Technical Motorbike cylinder head on FIRE engine!!!!

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Technical Motorbike cylinder head on FIRE engine!!!!

soozukisteve

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Hi there
**sorry to all who were interested in the cinq/uno turbo conversion.i broke my laptop and couldnt remember my password to log in to FF to update proceedings,so i gave up:bang:!!!!!
was just getting all my personal stuff off my phone before upgrading and found id saved it in a personal folder in there....dammit.........:idea:
Anyways,due to some unforseen personal stuff,cinq turbo is now no more and my punto 75 engined cinq has also gone..booo hooo..:cry:****


Now,onto my next hair brained scheme.

I now have a seic sporting abarth that would benefit from a decent power hike.
I also have in my possesion a low comp high boost van aaken(?) bottom end,T15 turbo,intercooler etc... that i was gonna put in but have been thinking about the possibility of grafting a motorcycle cyl head onto the 1108 to make a high revving screamer.
I am aware of the mini/bmw k100 conversion that is fairly popular so im trying to get as much info about it as poss.

Firstly though,i wouldnt mind hearing peoples thoughts on this as opposed to going the turbo route..

1.i shouldnt suffer from transmission woes as i wont be producing anywhere near the same amount of torque as a turbo even if the peak hp is the same(or more???)
2.i thought about using the crank from a 1000 FIRE uno (shorter stroke) but not sure if they are weaker!!
3.will try to use motorbike pistons ,matched to the head,which are designed to withstand high rpm which will allow a decent amount of lightening of the bottom end
4.I did hear a few years ago that someone dynoed a standard FIRE engine to destruction and it didnt let go until 14,000 rpm??do standard FIRE engines bottom ends hold up to being revved(obviously it would be balanced)
I reckon a 9-10,000 limit would allow me to get the peak hp out of the cams and head.
anyway,im just toying with the idea at the moment so any input would be greatly received.:confused:
steve
 
just getting the FIRE head sorted, and the valve train lightened and balance, the bottom end the same - you should be able to rev to silly RPM.

it sounds like a waste of time / effort / money trying to make the wrong head fit..
 
ive never been one to go the normal route!!!(one unfinished cinq/uno turbo money pit to my name!!)
there are a few reasons i have for contemplating such a task
-without going forced induction,the cyl head and inlet are always going to be a limiting factor in outright power as they were not intended to produce huge amounts power.
-i havent searched for this,but from my experience of these FIRE engines,i think it would be hard to get above about 90hp without swapping to throttle bodies(these are already fitted to later bike cylinder heads).
-is it just me(maybe-cos im a bike fanatic too)or isnt the thought of blasting past some saxo vtxrgti turbo at 9500rpm sheer heaven?...
-there are a lot of minis running around with the k100 head,both 8v and 16v putting out between 105 and 125bhp so there is a fair bit of info out there.
-why not a 16v FIRE?Already been done and cost too prohibitive to see the right kind of horsepower.
-late 1.4 16v plenty of power but far too expensive!
-For all i know,god might be looking out for me and all the bolt holes and drillings will all fit perfect........
-the k100 engine is basically a car engine(think it was from a 104?)and so size wise ,should be about the same.

I know i will have to look at the timing side as i will have to fit a chain(dont want a belt letting go at 10000rpm!!),and fuelling(may use bmw/fiat mix and match or standalone!)

Essentially,what im saying is,if the head matches up relatively easily,all the other stuff can be dealt with,without too much of a headache.im in no rush as ive got FIRE engines coming out of my ears and a seicento with a lovely purring(reliable-so far) engine.
 

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IIRC the reason the K100 head is used on the old A series is because the standard head is limited in what it can do with that Siamese central port, and the inlet/exhaust on same side of head, whereas the BMW head offers a proper cross flow head with no Siamese ports, so all in a much much better design.

The Fiat does not suffer any of these design issues and therefore I see no reason why you would want to run a bike head on one.

As Arc has pointed out, the Fiat head responds to work well, have a look at Johns (bigfiat) thread on his hill climb Cinq, its revs to near 9K IIRC and makes about 95bhp from a 1.1 & without using throttle bodies, which is pretty good as he was restricted to keeping original engine size, so had to make the most of it and work within the regulations of the series he competes in.

Therefore you could take essentially what he has done and be a bit more extreme as you do not have regulations to hold you back where he was.

As for cost, I don't follow the logic that going 1.2 or even 1.4 16V is too costly as I can't see how making a cylinder head off a bike fit and work is going to be any cheaper.

Aaron.
 
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I'm with Aaron on this. By bike standards, the K100 is no great shakes. All you're getting over a FIAT 16v is a lumpier cam and a shedload of engineering issues. By 16v mini standards, the K100 is pretty pathetic, the advantage is that it's cheap and fits fairly easily.

£ for £, the 1400 16v conversion is probably the best and most reliable out there. 110 brake or so and still room for tuning and/or forced induction.
 
