tbone heller

Why not build a spacer with studs to mount the slave out of some flat bar stock? The angle needed for alignment could be built into the spacer. Total cost of about $0.25 in material.

Titus

So this is why my ears were burning! Thanks Michael... I think!
Thanks! I have the build thread on a few different forums, but recently created v6Miata.com after some picture hosting issues and re-created all of my journal entries there. It is using wordpress so I can quickly add entries via phone app, so it will be the first place to get updates.

Gator Bait

Definitely meant to be a compliment. Your car looks just as great in person as it does in the pictures.

Titus

That picture is very deceiving due to the angle. From the proper angle, the bottom sides on the oil pan are right in line with the steering rack brackets coming off the sub-frame, the lowest point of the pan (center) is about 3/8" lower than that, and the starter is the lowest object in the picture, hanging about 1/2" lower than the lowest point of the pan.

Minitec has since re-designed the adapter plate to bring the starter up about an inch. They also will provide a lower capacity oil pan that doesn't hang down as much, and there are a few guys working on dry sump setups.

The lowest part of all is actually the exhaust Y pipe, where it crosses under the transmission. I have the y pipe from Minitec, and it is far from ideal. This is the only thing hanging down that kit owners have actually had ground contact with in real life. I am going to have a shop modify mine to maximize clearance.

Titus

That is an item I have noted to revisit, but I think the picture makes it look worse than it is. I believe the spacer is only about 6mm, and the Miata slave's pushrod just sits in the piston cup to allow some degree of misalignment. I suspect it becomes more of an issue with the stiffer pressure plates used on V8 swaps. Regardless, I plan to take a closer look at it. On a related note, the spacers were actually an enhancement not included in the first few kits. The instructions recommended hitting the corner of the block with a grinder to get the clearance needed for the slave to sit flush. when I found them among my crate of swap parts, I had to call them to ask what they were for.

Titus

Also, I have recently learned of a build that puts my level of OCD to shame...

577nitro

YIKES!!nice work who ever did it....BTW, If you weld two drilled tabs to the clutch arm end, you could then use say a 1/4 inch grade 8 bolt through them, and put a rod end on the end of the slave and avoid most if not all angular issues. One of my SCCA racing buddies did this many years ago, and it worked perfectly

Titus

Hmmm. I am having a hard time visualizing that.

I was thinking of just shaving down the spacers and slave ears a little. Basically the blacked out areas of this pic. I would also need to notch out the bolt holes a little.

577nitro

Looking at that picture, I can see that the arm has already been cut ,and yes it would be hard to visualize from that, but just think of the location that the rod is at, but having a tread on small uniball rod end, and the indentation portion of the arm having a bolt vertically and attached to the arm that then passed through the rod end. What it does is to greatly reduce the friction of the surface the way it is, and takes care of most mis-alignments

577nitro

Here is a nice photobucket link of a fellow down in OZ of his engine mounting. Not that he more correctly I think does not mount the engine to the subframe via the adapter only


IMG_1274.jpg Photo by joelhartley55 | Photobucket

577nitro

Here is a close up of the starter issue potentially rectified

MRM331

Titus, it's good to see you here. I've been following your progress and really think you're going to end up with a fantastic finished product.

I've been quiet recently as most of my "free" time has been devoted to getting my current V8 Miata ready for sale and researching/planning this eventual JV6 build. It's amazing what you can find out when you dive into the worlds of NSX forums where they are turning to this engine as a replacement for their wide angle v6's, the civic forums where they jam this engine in and leave it sticking out of the hood, the Acura and V6 Accord forums where they are modifying the engine with the chassis it came from and the sandrail guys who have been using this engine for a while. I've also spent a crazy amount of time searching 1hondaparts and other Honda/Acura OEM part warehouses comparing part numbers to see what parts are compatible with what.

