Hey guys Wanted to ask what have some of you done with the extra oil channel on the gx head to block it? or what allternatives are there?

Thanks

Why do you want to block off the hole? I am assuming that you are refering to the 1200 head & not the 1974 & later A12 head.

The hole that is drilled in the surface of the head will be sealed by the head gasket, so there should be no problem there & this would be the only hole that you could be refering to

Hi Dodgeman.

To make live easier, can you PLEASE explain what is involved in putting a A12GX head or even a 1200GX head onto a A14 block.

I am confused and may understand wrong, but was there more than one type of 1200 GX head?

I thought there was only one type?
Mine is the A12 with the distributor at the front and the A14's of today have the distributor at the back. I have never seen here in South Africa a GX engine with the distributor at the back. All original GX engines here have the front mounted distributor.

Ah okay so the oil coming from the head won't damage the gasket.. Great thanx

1200GXman i just talked to a guy who wants to help me and he says it bolts rite on, just use plugs to block the water ports and get a set of 40's

Quote: The 120Y GX [B210, 1974 to '77] used the newly re-designed A12 engine with the distributor at the back. The earliest of these later type engines used the 1200 [front distributor] head castings, but they were not drilled for the 1200's oiling ststem. Shortly after, the casting was simplified & the cast-in boss that allowed a horizontal drilling for the 1200 was deleted as it was no longer required.

Either of these heads will bolt directly to the A14 & work, but one should not use the later model [rear distributor] heads on the earlier [front distributor] engines without modifying the late model head to allow rocker oiling from the early block.

I don't know if using a standard 1200 or A12 GX head on the A14 will be an advantage since these heads use smaller valves than the A14 uses.
My suggestion is to use the larger A14 valves in the GX head. This will involve replacing the valve seat inserts in the casting with the larger ones & this is best done by a competent machine shop.
The oval port A14/15 heads that we saw here in Australia are almost as good as the GX head & are more than adequate for just about any performance oriented street application. These are often a better bet as they are more readily available, lower in cost & come with the bigger valves anyway.

In my 1200 GX head, I used the A14/14 inlets of 37mm dia, [up from 35mm] but used custom made stainless exhausts of 32mm. Standard 1200/A12 exhausts are 29mm while A14/15 exhausts are 30mm.

If the A14/A15 oval port head is just as good as a GX one, why are the people raving so much about a GX head.

If I do use my GX head on a A14 block, I am planning some mild work to it like the following:
Still the GX double valve springs.
Swirl flow on intake ports with a bit of a rough surface.also some port cleanup.
Gasflow of exhaust ports and also a bit of polish of the exhaust manifolds inside.
cc'ing of chambers and also a polish of them
Larger valves.

The GX cylinder has the largest ports in a 'production' A series head & therefore has the greatest 'potential' to make power. To fully realise this potential, particularly on an A14 or A15, it is desirable to use the larger engines valve sizes, or even bigger if racing is the plan.

For engines that are to be used on the street, at engine speeds up to the factory red line of 6,500 rpm, the A14/15 heads that we got in Australia have slightly smaller, but entirely adequate port sizes & they come with the larger valve sizes as standard.
This makes them the best VALUE head in this application as they come standard on most A14/15's, so no additional purchase is necessary, there is no need to upgrade the valve sizes, so more money saved, & the manifold studs are the same as GX, so the readily available manifolds will fit right up.

If going racing, then a GX head will need less porting, but it will need a valve size upgrade, while the A14/15 head will need more port work, but you can use the standard valve sizes if you want.
It's all a balance of specification, aplication, availability, & cost.

Either way, you would be up for a standard cylinder head overhaul as a minimum, plus double valve springs for the A14/15 head if you plan to rev it out a little.

Thanks Dodgeman.

Well, I am itching for a A14 bottom end and then the GX goodies.
But, on the other hand. I am thinking of the trick mod you did with A12GX engine to get it to 1300cc. 1300cc is not that far away from 1400cc and I think it will maybe do the trick and be a cheaper option than going A14 and then reconditioning it.

Last time you however said it is not advisable to bore the little end of the conrod to accept the larger wristpin of the A14 pistons.
If going the 1300cc route, I plan to give the engine a hard time because I have a spare one in the storeroom.
Don't want however a piston flying out infront of me at 7000rpm and also loosing a GX cylinder head with lots of work gone into it.

I bored the little end of my 1200 rods in that engine & it never ever gave me a moments trouble, but that was long before the INTERNET, & long before this club. Additionally, ... while I was never averse to driving in a 'spirited' manner, I never abused my engine in the same way that some people do to theirs. My engine rarely ever saw 6,000 rpm, ... never needed to.

This time round there are a couple of differences.
I am running a longer stroke crank, I have access to the Internet, & thanks to this site, I now know of an alternative rod, & I have the ability to source them.

So, there's the deal. You can bore your rods like I did & they will probably be just fine if you can keep the stresses within reasonable limits, but for me, another solution presented itself & I chose that option.

P.S.
My old rods, with a set of 76.5mm pistons attached are still around, in the hands of another member. Contact me if you want his name as he 'might' be amenable to a sale.