1100 engines

[Jono]

I have a 1098 which I fancy building into a mildy tuned torquey road engine for my son's Mk1.

295 head, 246 cam, twin 1.25 SU's etc.

However just realised it has the early 1.75" mains which I understand tend to snap.

Is this reputation overstated or should I bin the idea and find a later engine with 2" mains?

Cheers

Jon

[ianh1968]

As far as I am aware, it was only some of the inline Sprite 1098 engines
that had the larger mains...

(Says he, waiting to be shot down in flames...).


Use a tuftrided crank and keep to a sensible rev limit and it should be a nice engine.

Ian

[mk1]

99% of all 1100's had small mains.

As long as the engines aren't thrashed they can give years of good service.

M

[Jono]

Brilliant, the boy will be pleased as he's set on something a bit different!

A friend of mine had one built by KC and he loves it.

J

[Spider]

All the transverse, small bore, long stoke 1100's had 1.75" mains.

They are quite reliable, those that have 'let go' I'm sure had other issues (Harmonic Damper comes to mind) that then resulted in a busted crank.

[woodypup59]

I've got one in my otherwsie stock mk1 saloon.

A great torquey engine.

Much less rowing the car along with the gear lever like an 850.

OK you shouldn't rev it, but then I havent fitted a big valve head, twin SUs or LXCB so it won't rev.

[Bertam]

Very interesting thread.

What is considered a 'sensible' rev limit for a 1098 built to the spec Jono had planned for the engine for his sons Mk1?

[Spitz]

Jono

I have a similar build. 1098, +.040", SW5, 12g295 ( -.080" ), etc.

The first set of pistons I bought I was cautioned against as they had an oil ring below the pin and was possibly weaker than others. I ended up with a set of AE pistons.

Anyway....it's a great engine. I had a 3.44 in it and autocrossed it with success. I was cautioned about taking it above 6K rpm.....but I did so fairly regularly on the track.

It survived the beatings and now pushes a 3.1 in another car and it'll still keep up with a 1275

[AWOODY]

My 1100 engined mini is great, highly recommend it , 40 thou + 731 cam (it was built a long time ago ) some head work 2x1.25 su carbs 3.44 diff . On a recent club run with a lot of cooper S it kept up with no problem except for 2 VERY steep hills where it lost a little bit , but we were not hanging about and 400 miles later we had achieved 39.5 mpg ! and with my microcell seats I was VERY comfortable . Look at the Russell Engineering web site as to what you can do with a small block engine.

[mk1]

5,500 - 6,000 as an absolute maximum.

M

[davidnutland]

Does the 1098 use the same rods as the 998?

[mk1]

I believe that early 1100's used the original pinch bolt type of rod, but this was superseded.

M

[Cheeser]

In the early 1970's I ran an inline 1098 +60, 12g295,997 cam,lcb and HS4. It was a 1.75 main bearing with the crank toughened and balanced. It regularly ran very sweetly to 6k+ with good torque, but I'd only used cheap split skirt pistons, so would find bits of skirt in the sump! Can thoroughly reccommend this type of spec and found it a lot smoother than the 1275 that replaced it.

[YMJ]

1098.....my favourite motor. It was the first thing I did in 1980 to make my 850 go faster.
I'll never forget the exhilaration (and surprise) of climbing Wheaton Hill (near my house) without having to change down!
If you're not racing the thing, get it properly balanced by Rob Selby (or someone who knows what they're doing), rev to 6000rpm max and use a "Rattler" or a silicon crank damper just to be safe. No need for a 940 head - just a nicely ported 295 or similar with a pair of HS2s.
Lovely

[LDR209H]

There's been loads of threads on this but it felt topical for me.
1.Give Jim at R.A.C.E an MG 1100/Ad016 lump.
2.+80 pistons,his own '12G295' worked head or thereabouts. Sw07 cam. All balanced of course.
3. Add twin HS2s supplied by Glenn Bayley (I'm running out of plugs !),MS Freeflow and RC40 single box.
= magic sweet thing,just the right noises and loads of torks (J Clarkson).

[timmy201]

I have a crack checked and reground 1098 crank ready for when I build my spare engine, an RE266s cam from Russell Engineering, a set of HS2's and a magic wand 4 syncro box so it should be a bit of fun. I'm planning on one of the Accuspark programmable ignition boxes so I can set a rev limit too.

[Jono]

I'm increasingly liking the sound of this

I have an unused Kent 246 from another big bore build where I settled on 276 instead. Would this high torque, short duration, cam go well in an 1100?

I'm now thinking of using a 940 head and pocketing the block as I have a few in the garage and 295's are getting dear now.

Also, what flywheel set up would be most appropriate?

Cheers

Jon

[Spitz]

In my build we used a standard heavy flywheel.....also using a crank damper

[Cables]

my 1100 build to replace the tired 998 will be based on a near mint condition A+ 1100 engine (they do exist before people say).
Its going to have a fully worked 12g295 head and either a kent 276 or piper 270 cam (because i have both on the shelf), breathing through a pair of HS4's.
Should be a nice torquey motor.