19 replies to this topic

[timmy850]

Here are two good articles that use 1098 engines as a base. As the first article says it doesn't rev as well, but it doesn't really need to as it makes more power at lower revs (same head, carb, exhaust on both engines, just a different cam, rockers and dizzy). To make 40hp at the wheels, the 998 (KC-Mini2) is doing about 4500rpm, but the 1098 (KC-1100) is making that much power at around 3500rpm. Both these tests were done on 8.9:1 CR..


Comparison - at the wheels
Standard 1100 34-36bhp 44lb ft torque
Standard 1275GT 45-47bhp
998 'KC-MINI2' spec 48bhp 46lb ft torque
1100 'KC-1100' spec 54bhp 59lb ft torque

The second article shows that the engines are all at peak power at 6000rpm, so there isn't a need to rev it over that.

Article 1
http://www.minimania...al_Tuning__1128
Article 2 - Three part series
http://www.minimania...ll_Bore__Part_1
http://www.minimania...__Cylinder_Head
http://www.minimania...ld_Combos_Weber

Graham Russell Engineering in Aus is making the pistons and doing some work on small bore engines again.
http://russellengine...om.au/products/

How thick is your head currently, has it already been skimmed?

[087dave]

Hi

The head is 70mm so I don't think it's been skimmed..

[Cooperman]

A good spec for an 1100 engine is an over-bore to +0.060" which gives around 1175 cc (that's approximately), a 266 cam, a gas-flowed 295 head with CR set to 10:1, slightly lightened flywheel, HIF44 carb on a Howley inlet manifold, 3-into-1 ex. manifold and a 1.75" twin box Maniflow exhaust system. The torque would be awesome at mid-range.

That will give peak power at 5700 rpm, giving 300 rpm as a safe working margin when going for maximum performance.

Combined with a standard ratio gearbox and a 3.1:1 FDR, that would be great for overall road use.

[Vipernoir]

My current 1100 will rev to 65-7000 quite happily without snapping the crank, and I know of others who do the same thing.

What it will do however is knacker the piston rings very quickly indeed as the piston speed is massive. 

 

The new one will have a redline at 5500 and never* go over 6000.

 

*Yeah, right... I'm gonna cane it like always.

[timmy850]

I've heard good things about the Accuspark Blackbox Stealth units. They allow you to tune your advance and dwell ignition settings very quickly and accurately. The 1100 engines are known to be a bit picky about distributor settings, and with this you can set it exactly as you need. You can also set a rev limit to stop you over-revving your engine...