JV6 Miata during a pandemic

Rebuilding my 2nd Miata, a 2002 NB 6 sp base model with 160k on the clock.  The theme of the car is cheap performance and used parts with a few new things throne it to make it comfortable daily driver.

This is pretty much how I got it. It came with headers & 2 1/2" exhaust, roll bars and coil overs. I've done a few things to it by the time I took this picture.  Header wrap, wheel paint, foam ex, door bars, door card releifs, fender braces.

The car came with metalic front pads that worked great but eats rotors like crazy. Upgraded to a big little brake kit and new sport rotors. 

Nice project

With the Fender braces, do you feel the front end being stiffer or what improvement do you get with them. They look the part, whats the weight penalty?

In reply to ImthatGuy :

Those are the Paco braces and they made a huge difference. My car did'nt come with tower braces or even the under side front & rear stuff when I picked it up. I'm thinking when the PO installed the roll bar, out came the OEM braces.

Anyway these guys really tightened up the car. I would recomend the unpainted version and bolt and weld them inplace for best results from your race car. They weigh in about 6 lbs each.

I have been updating bits and pieces for awhile. The last big one was the suspension rebuild. I came across some Kiesler lowered spindles on Ebay and some SadFab bushings for a killer base to work from.

I'm a big fan of low unsprung weight, so I installed some light weight 2-piece rotors. The rears were no problems.

But,,, the fronts have been giving me a little trouble making the jump to 11.75" rotor and fit under the OEM wheel.

Things got very "grindey" so I went back to the 11" rotor until I fix this or get those 10" I've been wishing for.

The Kiesler lowered spindles have been really fantastic hooning around some of my favorite spots but the lack of track time has kept the tweaking very limited to butt feel.

I already have the engine and kit from SuperfastMiata and I have been collecting parts for a while.

The engine is a re-built j35a4 that I found in racing.junk.com.  It was built for a sand rail but the guy did not make the last payment so it sat on the shelf for a bit.  I am not sure whats inside it but the heads have been ported, and the bottom end looks good with red assembly lube.  (cross fingers that the iron liners were installed right.)  I have installed the pickup and oil pan already. 

Love the J35 in wifey's Ody, it should be a riot in a Miata. Looking forward to reading more!

That's a crazy looking oil pan. And are those JIC coilovers?

If you have an 11" LBBK and you want the 10", you just need to change out the brackets. If you're brave, you might also be able to machine the 11" ones down. It's not an exact 1" difference, but that's just measuring. 

I found those JIC on Ebay in Canada.  They still work really well so far. 

The 10's would be a package deal for autocross, I found some 14x7 rpf1 at a nice price. I was thinking how much weight I could lose. But I got to thinking about the other shoe, or tire that is. What sticky DOT meats are available for 14" rims?

I'm also enamored by the 15x10's & tires out there.  Maybe after jv6 is done.

Presently I'm working on the latest mod before switching to the real jv6 stuff. I just want to get the chassis sorted out a bit before I put in the super fun stuff or else it may never get put in.

I am installing a Guarino-Watson Racing drop seat pan in the car, I'm 6'2" 270lb and I've done some lowering with the stock seat but it feels like I'm riding on a toilet bowl.

Putting in a smaller steering wheel, extension and quick release got the wheel off my knees.

After cutting out the floor, I'm surprised just how close the cat is to my thigh. Chalked it up to perspective.

Here it is in placed. I really like this particular kit. Its the deepest I could find and extremely well engineered. The chassis rail extension is inside the car!  I really need the space.

This photo shows a lot of little details, #1 that's a C4 seat shell! And it's sitting on it's electric seat rails too. OMG in a Miata?

#2 the roll bar fits besides the shell while its all the way back on its rails, the seat back is tilted all the back and is parallel to the rear bulkhead.

#3 the head rest top is only about 3" above the shoulder belt bar. (seat is at lowest and furthest back)

#4 the side bolsters are set to fit me in. These are '94 leather sport seats with lumbar and fully electric. 

If you have pulled and restored a pair of C4 vette seats you know that have a flat mount pattern and the shell bolts flat to the top of the seat rails. These guys bolt directly to the dropped floor. Also they are comfortable and still pretty thin. 

OMG I miss my good welder. A Miller Dynasty 200DX, very up to date AC/DC inverter I used for Tig welding but you could also do CC/CV mig welding.

Unfortunately for me it was stolen a few months ago, just before I was gearing up to do the swap.  I ended up having to ask my buddy if I could borrow my old mig back that I gave him a couple of years ago when I got the new DX. 

If you were welding in the late eighties and witness the arrival of the inverter welders. Miller released the XMT 300 cc/cv power supply. When paired with a microprocessor controlled wire feeder it was a super smooth machine that could pulse mig & tig.

