Greetings from england

I heard the 1098 engines are quite common over in australia, where as over here in england they are quite rare, or more accuratly, unwanted.

But i was wanting to rebuild my mini and then go traveling round the country and such, so i figured the best way to do this would be with a low-revving tourqey engine.

Then i heard about the 1098 engine, and how its a much nicer engine as long as you don't rev it to death. Ideal i thought, and to add to this, it turned out the spare engine i got free with my mini was a 1098!

So i've been reading up on 1098 tuning, engine tuning in general, and the past 50 pages of this forum going back to early 2005 to learn more about tuning the 1098cc engine.

Here are the (very) rough specs i have planned, i'd appriciate it if people with give me some feedback on it, bearing in mind i'm going for economy and reliability over power.


Carb - 1 1/2" HIF SU, maybe with the "leaning device" in the great big book of Vizard to help the economy side of things. Or would it be worth going for a slightly larger carb?
Rockers - I was thinking of cleaning up and fitting the standard ones, unless theres any reason i should fork out a large wad of cash for uprated ones.
Valve springs - Same as above.
Head - Converted to unleaded fuel for a start. I had the standard 202 head in mind, though i would consider a 940 head if enough people reccomended it. A 295 head is most likley out of the question as they are getting rare here so they cost a fair bit.
Block - Bored out slightly, explained below in pistons...
Pistons - Right, tricky one now. I'm going to have to import the pistons from Aus i think as nowhere here cares much about 1098cc engines, but the big question, remembering this is an economy/reliable engine, how far should it be bored out? I was thinking either +20 or +30 (if +30 is excists) but again i'm open to other suggestions. Its a balance between reliability and power, which is why i stayed away from the +60 pistons
Cam - Also a bit tricky, i was thinking a sw5 cam, i'm not sure if any of you guys run it, but apparantly its a bit of an upgrade from a MG metro cam, it works from quite low down in the rev range which is why i thought it a good choice.
Crank - I'll be sticking with the standard 1098cc crankshaft, Not sure if having it reground and hardened and such will be needed. again open to suggestions.
Flywheel - I'm guessing since i'm using lower end of the RPM range i'll need a regular lightened flywheel, not a super fancy ultra light one?
Dizzy/igition/whatever - No idea whatsoever, i have yet to learn how this part of the engine works.

Gearbox;
diff/final drive - 2.9

I'll be getting parts such as the flywheel/crank/other? balanced properly, as i'm trying to make this a nice smooth runner as best i can.

Right, thats what i have so far. Does it all match up or in my stupidity have i totally ruined something? The theory is that i can use the low final drive to make it better for motorways AND keeps the RPM low so as not to press the weakness 1098's have at high RPM. Also being in the lower end of rpm should improve economy somewhat.

According to the gear calculator, i should hit 70mph (112kmph, motorway cruising speed) at 3600 revs, which sounds quite pleasing when one of my regular journeys will be 300 miles on the motorway

I'm guessing it will still be quite sluggish, but it shouldnt be TOO bad should it? It still needs to be drivable for everyday use, not just some bizarre motorway-only car.

Thanks for your time guys

if you want to do it cheaper, since you seem to have loads of 998's lying around... you can bung the crank/rod/pistons from an 1098 in a 998..


might save on any potential shipping...

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crank and pistons, rods are the same

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I'm a little bit thrown off now, are you saying the crank, pistons and con rods are the same on a 998 as a 1098? I thought the only thing that made the 1098 different was the cylinder head, pistons, and crankshaft?

No No No the crank and pistons are different.. The rods are the same on a 998 and a 1098 howver the thing that gives the 1098 more capacity is the crank... Basically a stroker crank.

Alot of us ausies are takeing the crank out of the 1098 and putting it in our 998 to increase the capacity, however with a stroked crank you need shallower pistons also out of a 1098..

So in short the only difference between a 998 and a 1098 is the crank and pistons. Everything else is the same.

This realy doesnt matter to you though as you already have the bigger crank and pistons

Mike

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If it cant be fixed with a hammer it cant be FIXED!!

The 1098 isn't as fragile as many people believe.

My first motor was a 1098 and being a P plater at the time, it got the nuts thrashed off it It was mildly worked with a 295 head... It ran for 3 years! before it gave up which I think is admirable considering the way I treated it and the 150 odd thousand k's we did together...

So I guess what I'm saying is... drop in a mild cam, work the head, kit the box and make sure it's all screwed together properly with all the correct tolerances and you should have yourself a nice reliable runner... I would say it would be a good idea to have your motor set up on an engine dyno to have your fuelling and timing/dizzy put right rather than guessing

Have fun and keep us informed

With the head: if you go for a 12G940 you will have to pocket the small bore block as the cylinders have a different spacing between small and big bore. The best choice would be a 295 but they are getting expensive (as you said), a ported and polished 202 will be fine. I think GR tends to use 202's over 295's anyway.

Mini Mike is right - the crank and pistons are different - I think the 1098 pistons are 0.100" shorter than the 998 ones - I could be wrong on that measurement but they ARE shorter.

