Hello guys, I have just finished re-assembling my A15 after the engineering work.

I realise now that I don't uderstand quite how the oiling to the head works - my Haynes manual isn't quite clear.

Does it reach the head via one of the head bolt holes or a seperate channel?

I see that one of the headbolts on the distrubutor side (the middle or No 1 hole) is marked "T" -
is this perhaps the oil channel?

Thanx for any advice

For engines that were made from 1974 onward [rear distributor] the rocker oiling comes upward via a drilling in the block, to another angled drilling that takes it to one of the head bolt holes.
This particular head bolt is longer as the threaded portion of the block is lower down, or deeper into the block. This means that the hole can have some of the thread drilled out completely & the bolt still has enough thread engagement.

Now we have a space around the actual bolt shaft that effectively allows oil to pass up alongside the bolt into the head. It doesn't come out the top because the washer & the bolt head form enough of a seal to prevent serious loss.

There is another drilling in the head that intercepted this head bolt hole & takes the oil to the base of the centre rocker pedestal where it continues to travel upward & into the hollow rocker shaft,&, ... well, you know the rest.

As I said before, this particular head bolt is longer than the others as it needs to reach the threads deeper down in the block & I think that it is 'waisted' down to the minor diameter of the threads to allow maximum clearance for oil transfer in a standard diameter head bolt hole.

The A10 & 1200 engines, up to 1973, used a separate drilling in the block & head to achieve the same result, but it was deemed preferable to change this when the engine was re-designed for the '74 model

Thanks Dodgeman. I was just concerned for a moment this morning when one of my clients (a retired Datsun mechanic)mentioned the "thin" headbolt where the oil channel runs through the head.

My A15's headbolts are all the same diameter. The bolt marked "T" is longer than the others though ,as you mentioned.
According to my manual (which is for the A12),the position for the "T" bolt is the middle hole on the dizzy side of the motor. Is this correct?

Thanks!

Yes you have that correct! I guess the manual for the A12 is the late model A12 with the dizzy near no.3, if so all the torque settings should be correct for the A14 if I remember right.

Cool,thanks white sedan!
Is there a way of priming the oil pump on a newly built motor that I should know of?

With VW motors its quite easy to spin the oil pump with a power drill to pressurize the system before start-up.

Unfortunately, the design of the A series does not really allow pre oiling before fire up, so lube everything well during assembly & hook up a good [big] battery & spin it over without the plugs untill you have at least 'some' oil pressure. If you have the tappets & timing correctly set, it will fire right up when the plugs go back in.

Hi Mustard

Are'nt you going to use this car/engine for classic racing?
If so, what have you done to the engine.
Just curious about what the racers do to their engines to get good reliable power.

Regards

I've kept it simple as I'm unfamiliar with Datto motors - Stock A15 with new rings on (good)used pistons,hone and new bearings.

The head has been flowed and reconditioned by a mate in the trade(stock valves,recut seats,new guides). The head has been skimmed to get the CR up to a modest 10.5:1. It has a 268 deg cam and twin 40 Weber sidies.

I'll build a warmer version next time around

Thanks Dodgeman for the thorough explanation

New cam? Don't forget to break it in (do not let the engine idle). See camshaft.


For more on the oiling system, see Lubrication Circuit