I hear what your saying and thankyou all for being honest about it.
I picked up on the k100 as that had been done before on the minis but had also investigated a few other cylinder heads that had bore sizes matching the 1108.
this of course doesnt mean that the bore spacing/waterways/oil galleries and head bolts will match up if at all.
I have seen a few 1.2 16v engines but people seem to be asking the earth for them and despite scouring ebay every so often(the 1.4 had been my first thought!!),i am yet to come across a 1.4 16v for sale!
I have been down the uno turbo/cinq route also,but due to circumstances out of my control,that project had to be junked!!!

Ill be honest,if a late model motorbike cylinder head dropped into my lap that fitted almost perfectly,i would give it a go but considering i would need to offer loads up to see if they would fit first,i think it might not happen...

Anyways,i always like to try something different so ill go back to the drawing board and see if i cant come up with something else.(will check out the high revving FIRE engine you mentioned first though!!!!)
 
I'm with the others on this. Waste of time trying to fit a motorcycle head to a FIRE block. You'll be trying to mate two totally different designs that were never designed to work together and I don't think you'd see much for your efforts anyway. The engineering costs alone would far outstrip doing other conversions which are more likely to give you more power for your £.

If you really want a screamer and like motorcycle engines, then fit a motorcycle engine complete. Yes, it's been done but it's proven and it works. You might lack low down torque but a 'Busa/ Blackbird/ Blade/ ZX12R/ GSXR engine will produce 150bhp+ without any mods.
 
Hang on, you want silly high RPM, and fitting a bike head will do this HOW?

Thinking logically its the bottom end thats going to give you the RPM you want, then you make the head flow to suit.

If you really want to improve the head then you could do a lot worse than sleeving the standard head and making it more down draught. Lots of work invoved in that, just what you want.
 
:eek:

Fair enough. Gotta cost a small fortune!

Not really: you block off the relevant passages with alloy bar and araldite (TIG if you're a perfectionist) and then drill and tap the head and block for the pathways. Probably run with solid gasket.

But I'd repeat, the Mini/K100 solution is really only a good thing if you can't afford a "real" 16valve head and, like Aaron says, it's largely because of the crappy inlets on minis that it shows such an improvement.
 
Your not looking. I bought a 1.2 16v off here a few weeks ago for £125 and i could of got one for £100 off ebay

ill consider myself repremanded!!!
whenever i have looked,i have only seen the breakers wanting hundreds for low mileage examples....admittedly,i havent been scouring on a daily basis,just periodically when i have time(im always too busy)

-as mentioned earlier,dry decking (if required)isnt quite as expensive and compicated as it sounds,but time consuming to get right.
-the cams and cylinder head are the main components involved in getting high rpm from an engine(although piston shape,comp ratio, squish area etc need to be matched to the cam/headwork).obviously,the bottom end has to be strong enough to cope,usually,uprated bolts/nuts mild lightening and a full balance will suffice unless silly revs are required.if the cam profile is rather harsh then a switch to solid lifters to prevent them draining down is needed and uprated valve springs to prevent valve bounce.
-the engine i was talking about (14000rpm) was,im sure,a standard FIRE just tested to destruction.I wouldnt swear to it as it was a while ago,but im sure it was a reputable dyno guy!!!
-what is the going rate for a 1.4 16v fire and are uprated cams readily available????
-i have also thought about the complete bike engine route but despite being a bit of a nutter when it comes to projects,i am still something of a purist so would like to retain some fiat in whatever hybrid i might decide to use.
-effectively,a motorbike head is similar to a highly tuned 16v car head(high flow capability,high lift cams,lighter valve gear,stronger valve springs,large throttle bodies that easily fit to the head etc...)

I think ill keep my eyes open for a 16v FIRE and do some sums for the high revving 8v before i make a commitment to either..
thanks for the input,will post again when i make a start.........

Feel free to reply with any more info(especially if you wish to redress the balance of the thread as its a bit one sided at the mo....boo hoo....):cry:
 
what is the going rate for a 1.4 16v fire and are uprated cams readily available????

IIRC Aaron got his engine and gearbox for £300! In this, as in much else, he was very lucky, but it gives you something to aim for!

It's a relatively new engine, so I don't think much is available for it cam wise yet, but a cam is a cam, is a cam......
 
It's a relatively new engine, so I don't think much is available for it cam wise yet, but a cam is a cam, is a cam......
All the 1.2 16v cams will work in the engine as I think they share the same head, certainly the C&B fast/max road cams are specified for the 1242/1368 16v engines.

What I don't know is if the 1242 & 1368 cam profile is the same.
 
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C&B have different cams for the 1242 and 1368 with different profiles.

Wolfracing suggest not to fit 1242 cams into the 1368cc that they sell. Probably because nobody tried though.

The cams will at least fit, as the heads are very similar ... but not identical!

The cost of the 1368cc is not the main problem, its then are as rare as hens teeth, hence why i did a 1242 16v while waiting to source a 1368cc.

I paid more than Aaron, he got an amazing deal! Well under what i'd imageine they are worth. They prob didn't know what they were selling, or thought there wouldn't be much demand.

A nice 1242 16v would be my choice tbh as they are nothing near as rare as the 1368cc, have good potential, and you can "easily" upgrade in the future.

Kristian
 
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