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Project Miatabusa Part 9: Thank God We Finally Found a Starter

Project Miatabusa, Part 9: Thank God We Finally Found a Starter!

by Dave Coleman

This seemed like a problem with two easy answers. The Miatabusa would need a starter. Miatas have starters, and Hayabusas have starters, so we should have our pick of starting options for this thing, right?

Except that no... 

Miatabusa original stater location

Here's a Hayabusa engine in its natural environment, freshly yanked from a crashed Hayabusa. You can see the tiny, 2-pound starter right above the big, black clutch cover. Attached to the nose of the starter, though, is a bulky gear reduction box that lets that tiny starter crank an 11:1 engine. That gear reduction box is about 2 inches deep.

miatabusa flywheel offset

As you can see with the gear reduction box removed and the Miata flywheel installed, there is simply no way we could keep the gear reduction box there. Sure, we could make the flywheel shaft longer, pushing the engine forward in the car until there is room, but if we move the engine even 2mm forward of its current position, the Hayabusa engine case runs right into the back of the steering rack. Not gonna happen.

Project Miatabusa Starter

Oh well, say goodbye to the 2 pound Hayabusa starter, say hello to the 10 pound Miata starter.

Only no...

Miata starters have a bulbous pinion support shroud that sticks into the bellhousing. This is great for supporting both sides of the pinion and making the starter more robust (or cheaper to make, since the shaft and bearings can probably be lower grade), but it means the starter absolutely has to fit into some part of the bellhousing that is made to accommodate this giant proboscis. 

Miatabusa hayabusa miata starter

The big starter notch in the bellhousing is the only place there's room for a stock Miata starter. Unfortunately, that's almost perfectly in line with the Hayabusa engine's crankshaft, so the starter won't be going there. 

Even a starter with an unshrouded pinion will still have to occupy some space between the flywheel's ring gear and the bellhousing, and the only place besides the starter notch where there's sure to be room is that big open space at the top of the bellhousing. That also happens to be the only place on the engine side with any room. 

So, the new starter would have to go approximately where the original Hayabusa starter went, but for entirely different reasons.

Miata hayabusa miatabusaSomewhere in the great wide world of starters, there's surely something that will fit in the notch between the Hayabusa engine case and transmission case, line up with the Miata flywheel, have the right tooth pitch for a Miata, and have an unshrouded pinion, right? Sure, but where?

Tim, naturally, found one in about 30 seconds, simply by turning around and grabbing the Tilton Super Starter that was sitting on his workbench. The starter was a leftover from an old project, but it just happened to be almost completely right. Everything was right except for the tooth pitch on the pinion (which was something for a Jeep). All we would have to do is order the one with a Miata's tooth pitch. Simple.

Discontinued.

No. Longer. Available.

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Comments
Wes Dumalski
Wes Dumalskilink
Monday, September 26, 2011 9:59 PM
This project kicks soo much ass!
bigmac88
bigmac88link
Monday, September 26, 2011 10:36 PM
^Agreed!
Dusty Duster
Dusty Dusterlink
Tuesday, September 27, 2011 4:05 AM
Dave, are you keeping a list of all the different parts that are needed for this swap for other people who want to build their own Miatabusa chimeras?
joelcrookston
joelcrookstonlink
Tuesday, September 27, 2011 4:52 AM
So many years wasted in biology and chemistry classes, should've been an engineer. This project kicks so much ass.
8695Beaters
8695Beaterslink
Tuesday, September 27, 2011 5:15 AM
Is the starter for Miatabusa 2.0 going to be the Hitachi starter you stole the pinion from?
rawkus
rawkuslink
Tuesday, September 27, 2011 6:08 AM
Does anyone else wonder what would have happened if Dave would have went to med school? I have a feeling cancer would have been cured using leftovers found in a Pifzer's trash.
OMG Its Weasel
OMG Its Weasellink
Tuesday, September 27, 2011 6:29 AM
No, I think if Dave went to med school we would start seeing mice with a transplanted gorilla heart and the brain of a dolphin.
Dave Coleman
Dave Colemanlink
Tuesday, September 27, 2011 7:29 AM
#8695Beaters,
Yea, the Hitachi starter, if it hadn't been broken, would have bolted in exactly the same spot on the adaptor. Every other Miatabusa can use the off-the-shelf Hitachi part.
Der Bruce
Der Brucelink
Tuesday, September 27, 2011 7:41 AM
Dave - I'm looking forward to the fruits of your labor and then the list of parts for reproducing crazy!

