mx5cartalk.com

Hi all

Just wanted to say hi to the community and introduce my current Frankenstein project.

In conjunction with a fella in Victoria Australia, I am building a Mazda B6 and Datsun A-series hybrid.
We are shoehorning a B6 head onto a Datsun a-series block. It involves a number of mods to both the head and block as well as a custom timing cover.

There has already been a motor running and in a car with this setup, but he only ran carbs NA. Very successful mind you.

Now I am planning on taking advantage of the EFI the B6 came with (MX5 NA6 only I believe) and turbo as well.

Since I am using a Datsun block from the early 70s, it means no pollution gear, no controls, nada. I only have to keep what the motor came with (nothing) and since they only care about the block number....

Currently I have;
a head that I believe came from a BF 323, although it could have come from something else FWD. Not exactly sure on its history.
an intake manifold from a NA6 mx5 (I believe)
Turbo from 300zx (T25 with custom internals for 300zx)
Datsun a15 block, with 78mm bore, H-beam rods, lightened flywheel (to 70s Datsun comp specs - Nismo)

What I am still chasing, unless I get better advice is
the Cam angle sensor for the back of the head,
an engine wiring harness for a MX5 NA6
turbo exhaust manifold.
coil packs and leads
front timing cover (to cover the cam wheels and belts)
I have been considering running the water from the back of the head (its a FWD head) as that's where the original thermostat was and using the chevy escalade hose and kia sephia thermostat setup. Else I have to convert to a front setup like the std mx5 has.

Right, now comments from the gallery!

What ecu will you run. If it's aftermarket ignore the factory coil packs and use late model corolla coil on plug units. They are heaps cheaper ($100 a set) and provide a better spark.

Y?

yeah I don't get this either.

Is it going in to an old nissan 1200 or something where you have to keep the block?

the biggest A series motor was their "stroker" which was 1.5L engine.

what will be the benefit of getting one of nissans crappiest motors and adding one of mazdas crappiest heads on to it then turbo charge it using a tiny 300zx turbo?


unless of course it will be close to this cool.
https://www.youtube.com/watch?v=Zy03MqqZGeY

I think the point is to retain the block for either class or rego reasons and get the best you can get from there.

sailaholic wrote:I think the point is to retain the block for either class or rego reasons and get the best you can get from there.

You have a point but for the effort a good head job [ OS valves port and polish and cc the heads] would have the same or better results .

To fill everyone in on more details

The car is a Datsun 1967 Datsun 1000. This car came with an a10.
This particular car has a number of restrictions that make this and ideal swap.
Mainly;
Engine bay restrictions, mainly in overall height.
Maximum engine capacity that can be legally allowed in WA. (both NA and charged).
Engine weight.

With a few tricks I can even use an a12 block, which means that I don't even have that engineered as a 10% increase is not required to be engineered. I will however be using an a15 block. An a14 block is identical in design to the A15, so I could use that as well and get similar results.

By going to a B6 head, which is the closest cross flow, multivalve, efi head that is cheaply available, the 1000 gains all the mod cons legally without all the problems of using another engine.

As for easyish engine options;
I can fit a E15/16 with relative ease.
G13B motors have been done with some success as well.
But both of these options have their drawbacks, and I still feel that the B6 option is the way forward over these and other engine options

Anything else, either is illegal, or makes the car a pig to drive.
I'm sure that as MX5 owners, you appreciate that your car is light and nimble and that jamming in the largest engine you can find is not going to produce anything other than straight line drag car.

The head that I am using appears to have come from a FWD of some description (I'm pretty sure its a BF Mazda 323). When I spoke with a Mazda wrecker here in Perth, he wasn't able to identify the head. I cant find any casting numbers on it, and the rocker cover only covers the valves, and not the timing cogs/wheels. It doesn't have any branding on the rocker cover either. According to him, my head doesn't exist. If anyone here has some ideas or places for me to find identifying numbers, I'm open to suggestions.

sailaholic wrote:What ecu will you run. If it's aftermarket ignore the factory coil packs and use late model corolla coil on plug units. They are heaps cheaper ($100 a set) and provide a better spark.

I plan to use an aftermarket ECU. the original plan was to use a delco from a commodore and reprogram it. My brother is a wizz on the delco and programming, but I will need to check if it will be compatible. Else it will be an aftermarket computer of some description. Thanks for the tip on the corolla coil-on-plug packs. Ill chase that down.

sailaholic wrote:I think the point is to retain the block for either class or rego reasons and get the best you can get from there.

Spot on.

lizard wrote:

sailaholic wrote:I think the point is to retain the block for either class or rego reasons and get the best you can get from there.

You have a point but for the effort a good head job [ OS valves port and polish and cc the heads] would have the same or better results .

Yes, if you have enough money. To get the same outcomes that I can with the B6 head and MX5 parts, I would need to spend 2-3 times that at least. Plus useable heads to modify that seriously are hard to find and very expensive.
Don't forget, everything needs to be custom made. There really isn't any bits off the shelf that I can buy for an a-series into a 1000, unlike the B6 mx5 motor.

Also, finding a Nismo only AY head for an a-series block is near impossible. I have only ever seen photos of one. The only known head in existence that I have seen photos of in the last 10 years is in Finland. There are possibly others in japan still, but I don't have the thousands needed to buy, plus these rare parts (if they exist) very rarely ever leave japan. Sellers just don't post them outside the country, even if you can find one.
Yes you can get 300hp out of an a15. Its a dyno pony and un-driveable.