What I think I'm leaning toward now is the following:

Engine:
I'll be starting with a 2001 sourced Acura MDX J35a3. While most start with the J35a4 from the Honda Odyssey it looks like the MSX engine may have some advantages:
-The cylinder liners are iron, not fiber reinforced metal
-The block is the same as the J32a2 block used by the type s Acura CL. This means it has extra external webbing making it somewhat stronger.
-The injectors and coils are the same as the S2000.
-The crank and rods are forged and if pulled (hold on) can be sold to someone looking to increase the displacement of their J32 to 3.5 liters.
-the heads are the same as the J32a2 and may actually flow better even with 1mm smaller intake valves that the J32a2. These slightly smaller valves are actually significantly lighter than J32 valves.

To this engine I intend to:
-Replace the crank and rods with those from a 2009 MDX J37 making it into as least a 3.6. I may also go for larger J37 pistons if I can figure out how to work around a small head gasket issue.
-Swap the cam for a J32a2 one as well as the valve springs. The J32a2 cam is slightly better. If it does not make that big of a difference at least it gets me a set of cores (the original J35a3 ones) to send out to be custom ground.
-Swap the intake with one from a 2009 AWD CL. Apparently this intake flows better, sits an inch lower and further back and weighs next to nothing. It's about $300 new which is a steal coming from the Mustang world. Hopefully this will allow me to not have to modify it to fit. I'm a little concerned with pulling intake air into only one side of the intake.

Rear:
I'm using a 1991 donor which means at the very least upgrading to a 1.8 rear. The best option would then be to go and get a set of rare Australian Miata 3.636 gears and have the rear rebuilt. This would be great but when I priced it out it actually came out $200 cheaper just to get a mounting kit from V8Roadsters for a Getrag. I'll be going this route as the end product will be 100% new, have a lower gear ratio and make the exhaust routing easier.

Exhaust:
-After looking at a few options I came to two main conclusions: A true dual 2" - 2.5" system would yield the best sound but a single 3" system would actually give the most power. I think what I'll be doing now is buying a $200 to $400 eBay header and J-pipe set for a Acura or CL and then using it as the starting point for a 2.5" down pipes to flowmaster Y-pipe to straight 3" out the back. After the axle I'll split it again into two pipes with one going through a substantial muffler (I'm leaning toward a Mac) on one side and the other going straight out unmuffled with a vacuum controlled exhaust valve to make it into a "dual mode exhaust".

There's more that I'm still working on,

-Jason

MRM331

OK, here's how this has developed for me the last few months since I first proposed it:

Here's what I need out of my next build:

1-As close to 300 hp as possible and at least 270/280 pounds of torque
2-ECU that has the ability to data log and be tuned
3-NO tunnel mods
4-True dual exhaust with a dual-mode function (in stainless)
5-"normal" ground clearance
6-A limited slip rear
7-Gearing that can reliably get me past 140 mph at the track I frequent most (Pocono)
8-Cost that justifies not going with another 5.0 or LSx (sub $15K total including chassis)
9-Miata-like weight including AC/PS
10-must be possible to supercharge it up to V8 levels if I choose later on

Point 1 and 2:

I would not be happy with the two standard engines that the kit is designed around. The J35a4 is a minivan engine with only 250 hp and FRM (fiber reinforced metal) cylinder sleeves which can or can not be bored or honed depending on who you talk to. The J32a2 is pretty nice IF you want to stay around 260 or so hp. This is an excellent option for someone who is happy with this as the cost for the whole build go down very nicely because the Miata 5-speed and 1.8 rear should work fine. Unfortunately both of these options will not work with a MS3 without seriously reworking the pickup system on the engine.