I have this 30 year old setup.  It's very programmable but not easy to program and the xmt 300 is a little problematic and had a tendency to "just let go" when you turned them on at full welding settings.  I'm trying to do sheet metal work with a 400 amp mig gun and .023 wire.  Lot's of bird nests, I think the liner is still for .045.  My spot welds are just all over the place and looking pretty crappy. Found out later I had a major switch in the wrong position and I did not use the voltage sense lead either.  Also I had to buy consumables too. The last time I bought a big shield gas bottle it was under $300, now they are over $500. So that explains my frustrations with this rig.  It never a simple easy thing.

Another nonproductive day spending money that belongs to Visa. I started this morning with the correct program in mind and my switchology perfect.  Only to rat nest the mig drive 6 times before giving up on the big #4 Tweco gun and getting something small to run the .023 wire. A hundred forty three dollars and a few hours later I had a new smallest Radnor gun with the right size liner in it and was gracefully welding again.  

Then I put everything away cause it was too frigging hot outside to weld in the sun.

Tomorrow is another new day.

The kit comes with a new oil pan and pick up. The sump is all up front and the back of the pan looks like a dry sump. The oil scraper is a welded in part of the pan floor. 

There is probably a lot of reasons the pan is shaped the way it is, but I bet because the oil pump intake is right below the front part of the crank is one biggy.

I think the J35a4 came with cast cranks and the J35a3 came with forged. At least there signs of it being balanced and if you could see up into the case you can see they put in iron cylinder liners. 

When I got the engine it was just a long block.

I was missing some important parts to make a running engine. BTW does anybody know if the crank snout diameter is the same as the V6 in the NSX?

They did some porting and smoothing on both intake and exhaust. Can't tell what cams are in either.

Anyway once I get the dam seat back in I will start getting the engine ready for install.

Started off this morning with a bunch of rat nests right off the bat. Then I had a flash. My wire feeder is a Miller 4 roller type so I thought I would remove the 1st traction rollers and maybe not force feed the 2nd set into rat nest oblivion. It worked much better after that.

I got the pan mostly welded together now. Still need to make another piece to fill in the gap between old drive tunnel and the new one at the front.

I will test fit again tomorrow and see if it still fits.

Got the pan all put together and tried the seat again.

Thie seat rack is at full height about 4" and all the way back.

I'm thinking like this it will be about the same height as a stock seat.

I have always liked the sports seats, they have a great design and don't look like they are 23 years old, just broken in.

I got most of the welding done except for one 2 foot long seam. The drop pan adds a 16 ga. stiffiner along 2/3's of side rail. The pan is already welded there on the inside about an inch or two above this seam. If I add this bead it will stiffened up the door area very nicely. After spot welding upside down under the car for two days, I'm going to get a professional welder buddy of mine to do this one. I'm really tired of setting myself on fire and being ant bait.

The next big fitment issue will be fitting the door bars back in around the side bolsters.

Now all this work was to be able for me have a comfortable seat for longer trips and get down a little lower and get my helmet under that bar when needed.  Then on the other hand, when somebody else drives my car, they can get a good fit behind the wheel.  

It's happened to me a few times not being able to drive because I could not fit in those narrow-ss seats. 

With a board across the top here is me with the seat all the way up and back.

The back of my head touches the 7 oclock part of the roll bar. This is the same position that a Miata seat with a foam-ectomy and stock seat rails would position me.

The next is the seat all they way down and back.

I'm a smidge ~ 1" lower then I was with the miata seat with a fixed lowered base.  Now honestly I'm really wanting to get as low as possible.  

The next two images shows how much the vette seat rails take up in the lowest position. 

So there's 4 1/2" in front and  2 1/4" in back to go. So I will have another set of holes for a thin slider setup and shed a little more weight after I get things sorted.

Great Project!

Will your starter go bottom, center, in that void in the oil pan? That's the way I've seen most J Miatas. 

What about engine management? 

In reply to wheelsmithy (Joe-with-an-L) (Forum Supporter) :

They clocked to started over to the drivers side for more clearance.

It is laid over in that pocket on the bottom of the pan.

The starter is from 84-95 Honda civic SOHC. There are more then one type, permanent magnet and field coil. I wonder if one of those gear reduction types will fit.

The engine management will be an Electromotive Rtec3.  More to come on engine stuff.

Nice! That looks much better.

The bottom center location was my biggest problem with this swap. Your set up looks like you could cantilever a skid plate off the crossmember. It might not be as bad as I thought, just made me question.

I see the motor mounts are still on the adapter plate, which, considering the power plant frame, looks fine to me, if a tiny bit weird. 

This is going to be a sweet ride. It looked great before you started adding all the good stuff. 

wheelsmithy (Joe-with-an-L) (Forum Supporter) said:

This is going to be a sweet ride. It looked great before you started adding all the good stuff. 

Thanks! I have been really eager to get back to the engine details, but the seat/drop pan has taken longer then I was planning on.

We'll guys I got the car buttoned up and took a test ride to some of my favorite hooning spots on the corvette seat. I had put it all the way back and down with the bolsters all the way in. Lumbar's flat and left the power not wired in.

