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a12gx head?


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#1 hynd5224

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Posted 03 July 2014 - 11:24 AM

This last weekend I bought what I'm pretty sure is an a12gx head. It measure out right, 30x36mm ports and the seats look like they are for 29/35mm valves. Plus its brand new in the original box with a part number that is 11041-H2XXX (you can't read the last 4 digits). So everything points to it being an gx head, but I have been wrong before. What do you guys think? Oh and what is one of these worth? I'm curious if I got a good deal...

 

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-Charlie


-Charlie

 

'71 Datsun 1200 Coupe  - Driving project


#2 ggzilla

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Posted 03 July 2014 - 12:17 PM

$150

Good score!
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#3 Morrisun

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Posted 03 July 2014 - 12:34 PM

A series racers will pay twice that for an molested AND then sum!



#4 hynd5224

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Posted 03 July 2014 - 12:59 PM

Thanks. The guy had it listed for $100 and I didn't argue. I figured it was worth at least that, but I wasn't sure, I've never seen another one for sale. 


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#5 gpimm

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Posted 03 July 2014 - 03:44 PM

Congratulations! That is the GX head for the 1200's/

 

According to my 1984 Datsun comp catalog the 110141-H2302 head is the A12 GX head to 6/73.

 

The 11041-H5703 head is the A12A, A13,A14,A15 GX head for 7/73 up.

 

The cost from the dealer in 1984 was $220.00.


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#6 ggzilla

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Posted 03 July 2014 - 04:04 PM

Agreed, it's the real deal.

Datsun Competition has a few mistakes. There was no GX engine after 7/73 (meaning after the B110 production ended, and B210 production began). The new twin carb engine was referred to by Nissan as the A12T. The main difference was the drilling in the head for the oil passage. In the B110 motor that oil passage was drilled in the head. In the B210 it is drilled in the block

There was also H2300 and H2301 head variations which have less accessory bosses on the head.
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#7 Ranman72

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Posted 03 July 2014 - 04:17 PM

Looks like a GX to me 

as far as I know the GX head is the only head with water ports in the A series 

good score for 100 



#8 ggzilla

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Posted 03 July 2014 - 04:24 PM

All A-series engines after 1980 have water passages below the intake ports, but they are smaller.

Another head with the large water ports is from Nissan Cherry X/1, and the previously mentioned A12T. The GX heads that Datsun Comp sold were simply production heads from these cars. They also sold a "competition" head which was the GX head fitted with the larger A14 valves and some other modifications.
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#9 njoz1200ute

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Posted 07 July 2014 - 02:16 AM

Nice find, will you be selling it or keeping it, as I am searching for one too?



#10 hynd5224

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Posted 10 July 2014 - 12:32 PM

Cool looks like I did find a good deal after all!  :thumbup:

 

Now to have it cut for bigger valves and smooth the ports out a bit. Oh and find an intake. The parts search continues...

 

 

Nice find, will you be selling it or keeping it, as I am searching for one too?

 

I will be keeping it, but good luck in your search! I just happened upon this while in pursuit of a 63a 5 speed that I still haven't found.


-Charlie

 

'71 Datsun 1200 Coupe  - Driving project


#11 hynd5224

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Posted 11 July 2014 - 05:08 PM

Nice find, will you be selling it or keeping it, as I am searching for one too?

FYI I did see a couple of GX heads for sale on datsun1200.com classifieds, two in the US (LA), one of which had valves & springs too.


-Charlie

 

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#12 IttyBittyDat

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Posted 19 July 2014 - 12:55 PM

"Oh, and find an intake. The parts search continues..."   

If you're going the 32/36 Weber downdraught carb route, your parts search may be at an end! I have an A14 oval port intake manifold that has been ported to within a millimeter of its life to ~36mm x ~30mm and it already has the Weber carb adapter on it.

BTW, finding a NOS GX head in original packaging is a unicorn find - finding it for $100 dollars is winning the lottery on top of that - jolly good show!



#13 Tom1200

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Posted 29 July 2014 - 07:52 PM

Just an FYI; to fit the 37/30mm valves you can cut the exhaust seat but you will need to fit a bigger seat for the intake valve.

I am an A-Series racer and just as a reference, last year I paid $750 for a complete GX head. It had race springs 37/30mm valves and porting cleaned up. You can still get the valves with undercut stems from SI and the springs from Isky. As far as porting goes note the seats protrude pretty far into the port, cleaning that up will make a huge difference.

Tom

#14 hynd5224

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Posted 30 July 2014 - 10:28 PM

Just an FYI; to fit the 37/30mm valves you can cut the exhaust seat but you will need to fit a bigger seat for the intake valve.

I am an A-Series racer and just as a reference, last year I paid $750 for a complete GX head. It had race springs 37/30mm valves and porting cleaned up. You can still get the valves with undercut stems from SI and the springs from Isky. As far as porting goes note the seats protrude pretty far into the port, cleaning that up will make a huge difference.

Tom

That's good info to know! Thanks Tom!

 

I did notice how far the seats protrude into the port. That, bigger valves, and cleaning up the rough spots in the casting is all I had planned. 


-Charlie

 

'71 Datsun 1200 Coupe  - Driving project


#15 vr0000m

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Posted 28 December 2016 - 03:05 PM

If anyone is still looking for a A12GX head I have one on an engine I am parting out.

The intake ports are out to 40mm x 33mm. 



#16 datzenmike

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Posted 28 December 2016 - 03:42 PM

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