V6 engine transmission adapter plates
iti_uk - 13/10/08 at 01:02 PM
Hello all, I've been pointed here by a friend who says this is the ideal place to find advice on what I am after. Apologies in advance for a
lengthy intro.
A little about me;
I own a 1997 MX5 (1.6L) and a 2.5L Duratec V6 engine, and I intend on putting the latter into the former.
My current problem is this. I want to retain the standard (albeit 6-speed manual) transmission from the MX5 in order to keep the "powerplant
frame" (PPF) and make the swap as reversible as possible. The bellhousing on this gearbox is not removeable, but the complete front housing is,
and to my knowledge, is interchangeable with the front housing of either the RX8 or the Lexus IS200 (all use the Aisin AZ6 gearbox, with different
bellhousing patterns (?) ). I am finding it tricky finding useful info on these alternative front housings, so I am assuming that they all place the
starter motor on the engine side of the flywheel. There is an area where this is possible on the V6 (at about 4 or 5 o’clock), so this is where I am
looking at mounting the starter.
Beyond this, I will need to have fabricated an adapter plate, since the bolt patterns are completely different. The thickness of this plate will
depend on whether or not I can house the nose of the starter motor within the bellhousing at all, or if it needs to be completely accommodated within
the adapter plate itself (resulting in a ~55mm thick plate).
Next, I will need to adapt a flywheel to fit. As I want to keep the standard MX5 ‘box, I will be needing a clutch to suit that rather than the clutch
which comes with the engine. I cannot use a standard MX5 flywheel as it uses a 6-bolt crank connection, whereas the DV6 uses an 8-bolt crank
connection. Either I can use an adapter/spacer, which can also take into account the extra offset required due to the adapter plate, or I need a
custom flywheel to meet my specs.
My requests are;
1 – does anyone have any further knowledge of the afore-mentioned housings. Do any mount the starter on the gearbox side of the flywheel?
2 – what are people’s opinions on flywheel spacers/adapters? I am concerned about this as I am looking at potentially 55mm of required offset, but
this may be significantly reduced if the starter motor nose can be housed partially within the bellhousing, or if the afore-mentioned gearbox front
housing allow for a gearbox-side starter.
And finally, who can I contact in order to get these items measured up properly and fabricated?
Thanks for reading.
Chris
zilspeed - 13/10/08 at 04:01 PM
You should speak to Clairetoo.
Her Fury has the Mazda V6 with what I believe is an MX5 gearbox.
Sweet looking installation too.
grazzledazzle - 13/10/08 at 04:52 PM
I'm running 2.5 duratec with cosworth T5 box.
10mm ali adapter plate, works a treat. You just need to experiment with spacing the starter to accomodate the plate and ensure the clutch and shafts
line up etc.
Liam - 13/10/08 at 05:20 PM
Your clutch surface, hence ring gear, hence starter longitudinal position will be determined by the clutch splines on your box input shaft. If
you're changing the 'o-clock' position of the starter to somewhere other than within the bulge in the bellhousing, you'll probably
therefore have to chop a bit out of the bellhousing to accommodate the starter nose. That's what I've done.
Hope that makes sense!
Liam
clairetoo - 13/10/08 at 05:21 PM
Hiya Chris 
First off - are you using the duratec because you allready have one lying around , or did you get it specifically for this conversion ?
I ask because the Mazda KLDE (from the Mx6/626 or Ford Probe) is a much simpler conversion - if you can find an Rx7 gearbox I believe it bolts
straight in . You wont need the 6 speed box with the 2.5 - I sure dont with the 1.8
Allso the KL is small , light , and powerfull - if you can find a Jap spec engine (KLZE) you will have an honest 200 BHP , more with throttle bodies
etc . (and it's good for 7500 RPM.......)
If you go with the adapter plate route , the starter motor can go anywhere it fit's in the car 
Liam - 13/10/08 at 05:23 PM
A picture paints 1000 words...
