12G940 or 12G295???
Turbo Mini Forums

Hi guys
I've had a look at other mini message boards about tuning my 998 Stage One engine, but some of them don't seem to know what they're talking about, and wondered if you could give me a hand. I have a 1991 998 engine that has been stage one tuned. At the moment I have a HIF44 (1.75") carb on it which I aim to get set up properly soon. I'm pretty sure that a 12G295 head would be best suited to my engine, but apparently as I have the bigger carb on my engine I can use a 12G940 (metro 1275) head on it. This would be easier to obtain, particularly as I need an unleaded one, and also cheaper! I've been told that I'd need to have the block pocketed and fit slightly stronger double valve springs, according to some bloke on the Minifinity message board.
Hope somebody can help,
Cheers guys

Steve

Rebuilding a 1992 mini...will be finished in 2019

sound spot on advice, never tuned a 998 but the metty head is supposed to give good results.

just need to pocket the block as they said they assembly without a gasket to check for clearance then the gasket acts as an extra safety margain!

If you pocket the block, theres no need for different valves or springs. If you just snk the valve in the head, then this is a necesity.
I'd go the 295 route everytime, as the 940 pocket-blocking needs the engine to be totally dismantled.

AND, the Hif44 is too big for a 998 engine in road tune. You'll gain driveability without losing hp changing for a 38.

http://www.ktv.no/~pjb-ktv/

In my time I've tried both, and infact my daily drive is a 998 with a 12G295 head.

As it goes I think the difference between the heads from a driving/power point of view is marginal, the 940 being the head that will ultimatley give you the most power.

Iain and Peter said it all really. Dump the 44 for a 38 is great advice (If we're using 44s on 150+bhp turbo motors you can imagine it's way to big for a 60bhp 998).

Wil

Fastest 998 mini in the world? 13.05 1/4 mile 106mph

Cool, thats very useful guys, cheers!
So its worth paying that little bit more for the 12G295 head (or 206 if I can find one!) and get it converted to unleaded? Then thats basically all the bolt on power I can get for my engine, then I don't know what I dont know what I'd spend my money on!
I dont suppose any of you lot have a decent condition HIF38 kicking around??
Cheers again guys

Rebuilding a 1992 mini...will be finished in 2019

Plus has any body got any idea how much roughly I'd be looking at for a set of valves, springs, collets etc., and where I could get them from? Cos theres a head I'm after which is in good condition but doesnt come with any valves etc

Rebuilding a 1992 mini...will be finished in 2019

Minispares do a full range of valves etc

Phil.

WWW.TURBO-MINI.COM

I got a HIF38 from the scrapyard (from a metro) perfect condition, hardly need cleaning, £5.

The 202 head is nowhere near as good as the 295 and not worth bothering with.

Edited by wil_h on 1st Nov, 2004.

Fastest 998 mini in the world? 13.05 1/4 mile 106mph

The 206 head you talk about is the same as the 295 head but older and rarer and no better. The 12G202 head wil h mentions is a 1098cc head and although better than the 998cc head slightly, not a patch on the 295.
Only thing you will need to check on a 295 head is the chamber volume. The 295 head was originally used on the 998 Cooper engines that had a raised dome piston. If you install a std volume head on a later 998cc engine then the compression ratio will be too low to give the increased performance you want.
As for finding one, you will have to keep searching till you turn one up. I remember buying one about 6 years ago, and they were hard to find then, so it won't have got any better.

Sorry read 202 rather than 206. Must get that eye test done.

Wil

Fastest 998 mini in the world? 13.05 1/4 mile 106mph

Wil,

Glad to heat that that carb was OK. Is the mini good on the commute then?

http://www.twin-turbo.co.uk
http://www.hillclimbandsprint.co.uk/default.asp

A man without a project is like a like a woman without a shopping list.

Still trying to sort the fuelling out, I've ordered a needle from Burlen based on the results of WIN SU. Not sure I believe it, it says my engine should have 67bhp (which is way more than likely) and adding a 276 cam it will then have 70bhp and will need the same needle.

When can I have a MegaSquirt?

Wil

Fastest 998 mini in the world? 13.05 1/4 mile 106mph

Does anybody know how much I'd have to have the 295 head skimmed to work well on my 998?
Cheers

Rebuilding a 1992 mini...will be finished in 2019

You'll have to measure both your engine and the head first.

Wil,

I guess you want the megasquirt for the turbo? I will get it off when I get home, late november is looking likely. I think Eric should have another timing wheel by now.

I think I am going to order some more boards when I get back so there should be another couple of megasquirts knocking around in the new year.

Or do you want it for the road car?

http://www.twin-turbo.co.uk
http://www.hillclimbandsprint.co.uk/default.asp

A man without a project is like a like a woman without a shopping list.

Ben, Road car. Thought I'd have one before I go to the RR. Save going twice. The turbo can wait til the new year.

I think I took about 2mm of my 295, that's for an A+ with flat tops running 10.3:1 CR. You'll have to measure it though as your's mihght have been skimmed before. Dont forget to check the depth of the oil-way before you decide how much to have skimmed off.

Wil

Fastest 998 mini in the world? 13.05 1/4 mile 106mph

Wil,

If you get intouch with eric, he can give you a wheel, a vr sensor, an EDIS, a coil pack and all the wiring advice you need. If you have all the fitted the car should run on 10degrees advanced. Then you can just connect the mega box in when I get it to you.

http://www.twin-turbo.co.uk
http://www.hillclimbandsprint.co.uk/default.asp

A man without a project is like a like a woman without a shopping list.