Datsun A12[S] motor * gearbox into a MkIII midget

[middie]

Just a bit of a challenge to the forum.

I've settled on the fact that I can't afford a 1275 in my "engine deprived" Mk III Midget.

Funds dictate that I buy something cheaper, and I've found an 81 Datsun Sunny (Australia) with an A12S motor and gearbox.

What problems am I going to face. Engine mounts, transmission tunnel, wrong things on the wrong side, etc.

Has anyone attempted this before, or should I just go back to saving my pennies/cents????

Thanks in anticipation

 

[bill_young]

I've heard of that swap, but never seen any photos or details. I'm not familiar with the Datsun cars sold down under or their engine numbering system, is the A12S motor a pushrod or a OHC? I've see an L18 engine installed in a Bugeye, photos of one are on the British V8 Newsletter site but it's not a finished project. From what I've read the early pushrod engine fits much easier than the L18. https://www.britishv8.org/Other/MarkWarner.htm

 

[aeronca65t]

We have at least one active meber here, ~RickB~ who has a Datsun-powered Spridget.

He may have some ideas for you if you contact him.

 

[RickB]

Hi, I have the 1500 version (A15) motor and the 4 speed gearbox currently running in my 78 Midget.

With the 1500 a little cutting up front was needed and the motor mounts had to be moved. The A12 is smaller, so it might fit right in. Measurements would need to be taken to know for sure.

I've got a 5 speed box that should fit right in, BillM and I will be doing that swap sometime when the weather warms up a bit here.

If you are lucky enough to find a GX head to go on your A12 and fit it with dual SU carbies then you will indeed have a very nice running car.

I suppose you might already know about them but there are a couple good forums for the Datsun (Nissan) stuff, here they are:

Ratsun forum, Engine area:
https://forum.ratsun.net/forumdisplay.php?f=14

Datsun1200 Club:
https://datsun1200.com/modules/newbb/

Keep us up to date on your progress!

 

[Billm]

I am fairly confident that the A12 (pushrod) motor, the A14 and the A15 are all virtually the same size (with the probable exception of the block height being about 1/4" different), just as the Spridget "A" blocks are basically all the same size.
"MrSprite" in Colorado also has the Datsun A-block conversion in his.

All-in-all I would wait for a proper Spridget engine/trans since the Datsun DOES require some metal cutting.
Bill

 

[mrsprite]

I am fairly confident that the A12 (pushrod) motor, the A14 and the A15 are all virtually the same size (with the probable exception of the block height being about 1/4" different), just as the Spridget "A" blocks are basically all the same size.
"MrSprite" in Colorado also has the Datsun A-block conversion in his.

All-in-all I would wait for a proper Spridget engine/trans since the Datsun DOES require some metal cutting.
Bill

I also believe all Datsun A series engines are pretty much the same size. I've only ever seen A14's and 15's (which are identical on the outside), so the A12 might be slightly smaller/shorter.....I'm not 100% sure.

The only cutting done to my Bugeye was to the front cross support (for lack of a better word....I don't know what to call it, but it looks like a 2"x 2" steel rod). This was to give clearance for the crank pulley and was reinforced with a notched plate of steel so little to no structural integrity was lost. The only other thing needed was some new motor mount brackets welded to the chassis. The rest of the mods were to the engine itself, like modifying the oil pan to clear the front crossmember, remote oil filter kit, etc.

If I wanted to I could install a stock 948 back in and you would never know it was ever modified. That's the beauty of my particular swap.....very little cutting was involved.

I will try to find the pics of what I am talking about....a picture is worth 1000 words afterall.


Here's a pic of the cutout on the front steering rack support. The notched reinforcement is not shown, but it uses the bolts/holes for the steering rack to attach both cut halves together and still give clearance for the crank pulley. This pic was taken almost 2 years ago (I think) and the engine compartment was dirty due to an oil leak. Just had to explain why it's so dirty!

 

[middie]

Thanks for all the replies, what a group of knowledgable people.

I looked at getting an A15 RickB, but was worried about fitting it under the bonnet as it is based on the "tall block" design. Did you have any problems shoe-horning it in?

I'm also looking around for a 5-speed box, which one did you eventually settle on?

Not too sure on the GX head. Can you give me more details please (i'm only new at this stuff).

About the A12 engine:

-----------------------------------------------

The A12 is a 1.2 liter (1171 cc) engine with 73 mm bore with a stroke of 70 mm. It has five main bearings on a forged steel crankshaft.

------------------------------------------------

The one I am looking at is coming out of an 81 Nissan Sunny, also known as the B310.

Please keep the advice coming. I can use all I can get.

Thanks again
Warren

 

[middie]

Hi MrSprite and Billm

I didn't see your posts until after I had posted the above reply. Must be the International Dateline causing the problem

.

You're spot on Billm, the "tall block" design was just under 1/2'' taller. But they are also harder to get over here. I agree with you about having an original BMC motor in, but funds and extreme scarcity at the moment has forced my hand.

Great pic MrSprite. I wouldn't worry about a dirty engine compartment, it's much better than my very EMPTY compartment at the moment.

Can't wait to see the other pics. The pic of the cut out has helped my confidence. How did you go fitting the radiator?

