Have i got the right setup?

[moggymaniac]

Hi everyone,

Basically i've had my moggy on the road for 2 years now, its got the 1098 still in it but it's running a tubular large bore exhaust manifold with custom stainless exhaust system, the inlet is metro 1 3/4" with HIF44 carb with a K+N cone filter. Head is as standard. The Only other mods to the engine are alternator and Accuspark 45D Electronic Ignition Distributor, and alternator.

The car is fairly nippy for it's engine size, but here's the issue: I have recently been outsized by my brother building a 100e prefect with a 1500gt pre crossflow cortina engine and the thing goes like stink! now obviously i cant expect that kind of power from my little engine without spending lots of money which i don't have. But it would be nice to get the most from my engine even if it gives it just a bit more poke, and i am wondering if what i have done to it is what's best for performance, and whether there are any relatively cheap alterations that i can make to boost BHP? I have considered the 12g940 head swap, but does it make much difference? the 1275 midget/ital etc engines seem to be going for a bomb on ebay at the moment, as much as fiat twin cams (seems silly for the sake of a 0.2 litre difference) so i doubt that's an option either. so maybe a bigger and better head next? what dyou think of the carb size? i also considered the weber route???

Thanks for taking the time to read the message

[moggymaniac]

also is the metro TURBO head any different to the 12g940 or is it the same thing? ta

[bmcecosse]

Your carb and exhaust are far too big for your standard 1098 engine, and will actually be losing you some power. They would be fine with a 1275 engine - but as you say, not cheap. The 940 head will make a huge difference for you - but do make sure you have exhaust valve clearance before fitting it. The turbo head has same size valves - so unless it's going cheap - don't bother. It has sodium cooled exhaust valves which are ubber expensive if they need replacing - so leave that head for someone with forced induction. Don't rev the 1098 above 6000 rpm or it WILL break. A crankshaft damper from a Mini engine is a GOOD idea.

[moggymaniac]

Great thanks, yeh my dad has made a few subtle comments about how the engne is over-carbed blah blah, but fair enough looks like he was right, i'll keep my eye out for a cheapish 940 head then? and if i keep that carb with the new head it should be better? wouldnt suggest a weber? do you know if the rocker assembly off my 1098cc head will fit straight onto the 940 or will i again have to buy the 1275 rocker assembly? not to worry i've never revved past 5000rpm anyway, the only place i feel i need to is the motorway and by that point the car shakes frantically so not a good idea to go further! unfortunately a type 9 box is also way out my budget but nevermind. will a different diff give me better acceleration off the line? currently running a standard one. Cheers.

[bmcecosse]

Forget the silly webber........ Yes you can use the 1098 rockers - BUT - you will need to realign them on the shaft to make them act directly over the exhaust valve stems. It's actually a very satisfying thing to do! Forget 5 speed box too. Your car should have a 4.22 final drive - if you want acceleration -leave it in there. With the 940 head and your carb and exhaust you should have 55/60 bhp which will make a worthwhile difference. I used to get 940 heads for £10/20 -try not to spend much more!

[moggymaniac]

haha ok, seen a lot of controversy on the subject of these carbs on this forum ;) anyway, thanks for the advice, if i do end up with a head that comes with the entire 1275 assembly i can still use the original push rods, right? or maybe i'm wrong, sorry i'm a bit new to all this! anyway will be on the lookout for a 940 might even have a look at a light DIY port and polish depending on how adventurous i'm feeling! 55/60HP, sounds BIG :O haha, so typically with the current setup i have, what kind of power return would you expect from that then? the engine is original with 45k on the clock. Cheers, jamie

[bmcecosse]

You can use the 1275 rockers if you get them with the head - but 1275 pushrods are LONGER = too long for a 1098. Yes - it's well worth doing some work in the valve throats of a 940 head - especially the exhaust where it turns the corner past the guide boss..... I suggest you may have 55/60 bhp from your set-up, with a 940 head fitted. A good standard 1098 is 48 bhp -so the increase is not HUGE - but it will make a good difference.

[moggymaniac]

sounds good, just had a quick gander on ebay, this guy is unsure of the head but if you look at questions it seems to be a 940, what dyou think? maybe thats why its fairly cheap (local too ) seems like a big enough difference to me for the lack of difficulty of the job! one final question and i'll leave you alone (for now ) can i sink the exhaust valves in further (if needed) myself, or will i need to get it done somewhere pro? is there a way to know if they need sinking in or not? and as for the inlet valves, i guess i can leave them be then? (sorry that was actually 3 questions) haha. Cheers, Jamie

[moggymaniac]

http://www.ebay.co.uk/itm/AUSTIN-MORRIS ... 500wt_1156

[bmcecosse]

Yes - that's a 940 head. Essentially - you need a minimum of 325 thou (0.325") clearance from the top face of the exhaust valve to the surface of the head..... Any less - and the valves will need to be 'sunk' by that amount into the head. I did this (at work - shudders at the thought... ) in a pillar drill using a 45 degree countersink bit - it took all of 10 minutes to do all 4.

[moggymaniac]

Awesome. thanks for your knowledge, will keep you posted and more importantly let you know the result WHEN i get round to doing it Thanks!

[welshrat]

There is a hugh amount of information in 'how to modify your mini' by david vizard, it covers morris minor engines. They occassionally come up on ebay at a reasonable price.

[moggymaniac]

great i'll have a look into getting one, thanks! Jamie

[brenh2002]

i have an excellent twin webber for sale if your interested

[bmcecosse]

[moggymaniac]

thanks for the offer brenh2002, i've decided to go with the bigger head and am on a tight budget! cheers, Jamie