Totally inferior mini engines handle 100kws 8-12psi using SU carbs and superchargers
and some turbo with injection 120kws with better rods and pistons crappy 5 port heads.
BMC mini have 70.5mm bores and 1070 has 68.4mm stroke 1275 81.4 plus mm.

so a superior A10 Nissan engines wont raise a sweat specially with 59mm stroke and
use A12-A15 pistons to lower comp and raise CCs if you like, J pipe, SU t15 etc.
Ford ecoboost 3cyl 1ltr turbos are cheap too 138hp - 150hp output snails.

So a a10 using a12 pistons. a15 head or is it best to use a stock a12 round/small oval port? Legally I can do a a10 turbo which I would think would produce more power then a cammed a12. I just worry about the 3 bearing crank that's all. What are the limitations of the a10's 3 main bearing cranks?

Quote:Depends on what you want

If you just want more CCs, fit larger pistons and or stroke the crank. No need to change the cylinder head

If you want the most HP to go with your swaps, fit the A14/A15 cylinder head, then rev the engine up to 6000 RPM before shifting. Or fit a GX head and rev to 6400 RPM

With the A10 head or round-port A12 head, rev to the Datsun 1000 stock 5600 RPM. A little less HP, but more relaxed driving. It'll still have more power at low and mid-RPMs than a stock A10


turbo question: A10 turbo. Has anyone done it? What are the limitations?

Gordon Dobey was 1968-1972 Nissan Works Mechanic and often told me just valve springs, shaved heead,
cam and rejetted stock carb is enough for an A10 to see 9k rpm reliably due bike bore stroke ratio.
His racing A10 redlined at 10,500rp with no roller rockers!

Again compare by yourself that many mini freaks boost their inferior 3 main bearing stock 998-1275cc for 100kws.
Austin A series weaker 3 bearing cranks, poor metallurgy, shared oil with transmission nasty for oil,
cast iron head, smaller bores, valves and weaker springs yet is able to make 100kw boosted.
Thats english wonky casted engines 2nd worse in the world just ahead of Australian casted holden 6 engines.
https://www.youtube.com/results?search_query=mini+998+supercharger

So if you can actually discern this simple information you can see the A10 is easily capable of double its factory hp.
Especially due to 59mm stroke which is the shortest stroke of all Nissan engines ever made.
The round port head is ample for the A10 and same for the A12 theres virtually no difference for the early front dizzy
motors for flow bar the extra capacity of engines and exhaust mani exit hole diameter.

The 59mm stroke as mentioned, superior metal, rods, pistons and better oiling system
than the mini is all you need to consider then just get a 1 3/4 inch SU, T15, J pipe
to suit A12 exhaust manifold, use manifold heat riser mounts for turbo support bracket
then get someone to tune it properly and have 100hp reliably. Run windscreen wiper water
pump to spray water into Su entry using a dash switch once up to temp.

90-100hp with better freeway use of the diff you have thanks to extra torque and
no need for 5 speed is very handy. I would only consider an A12 box as well due to
early A10 box is made like a tooth pick yet still handled my 100hp A15 before I
went to a 5 speed and everyone said it would break but didnt after endless abuse.

The hardness of the Nissan A10 A12 early blocks when I had it checked 12 years ago was
around 285-305 rockwell much better than RB nissan engines of 240-270.

Well im supposed to pickup an a10 engine tomorrow
I believe my diff ratio is now 3.9. Was told it has a 120y diff center

which 1000 model do you have matt?

It's a 1968 ute.
All I know is the last owner said he changed to a 120y diff

The 1000 ute came with a 4.11 diff ratio. Good for faster acceleration and carrying loads

120Y came with 3.889 diff ratio. Slower acceleration but reduced revs on the highway (meaning better fuel economy and less noise)


"120Y diff" can mean several different things: You can peek under the car to find out

* swapping the diff head. The H150 from a 120Y can be swapped for the H145 that comes in the 1000 & 1200

* swapping the rear axle assembly. Is possible, but unlikely as the 120Y axle assembly is 66mm wider. would need high-offset wheels and/or fender flares -- and the leaf pads need to be moved

* 120Y australia-assembled used a Borg-Warner 68 diff. Can be swapped same as the Japan-built 120Y rear axle assembly, but the diff head by itself won't work in Japan axle


gear carrier assembly ("diff head" or "pumpkin")



rear axle assembly



Borg-Warner: removable back cover Hexagonal with 8-bolts (Salisbury type)



Japan: welded back cover with no bolts (banjo type)




If you have the Japan axle, you can tell by looking if it's a H145 or the stronger H150

H145 flange is scalloped (not a rectangle)



H150 flange is rectangle

Be thankful you are not in Victoria or if you visit remember unless they changed the speedo drive gears in the gearbox your spedo reading is out and in Victoria they can and will book you for 1 kmh over the limit.

Easy to pull the speedo drive unit from the gearbox to check if they changed the driven gear which is the one Nissan change to take into account different differential ratios.

You may want to drain the gearoil before pulling the drive unit from the gearbox it is the part the speedo cable screws onto held in with one bolt.

Good explanation is in the tech wiki with photos