8 valve heads

[djoptix]

Just seen a feature in French Cars on a rally 205 which uses an Mi16 block, 8 valve head and Jenvey throttle bodies. They reckon it makes about 210bhp (n/a too!)... any thoughts? Luke I remember having a conversation with you about heads and you reckoned the Mi16 head isn't as free flowing as it could be...

210bhp from 8 valves seems like a lot though!

[Timmo]

have seen the article! a lot of works gone into that engine though!
would make for an interesting drive though!

[thanuttiscotsman]

certinly sounds interesting!!

rossco

[Toddman]

Will prolly have that article so will have a read but without lookinmg I can say that the mi bottom end boasts stronger liners nad block along with the better crank and rods making it a cheap bottom end for high performance 8 valves.

The mi head is excellent in std form but ypu can go better if needed, one restriction is the port angle my mate running an mi bottom end with vaux/cos head in his 205 mentioned this the vaux head allowed more free flow and when the roller barrel TBs were fitted you could see the valve heads through the throttle.

The 8v will have been built for regs but if a 16v head was used to a similar spec you would be looking at a good chunk more power.

Cheers
Luke

[Channel Hopper]

Porting and putting the larger valves in the 16V head will release a lot more power, but the cost undoubtedly be prohibitive.

If you want to scream the nuts off an 8 valver, beware of the possible issues with higher reciprocating mass (unless you have Desmodronic gear fitted).

[Vanny]

What on earth is Desmo gear i thought? and found the answer here;

http://www.usq.edu.au/users/grantd/moto ... /DESMO.HTM

[Anonymous]

I always heard about desmos but never knew how exactly work
Nice article!

[Toddman]

A good system but doubtfull you would have any issues with an 8v mi - if you are going well into double figures i.e. over 10k rpm then possibly worth looking into but a good build will cope with 10k no worries, we used to get close to 10k with som eof the minis.

Cheers
Luke