Rescued attachment DSCF0041.JPG
locost_bryan - 14/10/08 at 01:59 AM
Mazda KL V6 into Miata here.
Don't think the Duratec V6 has an RX7 bolt pattern - Mazda like to change the bolt pattern when they design a new engine family. 
Your best bet is a Jag S-type V6 gearbox, as it is a variant of the Duratec. Was discussed on here a year or two back.
iti_uk - 14/10/08 at 08:52 AM
Thanks for the replys, guys.
I have seen the KLiata around, and it's a nice swap, but I prefer the Duratec V6 engine (which has also been done before). Neither is a straight
bolt-on to any rx7/mx5 bellhousing afaik.
Also, if I use an RX7 gearbox, I'll have to mess around with modifying the PPF, and I want to avoid doing that.
Is the KL smaller than the Duratec? I was under the impression that it was slightly larger?!? If the KL is actually smaller, I'd be sorely
tempted to use that instead - more aftermarket support, an actual Mazda unit, etc etc. My aim with this project was to do it as if it had come like it
from the factory (as much Mazda group parts as poss), so that would fit in nicely with that philosophy.
A 10mm ali plate adapter sounds wonderful - I'll need to get my tapemeasure out again.
Thanks,
Chris
p.s. I'm a member (same username) of forum.miata.net, which is where I've been most active on this topic. It also has a nice conversions
section.
[Edited on 14/10/08 by iti_uk]
Maybe the RX8's gearbox has the starter on the 'box side - this is apparently not the AZ6 but the Y6M (or is it a typo on the site? Same
box?) and it shows the starter on the 'box side... This could be an avenue to follow.
Also, Liam, is that a 4WD se7en I see in the background?!? Insane!!!
[Edited on 14/10/08 by iti_uk]
iti_uk - 15/10/08 at 01:37 PM
Any takers?
Anyone know which is bigger? (Mazda) K-series V6 or Duratec V6?
Anyone got any names of good machinists who can carry out the fabrication of the adapter plate?
Chris
flibble - 15/10/08 at 02:22 PM
If you can't find any accurate measurements for the KL engine I can nip out and measure mine in th MX6 next time it stops raining, not sure how
accurate I can be though, it's tight in there!.
iti_uk said:
"If the KL is actually smaller, I'd be sorely tempted to use that instead - more aftermarket support"
I love the KL's but support for the KL-de/ze engine is sorely lacking, goto any Probe/Mx6 forum and you'll find people having to be
"creative" as the aftermarket is just not there (unlike the miata).
Kev
clairetoo - 15/10/08 at 06:53 PM
Well...........I've got two KL's on the garage (Probe and Mx6) plus the K8 in the car 
KL - 409mm from back of block to front of stock pully , 580mm across the heads , and 560mm from the top of the heads to the bottom of the sump - 380mm
to crank centre (add about 30mm for the stock injection plenum)
Any help ?
clairetoo - 15/10/08 at 06:56 PM
quote:
Originally posted by iti_uk
Any takers?
Anyone know which is bigger? (Mazda) K-series V6 or Duratec V6?
Anyone got any names of good machinists who can carry out the fabrication of the adapter plate?
Chris
I currently have a KL to fit to another Fury - if I was making more than one plate I could see about getting a few water-jetted ? The flywheel I can
machine `in-house`
(have a look at my archive - plenty of piccies there...)
iti_uk - 15/10/08 at 07:57 PM
quote:
Originally posted by clairetoo
Well...........I've got two KL's on the garage (Probe and Mx6) plus the K8 in the car
KL - 409mm from back of block to front of stock pully , 580mm across the heads , and 560mm from the top of the heads to the bottom of the sump - 380mm
to crank centre (add about 30mm for the stock injection plenum)
Any help ?
