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Price of a 12G202
https://www.ausmini.com/forums/viewtopic.php?f=2&t=15250		 Page 1 of 1
Author:  Smokie [ Fri Jan 20, 2006 9:46 am ]
Post subject:  Price of a 12G202
Can anyone tell me roughly what a 12G202 modified head with rockers, etc, ready to bolt onto a 1049 block would be worth?
Author:  fuzzy-hair-man [ Fri Jan 20, 2006 10:13 am ]
Post subject: 
You can get 12G202 heads pretty cheaply I think I got one off ebay with rockers valves etc for ~$30 this was standard though...

The more popular bet if you want performance from a small bore head is to get a 12G295 or 12G206 head these are based on the same open chamber design as the 12G940 head but they are hard to find (came off 998 Coopers and Sprites)

Because the 12G202 head can be got so cheap I reckonit is a good head to try messing about with modifying yourself get Vizard's yellow bible and it tells you how.
Author:  drmini in aust [ Fri Jan 20, 2006 10:32 am ]
Post subject: 
Problem with a 295 head is, it needs a heap (.080" up) ripped off the face to get the C/R up to something decent, with the standard dished 998 & 1098 pistons.
998 Cooper was 9.0:1, had D-top (pop-up) pistons, but these have been NLA for yonks.
If doing a modded 202 head, the chambers do not need to be ridiculously big like the 295 (which are 28.4cc).

Just open them out as in Vizard's book.
I'll post some pics here later. :wink:

<edit>
here's 2 pics of a 12G202 head, modded to go on a 1220cc Sprite (68mm bore).
Chambers finished up at 27.5cc, valves are modified 1275- 33mm/27mm, has Rover 998 unleaded inlets in exhausts.
Pics taken before final polishing.

Image
Image
Author:  Smokie [ Fri Jan 20, 2006 11:01 am ]
Post subject: 
fuzzy-hair-man, would like to try and do it myself but not having any equipment or knowledge to do it, I would much rather buy one already worked over..

Anyone have one for sale??????
Author:  fuzzy-hair-man [ Fri Jan 20, 2006 11:08 am ]
Post subject: 
I haven't tried it but I don't think you need all that much equipment a dremel and a good bit ?

Vizard's yellow book is very good it gives excelent diagrams not just "take a bit outa here and there" really makes me think I could have a go myself.... and if I stuff it whats $30 :D

I understand where your coming from though...
Author:  drmini in aust [ Fri Jan 20, 2006 11:11 am ]
Post subject: 
fuzzy-hair-man wrote:
I haven't tried it but I don't think you need all that much equipment a dremel and a good bit ?

Vizard's yellow book is very good it gives excelent diagrams not just "take a bit outa here and there" really makes me think I could have a go myself.... and if I stuff it whats $30 :D

40 years ago we did them with a Black & Decker drill... :lol: then I built a flexible shaft grinder.
These days a 1/4" air or electric die grinder is the way to go. The toy Dremels they sell with the 3mm chuck don't cut it. :cry:
Author:  EST-071 [ Fri Jan 20, 2006 12:03 pm ]
Post subject: 
Smokie wrote:
Anyone have one for sale??????

I have one, but postage to you from Sydney will be a killer.
Pete
Author:  Mike_Byron [ Fri Jan 20, 2006 12:19 pm ]
Post subject: 
Postages costs on a head are not that bad
The heads are about 16 kg and its less than $20 to post it.

But any second hand head you buy should have a service done on it regardless of if its worked or not. Work should include acid dip, hardened exhaust seats, valve guides and a surface grind skim as well as new valves as required. Most heads develop a warp over time. The cost of this is between $200- 250 on top of the cost of the head and the postage.

having said that - this sort of work should be part of the head modifying process and a reputable head modifier would give you a "bolt on" head.
Author:  udomatic [ Fri Jan 20, 2006 6:44 pm ]
Post subject: 
Quote:
The toy Dremels they sell with the 3mm chuck don't cut it.


Why's that Doc?

My Lithium Ion Dremel (10.8v) with grinding stone makes light work of deburring steel...can't remember what size chuck though but I think it would be up to the job.

I plan on getting a 202 head for Udo down the track so I may give it a go...
Author:  drmini in aust [ Fri Jan 20, 2006 6:55 pm ]
Post subject: 
udomatic wrote:
Quote:
The toy Dremels they sell with the 3mm chuck don't cut it.


Why's that Doc?

My Lithium Ion Dremel (10.8v) with grinding stone makes light work of deburring steel...can't remember what size chuck though but I think it would be up to the job.

I plan on getting a 202 head for Udo down the track so I may give it a go...

You are taking cubic inches of cast iron out when you port a head, not just polishing it. :lol:
Polish = Bling = useless for power. Shape is more important. :wink:
Metal removal needs power...
Author:  udomatic [ Fri Jan 20, 2006 7:39 pm ]
Post subject: 
Hmmm...yes, could get rather frustrating.
Author:  drmini in aust [ Sat Jan 21, 2006 12:37 pm ]
Post subject: 
Pics added to my post above.
Author:  Hagar [ Sat Jan 21, 2006 4:20 pm ]
Post subject: 
I've been playing with a 202 head and a ' toy' rotary tool. I got the head for nothing and the tool was $30 on special at Supercheap. I have no experience porting and polishing, all info used was found on-line. I'm not trying to turn the Mog into a rocketship, just trying to get a bit more from him.

Starting with the head full of mud wasp nests (it had been on an engine in a shed with the plugs and manifold studs removed, so the face is good, but chambers rough), I found the rotary tool to be more than adequate at removing cast iron quite quickly. In fact it was almost TOO fast. The trick seemed to be to use virtually no pressure and not quite maximum speed. The supercheap grinding stones were ok, but the moment you put too much pressure on them they wore down to the shaft.

These pice are from partway through the exercise.

Image

Fully expecting the whole experiment to be a dismal failure, I was pleasantly surprised at how smooth I was able to get the chambers and ports on just the first pass. I'm not finished yet, need to do a light polish and have the head skimmed (apparantly 60thou) to maintain compression ratio. I'll be interested to see if it makes a difference, but if it doesn't I'll be out about $100 for the whole exercise.
Author:  h0nk [ Sat Jan 21, 2006 4:27 pm ]
Post subject: 
Looking good! I had a go at a bit of a port and polish job on my 998 head not too long ago... mine turned out better then I expected, aswell!
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