97 replies to this topic

[oltonlad]

thats a great vid and love the cars name!

Whats the idea of using straight cut drop gears? Ive seen a lot of people using them. Is it a cheaper way of getting the straight cut box noise or is there a reason?

What kind of speeds does it manage?

When im back at work i will look at the collection of bits i have, the most important bit is i have two complete engines now!

So is the difference in performance noticeable between the 1098 and 998?

cheers, the reason that i used the straight cut drops is so that i could alter the final drive, at the moment the final drive is 3.59:1 which is a result of mixing a 3.44:1 diff with 1.04:1 drop gears, i wanted a final drive that was in between the 3.44 and the 3.76, as for the speed, i'm not sure of the top speed as i havent tried it but it will only pull 95-100mph due to the gearing anyway, the 1098 engine has a lot more torque than the 998 and is a much nicer engine to drive in my opinion, you have to scream the tits off a 998 to make it go anywhere whereas you dont with a 1098.

[Danthefestaman]

Ah i get you, would you still go for a straight cut box long term?

Well i had a quick look at the flat top pistons i got with the 998 and the skirts look like they are scored so they might just be scrap value.

Also if i was to use the Acd rt cam can i use the fixed duplex timing chain i have or would i need to dial the cam in?

I think i will use the 1098 and then sell off the 998, i had to buy it though as it came with the gear box and all the clutch set up. Are the any parts off the 998 that i could use on the 1098 to make it better with no extra cost? Like are the flywheels any different?

With regards to the engine, Do i need to uprated the head studs and any bottom end bolts to run a simple engine with just uprated head, cam, and a bit of balancing?

[oltonlad]

Ah i get you, would you still go for a straight cut box long term?

Well i had a quick look at the flat top pistons i got with the 998 and the skirts look like they are scored so they might just be scrap value.

Also if i was to use the Acd rt cam can i use the fixed duplex timing chain i have or would i need to dial the cam in?

I think i will use the 1098 and then sell off the 998, i had to buy it though as it came with the gear box and all the clutch set up. Are the any parts off the 998 that i could use on the 1098 to make it better with no extra cost? Like are the flywheels any different?

With regards to the engine, Do i need to uprated the head studs and any bottom end bolts to run a simple engine with just uprated head, cam, and a bit of balancing?

i have used straight cut gears in my last 3 mini's and the noise/sound doesen't bother me at all but some people say that they get annoying after a while, its down to personal preferance i guess, as for the cam......any performance camshaft needs to be dialed in with a vernier gauge (although some people on here reckon that you can get away with lining the dots up which in my opinion is a load of bulls**t)
you can use the standard head studs (new ones), there is no need to uprate them or the bottom end bolts on the spec of engine that you want....although i would fit a centre main strap on a 1098.
the only difference between the 998 and 1098 engines are the crank and the pistons....everything else is the same (except the later 998 engines which use the verto clutch....... and the cylinder heads)
if you are using a 12G202 head then i would have it skimmed by around 50 thou to bring the compression ratio up to a decent level, or if you can get hold of a 12G295 cooper head then that will be much better (skimmed 80 thou).

[Danthefestaman]

Well i love the straight cut noise and besides i wont use the car every day! A friend of mine had a straight cut with his mini speed 1400 he had as it was eating gearboxes.

So i will get the centre main strap and sort new studs e.t.c.

Do you need to use roller rockers or is that just a way of getting higher lift with out chaning the cam?

I see you run twin hs2`s does it make it better over running a single carb? Id love to run a weber but im guessing its overkill!

The head i was told is already skimmed to 20 thou and used on thr 998, i will be handing it to a company in silverstone to have it sorted anyway, Would you get it unleaded converted why it was off?

Sorry its 20 questions but its been so many years since i had a mini i have no clues anymore.

[oltonlad]

Well i love the straight cut noise and besides i wont use the car every day! A friend of mine had a straight cut with his mini speed 1400 he had as it was eating gearboxes.

So i will get the centre main strap and sort new studs e.t.c.

Do you need to use roller rockers or is that just a way of getting higher lift with out chaning the cam?

I see you run twin hs2`s does it make it better over running a single carb? Id love to run a weber but im guessing its overkill!

The head i was told is already skimmed to 20 thou and used on thr 998, i will be handing it to a company in silverstone to have it sorted anyway, Would you get it unleaded converted why it was off?

Sorry its 20 questions but its been so many years since i had a mini i have no clues anymore.

the best rockers to use are 1.3 ratio roller tipped ones, the twin hs2's give more torque over a single carb, you could use a weber or dellorto 40 but theres not much point with a 266 cam really and they are really fussy carbs too, you would soon get fed up of it being difficult to start etc, stick with su's whether single or twin, when you hand the head over to the machine shop see if they can measure the cc in the head, you need about 24cc if possible, as for converting to unleaded, it depends on whether your car is a daily driver or not, if it is then i would say yes get it done, i didn't bother as our mini only does around 1500 miles a year.

