New Zealand Datsun Club

Just a few pictures of the recent work I've completed on my a15 race engine build. Starting with the spare a15 block purchased for $200 on trade me. The coby extractors about $260incl, trade price, made to suit twin carb (two options on extractors). The flywheel from an a12 engine is already lighter than a15 one, minus another 3kg off on a lathe. Coby extractors "standard" can still restrict an exhaust outlet as the flange holes have been opened up on mine for this reason, good idea to not match the extractors to the head port... a lip from the head down to exhaust stops gas back flow in the into the head but I have ground the exhaust flange to the max of the pipe size for flow.

Twin 40 Dellorto with ram tubes dirty filters & soft mounts purchased for $650 from TM. Possibly needing larger jets and a good tune. Then the head work begins, coppied a mates race head from a 1200 coupe track car. Looking at DIY head work? I'm told $2000 was the cost 15 years ago for a race head job. Its possibly more now. I've got the die grinder but still spent approx $300 on Rotary tool kit and alloy grinding tips then 30-40plus hours grinding, sanding, buffing, use old valves to protect the valve seats or plan on replacing valve seats! that grinder will get away in the chamber, lesson learnt for me, two new valve seat inserts required and a full valve grind that was expected anyway, guess I've saved $1200-$1500 but you need to be skilled with tools! The next head I do will be quicker, the cutting tools can snap & the risk of stuffing a head is high in my view. See progression pictures.
I don't have a side view of my ports now finnished, the idea is to raise the inlet port towards the top of the head, in my case, oval ports and direct flow straight down towards the valve. I also raised my manifold slightly to gain this.
The buffed chambers are my head, they look nasty untill you see the finnished project.
(Attached is my mates head ports to give an idea)

Mazda 1500 flat tops $400 trade, need to deck the a15 block down to match and inlarge con rod little end by 1mm, these are max oversize for the a15. Then check piston to valve clearance and machine groves if contact occures.
Port matching head to inlet manifold. Manifold off TM $130.
Head has holes for water into old manifold must be blanked and new manifold needs two fresh mount positions at the top secured by thread inserts. The high compression pistons replace the dished down ones to allow a stage 4 fast road camshaft $180ish and heavy valve springs required also $120ish.

Thanx for sharing man, I look forward to seeing what happens to the bottom end to match, looking good so far would be good to see a bit of detail on the porting if you can share it.

Just an update on the project, still waiting for my engine at the engine shop grrr holding back! was to be ready weeks ago and in the car by now. I've been keeping busy on other bits anyway. Painted up the wheels that came on the car as i was not happy with the wheels I had fitted to it and the budget won't cover the wheels i'd really like. 14'' 80's dished wheels are like $1000+ these days. Gearbox had a tidy up to hide the dirt and a fresh up inside.

Great job
I also have a stock a15 and i will be looking at this to get some ideas as to what i will want,but i'm not going for race just street.by change what's the size of valves,ports and pistons.Do you suggest i open the ports on my extractors as well?

Widened Steelies also look the biz if you are looking for something to set the car off without the huge bill.

darrenwilson wrote:Great job
I also have a stock a15 and i will be looking at this to get some ideas as to what i will want,but i'm not going for race just street.by change what's the size of valves,ports and pistons.Do you suggest i open the ports on my extractors as well?

I Don't have any measurments with me at the moment, all my parts and engine have been sitting at the engine shop for months. My plan is to list piston part numbers and some details when I get it all running. I've had a look at your car & would say, unless you are going to plan on buying side drafts, spending money or time on porting... then change a compression ration $$$$ (flat top pistons, decking the block etc) I'd not port the head. Its a waste of time and money doing one or two mods but leaving the rest, twin side drafts won't run well on a standard motor but you have no reason to change ports etc unless you have a race cam and side drafts really. Also keep in mind my engine build has cost me thousands as a trade mechanic, you could buy a later model engine and fit it for cheaper? but I wanted a classic race engine.

Tidy up of engine bay as it was looking tired and dirty, colour match in a can is great with a clear coat on top, mask out the bits in the way and its done.

There is nothing uglier than when someone paints over the strut tops. Good to see you're making the extra effort.