19 replies to this topic

[Peter jack snelgar]

where do I start, 

after having six minis, varying from basket case to road worthy, I moved to France, sold them all, and bought a new one when I came back. one project, one dream,. one beast. 

it is a 1985 Austin 998 standard untouched, as factory, rusty, pile of rubbish MOTed and on the road needing love.

so far, I have rebuilt cooling system, radiator, pipes, water pump, thermostat, and housing.

I am just redoing ignition system, points, coil, distributor, HT leads, spark plugs, new battery.

Next mission, to rebuild second engine to replace and arrange new build of old engine already in the car. To produce 70 bhp with reliability at the fore front of everything. (any help, much loved, and thanked)

pictures will follow. 

With the input of my girlfriend/fiancé/lover, new paint, new interior, styled to her liking.

So in a nutshell, an every day car in use with slow progress, being built from the ground up while in use everyday until November with a month of painting and December a month of rebuild. Any interest, any help, thank you.

ogh and her name is beast hence the title  the beast 1.jpg   43.16K   5 downloads

[unburntfuelinthemorning]

Greetings and welcome back to Mini land.  I like a rolling rebuild.  For a reliable 70 bhp I reckon a lot of people here will say to base it on a 1275.  If you're keeping the 998 though a lower diff ratio will bring the car to life. 

[Peter jack snelgar]

Hi and yep sticking with 998 I have 2 engines one in running to be revamped and one to rebuild with simple upgrades till other is built. Diff will happen with time and budget is what I want so any suggestions big small and cheap expensive will be looked into. This is a car for life how I want.

[unburntfuelinthemorning]

I'm in the same situation with 998 engines.  You'll have to increase the breathing ability substantially with inlet, exhaust and head improvements.  I think then it comes down to picking a sensible diff ratio and selecting a camshaft which will provide the characteristics you're after as well as an appropriate compression ratio for the cam you choose.

 

(Edit: spelling)

Edited by unburntfuelinthemorning, 09 March 2019 - 07:50 AM.

[Retroman]

Welcome to TMF

 

Sound like a good interesting project, the BV reg may well be local to me originally being Blackburn prefix.

 

Unburnt has covered a lot of the relevant areas above, I would increase the cc as much as possible, the 998 will go to plus 0.100"

 

or even 68mm which gives 1107 cc and helps the bore/stroke ratio too. We have had 80+ hp on 68mm albeit running a 270 cam

 

a vizarded hif38...and a standard 35mm 12G940 head [cheaper than a 295]

 

Makes a really good hi-breed ..an 1100cc 998 with a 1275 head !!

[unburntfuelinthemorning]

I like the idea of 1107cc but then there's nothing left for a future rebore.  How did it drive with a 270 cam Retroman?

 

Oh and want was the fuel consumption like?

Edited by unburntfuelinthemorning, 08 March 2019 - 01:35 PM.

[Retroman]

The 68mm is sort of the limit, but I think some other pistons may be available, its one to look at for the future, may come down to bore wall thickness too.

 

With the 270 and a 940 head it was what you would expect, below about 2800 revs at was pretty meek but once the cam had effect its wonderful with a really good flat orque curve right up to about 6k, they lad loves it as its so good to drive, smooth and pretty quick, with perfectly good town manners...

 

 

No idea what the fuel consumtion was like, that was never the goal, but I usually find if you drive a tuned Mini really hard it will drop probably to the mid teens and drive the same car quietly and over 30 MPG is possible.

[Peter jack snelgar]

all sounds good but I am trying to do everything myself even a bit of welding so forgive the naivety but boaring 1107??? diff no probs, flow of intake and exhaust no probs but that's beyond me and garage capability's defo need help with that.

having said  that is that not getting away from the 998 build or is that just curving the idea into a plan?

the engine has at least a month and half to be put to plan so have time to think for know I have 998 to rebuild as efficiently as possible not to budget but to work for the nxt 6 months to rebuild the other. and have to think for me a ok ish mechanic to be able to do.

fuel consumption is never a goal for now so that is not in my head but don't want a 8mpg car either lol.

my cousin has a 1380 built 1275 stage 4 head massive cam and all he gets is a head ace with a gasket hear a leak there I don't mind but its not a bridge I want to cross right know.

[Peter jack snelgar]

I've in the same situation with 998 engines.  You'll have to increase the breathing ability substantially with inlet, exhaust and head improvements.  I think then it comes down to picking a sensible diff ratio and selecting a camshaft which will provide the characteristics you're after as well as an appropriate compression ratio for the cam you choose.

 

what diff that's where I get stuck and need help

[unburntfuelinthemorning]

The 68mm is sort of the limit, but I think some other pistons may be available, its one to look at for the future, may come down to bore wall thickness too.

 

With the 270 and a 940 head it was what you would expect, below about 2800 revs at was pretty meek but once the cam had effect its wonderful with a really good flat orque curve right up to about 6k, they lad loves it as its so good to drive, smooth and pretty quick, with perfectly good town manners...