[Danthefestaman]

I suppose it makes sence thats why they used them on the coopers! I remember my friend ran them on his 1400 but it was a pain to get it to idle and he switched to a weber. We are lucky in Northants as we have Northants Motorsport who are extremely good with carbs. Would you recommend new or can you clean up a set of used ones?

Next theng is the ignition, i used to be pretty good at setting up points but can you get an electronic set-up or a coil set-up? I remember aldon used to do different colour ones for different stages of tune!

Il be back at work monday soi can start taking pics and sorting a complete engine out!

Thanks for your help im trying to pick up everything!!!

[oltonlad]

I suppose it makes sence thats why they used them on the coopers! I remember my friend ran them on his 1400 but it was a pain to get it to idle and he switched to a weber. We are lucky in Northants as we have Northants Motorsport who are extremely good with carbs. Would you recommend new or can you clean up a set of used ones?

Next theng is the ignition, i used to be pretty good at setting up points but can you get an electronic set-up or a coil set-up? I remember aldon used to do different colour ones for different stages of tune!

Il be back at work monday soi can start taking pics and sorting a complete engine out!

Thanks for your help im trying to pick up everything!!!

my girlfriend bought the twin carbs for our mini as a prezzie, they were totally refurbed and highly polished, not cheap either at £300 for the carbs with the cooper s manifold, then i had to buy the K&N filters which were another £80, you can recondition a set of old carbs but make sure that they are a matching set to start off with.
you can get electronic ignition kits for the distributors so thats not a problem, aldon still do the performance distributors, you would need an "aldon yellow" for your engine.

[Danthefestaman]

Great, just had a look on ebay but only found 1 set that had no linkages, i will look again later when i have more time! Thats one good girlfriend i dont think mine would do that for me!

Might have a look in my old college books to see if ican find anything out about measuring CC.
Next week i should get some free time so il get cracking on putting it together!

[oltonlad]

Great, just had a look on ebay but only found 1 set that had no linkages, i will look again later when i have more time! Thats one good girlfriend i dont think mine would do that for me!

Might have a look in my old college books to see if ican find anything out about measuring CC.
Next week i should get some free time so il get cracking on putting it together!

to measure the cc of the head, get a syringe (from boots or wherever) and a plastic cd case cover, drill a small hole in the cd case cover and lay it flat over the top of the chamber, fill the syringe with petrol and fill the chambers through the hole in the cd case, make a note of how much petrol is dispersed into the chamber (there will be markers on the syringe.....1ml=1cc) until it is full.......job done.

[Danthefestaman]

Is there any risk of clearance problems if you go to mad? Not that i would as my machine shop will advise me on whats best.

Also i noticed you are using a 1275 gt gearbox how does that compare with the 998 box? Im a long way off sorting the gearbox but its good to know!

[brad-the-bear]

don't want to steel the topic but if i put a ACD RT cam in my 1098 and put a 12g940 head on what would i need to say to the engineers about pocketing, e.g. amount of pocketing to be done?

thanks,
brad.

[oltonlad]

Is there any risk of clearance problems if you go to mad? Not that i would as my machine shop will advise me on whats best.

Also i noticed you are using a 1275 gt gearbox how does that compare with the 998 box? Im a long way off sorting the gearbox but its good to know!

the machine shop should be able to check if the head has been skimmed and by how much it has been skimmed, the 1275GT gearbox uses the same close ratio gears as the cooper "s", the drop in revs is much much less between 3rd and 4th gear compared to an A+ gearbox, the ratio's in the earlier pre A+ gearboxes are much better than the A+ ones anyway but the close ratio gearsets are better still.

[oltonlad]

don't want to steel the topic but if i put a ACD RT cam in my 1098 and put a 12g940 head on what would i need to say to the engineers about pocketing, e.g. amount of pocketing to be done?

thanks,
brad.

you need to find out the lift of the exhaust on the cam, get in touch with AC dodd on the forum as he developed the cam and he will be able to advise you on the pocketing side of things.

[Danthefestaman]

Great i have a pre a+ box so im a bit better, there is a fault with the box anyway so i will get it sorted!

Pretty sure the head had 20 thou knocked off but thats not to say it hadnt been done in the past!

Im going to re-assemble the 1098 first as there are some studs and bolts missing so i need to piece it back together and then at least i know it will work when its done!

And feel free to jump in on the thread as long as its to do with the 1098 so we all learn a bit and get some great engines built!

[oltonlad]

you will be pleased with the 1098 (i was), i took it out today, the only problem that i've got now is that i cant stop the damn thing.......i need some "s" discs now, its far too quick for the drums to stop it!

i cant wait for santa pod.......and show the 1275 boys what the small bore engines are all about......

Edited by oltonlad, 09 June 2012 - 06:01 PM.