1098 tuning

[daglocks]

Hello piston heads
I am rebuilding a Microplas mistral with Morris minor engine and running gear.
While the engine is out, I want to give it a mild tune without spending too much cash as thats not my style, and, well, its a Morris Minor engine!

What I thought was, skim the head to up the C.R.
Port the existing head and manifold, and fit a bigger bore exhaust, keep the same SU with a velocity stack.
Stronger valve springs.
Lighten the flywheel (its a very light chassis and body)

There, that won't cost much. What is council's opinion?
Andrew

[Lotobear]

..find a 12G295 head and an MG metro cam - fit them and use a single 1.5" SU or a pair of 1.25" SU's and a good (Maniflow) 3-1 exhaust manifold.

Limit your revs to 5,500.

Should be a nice little motor

[kilarney]

I would go for 12940 head and pocket the block as its cheaper and better plus I would go for an sw5 cam as you need to keep the power lower down on the long stroke else you will snap the crank, ask me how i know. I ran the 1100 with twin 1.5" and an lcb plus aformentioned head and a fast road cam and it went like the clappers for a while - the revs did for it. I have the 12g295 and an mg cam on a 998 now and its ok but wish I had fitted the sw5 and the 12g940

[VYT]

There was an article in Cars and car conversions, late '81 early '82 which tuned a 1098 motor for a mini. 80bhp was the target. 12g295 head with a fair bit of work done to it, LCB exhaust manifold, modified single 1 1/4" SU I think. I built my mini to their spec but was better with a weber 28/36 than the SU.

[Dinlowgoon]

VYT said:

There was an article in Cars and car conversions, late '81 early '82 which tuned a 1098 motor for a mini. 80bhp was the target. 12g295 head with a fair bit of work done to it, LCB exhaust manifold, modified single 1 1/4" SU I think. I built my mini to their spec but was better with a weber 28/36 than the SU.

Great carb the 28/36,ran one on a modded 998 in the '80's. There's some dodgy looking manifolds out there with 90* bends,best avoided. It's a fit and forget once the setup is done as opposed to constantly farting/fettling twin su's.

[Orcadian]

Always remembered from the early Triple C (the aforementioned Cars and Car Conversions) days with Clive Trickey and David Vizard that the 1098 unit was good to tune but needed a centre main bearing strap to prevent early crank failures. Not sure if they are still available anywhere but not too difficult to make and with a north/south engine no problem with fouling the centre web on the box.

Ian

[ace01]

Calver does some excellent 1098 pistons that will give a good CR without too much skimming of the head required.