After a lot of research I found that the generation of the J engine after the above actually has a setting in Tuner Studio called "Honda-Acura Mode" that will work with the factory cam and crank sensor. After more searching I found a few .MSQ's files on line for these engines so I would not be starting from scratch building a tune. The rub is that all of this generation of J engine has integrated exhaust manifolds (IEM) which sort of scared me away. My plan was to try to use a set of ebay J headers and try to fabricate from that. However the more I looked into it the more I realized that the advantages of the IEM's outweigh the fears I had. Exhaust routing in the engine bay is greatly simplified. At this point I was OK with IEM's. The next step was to see what J engines will bolt to Minitech's adapter plate. It turns out that Honda only has(d) two bell housing bolt patterns during the entire run of the J, the type that Minitech uses and the later one found on some early awd cars. By comparing bell housing part number and visually comparing pictures of the back of the engines I found what engines I could and could not use.
My research showed that I could go all the way up to a mid-2000's J32a3 which I picked as my staring point. This engine made 270 hp from the factory and with the Pre-cats deleted should make about 290. The heads are one of the best intake-only VTEC J heads made and the cams are also one of the most aggressive. Additionally the block has steel sleeves which makes the next thing I'm about to discuss possible:

The MOST powerful J engine built is the J37a4 found in the 2009-2014 Acura TL SH-AWD. At 305 hp and 271 pounds of torque it looked to be the best choice for my build. Unfortunately it can not be used in this application for two reasons: the bell housing is the one that does not work with the kit and the heads have VTEC on both the intake and exhaust. While that is awesome, it makes the heads about 1 inch taller which would not work in the Miata bay (an awesome side benefit of this is that the intake manifold was shortened to make that work in the TL and can be bolted onto a earlier intake only VTEC engine to yield a manifold that sits an inch lower, flows better and only weighs 7 pounds).
So, the J37a4 was out. I really wanted that extra .2 liters though. I looked again into the J37 series and found that the first one, the J37a1 from a 2007-2009 MDX did not have the taller dual VTEC heads that would not work. Despite this it still has 295 hp and has the best single VTEC heads and most aggressive cam shafts which are also hollow.

With this knowledge I formulated a plan to purchase both a pull out J32a3 (about $500) and a J37a1 (about $1500) and combining the two by boring out the J32's 89mm bore to 90mm and swapping the entire rotating assembly into it. The heads would be the J37a1's which would give me an extra set of solid cams should I decide to have them custom reground at some point to really push the engine. This in the end would give me a 320 or so HP engine (using higher compression pistons from a J37a4) with close to 380 foot pounds of torque for around $3500 when all was said and done.

Point 6 and 7:

This gets me to point 6 and 7, the drive train. Now that I had my engine and computer planned I looked to see if the stock Miata components could handle it. I was not confident they could. I decided the best option would be a Miata 6-speed (about $700) and V8Roadster's Getrag kit that maintains the PPF. With the purchase of a 3.2 Getrag to go with it the cost of this came to about $2100 which is actually cheaper than it would have cost me to purchase a Miata 1.8 rear and have it rebuilt with the mythical 3.636 Miata gears (about $2500). The drive line was now set.

Point 9:

The more I looked into it, building it with PS was less and less of an option. I do not like the idea of a side intake and the SH-AWD manifold I planned to use could not be modified as such anyhow. I'm sure that a mount could be made to attach the Miata PS pump to the side of the engine as we do with Fords but i really did not want to have to deal with fabricating with this build. I already had the possibility of the IEM's not working with the steering shaft and didn't want to take on another possible point of "thinking".
After looking into the options that are out there I found several reviews of the rather rare NB manual rack saying that it was far superior in feel to the NA one and a depowered NA or NB rack. I looked on a few parts sites and found that the cost of a new one is actually substantially cheaper than any other Miata rack at under $300. I figured I'd have Minitech build my subframe for a NB and go with that option (NB manual rack). The final weight using any J engine should not be more than a stock Miata. The engine actually weighs almost the same as a BP.
Minitech claims that a set of custom lines is all you would need to hook up the AC. As I do this for Fords already I didn't see this as a problem until I looked into point 10:

Point 10:

While V6 power seems fine I have been driving V8 Miatas almost daily for the last 10 years. If I am not happy with the result (if it does not reset my spine alignment every time I punch it) I'd like there to be an option that can take me back up to that power level.
There are screw-type supercharger kits for the J engine available. Unfortunately they are all designed for FWD applications and place the supercharger itself to the left of the engine above the trans. This would put the super charger under the dash which while interesting, is not really what I'm going for here. I looked into turbo-style superchargers and found that while no one makes a kit a "guy on facebook" makes aluminum mounts that allow you to piece together a kit using a Rotex unit and other parts. This was an OK option except that it mounted the unit in place of the AC compressor. I do not live without AC. That, combined with the fact that I'd have to choose the compression ratio around how I eventually want to go made me not 100% happy with this.

