69mm offset bore and 16 valve k head.
Turbo Mini Forums

surely this would work, as it makes almost consistent bore spaceing.

couldent you theoretically put a 16 valve head on it as its almost at the same as the big bore blocks.

Thanks

Sam.

i know its been talked about alot however i havent seen any solution like this talked about.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

if you wouldent mind matey it would be intresting to see i think i might just have to venture and spend 4/500 pounds doing this. i dont count the head in the expenses as ill be useing it on another engine. if you could get to 69mm youll be at big bore size anyway so im sure it would just bore wall flexing and such.

Edited by Sam on 7th Dec, 2007.

I still believe that it should be possible to bore a small bore out till big bore bores by utilising the big bore cylinder spacing.
Anyone thought about using liners?

The BMW K1100LT has 70.5mm bore + consistent bore spacing (circa 75mm)
So if you had almost consistent bore spacing you would need a bigger bore then 70.5mm...

On page 376 of TBASE Vizard talks about using Imp pistons at +0.040" which are 69mm. He is only offsetting the bores by 0.025", but warns of problems with the boring.

Liners would be essential if you are going to any greater offset.

The cylinder walls are cast to the standard bore spacing. There is not enough metal between cylinders 2 and 3 to get them close enough together.

I'm currently considering boring an 850 to 66.6mm using +0.080" 998 pistons.

The attached shows the bore spacings. Black is the 850 bore, orange is the 66.6mm bore at maximum offset and the yellow is the K100 bore spacing.

I still need to measure the thickness of the cylinder walls to check there is enough metal to do this.

Attachments:

17.32kb

Edited by Paul S on 10th Dec, 2007.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

hmmm, how much cost linering the block?
I still love the idea of a short stroke 1300 (silly me)

Attachments:

14.6kb

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

Did you account in you graph that the valves have an angle compared to the pistons. IE 9,5mm lift maybe only 8mm lift if you measuresed perpendicular to the block surface.

No, but the valve angle is only 20 degrees from the vertical and the cosine of 20 degrees is 0.94, so makes very little difference at the lifts I'm interested in.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

not possible then i guess i sore an image of a small bore block offset bored and i though it looked fairly even on the bore spacing, i guess the problem being is that with a 16v head having exhaust valves on each side of the cylinder, pocketing the block would just start to open up the bores into each other.

ill have to stick to a 8v head then :(


thanks Paul for your help

Sam

No problem.

I'm deliberating over the same issues at present.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

its pissing annoying about the bore spaceing. ill be building a twin cam n/a engine shame i cant do it with the 16v on a small block. i haven't seen it done yet

if i could get hold of a 970 engine although its a big bore it might be fun to use that instead.

Hmm, would a 970cc a bit of destroying hertitage? Weren't there only a 1000 of these blocks ever made?

An other option could be using std overbore with the original bore spacing and (probably) massive block pockets.
I dont know if that would make any sense.

well a big block could have a short stroke crank so it isent a problem to get it to 970ish. 8v isent a problem. however 16 valve is a problem because basically you have to pocket 2 sections of each bore and they will open into each other.

dont know if it would be worth looking at but i had a quick look in the motorbike wreckers the other day and the bore spacing on a 2001 triumph tt600 looks very close too. they also run a similar bore size.


Edit: triumph use a 68mm bore


Liquid-cooled, DOHC in-line 4 cylinder

Bore & Stroke 68 x 41.3mm
Capacity 599cc
Compression Ratio 12:1
Maximum Power 110PS (108bhp) @ 12,750 rpm
Maximum Torque 68Nm (50.5ft-lb) @ 11,000 rpm

Edited by benjamin on 15th Dec, 2007.

1152cc turboed mini clubman, most powerful 1.1L a-series?

http://boostmini.justboard.net/

Hi,
Weren't all the S blocks the same, they just decked them to make the 1071 &970?
Cheers,
Gavin :)

VEMs Authorised Installer / Re-seller. K head kits now available!

WB/EGT gauges. Click here for customers write-up

Visit www.doyouneedabrain.co.uk

My Mini build diary

On 15th of Dec, 2007 at 07:51pm benjamin said:
dont know if it would be worth looking at but i had a quick look in the motorbike wreckers the other day and the bore spacing on a 2001 triumph tt600 looks very close too. they also run a similar bore size.


Edit: triumph use a 68mm bore


Liquid-cooled, DOHC in-line 4 cylinder

Bore & Stroke 68 x 41.3mm
Capacity 599cc
Compression Ratio 12:1
Maximum Power 110PS (108bhp) @ 12,750 rpm
Maximum Torque 68Nm (50.5ft-lb) @ 11,000 rpm

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

Maybe,

but thats 13000 on a 600,

on a thousand they'll be a fair bit tamer, possibly still too lairy though.

So who is going to buy that head gasket on ebay ending in less than 20 minutes?

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

ok had a little read up on them. there are 3 bikes with the same engine, daytona 600/650 , speed4 and the tt600

The TT600 has the hottest cams of all the engines. and the exhaust ports in the tt600 and s4 are oval where as the ports in the d6 and d650 are round.

the s4 has much more midrange so maybe better cam choice?

1152cc turboed mini clubman, most powerful 1.1L a-series?

http://boostmini.justboard.net/

Ooo this could be an interesting project!!

Surely it would be quite easy to reprofile the cams to suit. Or am I speaking out of my arse?

https://www.facebook.com/pages/Fusion-Fabri..._homepage_panel

www.fusionfabs.co.uk



1/4mile in 13.2sec @ 111 terminal on 15psi

oooo, new conversion....

i like!!!

I would be happier with a bit of Triumph under the bonnet than BMW.

It still would not fit the small bore but may be OK for 1275s.

Someone needs to buy a head gasket to check that the head studs will go in the block.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."