I'm workign on getting my A14 up and running and I'm trying to figure out the head bolt situation.

Could someone confirm that the special headbolt for the A14 should be about 1/2" longer than the others (center bolt on the spark plug side)? I understand that this is supposed to be a thinner bolt for oil to flow around but no one has confirmed it should also be long.

The old one I pulled out was long and so is my replacement. Just want to make sure it's right. I'm still tryign to figure out why I don't get oil up top when I hand crank it.
thanks
Michael

It's possible that the A14 has an A12 head.

So the bolt situation could be different from my memory. Maybe you've had the wrong headbolts in the engine for a while.

The 'different headbolt' is marked on the top differently to the others.

You might need to crank with the starter to get the oil up top..

I'm sure someone who is more A-series friendly can help you out.

The center bolt should be recessed on the top of the head,and a little longer. you would have to crank the engine awful hard by hand to get oil pressure, if you can, use the starter .

I have not had much to do with these 'new fangled' A series engines before, so I can not be 100% sure, but to get oil to the rockers, a drilling was made from this bolt hole to the oil gallery. To ensure that oil got past the threads, this hole was drilled to the major diameter of the thread far enough down to get past this oil drilling.
This then effectively reduced the available thread purchase length, so the simple fix would be to drill this hole deeper in the first place, which simply moves the threaded section deeper into the block.
This in turn would necessitate a longer bolt. One that had a reduced shank diameter to allow the oil to use the head bolt hole in the head as an oil gallery.

What does this odd head bolt of your look like again?

If you have a look at an A series cam, you will notice that there is a shallow groove around about 25% of the circumference of the middle cam bearing. In a running engine, with normal oil pressure, the rockers get only a 'squirt' of oil when this groove lines up with both the pressure side gallery hole, & the delivery side gallery hole, so here's the plan.

Crank the engine untill you have established that you have oil pressure in the block. Even a very low reading is OK here, so long as it is actual oil pressure. Move the rocker arms to one side a little & squirt some oil on the shaft where the rocker sits. You will need to turn it over to access all rockers in turn.

Start the engine. Watch closely to ensure that oil pressure is normal, then keep your eyes on the rockers. The engine will need to fill the hollow shaft with oil before oil is forced from the rockers under some pressure, but give it a moment & if you are worried, then just squirt a little oil on the pushrod sockets & valve tips while it is running. Unless something is seriously amiss, you should have oil flying all over the place in short order as a result of normal oil delivery.

In all cases, A-engines have the oil flow though the right center head bolt hole, hence the smaller-diameter bolt.

- The engines through model year 1973 have the oil passage drilled in the head. These engines are easily identified because they have the distributor under the #1 spark plug.
- The 1974 and newer heads have the oil passage drilled in the block.

So if you put newer head on old block, you need to drill a passage.


Boss on outside of head for oil passage
Some of the newer heads have the boss, undrilled, while even newer heads have no boss.

In my case the No.1 head bolt, the special one is the one on the far right of this photo.



It is marked with a T on the head. (might be able to make it out in this pic)

Thanks all. Ben what's up with that shorty on the left??

But anyway, it looks like my bolt is in the correct position. And thanks for the detailed description Dodgeman. I was trying to figure out why the books say "smaller diameter" when in fact the diameters are all the same. It's just that the threads were moved down to accomodate the oil passage.

Here are pics of my old bolts and the new installed ones. The "12T" one is in the correct position so I will assume that is not my problem (if I have one at all). Maybe as soem of you said it's time to crank her up and just see what happens.

The short bolt was in the engine when I pulled off the head?? Had a weird top on it too....

Got rid of it on the rebuild and used another head bolt from a 120Y which also had 13 stamped on the head.

Was all a bit weird - but I think every Datsun owner who hasn't owned their car from new has had a few of those moments the..."What the hell? How was this car able to drive around with this bolted there!"

Good luck Michael - give it a kick, just listen carefully. One extra thing you could do is spray to rockers at least with some assembly lube.

It's Molykote in a can - some sort of gray graphite like stuff - I've sprayed it all round when re-assembling.

It's purpose is to lubricate parts on first start before they are adequately coated in oil...don't know why I didn't think of it before.

It's the grey stuff on the crank below

Thansk Ben. My Isky cam came with some pinkish assembly lube that I applied liberally to the parts I assembled. I may add alittle more before starting.

Our projects are nearly in sync...I plan to be starting mine this week - engine is in, just got a few wires and cables to hook up...can't seem to find my clutch cable.