1098

[LDR209H]

Anyone built a tuned/hot one recently ? (tumbleweed blows by ...)
Yes the crank is the stumbling block - want to give a 998 Cooper some ooomph but still look standard,and still run on HS2's.
The Vizard bible talks about Hillman Imp pistons > 1215 cc is this still feasible ?
Have a pretty much complete MG1100 motor,is this the best to use or are later blocks better ?
I always support the underdog !! (I'll be doing a 997/boat anchor next!!)

[Lord Croker]

This has the makings of an interesting thread, I have been considering building a replica of the Speedwell 1152cc engine, based on an A+ block (only to keep things looking original), I don't think there is any disadvantage in using the older type block. Hillman Imp pistons were used in Mini blocks to increase cubic capacity, but you need a good quality head gasket as they were prone to blow between cylinders 1&2 or 3&4 as the gap between cylinders reduced with the bigger bores. 1100 engines can be very smooth despite the long stroke, with careful balancing of the crank assembly.

[doctor jon]

1098's are more about torque than top end power, so if you are sensibile with the revs the standard crank is fine.

Large over bores are still possible, Imp pistons are cheap and readily available and you can buy 1098 pistons at + 80thou and + 100thou. Getting quite hard to find 1098 pistons in any size in UK, I had to buy mine from Australia.
Probably best to avoid boring to Imp size, so + 40thou (1132) or + 60thou (1148) is fine.

They can use "hotter" cams than a 998, a 285 cam works well with a decent head. The 997 Cooper or MG Metro cam are great road cams.

I prefer the 12G 940 head but that's up to you.

This is the spec of my last 1150 engine

1100 block bored + 60thou.
Balanced bottom end.
Piper 285/2 cam.
Big valve 12G940 head.
Single HS6.
RC 40 exhaust.

They do make great road engines so give it a go.

[LDR209H]

Yes I've been going through some old threads and +060 seems about right. Any more and you get block flexing and blow-by. That's good news I can use my old MG1100 mill,found this place selling the pistons

http://www.sussexclassiccar.co.uk/shop_ ... d1269.html

Thanks for the cam tips,which exhaust manifold do you reckon ? 3-branch or LCB ?

Will keep the '295 on mine but will see about sourcing one with bigger valves,gas flowed,ported and matched to inlet etc.

Dr Jon,did you get yours dyno-ed ?

[Vegard]

Those pistons are rubbish compared to the Hypatecs from Aus. The ones pictured there have a HUGE oil drain slot. Hardly a performance design. The Hypatecs I bought for turbocharging. A completely different animal.

http://home.online.no/~lyngset/1300.cfm ... =&pExPic=0;

[Lakeland997]

Keith Calver does some nice flat top 1098 pistons:

http://www.calverst.com

[Lord Croker]

Thanks Lakeland997, those pistons are just what I've been looking for LDR209H, I always favour the LCB exhaust manifold combined with twin HS4 SU's, but that's a personal view & I am regarded as rather eccentric, with a touch of Victor Meldrew about me, but it works for me, most people think my 998 is a 1275 by the way it goes like a rat up a drainpipe! How does a 285 cam compare with a 649? My only knowledge of cams is restricted to to BMC / BL special tuning versions, as they are the only ones I've ever used (& still do).

[doctor jon]

The pistons sold by Calver are Hypatec and they are very good. I bought some from Mini Sport in Australia who sell Hypatec and Mahle but watch out for expensive postage costs and import duties.

If you are using a 295 head then best to use a Cooper 3 into 1 exhaust manifold, with a 940 head a medium LCB works well.

A 285 cam is similar to a ST 544, the Piper 285/2 has later exhaust valve opening and works very well with an overbored 1098 and 940 head, still ok in a road car.

A 1098 bored + 60thou with a 997 Cooper cam and exhaust manifold, 295 head and twin HS2's will be good for 62 - 65 bhp, if you use a big valve 940 head and a 285/2 cam then 70+ bhp is achievable.

Ignore anyone who claims a 1098 can't be modified, "the crank will break" or "you will never get more than 60 bhp out of them".

