Hey everyone, I've got a 998 1978 Leyland with a few slight mods, such as extractors, bigger cylinder head, 1.5" carbie, and it's red.

Oh yeh and a skull gear knob which really makes it fly.

But I would like more power(who wouldn't) and I was wondering would it be a good idea to bore out the engine and retain the shorter stroke (more revs? yay)
or whether I should buy a 1100 with a longer stroke (more torque yay). I plan on putting different cam and fiddling a bit more with the carbie as well.

Opinions appreciated....

The 998's so-called `shorter stroke' is not that much shorter than a 1098. 3.000" instead of 3.296". But it robs you of 100cc, which is 10% of your capacity. Blocks are the same. Even a 998 motor is still way undersquare....
For the street, a bored 1098 will go harder than a bored 998. Will have lots more torque, too. If bored to +.060" you will have 1152cc. Ain't no substitute for cubic inches..
Then add the usual goodies- big valve head, cam, carbs, yada yada..

OTOH, if you really want even more power, go find a 1275 motor and work that over.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

Yeh but how easy is it to find a 1275!!
I should have more chance of finding a 1100....well. I won't need to do it for 4 months or so, but then hehe, I can spend heaps of money on my car.

Ahh well, I'll start looking for a 1100 then.
Thanks for the reply.

You could put a 1098 crank into your 998 block- it's a drop-in fit. Rods are the same, only the piston pin height is different. Rebore it to +.040" (1132cc) or +.060" (1152cc), and Yahoo!
You won't even have to change the engine number...

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

all hail Drmini... we're not worthy. Wish I knew him in person

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You're only supposed to blow WHAT off?

My last 1098 was 1220cc.... while it lasted. Was good for low 16s at Castlereagh.
But it didn't like being revved to 9,000- the piston circlips broke up, gudgeon pin scored the bore, the new crank had 8 cracks in it after 20,000 miles..

Yeah I like hot 1098s, but keep them to 7,000 or less if you want them to last!

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

Hey Kev,

i still have a couple of 1100's sitting around and am finally thinking seriously about what i should do with them.... i'd be using it for a daily driver so i wouldn't want it to be too peaky etc. (....but as much grunt as possible would be nice )

any suggestions on specs??

cheers
-jimmy

I'd put a 295 head on (or get yours well ported with 29/27mm valves and chambers reshaped), make C/R around 9.5 -5 10.0:1, S valve springs (7000 RPM)
Graham Russell RE13 cam, or something else around 270* duration,
Stock pressed metal rockers (not the later sintered crap),
LCB manifold and 1-3/4" ex system,
Twin HS2s with trumpets and filter socks (or K&Ns with stubstaks),
Electronic ignition (either use a Jap dizzy, or fit a Pertronix ignitor to yours),
4 synchro box,
Disc brakes to stop the sucker.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

yeah after exams (coupla weeks time) i'll be having a go at some honda discs and i'll start on the donk after i have them sorted.

thanks for the advice doc, no doubt i'll be picking your brain for a while yet

-jimmy

so how much power would a 1098 with them mods pull u reckon?
because i have a 1098 and since funds are lookn really poor right now, it might be worth heading along that track.

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regards,
MiK

It's not worth working over a worn engine, whether 1098 or whatever. And if it needs a rebuild you can do the same to a 1275 for similar money and get more HP.

Having said that, I'd say 80HP+ from a bored 1098 is pretty easy, you can probably get 100 or more with enough $$$, but it won't have reliability, ie last...

My 1220 had a worked 12G940 head, pocketed block, and twin HS4s... back then it probably had 90HP maybe but like I said, was not reliable.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

Okay, forgive me if this is a dumb question but I always let my mechanic handle these things,
If I drop the 1098 crank in and then different pistons, would that mean the engine is effectively a 1098? beacause as you say the stroke is the only difference.

If this is the case, I was thinking maybe of putting a different cylinder head on again, one with bigger intake and possibly a smaller combustion chamber for a higher compression,
would this work?
What cylinder head would be best? would I need to get a different intake manifold? or would that depend on the head?
then of course, some sort of mildly lumpy cam, something that will give me power at low revs as well as higher revs.

any other suggestions??
Oh yeh I'd bore it as well.

Yes a 1098 crank and new oversize 1098 pistons will make your 998 into, er, a 1098, but even bigger.
+.040" overbore will give you 1132cc, +.060" overbore will give you 1152cc. But be sure you order these pistons for a 1098- the pin to crown height is different by 0.148" to a 998.
re your other Q's see my post above.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

Just out of interest, can you go the other way? ie, put 998 crank and pistons into a 998 block? I always thought that the blocks were physically identical except for the engine number, but I have also heard that the block height is different?

Anto.

i think he means 998 pistons and crank into a 1100 block ??
makka

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