hey guys,

have any of you fitted a 1400 head on a A-12? how much of mission was it does it bolt straight on? and what sort of power gain is there? is it cheap horse power

many thanks
nicholas

1400 head will need modification to make the oil galleries line up otherwise the rocker assembly on the 1400 head will be starved of oil. head needs redrilling and welding afterwards to supply oil to all the necessary bits(rocker assembly). It's a good way to go if you are prepared to do the work. Very good flow is available if you fit the right 1400 head because the ports are just asking to be opened up.

You do not mention which model of A12 engine that you have. If it is a 1200 engine then the following will apply, but if it is the one with the altenator on the distributor side, then it is a straight bolt on.

I fitted a 120Y GX head to a 1200 & the same problems apply.
Simply study both heads very carefully & figure out how the two designs differ in the supply of oil to the rockers, then copy the 1200 one. From memory, it needed two small passages to be drilled. The size can be determined by simply placing a drill bit into the 1200 head to check that you have the right size

There is no need to weld anything if you have access to a comprehensive tap set. Just tap the newly drilled transverse hole with a 1/8" gas thread, or it's metric equivalent, & fit a suitable plug. Thats what i did back in about '86 & it's still on the road.

Even without porting, if you want to keep it low buck, the A14 head will yeild better flow figures as the ports & valves are bigger than the A12. Just compare the combustion chamber sizes & measure them if necessary, as any increase in volume means a reduction in compression ratio & there are a couple of diferent A14 heads.
Chris

the alternater is on the same side as the dizzy. which gasket do i use now? 1400 or 1200? many thanks chris, you a great help
i'll pm you if i have any more questions
thanks
nicholas

Nicholas
You just gotta do something with that avatar of yours. It's hypnotic, & since i live alone, so it has other effects. Ohmygawd she's cute.

As for the head gasket, see if you can get a used A12 one as a sample. Place it over the A14 head & line up all the holes. See if the combustion chamber overlaps the gasket. If it does, then use the A14 one, if the combustion chamber is completely within the gasket opening, then use the A12 one.

I have never done this before, so i can not say from experience which one to use.
Perhaps someone else can help here.
Chris

I just put a new head gasket on my a12 (with an a12 head). i got it from repco and it said a12, a14 and a15 head gasket. fitted fine and didnt need retorqueing. cost about $15 i think.

Quinn
You are most likely right. "Replacement" gaskets are likely to be for the 76mm bore size & will fit around a 77.5mm bore. [third oversize] This will work fine.

The reason i mentioned the A12 gasket is because he will be facing a potential compression ratio problem, & if a genuine 73mm [+ oversize] gasket was available, it just might give that extra whisker of help in this department. Every little bit counts.

The monotorque gaskets are good, but i still retorque, & do it again periodicly with molly lubed bolts, as alloy heads have a habit of squashing gaskets a little when they get hot, then relaxing the pressure a little when cold. After a while, the gasket seems to lose some of it's resiliance & the tension on the bolts is diminished. I retorque periodicly because it's easier & cheaper than replacing head gaskets.
Chris

http://www.gaskets.com.tw/data/pdf-catalog/takoma-nissan-01.pdf

have a look at how many different gaskets are available for the a series!!!!!!

all with different passages

I guess it all depends on where you get your gaskets from and how well they are manufactured - I have seen some pretty poor excuses for head gaskets in the past. I have this head modification done to my coupe and I have to use the A14 head gasket but I also have the early block type and run high compression.
Do what Dodgeman has suggested and carefully lay the gasket onto the mating component faces and check water gallery locations and oil feeds etc. If you are careful and dont rush things you should be OK.