[Tupers]

I've actually got an A+ 1098 short block with Imp pistons in it (currently dissembled) that I was going to use in my estate. According to my local engine builder they make for a fantastically torquey engine.

[bill773mini]

I've got a 1098 +60 in the Heinz, ported 295 head, SW5 cam and twin 1 1/4's on a 22g 68 box. It's the best road engine I've had. So much torque. It'll pull from 25 in top and is still pulling at 80. It'll rev too.

Not as quick as my fuel injected 5 speed 1380 but a much nicer engine.

[LDR209H]

Thanks to those who replied,much appreciated.
I'm coming round to the idea that Bill's config is looking ideal,hoping to go the whole hog with the 295 head though.
What about 1.3 rockers ?
I used to run a 28/36 DCD on a 998 cooper back in the 80's - tempted again (the noise was brilliant when the 2nd choke opened up)
but will probably lose a few HP over twin SU's,we'll see.
Looking forward to it.
P.S. Bill what ratio diff ?

[goff]

Just to had a little bit more to this thread
I have seen a few of these 1098 engines fitted with imp pistons ( also a 998 ) in the early 70s mainly used for grass track racing and they were a good conversion, I am sure they came about as a cheap alternative to a 1275 motor, 1275 engines were quite expensive in the late 60s/ early 70s ,Lots of rotten 1100s about though for a tenner each, I put a few of these 1098 engines in 850 cars after Swapping the diff for the 850 one and you got a remote as well, dirt cheap conversion in standard form and if you got the mg 295 version even better and that beats trying to tune a 850 any day.
What doctor Jon says is true , But i have seen one with a broken crank after being revved to high in a low gear, Its a long stroke and bags of torque, But don't over rev it.
If you want to do a 998 engine ( same block ) It can be done , You will have to have the top of the block machined more than the 1098 and you will break into the water pump top bolt holes ( just ) , Ok what you do is don't machine the block were the engine number is and that will leave a step were the third bolt goes ,so you would only break into one, Braze it up, Re-machine it and you can drill and tap a smaller size hole for the forth bolt, That would give you a good high revving engine .There are some 1098 +10 thou pistons on ebay new old stock , solid skirt, small dish for £100 , I bought a set ,Good quality. item 271260872175
Hope this helps.
regards
Goff

[bill773mini]

Thanks to those who replied,much appreciated.
I'm coming round to the idea that Bill's config is looking ideal,hoping to go the whole hog with the 295 head though.
What about 1.3 rockers ?
I used to run a 28/36 DCD on a 998 cooper back in the 80's - tempted again (the noise was brilliant when the 2nd choke opened up)
but will probably lose a few HP over twin SU's,we'll see.
Looking forward to it.
P.S. Bill what ratio diff ?

It is 3.44 I think, I'm sure I should know!

[tedmcedd]

I came on about to ask about 1098s... as I am Planning on building one for my A35 Van....

I had a 1098 in my mini, with a 295 and twin hs2s, and a lucas 45... I got 58hp at Minisport rolling road...


Now.... I have a moggy 1098 (I was after a sprite one as they have bigger main bearings, but hey ho!!)

I also have a set of Imp pistons bought years ago with the same Idea! Now I'm all for being different.... So I dont care if the crank is 'weak' and the bores will be 'too close' because Im not going to be racing.... I just want bags of torque for the many hills on my commute.... and the smokey 850 is driving me mad....

I have a 295, a NOS Lucas 45D4, and my block and imp pistons....

Should I cam it? or I do have a set of cast 1.5 rockers....?

I have a midget diff and some hardened halfshafts and I was also going to use a Ford type9 gearbox.... (sorry, non mini talk!!) I already have midget discs on the front....

I may even go for twin HS4s instead.... hmmmm....


All good fun!!

Ed

[Ollie78]

I'm looking into the possibility over boring the 998 for my car. CalverST is selling the hypatec pistons at up to +0.100 for 998 and 1098, I don't think that's quite as big as imp pistons. Does anyone have any knowledge of head gasket reliability with these over bores? On the CalverST site it mentions the standard gasket overhangs the bores at over +0.060.
I like the idea of keeping the car small bore as its more original, I thought the over bore would further improve the characteristics of the 998 making a bit more square.