now ive had both a Minisport 7 port and a BMW K1200rs conversions in the past but these were on relatively large A seires engines. However, I want my car to keep beneith the 1000cc threshold so I'm not sure whats best this time around. I have been pretty adament with starting with a 970s bottom end but sitting down and thinking about it, to begin with atleast, i'd be happy in starting with a small bore engine to begin with. Main reason being parts availability should poo poo hit the fan which i can see happening with such a highly strung little motor.
So, is there a head out there that suits or works well with a small bore block? More importantly sub 1000cc. I know the Ardens work well.

Like I say, this is just to get me a couple of seasons under my belt with out the worry of huge financial hits when it needs new bits and bobs. I intend to build a rep of my cars old engine (999 Arden 8 port) albeit with modern injection but that a while off yet.

Im open to ideas too guys regarding the bottom end so please feel free to throw some this way.

[rich@minispares.com]

the arden wont work on a small bore block, so you would be looking at a 970 / 1071 / something exotic.

if you want to use a small bore, then look at the s/c 7 port - will kerr has had great success with his 998 turbo version - and its proven to work well

[Oldskoolbaby]

the arden wont work on a small bore block, so you would be looking at a 970 / 1071 / something exotic.

if you want to use a small bore, then look at the s/c 7 port - will kerr has had great success with his 998 turbo version - and its proven to work well

Yes your right about the Arden. I meant to type they work well on 999's. I didn't realise the SC head worked on small bores. I was only looking at their 8v twin cam conversion the other day as its the only twin cam I can find that works on the 998 block.

[Smiffy]

Wasn't someone in holland, sweden or at least in europe doing a alloy 7 port/8 port. Cnc'd on a 5 axis machine, saw some pic's of it, but nothing since ?

[69k1100]

There was an engine sold recently on the aus mini forums utilising a Honda CBR head.

[Oldskoolbaby]

Wasn't someone in holland, sweden or at least in europe doing a alloy 7 port/8 port. Cnc'd on a 5 axis machine, saw some pic's of it, but nothing since ?

Yes ive seen a few video's of that head/car. Looks to perform ok but there is a weird center port that doesnt look to reliable in my opinion. Technicaly id call it a 7 port. The power they say it produces is abit optomistic aswell in my opinion. 135hp from a 998 is going some! My car had to rev to well over 10,000rpm with a large bore block and 8 ports to get 115-120hp. Would love to see one hit the 130 mark though.

Wouldnt mind seeing some pics of the CBR conversion.

[mk1]

Will H's 998 Turbo got very close to 200 bhp, fairly reliably.

M

[Oldskoolbaby]

Although I'd love 200hp and reliability it needs to be natural aspirated fella.

[mk1]

I agree, forced induction is just cheating

But Will's figures were real ones.

M

[Frogeye61]

Wasn't one of the first twin cam jobs on an 850?
http://www.lojomo.com/

[Oldskoolbaby]

I agree, forced induction is just cheating

But Will's figures were real ones.

M

Not doubting the 200+hp figures at all. Looks a great bit of kit.

Out of curiosity, what is the absolute maximum offset over bore on an 850 block and what abuse rpm wise can the later 850 cranks take? Was picking ideas out of the air today and didnt know if i could use the 850 as a start off as i know its essentialy a de-stroked 998. Ive got zero experience with 850's so hense the question.

[Spider]

Wouldnt mind seeing some pics of the CBR conversion.

I don't have any pics however here's some video to tie you over

http://www.youtube.com/user/davidnrosenthal09

I'll have some pics late next week.

edit> Here's a pic I do have on file of the Inlet Port