Come on guys, Dave would've totally been kicked out of the medical community for his advancements in what would've been known as the "Moreau Project". BUT "Dr. Moreau" would've been embraced by the xeno-biology community for his work in making animal people :)
Rockwood
Rockwoodlink
Tuesday, September 27, 2011 7:41 AM
Can you drill a hole in the bellhousing to allow for access to the hidden starter bolt? I know it's easy to remove the engine, but something about removing the engine to replace a starter seems inherently wrong to me. Almost like Ze Germans designed it... ;-p

I love those hole in the wall rebuild shops. Alternator rebuild shops are a fun place as well...
jeffball610
jeffball610link
Tuesday, September 27, 2011 7:49 AM
So, I guess swapping the proper pinion gear from the Miata starter to the other starter was too much trouble.
Off the shelf parts are underrated on custom projects. This car would be done if these parts were available at Pepboys, Autozone, O'Reilly etc.
Alex Vendler
Alex Vendlerlink
Tuesday, September 27, 2011 8:01 AM
It wasn't too much trouble. It wouldn't fit as the two starters don't share the same design. Believe you me, we love off the shelf solutions for this kind of stuff. The AutoZone near me knows me well.
Rockwood
Rockwoodlink
Tuesday, September 27, 2011 8:01 AM
@ Jeff: It might be too much trouble if the pinion gear was designed for a different shaft diameter.
Marillionado
Marillionadolink
Tuesday, September 27, 2011 8:18 AM
Dave, how did you know the Bobcat's starter was similar to a 1986 Toyota Camry's? :-)
Dave Coleman
Dave Colemanlink
Tuesday, September 27, 2011 9:02 AM
Rockwood,

You're right. If we never find a better starter for this kit, the easy solution is to pre-drill an allen-wrench access hole in the bellhousing before bolting the adaptor plate on. Just use the adaptor as a drill guide, pop a hole in the back of the bellhousing, and a skinny little allen wrench can easily get in there and loosen the bolt.

Still, this starter should be so under-worked, it will likely never fail.
SkullWorks
SkullWorkslink
Tuesday, September 27, 2011 9:08 AM
Yeah even with the gear multiplication working from the flywheel back to the crankshaft that starter probably won't even notice it's turning much, and you'll have more than enough RPM to get it fired
mxpop
mxpoplink
Tuesday, September 27, 2011 9:16 AM
"Here's a Hayabusa engine in its natural environment, freshly yanked from a crashed Hayabusa."

Not sure if you meant it this way but a Hyabusa's natural state is a crashed state....

FWIW, certain year OEM 'Busa starter clutches were prone to major failure (cracked cases). IIRC, it was due to inadequate cast-in support as well as too much lash in the clutch. It rarely surfaced in a bike but did often in cars/buggies. Good upgrade fellas!

Did this new plate add thickness that requires a new output shaft or??? Couldn't quite tell in the pics above.
Dave Coleman
Dave Colemanlink
Tuesday, September 27, 2011 9:23 AM
#mxpop,

How many miles do you think the average 'Busa owner can stay on top of one of those beasts before it falls down? Craigslist suggests its not many...

Not quite sure what you mean by output shaft. You mean the pinion shaft on the starter? If so, no. The adapter plate was slightly thicker than the original starter nose cone, so we were able to cut a relief in the adapter plate to perfectly match the inside contours of the original starter nose.
Rockwood
Rockwoodlink
Tuesday, September 27, 2011 9:28 AM
My buddy managed to stay in the saddle on his for 10k miles when he was 18 years old. Pretty sure that's proof that the laws of physics aren't concrete...
mxpop
mxpoplink
Tuesday, September 27, 2011 9:29 AM
Exactly my point. Busas are the perfect donor beast for car/buggie kits cuz they are great motors and are in steady supply thanks to bike owner's shortcomings of talent...

No, I mean your custom made output shaft (PTO) for the motor that the flywheel is attached. It seems that this new starter plate may require length be added to this shaft.