Point 3:

The J kit requires no mods, not even "ear cutting".

Point 4:

I'll discuss this at a later point as it's sort of independent from the rest of the build. I have a nice system planned out that will emulate the dual mode systems that GM and Jaguar use on their V6's. The only worry I had in this area with the J build is that the kit utilizes the PPF. I'm not sure that their is enough room on the passenger side of the tunnel to fit a 2.5" pipe, cat and resonator and maintain point #5. I don't think its a major problem but still a worry.

Point 5:

This worries me with this build. I have dealt with Monster Miata "pretzel exhaust" on every build I have done so far and really want a different option this time. Even the Ford replacement build I was planning before getting the V6 bug was to incorporate a bare V8Roadsters subframe that I would send out to Martin to have Ford mounts added to and off the shelf headers. I'm not 100% confident that the oil pan, passenger side exhaust and low-mount starter would not leave me with the same headaches as the MM exhaust situation. More on this later...


Point 8:

So that leaves point 8. The final price for the build over the cost of the car came out to around $12,000. Including the donor cost and upgrades (roll bar, track brakes, etc) the whole cost comes out under my $15,000 limit but not by much. I was 99% sure I was going this route but still felt I had to to investigate the other available options before becoming a full on Honda fan-boy. More on how that tuned out later.

-Jason

ToySnakePMC

I, too, have had a slight bug (very slight bug compared to this!) to do a J swap. My few hours of research only scratched the surface. You, on the other hand, have it nailed down to the 9th degree! Thanks for posting this up in case I get to pull one of these builds off in the future. I probably would do a stock J swap with the idea of a flip at some point... (Got 3.5 Miatas now!) and this in-depth info is killer. Can't wait for your build to take off - it's gonna be awesome.

577nitro

I too had reservations on how the adapter left the starter way too low, but after talking with BJ at Minitec, I went ahead and bought some of their kit. Attached are some photos taken of what must be done to the oil pan to use the new "clocked" position of the starter

RichW

Forgive me- just a brief tangent. I am new here but have read much in my endeavor to decide what I want.
1) There's the LS option which is mouth watering but expensive.
2) There's the Ford option, stock 302= 225 hp, 300ft-lbs.
3) then there's the Honda J option (which is why I am asking this here) 260hp, 240 ft-lbs.


I've never had the experience of driving any of these, and I'm looking to build a daily driver, local and highway. The Honda conversion looks very appealing as simpler and less cost, but the torque is substantially less than the 302, hence a weaker acceleration, and no V8 rumble! I guess a lot has to do with gearing and Jason's solution using the Getrag diff offers some options.
Anybody out there to offer some feedback for someone who enjoys driving the Miata exclusively all summer?
Rich

MRM331

There's also a fourth option, the LFX V6.

I haven't posted this elseware yet but after looking very closely at the JV6 option I think the LFX is the direction I'll be going for a number of reasons that I'll elaborate on when I start an actual thread. What it comes down to from my research is:

Honda J:
Under $10k to swap
250 hp/ 250 torque (aprox) max
Advantage: VTEC coolness factor, stock Miata from clutch back
Disadvantage: Without some serious engine building/frankensteining and driveline changes (Miata 6-speed, Getrag) the above is your limit.

