12G202 head modding
Turbo Mini Forums

Hi gents,

I started modding a 202 that I bought for the deerest sum of 20£.

Here it is as I bought it :



As the perfect newbie, I worked the chambers before noticing the ports are in pretty bad shape, particularily the centre exhaust port.


At first, I intented to reuse the valves so I cleaned the first set then I noticed one of the exhaust port is shot.

This head is intended for a N/A 998 pepped up on the cheap.

But I can't make up my mind about the exhaust valves, keep the standard size valves or go OS.
OS means I'll have to have the seat recut.
Also, I have no idea if the OS exhaust valve is required on such a low power application ...

Anyway, next pics tomorrow

Edited by Advantage on 2nd Mar, 2011.

Rusty by nature

Depending how bad the valve seats are you may find by the time they are recut that the valves sit very low, & in some extreme cases almost falls through, so you may find you need to go up in valve sizes in order to get a decent seat.

WWW.TURBO-MINI.COM

be carefull looking at the exhaust seats most small bore heads i have stripped had burnt-eroded valve seats. If you can get away with just a recut standard valves are cheap oversize ones are quite a jump in price. You could always have hardned seats fitted to runs it happening in the future. This is what i should have done on the 202 i did i just got away with new valves but could do with new seats really which i will do when i next have the head off or prep another head from stock.

My small bore turbo project http://www.turbominis.co.uk/forums/index.php?p=vt&tid=473901

You cannot use std valves at a guess. First of all, they won't clean up the old seat, second they are too small for a performance 998. Minispares 26,5mm ones are perfect, and cheap.

Some 202 pictures here:

http://home.online.no/~lyngset/enginestuff...t=25&pDispType=

Thanks for the comments.

I found out today that I need to go OS anyway as the burned exhaust took a part of the seat with it ...

So here we go : Standart 202 inlet valves and OS exhausts (at 3 times the price, ouch)

Rusty by nature

Ho and day 4 pics by the way :




Shall I mention all the work so far has been carried out in the kitchen ?


And the weight of the head is 12,8 Kgs and I was planning to gain some on that.
We'll see how the seats clears before going any further.

Rusty by nature

yep sounds like another typical small bore head. If your changing the valves bare in mind the guides might be a different fit on the new ones. Also the guides probably wont have the grove for seals so if too loose you will get the usual puff of smoke. Keep up the good work carefull with the kitchen.

My small bore turbo project http://www.turbominis.co.uk/forums/index.php?p=vt&tid=473901

The seat :



Freaky combo : valve and seat !

Rusty by nature

Rusty by nature

The Neway cutters either have a single angle cutter on one side, or a different angle on on two sides. Either way you'll need either two or three cutter to create a 3 angle seat.

WWW.TURBO-MINI.COM

Yep i have a set of neway cutters that vary enough for small bore heads to largest valves for the large bore the only thing i havent got is the cutter guide for the turbo size valve guides and unless im really stuch i wont for arond £50 for a stick and collet. I cant remember the cutter numbers i have but can find out if you want they set me back £350 so you have to know you are gona be playing with heads for along time lol

My small bore turbo project http://www.turbominis.co.uk/forums/index.php?p=vt&tid=473901

Rusty by nature

Neway is junk. Get the seats done at someone who knows what they are doing. Also, the condition of the guides does not matter as you will be porting it, the guides will need to come out anyway.

neway are junk? I think not i know alot of companys that use them and have used them in work and hobby for 14 years now. Ok they take some time if your going huge valve from small but thats never been a problem.

My small bore turbo project http://www.turbominis.co.uk/forums/index.php?p=vt&tid=473901

Rusty by nature

wrong the guides i have are collet type so self centreing and also have precision ground guide for mini guides you use a second cutter to narrow the seat once the valve height has been set or if you are not cutting 3 angle you widen the port to narrow the seat.

My small bore turbo project http://www.turbominis.co.uk/forums/index.php?p=vt&tid=473901

Any home tools falls in the "proper" category ?

Rusty by nature

However, most of us do the best we can with whatever we have and can afford.The results that some get with this approach is pretty impressive IMO.

Advantage.
I have a Neway set. It is self centering. I can cut 75, 45 and 15 degree angels. Can´t cut 30 degree seat angle YET.
I usually charge 100£ for 8 valves, but for you i´ll do it for free.
All you have to do is to drop it off at my place, or go to the post office

If i have more toys than you when i die, I WIN

That's very kind of you but carrying an heavy item abroad can prove very expensive as I just checked.

It would be 424 euros to Danemark and back wich shall allow me to buy a neway set or have those done with proper tools ( )

Rusty by nature

I can't see the point into giving any money int this S...

it does ahve the same ports has a std 998 head, just bigger valves, but then these ones are dead
it does have a bigger vlume : need a lot of skim=money
it needs valves , port work, guides, cutting seats...

if you find a proper 295 head I'll understand,
with no money to put thru this why not drop a 33/30 1275 head?

+1 avec fab
and if you want i have some 998 head in stock