8695Beaters
8695Beaterslink
Tuesday, September 27, 2011 1:08 PM
When this goes on sale as a kit, I'm going to be seriously looking at one. If I sell my old project and parts, I actually might have enough to buy a Miata, a Hayabusa motor, and the kit (provided it costs about the same as any of those other two major parts combined). There are still plans to sell the conversion parts right?
Dave Coleman
Dave Colemanlink
Tuesday, September 27, 2011 2:47 PM
#mxpop,

That "new starter plate" is actually the same old bellhousing adaptor we've been working with all along, we just cut a new relief in it for the starter. We were planning to do something like this the whole time, it was only the details of which starter we should use that had to change.

Guess I should have made that more clear in the story.
mxpop
mxpoplink
Tuesday, September 27, 2011 4:34 PM
^^^ Guess I coulda looked at back articles to see that but that woulda required computer skillz.... Thx

Q: Are you keeping/making ram air?
8695Beaters
8695Beaterslink
Tuesday, September 27, 2011 4:52 PM
It's a bit confusing to see at first, because this is the first time we the readers have seen the backside of the bell housing adapter. All of the pics so far have been from the front. Tim really does some nice work, it must have taken a long ass time to machine just the bell housing adapter.
mxpop
mxpoplink
Tuesday, September 27, 2011 5:04 PM
I must be crazy cuz I see two custom plates in this pic. The 1st one was much deeper which I recall from the last article. Maybe I just missed this other one. Maybe just losing my eyes, memory or both...

http://photos.motoiq.com/MotoIQ/Project-Cars/Miatabusa/i-3nGshd8/0/M/60942977350cb5e15797b-M.jpg
mxpop
mxpoplink
Tuesday, September 27, 2011 5:07 PM
This pic shows just the 1st plate installed (adapter/housing) I was recalling.

http://photos.motoiq.com/MotoIQ/Project-Cars/Miatabusa/i-zsW9rcV/0/L/6094835034e2f6be7e12b-L.jpg


No matter, lookin good whatever I'm seeing ;-)
Option13
Option13link
Tuesday, September 27, 2011 5:38 PM
I've been waiting for this update all week. Can't wait to see the next one!
Dave Coleman
Dave Colemanlink
Tuesday, September 27, 2011 5:38 PM
There is one wedge-shaped plate that bolts to the Suzuki clutch cover and holds part of the new shaft. Then the big bellhousing adapter bolts to that (and the block). This modular design saves wasted aluminum chips and makes it easier for us to make a plate for VW/Porsche bellhousings for mid/rear engine applications.
mxpop
mxpoplink
Tuesday, September 27, 2011 6:07 PM
Got it :-)

It first appeared that there was just one part that took care of the wedge and bellhousing needs. Makes sense to do it with seperate wedge piece and adapter in order to accomodate more apps.
Rockwood
Rockwoodlink
Wednesday, September 28, 2011 6:54 AM
A Karmann Ghia or 914 with the front/rear wishbone conversion and this motor would be pretty awesome...
Rockwood
Rockwoodlink
Wednesday, September 28, 2011 6:54 AM
Or an Elise...

Wes? ;-p
Option13
Option13link
Wednesday, September 28, 2011 11:17 AM
Given how much CNC you guys are doing, why didn't you just fab up the appropriate gear instead of looking for months? I know that's more work than it sounds like, but you guys obviously have serious talent.
Matt
Mattlink
Wednesday, September 28, 2011 3:57 PM
What do you guys plan on running for a flywheel and clutch combo? I suggest you check out 949racings offerings. 11.7 lbs and 250 lbs/ft holding capacity. Should be good for the busa's rev happy engine
Dave Coleman
Dave Colemanlink
Wednesday, September 28, 2011 4:11 PM
I plan on using 949racing's twin-plate clutch eventually (http://949racing.com/miata-twin-disc-clutch.aspx). The super low-inertia clutch discs will lighten the load on the synchros, making the gearbox shift faster, which should really be nice with this engine. We're starting out with the stock clutch and flyhweel, though, since we're just plain curious how it will feel (remember, it turns at 0.6 the speed of the engine, so it should still rev quickly.)
Der Bruce
Der Brucelink
Wednesday, September 28, 2011 7:53 PM
I'll be forced to watch this, hoping Miatabusa will provide such crazy fun!

http://www.youtube.com/watch?v=CdJ84nho3_k&feature=related
Rockwood
Rockwoodlink
Wednesday, September 28, 2011 9:32 PM
^^^

The hoonage is far better in this video, mainly because of the stoppie at the end...

http://www.youtube.com/watch?v=sLtMh20qIp8&feature=related

So full of win.
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