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"In two years time your car will be like a lady's clothes, out of date, my car will still be in fashion when I am dead" - Sir Alec speaking to Pininfarina

yeah, everything you've said sounds great.

go with a 202 head, port it and fit bigger exhaust valves, all the power is in the head so if you can "unshroud the valves" then that would help alot too.

standard valve springs , standard rockers are a bit lousy tho, pressed steel cooper S type rockers are better than the later type.

try and get the compression as high as you can while still running on standard unleaded.

standard crank and rods should be fine, the main problem is when they see high rpm.

if you can, use twin inch and a quarters, otherwise an inch and a half will be ok.

yeah the bigger you bore it the more power you have, more compression and the less oversquare the engine will be.
go 40" over pistons

the lightened flywheel should help compensate for the low final drive.

sw5 cam is an excellent choice for a roady, and the one i would pick, especially with a 2.9 FD
I am running a 731 cam in my 1100 and it sees 7000rpm but its not the best choice for an economy motor because it lacks low down power.

for ignition, fit a petronix or some sort of electric pointless system, vizard says this will improve fuel economy!

keep the revs below 6000 rpm and it should last a long time.

This might answer some of the questions you have.

http://www.minimania.com/web/SCatagory/ ... ticleV.cfm

While we are at it, from the table 3 here what do people think about using 1 3/4 carbs against twins?

http://www.minimania.com/web/DisplayID/ ... ticleV.cfm

maybe for max power, but twins work better than a single, with a single your number 1 and 4 pistons run lean.

on that article GR does say he would run twins, just with a better manifold.

I'm a few steps behind Cactus but my aim is the same so keep this post going folks!

Good luck with it Cactus

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Hmmm... all very good info, thanks guys

I think i'll go with a worked 202 head, as i already have one and it saves doing more work on the block. Plus the 940 heads don't (from what i hear) "flow" well on a small bore block as parts don't line up very well.

Just to dump some thoughts here, from reading the bible of vizard again.
-The leaner the engine runs, the better economy
-The leaner the engine runs, the more chance of a lean-misfire
-The better/powerful your spark/ignition is, less chance of lean-misfire

So going by that, i should find out which ignition system can offer me the best spark, so that i can run a lean as possible. I wonder if uprated spark plugs excist or would be useful.

I didn't know about 1 and 4 running lean on a single carb, this would mean i can only run as lean as the weakest cylinder. Even with that though, i think i'm still going to run a single carb. Twin carb setups can be expensive, but more importantly harder to match the pair, considering i'm going to be fitting one of the "leaning devices" to it that vizard mentions.

Maybe when the engine it going if i want more i'll think about twin carbs, but for now, my first engine build, i'm going to try and keep it simpler i think.

About the 202 head, i'm not really sure what to have done to it. I'm not sure i like the idea of just dropping it off at an engine tuners and saying "work this". I'd like to know which jobs can be done to the head, and more importantly how reliable the modifications are. I don't think mini engine tuners over here would know much about tuning a 202 head, so i'd like to be quite specific with my instructions to them.

And about the 1098 not being as frail as people think, is one of the things i'm trying to prove by this. It seems over her 99% of the people belive them to blow up the second you blip the revs, they are less sought after than 998cc engines by FAR. Infact most of the people i spoke to about when i mentioned using a 1098 said i was being rediculous and/or stupid. Luckily someone with sense pointed me to australia where people actually understand the 1098.

Spaceboy: Are you sure +40 pistons would be suitable? Seems like it might be a tad high, but then i have NO idea about the reliability/power ratio between piston sizes. If +60 is the highest and makes the block unusable afterwards(?), does that mean +40 is a decent comprimise?

Thats about all i can think of right now... cheers again guys

I've run various 1098 motors in my Mini and I think they are great. I've had them die on me, but in no way related to their capacity. I've revved the tits off them and never had a failure. So I say go for it.

I just put a 1098 + 60 thou in my car, it goes really well and it's running a stage two cam, standard 12G202 head with double valve springs and oversize exhaust valves. It's only got a single HS2 on it at the moment because it's just run in, that strangles it a bit. But I had my 40DHLA Dell'orto on it and it went really well.

As for the oversize, I would just bore it out to the next oversize, either 20, 30 or 40, depending obviously on the condition of the engine and the pistons available. I wouldn't bother going to 60 for a perceived performance increase because it's negligable.

The type of carburettor you run basically boils down to what you have at your disposal. If all you have is an HIF38 then use than with a decent inlet manifold and filter, and then upgrade to an HIF44 down the track to get a few extra hp. Twin HS2s would be good too but are more expensive to buy and harder to tune, but they do look tops

As for the diff, I run a 3.44:1 and it eats gear changes, it would be much nicer with a higher diff like a 3.1 or 2.9 for relaxed highway use. It still has enough torque to manage it I think.

Just go next size up on bore.

They die eventually, and wear a lip in the bore and the rings are the first to go, but all they do is burn a bit of oil and lose some low down torque but they are not the hand grenade many people believe them to be. I'd take one over a 998 any day of the week.

1098's are great little engines. I've thrashed mine for the last 4 years with no problems and it's one of the highest powered small blocks out there making similar power to a stock cooper S.

Here's some video of mine in action:
http://users.on.net/~adslqru2/Wakefield.Skyline.Me.Small.wmv
http://users.on.net/~adslqru2/Wakefield.Slide.Small.wmv
http://users.on.net/~adslqru2/rodchange.gearchange.wmv

And they rev too..shift light isn't even on

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Starlet Conversion:
http://www.ausmini.com/forums/viewtopic.php?t=15484

hey josh,

could you please post your specs of the 1100 engine you had in your car....

quite interested as it bloody hooked in the videos....

cheers

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