1. 1st mistake, I had put the oem seat belt receiver in a bad position. I picked it because its in a good metal spot (3 layers thick) and I grabbed the Miata receiver and bolted it in.  It ended up behind the seat, I need to find one that has a bit of extension. 

It took about 20 minutes to actually click the belt, I was determined to try this seat out. Later I would have to wiggle out from under the belt because it would not release.

After the 2nd or 3rd hoon spot I was feeling the seat. The bolsters hit me square on the floating ribs and I could not ease them up. For some reason the low bolster action was making me fill nauseous. For me they should be 2-3" higher up to do work on my true ribs.

Also the seat bottom has demonstrated to be too narrow for my butt, again...

I have another seat here in the garage I want to try out from a Fiero. It's has some pretty trashed up upholstery but the side bolsters are not as crazy pronounced as the vettes.

Tried out the seat again after adjusting the bolsters fully out. (much better) and tilting the seat towards the transmission tunnel. I had noticed I was leaning on the door prior so I stuck in  1/4" spacers on the outside two rail mounts and now not so much. I could go for another 1/16".

The plus side of tilting the seat over gives me more room to re-install the door bar.

I need all the room I can get here.

I have had the engine for a while and have worked out a plan for it. As I posted before I got it as a long block so I did not have any accessory parts or drive, no intake, no exhaust, and no wire harness or sensors except the crank and cam sensors because they are behind the timing belt. And no plumbing. 

So I started fishing around ebay for parts. As you guys know you can find the parts, but they may not come with fasteners. And there is a LOT of special nuts and bolts to the F35. So my plan turn to buying a complete drop out engine with alt & compressor still on and use it as my doner engine rather then get nickled & dimed getting the engine fully dressed.

My engine will be controlled by https://electromotive.com/our-products/tec3r-engine-management-system-2/  I have a couple of these units around so in it goes.

The 1st hurdle is getting the 60-2 crank trigger that the ecu works from swapped from the Honda's 24 toothed trigger wheel.

The crank trigger wheel is part of the timing belt drive pulley.

All this lives behind the timing belt.

It is very fortunate that a second source of Honda JV6 parts comes from Honda marine 200-225-250 HP outboard motors.

The marine crank pulley has the timing wheel as a separate piece that allows for some changes.

So I made a new 60-2 tooth reluctor wheel in accordance with the tec3r timing.

So the next step is to make a mount for the chisel point sensor. I don't think the big honda sensor could see the finer pitch.

It needs a fairly precise position with about +/- .01 tolerance.

Honda has a cam sync that plays plays a big roll in its timing paradigm. The tec3r needs it to provide a sync to be fully sequential fueling. 

  The honda has two sensors and 4 timing pulse each, some degrees apart. I just need one. I need to call Electromotive and see if the ecm will just respond to the edge of the 1st pulse and ignore the rest, or do I have to do some mishaniganse to make it output a single pulse. Simple to machine off all but one of the teeth and use only one of the sensors.

The rest of the sensors are pretty straight forward, I just need to swap GM for Honda and I'm cool.

Everybody seems to comment on the engine mounts.

Just about every piston aircraft engine I ever seen is mount at one end.  I can't say anything about how it feels or how much things move around untill I finish and drive it. I will let you know.

The clutch comes from a 2000 Civic SI specified by Mini Tec. In keeping with the minimize unsprung and rotating mass I went looking for a proper lightweight clutch & flywheel.

As I'm looking at this I can't remember how much it weighs, something like a 10 lbs flywheel.

The flywheel and friction surface are chrome moly. I'm guessing the Honda B engine can hit some high rpms.

I hoping that the weight savings from running a solid disc out weighs the grabbiness I expect.

The starter used is mounted to the oposite side of what the flywheel is originally designed for.

So you have to grind off the tack welds and flip the starter ring and tack it back. 

The kit comes with a flywheel spacer and longer bolts.

and it's HUGE!

The flywheel really hangs out there.

Looks like everything lines up!

Another issue with the J series motor is the coolent plumbing as pertaining to the Miata home turf.  All the plumbing on the J35 exists over the bell housing in a big cast alum housing. Mini Tech wants me to massage the firewall a little to clear the thermostat and hose with a hammer. I did fine some cool pieces from https://www.powerrevracing.com/Honda-J-Series-s/1877.htm that will let me plumb direct to the cylinder head with AN fittings.

The water inlet is in the middle of the Vee with a SS water pipe the plugs into the back of the water pump.

It's just a o-ring seal on both ends with the water pipe trapped in place by the rear piece.  I'm thinking if I make a pipe to go from the remote thermostat around the back of the motor to somewhere near the original lower miata hose.  The top hose from the radiator can be supplied by those relocation kits.

The car already has an upgraded aluminum radiator. I thought I would try Evans water less coolant and see how it works. Anybody out there that has tried it, please let me hear your thoughts of it.