LFX:
Around $15k to swap
320 hp/280 torque
Advantage: Almost completely flat torque "line" due to Constantly variable valve timing, less weight than a stock bp, 5000 mile donor engines can had for around $1500, no more chassis mods than a 5.0 swap
Disadvantages: GM built it (sorry Jim ), still relatively new swap, thats about it

Ford 5.0 "based"
Around $15k to $20k to swap
300 hp/300 torque
Advantage: with the proper ecu and a few more bucks LSx levels of power can be had, very few chassis mods, cheap parts
Disadvantage: it is inpossible to find a usable donor Mustang engine at this point which means most of these swaps start with the building of a custom engine. This could also be seen as an advantage if you have the skill of resources

LFx
400 hp/torque
From $20k if you do it yourself to $40k if you have those folks in Colorado do it for you.
Advantage: newer tech, 400 hp is the starting point where with a Ford its pretty much the limit, its the current swap everyone is talking about.
Disadvantage: lots of cutting and welding, high cost of donor parts, its debatable how much power above 400 hp is even usable in a Miata without seriously modifying the wheelwells.

So, in my opinion the the LFX is a very logical "modern" alternative to the Ford option, expecially if you want over 300 hp. If you're happy with the around 250 level the JV6 option is a strong one. If you want to hit the 400 level and like tinkering go with the Ford, if you want that level of power without building an engine go with the LSx.
Anything below 250 can be done with a supercharger or turbo for a lot less work and money than an engine swap.

-Jason

MRM331

Oh, and for anyone who thinks a V6 can't sound good watch this:


-Jason

RichW

"There's also a fourth option, the LFX V6."




I'm having trouble with three choices and your now giving me a fourth? Are there any build threads out there? Who makes the kit?


Rich

acedeuce802

I don't think price is as large of a gap between the LFX and LSx as you make it out to be, unless you're using the latest and greatest LS3 crate. Pretty much all the swap kit parts, and supporting parts/materials are going to cost the same between the two. I got my LS1+T56 dropout for $2800. Your quote of $1500 sounds like it's just the engine (which seems to be correct from a quick eBay search), so I'm sure a full Camaro engine+trans dropout will be nearing what I paid for an LS1+T56.

I'm not saying the LSx is a better swap, but I don't think price is the deciding factor. I think the LFX should be considered over the LSx when weight, balance, and refinement is a concern.

I think the V6 swap is only worth it if you really think the "swap" itself is worth it. It's not going to be any faster than a well sorted turbo Miata, and it'll be more expensive. But it will be cooler and sound better.

The EcoTec swap seems like a new budget friendly swap that will be pretty competitive. I'm excited to see people try the Solstice transmission with the swap, I think all the ones I've seen have been using Miata transmissions, which limit the torque to 250 or 300 (for 5 or 6 speed).

Rich, let us know what kind of power you're shooting for, and what kind of fabrication skills you have. A 250 whp swap will vary very differently from a 350 whp swap, for obvious reasons. If you make a rash decision on an engine swap now, and end up wanting more power, hopefully you don't have to redo a lot of what you've already completed. This is the main reason I'm starting with a bone stock Camaro LS1. It'll be right around 300 whp, but if I want 350, 400, or even more, it's possible without tearing the whole car apart again.

MRM331

You are correct, you can get a used LSx pullout for what you quoted. From what I've seen though by searching sites like car-part and even eBay is that you can get almost new LFX engines for the $1500 I quoted above. I've seen them with literally 5000 miles on them for that amount. So while you can get an LSx for the same money you can't get one as new.
From the review I've read about V8Roadster's first LFX build it sounds like it actually pulls harder in 1st, 2nd and 3rd gear than their V8s. Of the four choices its the most modern engine of the four.
Honestly the only hesitation I still have with the LFX is the dual-mass flywheel which weighs a ton and makes clutch choice limited.

-Jason

portabull

that is exactly how it sounds in a miata.... it reminds me of my ford sho which had two personalities. one was meek and mild until you stood on it and it hit
3500 rpm, then it really came to life. the lfx is like that too, stand on it, and it speaks up.

grubinski

This. :-)