 

 

No idea what the fuel consumtion was like, that was never the goal, but I usually find if you drive a tuned Mini really hard it will drop probably to the mid teens and drive the same car quietly and over 30 MPG is possible.

88 MPH @ 6000 rev/min - is that a 3.76 diff?  Bet that accelerates!

[unburntfuelinthemorning]

all sounds good but I am trying to do everything myself even a bit of welding so forgive the naivety but boaring 1107??? diff no probs, flow of intake and exhaust no probs but that's beyond me and garage capability's defo need help with that.

If you're rebuilding an engine you're going to need to have it bored to the next oversize at least (unless there's no wear in the cylinders).  Taking it to 1107 cc is the maximum bore size for available pistons.  No one rebores engines themselves unless that's their profession.

[unburntfuelinthemorning]

 

I've in the same situation with 998 engines.  You'll have to increase the breathing ability substantially with inlet, exhaust and head improvements.  I think then it comes down to picking a sensible diff ratio and selecting a camshaft which will provide the characteristics you're after as well as an appropriate compression ratio for the cam you choose.

 

what diff that's where I get stuck and need help

 

 

 

I've in the same situation with 998 engines.  You'll have to increase the breathing ability substantially with inlet, exhaust and head improvements.  I think then it comes down to picking a sensible diff ratio and selecting a camshaft which will provide the characteristics you're after as well as an appropriate compression ratio for the cam you choose.

 

what diff that's where I get stuck and need help

 

998's from the 1970s normally had a 3.44:1 diff ratio which worked well.  In the 1980s this went up first to 2.76:1 and then back to 3.105:1 when 12 inch wheels were introduced.  The 1980s ratios were higher and gave better crusing fuel consumption but were overgeared for the low capacity engine.  The 1970s ratio gave a more lively car with better acceleration.  Vans like mine had a 3.76 ratio which makes them very sprightly but quite noisy at motorway speed.

[Peter jack snelgar]

ok so if a bored engine is needed or a hone as a rebuild is happening any ideas on were I live middle of Scotland so need help with contacts. 

as the graphs above are depicting is this the limit of the engine in 998 and with the mods that were made and I think I would like to tame it a little so bore size ???

thanks for the advice and I will get as much information on anything I can to speck my engine hence the questions I can build the car the engine is a new thing for me by myself.

[Peter jack snelgar]

ogh and flat piston or cupped for rebuild

[Retroman]

 

I've in the same situation with 998 engines.  You'll have to increase the breathing ability substantially with inlet, exhaust and head improvements.  I think then it comes down to picking a sensible diff ratio and selecting a camshaft which will provide the characteristics you're after as well as an appropriate compression ratio for the cam you choose.

 

what diff that's where I get stuck and need help

 

 

The starting point is what you have now, which may be a 3.1

 

A lower diff is needed for some decent performance and the smaller the cc the lower it needs to be.

 

http://www.retromini...d=19&chapter=20

 

Have a read might help you get your head round it.

 

 

 

The 68mm is sort of the limit, but I think some other pistons may be available, its one to look at for the future, may come down to bore wall thickness too.

 

With the 270 and a 940 head it was what you would expect, below about 2800 revs at was pretty meek but once the cam had effect its wonderful with a really good flat orque curve right up to about 6k, they lad loves it as its so good to drive, smooth and pretty quick, with perfectly good town manners...

 

 

No idea what the fuel consumtion was like, that was never the goal, but I usually find if you drive a tuned Mini really hard it will drop probably to the mid teens and drive the same car quietly and over 30 MPG is possible.

88 MPH @ 6000 rev/min - is that a 3.76 diff?  Bet that accelerates!

 

 

Correct, it does exactly what it was designed to do, a real fun road car on a budget..., 3.76 is what a small cc Mini needs to do any real acceleration, which is exactly where the factory went wrong...chasing economy and using anything less than 3.0 is and was madness, they should have used a 5 speed overdriven 5th gearbox and a 3.76 for small bore engines, best of both.

 

ok so if a bored engine is needed or a hone as a rebuild is happening any ideas on were I live middle of Scotland so need help with contacts. 

as the graphs above are depicting is this the limit of the engine in 998 and with the mods that were made and I think I would like to tame it a little so bore size ???

thanks for the advice and I will get as much information on anything I can to speck my engine hence the questions I can build the car the engine is a new thing for me by myself.

  

I can't help with mid Scot contacts, but put the message out on here, someone should know.

 

The engine on the printout is by no means the performance limit of a 998, but as a good road car with performance and low speed drivablity it will take some beating.

 

Plus 0.060" on the engine which is a good increase. Boring to a bigger size is the cheapest and easiest way to increase performance, a good cylinder head next, along with a camshaft, 3 branch exhaust manifold and an alloy inlet.

 

Have a read of David Vizards A series engine book, there is a lot in there