12g295 head!what to do
Turbo Mini Forums

hi all i gotta 12g295 head for my 998cc turbo conversion!

It hasnt been skimmed before!
I gotta few questions to ask!
1:When i take the valves out what am i looking for to see if its unleaded or not?

2: What do you suggest doing to the head? Should i port it, get it skimmed or any thing like that? or should i leave it standard?

3: Should i change the valves or any thing else for that matter to make it cope better with the turbo?

Just looking for your views as there better than mine!!!! :)
Thanks all martin

I have one of those also. It is in need of some cleaing to say the least. Is it worth getting the l/free conversion? And what else could I do to get the most out of it (on a bit of a budget...)?

BTW any news on the maga7ine? :)

http://mini.twisted-design.net/blog/

cheers Peter :) thanks for the help as always.

Looking forward to the new magazine also :)

http://mini.twisted-design.net/blog/

What sort of peopl ewould have a suitable tank for me to bring my head to...? remembering I live in the Rep of Ireland and some things are in short supply over here :/

http://mini.twisted-design.net/blog/

Ask at your local engineering machine shop, they sometimes have some sort of dip, or at least access to one.

It's not essential, a good bit of Gunk or similar, a toothbrush and a wire-brush on a drill and it can be got reasonably clean.

Wil

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

www.twin-turbo.co.uk

Thanks guys I'll have a look around or get suck in with my toothbrush :)

http://mini.twisted-design.net/blog/

not being funny, but i really wouldnt use your own toothbrush.... have you got any housemates? or a brother or sister? borrow theres!!!!

lol

And on the 7th day........... God created turbochargers!

lol - i'll nick my wife's

http://mini.twisted-design.net/blog/

whats would you say the largest valves you can safely put into a 295 for turbo use?

I notice Petes using mg 1275 valves.

There is one on ebay at the minute with 33.3 and 29.5, would this leave too little metal between the valves to prevent cracking???

"Turbo's make torque, and torque makes fun"

"did you know you can toast potato waffles?"

I've just done a 295 N/A head. I'll get some pictures over the weekend!

cool!

Now Ive finally got a 295 to use, ordered (touch wood) some new valves and guides from minispares.

Going with:

C-AEG587 Exhausts (1.040")
C-AEG58 Inlets (30.93mm)
Manganese Bronze guides

As far as head mods are concerned, Im just gonna remove the guide boss's for now.

Ive heard mixed things about the triple groove collets, whats the general consensus on these? Also, will these fit the std 295 top caps?

"Turbo's make torque, and torque makes fun"

"did you know you can toast potato waffles?"

Triple collets are OK. Don't worry. Get some A+ top caps with the raised ridge. The angle on the triple collets are different from the single ones.

Long weekend btw :)

Just ordered (touch wood) some new valves and guides from minispares.

Going with:

C-AEG587 Exhausts (1.040")
C-AEG58 Inlets (30.93mm)
Manganese Bronze guides

Not going mad with head mods, just following the general advice and grinding back the guide boss's back, bulleting the guides etc.
Got a few tungsten carbide burrs cheap off ebay, should speed things up a little.

One thing thats bothering me a bit (not much) is Ive heard mixed things about the triple groove collets, whats the general consensus on these? Also, will these fit the std 12g295 top caps?

Sticking with the std 295 double valve springs, as its only on the std 998 A+ cam, unless you guys advise otherwise.

Will post pics up as and when i get things done.

Joe

"Turbo's make torque, and torque makes fun"

"did you know you can toast potato waffles?"

I put 940 sized valves in mine: BIG MISTAKE!

If you do it the valves will hit the block just like they do with a 940 head and you have to put pockets in. You might aswell use a 940 imo.

Cheers Vegard, had a chat with Shabs last night and he said I needed new top caps...

Do all A+ have the raised ridge? Or only some?

Can I rob the ones off the donor 998 A+ for example?

Thanks again

"Turbo's make torque, and torque makes fun"

"did you know you can toast potato waffles?"

All triple collet top hats are of the raised version. The ones off your 998 A+ will be perfect :)

bonza

the valves have just arrived this morning,
tried my best to take some pics, but the macro mode + coffee induced shake made them a bit blurry:

Bronze Manganese guides:



Inlet:



Exhaust:



Exhaust:



Intake:



The guides have come with tapered ends, do you guys taper them even more (to the port roof?)?

Cheers

"Turbo's make torque, and torque makes fun"

"did you know you can toast potato waffles?"

You mentipon earlier that you're not going to port the heads much. If so, there is no point in tapering the guides more. Especially not on the exhaust. Possibly a little on the inlet, but I wouldn't bother to be honest.

bit of an update...

won a much better 295 casting on ebay, already ported slightly etc but unskimed

picked it up form the machine shop this morning, its had a very light skim and valve seats cut, also got the turbo exhaust manifold skimmed flat as the centre branch had grown making it 'rock' on the head slightly.

some pics:



you might be able to see the removal of the guide boss's (not done by me) on these:















Now its back form having the seats cut for the larger valves, i was going to put some engineers blue on the valve, and see exactly where it seats in the head, then grind the inside up to the blue to open it up as much as possible.

Or is there a better way?

"Turbo's make torque, and torque makes fun"

"did you know you can toast potato waffles?"

*edit*
deleted due to being dim and comparing an inlet port vs exhaust...

Edited by joeybaby83 on 27th Jan, 2007.

"Turbo's make torque, and torque makes fun"

"did you know you can toast potato waffles?"

a shallower radius is not the same as a shorter radius ,and he didnt say modified 940 er .... put that beeer away right now youv had enough !!!

oh yes ,,and whats god got to do with it !!!lol

Edited by robert on 19th Jan, 2008.

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

Just bead blasted a 295 this weekend:





Junk!