TTT wrote:what will be the benefit of getting one of nissans crappiest motors and adding one of mazdas crappiest heads on to it then turbo charge it using a tiny 300zx turbo

As for the turbo selection, my reasons are that the 300zx t25 unit is capable of 15psi reliably, are cheap to find, and suitable for 1.5-1.6l capacity motors. Yes I have a myriad of turbo selections available, and I am open to suggestions. If anyone here has some suggestions, please pipe up. After all, its the reason I came to this forum. To discuss with like minded people, something that is a little different that what you are used to.

On the crappiest motor and head comment. Considering that the a series from Datsun first was available in 1967 and production in domestic cars only stopped in 2006, and in industrial applications in around 2010. So for a crappy motor, its been used in various guises for about 40 years.
As for the Mazda B6 head,(I'm not such a guru here so I may well be wrong) first introduced in the mid 80s for the BF Mazda 323, and used by various manufactures up to about 2006 in the Kia Sephia. Again, for a crappy motor to last 20 odd years, it cant be that bad.
I'm sure that you will be able to shoot down my comments with 1000 points about fuel economy, hot spots, power, blah blah blah. Still, the timelines say something as to the Mazda/Datsun motors apparent crappyness.

Sound cool and I applaud your effort to try something different.

I'm always happy to see someone try something not done before and learn from their attempts (or lack of) - best of luck and I'll be keen to hear and see pics of progress.

Thanks gslender.

This combo is proven with a running version in a 120Y, although he did use an a14 block, with side draft carbs NA. Much simpler than I am attempting, but successful non the less.

One of the biggest benefits that I am hoping to see over heavily worked an A15 is reliability and cost effectiveness. There is a fella I have met here in Perth with a 280hp A15 running in a 1200 ute. According to him, the total build cost was around the 20k mark and the power comes on so fast and hard that its basically un-driveable. He is keen to offload the motor at a bargain 10k asking price. I'm pretty sure that I can get this build for well under half that.

I like it!!! Was going to suggest the swift motor but looks like you've already Considered it.
A couple of years back a guy was doing the swift dohc head on an a series 1275 mini.
Not sure what happened with it but a great way to get an alloy dohc head in a mini without having to chop the subframe.
Forget about the haters and keep on creating. I know I'm keen to see how this goes , so two thumbs up from me


Sent from my iPhone using Tapatalk

speed wrote:Forget about the haters and keep on creating. I know I'm keen to see how this goes , so two thumbs up from me

Thanks for the support speed.

There are quote a few SOHC options that I can look at. The E15/16 from the Nissan Exa has been done plenty, the G13B Suzuki, the GA16 from the Pulsar, plus others that are technically legal. The biggest issue with the Datsun 1000 is the engine bay. Its damn small between the front suspension cross member and the bonnet. The std A15 setup only just squeezes in under the bonnet.

But since I want DOHC, EFi and turbo, the Mazda B6 head is a pretty good option. If I could do this with Datsun I would, but its just not do-able unless you have that money tree growing out the back.

One of the reasons I joined up here was to try and get some technical information about the Mazda B6 head and its accessories. I've already got a good lead on the corolla coil-on-plugs, so I am appreciative of that.

What I am still chasing, unless I get better advice is
the Cam angle sensor for the back of the head. The head I have is a B6 head, with the CAS on the intake side of the head. When I went to the auto shop, the offered me replacement parts for the inside, but not a complete unit.


an engine wiring harness for a MX5 NA6
The plan here is to utilise as much of the std mazda stuff as I can to make my life easy. Ill cut out the unnecessary stuff, or at the very least utilise the std plugs/connections

turbo exhaust manifold.
Ive been looking about on fleabay and other places in the internet. Anyone got suggestions for a low cost exhaust manifold.

coil packs and leads
Looks like its the corolla setup here.

front timing cover (to cover the cam wheels and belts)
How is this setup? Is it in two parts? I assume that Ill need to cover these up for rego purposes, so I'm hoping I can use a factory cover set and modify it to suit the new timing cover setup.


Thanks in advance

If you have exposed cam gears the head would be off a SP model 323 which was the first model to get a twin cam. Bg maybe? Certainly pre BJ. It is two parts a plate behind the came gears and then a plastic cover over the top. There is another cover lower down but your probably in Datsun territory by then.

Post a wanted add here a CAS should be pretty easy to get. You can also use the BP CAS. They look a bit different but are 100% swappable.

Maybe jump on Facebook and search nitrodann. He does a lot of turbo set up for people here.

If the head is indeed from an early 323, then hunting down parts becomes easier.

Attached is a picture of the head I have. Its strange. It seems to have no markings indicating what its from.

The intake manifold in the pic came with it. That might indicate its heritage somewhat.

This link takes you to another Datsun forum, which shows some of the mock up pictures done by another fellow Datsun nut.
http://datsun1200.com/modules/newbb/viewtopic.php?topic_id=61554&viewmode=flat&order=ASC&type=&mode=0&start=10
For the cam wheels cover, anything is currently better than nothing.
I was hoping to get my hands on a complete setup and then modifying what I can to suit.

Whoops forgot it's a 1.6. So my earlier info is wrong in that it's probably one generation older then I first thought.

Defiantly not a mx5 valve cover or inlet manifold.

Bit surprised the rear plate for the cover isn't there. Mine looks like this with the cover removed - it's the bp valve cover off the 323.



Sorry for the horrible pick best one I had on my phone. You can see the back plate behind the cam wheels.

Should be a number cast into the back of the head down near where the head meets the block if it's like a BP head.

viewtopic.php?t=48599#p806375

There is a photo in the build thread here off how the BP cover works in it's factory application.