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16 valve twincam head conversion
https://www.ausmini.com/forums/viewtopic.php?f=2&t=47494		 Page 1 of 2
Author:  david rosenthal [ Wed Nov 12, 2008 12:27 pm ]
Post subject:  16 valve twincam head conversion
For all who inquired about my 16 valve twincam conversion for small bore and 1275 engs, here are some pics of the head and spacer plate set-up.
I am setting up this head on a rebuilt 1100 eng and doing some improvements with oil pump and belt drive set-up to drive water pump and alt off the timing belt. Build one and you can always find better ways of doing it.
I hope to have this eng running over the weekend and will post pics later.


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Author:  mattsmadmini [ Wed Nov 12, 2008 12:40 pm ]
Post subject: 
That looks yummy David...

What heads are you using? yamaha or suzuki or something? lol

Cant wait to see them going!
Author:  sports850 [ Wed Nov 12, 2008 1:29 pm ]
Post subject: 
Now that looks interesting , how did you find the head that suited (and of course what is it , car or bike ?) ? What sort of compression ratio does it have with the spacer plate fitted and how does it compare overall (work required etc) with the BMW twin cam heads ?
Author:  Kennomini [ Wed Nov 12, 2008 6:58 pm ]
Post subject: 
Yeah don't be so secretive....give us some juicy details :P
Author:  Angusdog [ Wed Nov 12, 2008 7:09 pm ]
Post subject: 
Some of the bike boys are getting pretty pissed off to come back and find their bike's now got a non-crossflow two valve head and twin SUs...
Author:  mattsmadmini [ Wed Nov 12, 2008 7:16 pm ]
Post subject: 
kawasaki???? :lol:
Author:  drmini in aust [ Wed Nov 12, 2008 7:20 pm ]
Post subject: 
H****. :wink:
Author:  mattsmadmini [ Wed Nov 12, 2008 9:49 pm ]
Post subject: 
drmini in aust wrote:
H****. :wink:


really??? snap hey... them cbr boys will be upset :P
Author:  david rosenthal [ Wed Nov 12, 2008 10:31 pm ]
Post subject: 
Kev wins the door prize
It's off a honda bike but not a model that is common here is Aust. The japs have plenty. A mate of mine who races bikes imported one and after checking 100's of heads I did a rough measure and it looked promising.
He HAD a spare eng, but it now missing a head[replacements coming from japan] and he tracked down another for me. The original one has two bent inlet valves, thanks to a stripped timing belt and a sh*t oil pump.
The bike std bore is 68mm[half way between small bore and large bore mini. The cylinder head is evenly spaced so two bores will have a small overlap[app 3mm] Valve dia inlet 27mm and exhaust 24 mm double std head. v/v lift 10mm.
The head requires boring along cam lines to fit extension shafts for timing belt drive and dist/oil pump drives.
I am now using a good old type mini oil pump but it is now driven off the exhaust cam. No more stripping down eng to change oilpump.The oil pick up it via the plate on gearbox [Eng block blanked off] with pipe to pump. The pressure side feeds back to external fitting near relief v/v and using the existing relief v/vand feeds to filter etc.
The ign is a honda elect dist driven off the inlet cam.
The bike crank rotated anti clock oposite to mini so now the firing order is
1 2 4 3 instead of 1 3 4 2
The original bike sensor and computor could not handle this ,so back to the good old reliable elect dist.
The timing belt drives the water p/p and alt, only one belt to worry about.
The clyinder head bolts match the s/plug side of block within 2 to 3 mm and the cam follower side the head bolts fit into block web[morris 1100 blocks appear to be thicker here than clubman blocks]
I am running honda CD quad carbs[35mm butterfly] The original fuel injection for was designed for economy and polution. Not H.P.
I think that I have covered all, if not just ask
Author:  mad-mk1 [ Wed Nov 12, 2008 10:37 pm ]
Post subject: 
yum yum yum

sorry i missed u the other day, would have loved a squiz at this beast :)
Author:  david rosenthal [ Wed Nov 12, 2008 10:52 pm ]
Post subject: 
Jamie Lucky I hide things,when you were here the test eng had just gone "BANG" The head is being repaired and the old block rebored etc to fit bike pistons.
I am building up another eng using the rebuilt 1100 eng. should have it running after weekend. give you a call for a look see. I might put it in the "flintstone clubby or the moke"
Author:  mad-mk1 [ Wed Nov 12, 2008 11:05 pm ]
Post subject: 
david rosenthal wrote:
Jamie Lucky I hide things,when you were here the test eng had just gone "BANG" The head is being repaired and the old block rebored etc to fit bike pistons.
I am building up another eng using the rebuilt 1100 eng. should have it running after weekend. give you a call for a look see. I might put it in the "flintstone clubby or the moke"


oh yeah sounds good:)
then we can do this to your paddock again:
Image
Author:  mini-dunger [ Thu Nov 13, 2008 12:46 pm ]
Post subject: 
dave would like an apprentice/crap kicker?


I will work for free?
Author:  Kennomini [ Thu Nov 13, 2008 4:40 pm ]
Post subject: 
david rosenthal wrote:
The bike crank rotated anti clock oposite to mini so now the firing order is
1 2 4 3 instead of 1 3 4 2

So the engine is still running clockwise but the head is now running backwards from factory spec correct :? :?:
Author:  david rosenthal [ Thu Nov 13, 2008 11:37 pm ]
Post subject: 
The cam lobes are symmetrical so they can rotate either direction. The firing order on the bike is 1 3 4 2 but anti clock rotation. If you rotate the cam in opposite direction the firing order is 1 2 4 3.
Both engs have same crank pin design. I.E. No 1 and No 4 T.D.C and No 2 and No 3 B.D.C. so with dist. rotation it is just a matter of changing spark leads around to the required new firing order.

On large marine diesels the cam shaft is end for ended in eng so that each eng rotates in opposite direction. The firing order is " mirror" sequence between the engs. Quite common with 8 cyl inline Blackstone engs.
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