23 replies to this topic

[Albino_Hedgehog]

Hello,

I am looking at swapping out my stage 1 998 for an 1100 engine on my road going car.

What would people opinions be?

[Staddon]

Not too familiar with the 1080, but I'm sure a lot will possibly speak of the 1275 engines. From what i hear, they're nice for daily use as have decent torque and can achieve good power whilst still being bulletproof engines. I've had a look around and you can pick up some 1275s for around 600 

[dyshipfakta]

Unless the 998 is a lemon don't really see the point

[Stevie W]

Hi,

 

The 1098cc engine is a good little unit, because of it's long stroke it's effective at producing relatively high torque values, which is what's needed for acceleration. However, the long stroke means that the crankshaft isn't especially strong and these engines don't take kindly to sustained revs over 6000rpm because of the crankshaft weakness.

 

I used to have a Clubby estate with the 1098cc engine and it ran well with comparatively good acceleration....

 

Cheers, Steve.     

Edited by Stevie W, 15 June 2016 - 07:49 PM.

[Spider]

In terms of overall performance and drivability, IMO the 1098 in standard form is a big leap forward.

[Cooperman]

If going from a 998 to a 1098 you could fit a slightly better cam, but one which give good torque rather than a lot of top end power at high revs. The 1098 doesn't like over about 6000 rpm, so peak power should be at about 5500 rpm. Fit a gas flowed head with the comp. ratio at around 9.75:1. Then fit a slightly higher ratio final drive, say a 3.2:1 to make best use of the super mid-range torque.

[KernowCooper]

You could rebuild and turn your 998 into a 1098 with the rods and crank from a 1098, they share the same bore size

[timmy850]

You could rebuild and turn your 998 into a 1098 with the rods and crank from a 1098, they share the same bore size

Crank and pistons are different

Rods are the same

Edited by timmy850, 16 June 2016 - 10:27 AM.

[KernowCooper]

They may have different pistons but as far as my info shows the bores are the same size at 64.59mm

[fwdracer]

Am I the only one thinking they make a great boat anchor? If you are pulling an engine out, at least make the effort worthwhile and fit a 1275....

[timmy850]

The pin height is different to make up for the different stroke.

As for the revving capability, read this thread particularly the post by GR (Graham Russel) who builds lots of A-Series engines.
http://www.ausmini.c...=994162#p994162

[Spider]

The later 998 A+ Rods, that took the press fit pins are different to those fitted to the production 1100 engines.

 

Hmmm,,,,,, does that guy ^ know how a crank works? Talking about cranks twisting from 'on and off' throttle?  They do this many times every revolution in normal running.

[Drydave254]

For me, 1098 every time.
I've used these in 1098, 1150 and 1220 form on the road and in Autograss racing where they're thrashed mercilessly in 2nd gear.
They make a significantly better engine on the road, and they DO rev.
Truth is, any engine built for "spirited" use is going to have a short service life. I suspect a poll on major engine failures would reveal piston failure, bearing failure, dropped valve etc. all to be above broken crankshafts.
As such, maybe people are falsely steered away from what I believe to be a good option. Yes 1275's going to be better every time, but not thick on the ground these days.
They are still used in budget class 4 engines (up to 1130cc) with race cams and rarely give any problems. That said however, I believe such engines would be using up the fatigue life of the crank over time and would need "lifeing."
Another benefit with these motors is that they can usefully use more cam without necessarily having to turn the extra rpm.

Sitting back for the flack.

By the way, the only crank I've ever broke was an original 1071 en40 on 10/10 grind.

Copied from the ausmini forum:
NOT850 wrote:
Torque is my main aim for the engine. Nearly everyone says that the 1098 shouldn't be revved over 6000rpm.



Hi Not850
The problem with the rumour about not revving 1100 past 6000 RPM was started by David Visard when he wrote in his book and put the fear of god in every body,ask him how much testing and development he has done with the 1100 and you'll find very little.
I'v been building these motors for a long time and I have NEVER broken one yet,but I have broken 998 cranks, the problem is people tell how they have broken or cracked an 1100 crank but never seem to mention when they have broken a 998 crank.
We run 1100 cranks to 8000 rpm in a lot of engines be it mini's, sprites or open wheeler race cars, like any thing put it together right and it will be reliable, if you are going to abuse your engine you will break it no mater what motor it is be it an 850 998 1100 or cooper s, just ask around about how many people have broken or cracked Cooper S and i'll bet there is more "s" cranks broken than 1100, and yet they have a shorter stroke and bigger mains giving it more over lap.
The thing with a mini is if you are going to make a performance engine be it a fast road car or a race car the lighter the flywheel the better of you are, on my fast road cars I like to use the MINI SPARES ultra light one with the light backing plate, and no I don't find it to light on the road, the thing that does a lot of damage is on and off the throttle at high RPM resulting in the crank twisting back and forth, hence this is where the light fly wheel helps.
These little 1100 are a great little motor don't be afraid to build one and give it a buzz.
Graham Russell


_________________
"It's better to be not informed than ill-informed"

Edited by Drydave254, 16 June 2016 - 10:42 PM.

[limby2000]

I've got a 1098 crank and pistons in my 998 a+ the only difference is the push fit rods, I did have to modify my gearbox for clearance as 3x of the big end,a fouled the casing. Took 10 minutes with the powerfile. Although mine is auto, manuals may be ok

[Albino_Hedgehog]

It has been suggested to use a crankshaft damper.

Could I have more information on this damper please

Thanks