Head
Turbo Mini Forums

Im collecting parts for my 998T build.

I have an A+ block
1100 crank
Still undecided on pistons
I think it'll be a 266 cam

I have a choice of 202, 295 or 940 heads which are sitting in the garage. Whichever one I use will have a mild porting job and modified chambers, but which do you think would be the better choice. Obviously a 940 will need the block pocketed which is no issue.

Ive had great success with an old 998 n/a with 266 and ported 202 which was very good and beat any std Rover Cooper on the road around MK so this with a turbo seems a good idea to me.

Any thoughts?

Paul

I seriously doubt it!

I know Keith Calver really rates the 202 heads as they can be made better than the 295 heads. It takes time though. His reasoning was that a 295 is good, but lacks material some places where it shouldn't, the 202 didn't, but is not as good by far, when standard, compared to the 295

In all honesty I would go 12G940 Paul its a rocking setup and with little or no porting it will flow very well for a 998.

I am driving a 998 every day it is fitted with a 12G940 and 286 cam circa 10:1 compression and It keeps up with most 1275 and even a few 1380 :).

Considering the similarities in spec between the hillclimber and the road 998T, I would say that the 940 on the hillclimber has more potential.

We run standard MG valve sizes and have just had the guide bosses removed and the chamber slightly enlarged. I found the most important thing with the 940 is to keep the chamber within the limits of the 998 gasket (and hense bore) and also keeping the chamber shape gave results. This limits the size of the chamber available which means you'll need dished pistons.

I have also found that the BK450 is a better head gasket than the 998 ones readily available, and you can only fit these with the 940 fitted.

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

www.twin-turbo.co.uk

If doing a "mild" job, the 295 would be far less time consuming to get right.

With a small turbo port runners would be big on a 940. I've fitted a modified 295 to my 1131T...

Edited by Vegard on 27th May, 2009.

See my new thread in the 998 section :)

I was thinking that a 940 with the guide bosses removed would be cheaper than a ported 295 or 202 to give the same results due to the 940 ports being bigger in the first place.

I do like the idea of using BK450 and 11 studs TBH which is only possible on 940.

Ive read a bit using the search button and I know the 2 waterways need blanking, do we need to put any in anywhere else? or use a bypass hose? or even dry deck it?

Im trying to get it into my head that the crank and rods only need balancing and not the full works that the sprint gets, what do you guys think on that? It'll have a ultralight flywheel just for the strength more than weight saving.

Cheers guys
Paul

I seriously doubt it!

paul,
im building something v similar except n/a.
ive chosen the 295 head ,a cam in the 266 type of range ,10.5 cr .i chose the 295 head for port velocity over the 940 ,to build up lower rpm torque .
at the moment im investigating the thing g russel talks about ,where you machine down the 998 pistons to get a flat top piston cheaply ,seems to be a bit iffy to me ,very thin piston and short ring to crown distance ,unfortunately only other pistons i have are 6cc ,so id have to take 3mm off a stock unskimmed 295 ....bit of a shame .

regards
robert

Edited by robert on 27th May, 2009.

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

Robert are you going to over bore the motor if not why not run the standard Flat top piston that came in all the late 80's 998s I have about 5 sets here ?

thanks paul , appreciate the offer . i have a set here too, i was checking it out and, with the longer stroke of the 1098 ,they stick out of the bore 3.15mm , if i machine this off this leaves it v close to the top ring and a bit thin in the crown ,very dissapointing ..i dont want to skim this head .

Edited by robert on 27th May, 2009.

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

Why not use a 1098 block?

I seriously doubt it!

the 1098 block and the 998 are the same i think rob .the 98 pistons i have are a plus , the 1098 ones are pre a plus .

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

I defo would ude the 295 head,
the chambers are right as the in and out flow,
as for cam the mg one rules, it's cheap too. I wouldn't use the 266 stuff.

yes vegard ,the block i have has a little flange.

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

I love a little flange!

I cant be fussy

Me too!

If something is worth doing, it's worth doing half of.

I prefer a tight flange to a little one...

To be fair flange is flange.

If something is worth doing, it's worth doing half of.

even when it covered with a thatch like a thirteenth century barn?

never been to basildon then...

I wondered how long it would take to go off topic. lol

Paul

I seriously doubt it!