Don't worry about the "funny" extension on the front of my pic. The car came with a Sebring???? fibreglass nose and this was added to allow the new nose to bolt on.

cheers
Warren

PS: If anyone wanted to find about a bit more about Nissan's A series engines, this is a good site:- https://en.wikipedia.org/wiki/Nissan_A_engine#A13_.281979-1982.29_-_Short-Deck_Engine

 

[mrsprite]

Great pic MrSprite. I wouldn't worry about a dirty engine compartment, it's much better than my very EMPTY compartment at the moment.

Can't wait to see the other pics. The pic of the cut out has helped my confidence. How did you go fitting the radiator?

I'll try to find the other pics, but I've had several HD crashes over the past year and many are just gone now. The radiator is a stock Bugeye unit that has been converted to a 3 row core. I'll snap some pics of it tomorrow to show you....as far as I know, it mounts up just like a stock Bugeye/Spridget (but I don't own a stock one, so I have no idea how they mount). I do plan on installing a more modern aluminum radiator at some point though. In the extreme heat )100+* F, it runs a little warm. I wind up running the electric fan fulltime on hot days just to make sure nothing overheats.

I also don't know much about the A12S except that it I don't believe it was available in the US. The GX head has oval exhaust ports, bigger valves and has twin 35mm Hitachi SU carbs.....a pretty slick set-up that helps the engine breathe. My A15 has this set-up and it's pretty peppy. I am very happy with the power and reliability as well as the fuel economy (30-35 US, with the occasional 40-45MPG every now and then....when I keep my foot out of the throttle.)


I'll try to find more pics for you.

 

[middie]

Hi MrSprite, any luck with some more pics yet???

 

[mrsprite]

Hey....thanks for reminding me! I did find a ton of pics from a couple of years ago when I removed the engine to replace a busted clutch. The engine is pretty greasy (had some oil leks), but you can see the mods that were made to get the A15 to fit.

Give me some time to get the pics uploaded.....I'll post a few here, but in all honesty there are just too many. PM me your e-mail address and I'll send you a lot more than what I'll show in this thread.


Mike

 

[mrsprite]

OK....here are a few pics. It seems most of mine are huge, so I will need to re-size them before I can post them (so probably not until tomorrow....too late right now).


Here is a shot of the reinforcement piece around the crank pulley where the frame was notched:

Here is the oil filter relocation kit I am using (it's also the source of much of the leaking oil!). The filter is for a Ford truck and the capacity is needed due to the cutting up of the oil pan (which I can't show due to large size of pic).

Here is a shot of one of the motor mounts. It works great and utilizes stock Spridget transmission rubber mounts.....cheap and easy!

That's all for now. Hopefully this helps a little bit. Once I resize the others you will see what else went into modifying things to get it to fit. The notch on the steering rack support is teh only cutting of the chassis that was done......all other mods to get the engine to fit were done on the engine itself.

 

[John_Shep]

G'Day Warren,

--"The car came with a Sebring???? fibreglass nose "--

Do you have a photo of the bonnet that you could post??

John Shep

 

[bugimike]

I have a "junker" in the back yard that I bought for parts that has a rather crudely installed Datsun A10 (1952cc) engine and tranny installed. The engine seems to fit just fine (an over-sized radiator caused the DPO to butcher the bonnet!), but the trans tunnel is a total butcher job! I did at one time get the thing running and took it for a short drive around the 'hood

 

[mrsprite]

I have a "junker" in the back yard that I bought for parts that has a rather crudely installed Datsun A10 (1952cc) engine and tranny installed. The engine seems to fit just fine (an over-sized radiator caused the DPO to butcher the bonnet!), but the trans tunnel is a total butcher job! I did at one time get the thing running and took it for a short drive around the 'hood

Interesting swap.....just so you know, that is not an A10 (or any Datsun A series engine). If it's a 1952cc, then it's probably an L20B.

FWIW, an A10 is a 1000cc/1L engine.

 

[bugimike]

All I had to go by was the engine plate provided by the DPO! On closer examination of the plate, engine type is listed as a Z20! The Datsun type (where I made my error in reading the plate!) is WHLA10! Not really that familiar with Datsun nomenclature! :smirk:

 

[racingenglishcars]

There's a BE all over the net right now with the A15
https://www.gatewayclassiccars.com/displaycar.php?stock=658&location=CHA
(Funny tail lights and uselss roll bar.)

 

[middie]

Thanks Mike, those photos are terrific. If you could email some more I would really appreciate it. Address is
butlers -- at -- liquidinternets -- dot -- com.

I like your ingenuity in adapting the oil filter, I'll be taking a much closer look when I get into the project.

The picture of the Sebring front is in the avatar. If anyone would like to see a closer pick I can supply later. I've just been told that I'm only allowed to upload one picture????

cheers Warren

 

[bugimike]

I may be wrong (and somebody please correct me if I am!), but I believe that means one picture per post (among other benefits to subscription...not the least of which is BCF survival!)!? With a subscription membership, depending on the grade of subscription, you are allowed more pictures per post!

 

[John_Shep]

G'Day Warren,
I didn't notice the Avatar pic.
I have the same bonnet but modified with flares.
Do you know who made it? I believe that it is an Aussie one and there aren't too many of them.
You can e-mail me at john@lenhamspridgetregister.com

There are more photos at my web-site lenhamspridgetregister.com

Cheers,

John Shep.