Excellent, you're a legend! Ok, so that compares to:
DV6:
Length from front pulley to air intake manifold face = 580mm
Length from front pulley to gearbox mounting face = 485mm
Max width (minus exhausts) = 650mm
Max height (from bottom of sump) = 655mm
Crankshaft centreline from bottom of sump = 195mm
Height above crankshaft centreline = 460mm
So, it looks like the K is the winner. By some margin, too.
quote:
Originally posted by clairetooI currently have a KL to fit to another Fury - if I was making more than one plate I could see about
getting a few water-jetted ? The flywheel I can machine `in-house`
(have a look at my archive - plenty of piccies there...)
That would be fantastic! Would it be possible to mount the starter engine-side? I'm quite keen to not cut up the gearbox. On the DV6,
there's space at about 4 o'clock, where you have your placed at around 8 o'clock - is there room on the other side?
PS. is that you with the muscles? Nice car btw.
Chris
[Edited on 15/10/08 by iti_uk]
clairetoo - 15/10/08 at 08:49 PM
Nah..........not my muscles
As far as I can see . the starter motor is gearbox-side on the V6 in it's original layout - whereas on the Mx5 it is engine side . The thing with
the KL/Mx combination is that there is nowhere to put it !
Mine finished up pretty much where it is on the Rx7 box by chance - I wouldnt worry too much about cutting an Mx5 box as the most I've paid for
one is £50 (plenty on ebay...)
I will see about getting the adapter plate drawn up , and find out the cost of the ally......
iti_uk - 15/10/08 at 09:15 PM
quote:
Originally posted by clairetoo
Nah..........not my muscles
Ahh. How about that drag-bike? That looks.... fast!!!!
quote:
Originally posted by clairetooAs far as I can see . the starter motor is gearbox-side on the V6 in it's original layout - whereas
on the Mx5 it is engine side . The thing with the KL/Mx combination is that there is nowhere to put it !
That's true.
quote:
Originally posted by clairetooMine finished up pretty much where it is on the Rx7 box by chance - I wouldnt worry too much about cutting
an Mx5 box as the most I've paid for one is £50 (plenty on ebay...)
I will see about getting the adapter plate drawn up , and find out the cost of the ally......
The only problem is I'm planning on using the 6 speed MX5 box, and that's a bit rarer, although I know the RX8 uses the same 6spd box (AZ6)
but with the starter on the 'box side, so swap the front casing and voila... Although I've got a feeling the bolt pattern is different on
the Renesis engine
When would you be making the adapter plates, and what would you want for one? I think, in the end, I would be prepared to cut into the 6spd
bellhousing. But only with a tear in my eye... :'(
Chris
clairetoo - 15/10/08 at 09:24 PM
quote:
Originally posted by iti_uk
Ahh. How about that drag-bike? That looks.... fast!!!!
Chris
0 to 60 in................... 0.97 sec Yep , a bit quick ! (oh , and 0-170 in 8.1)
Not bad for home-built and lo-cost
NS Dev - 15/10/08 at 09:34 PM
You are mad as a sack of badgers Claire, but most valuable too lol
iti_uk - 15/10/08 at 09:37 PM
quote:
Originally posted by clairetoo
0 to 60 in................... 0.97 sec Yep , a bit quick ! (oh , and 0-170 in 8.1)
Not bad for home-built and lo-cost
Crumbs. I've experienced a 600hp, 800kg, 4wd, slick-clad Metro 6R4 replica, and that was borderline painful (partially because I wasn't
expecting it - 0-60 in ~2.5s). I can't begin to imagine what 0.97 0-60 (or 0-170 in 8.1) feels like... And while hanging from the handlebars...
Chris
Liam - 15/10/08 at 09:48 PM
quote:
Originally posted by iti_uk
Also, Liam, is that a 4WD se7en I see in the background?!? Insane!!!
It is indeed - mu ha ha haaa!! And that adaptor plate is to fit to a to-be-turbocharged 2.7 honda V6. That Mazda V6 is a great choice though too.
You'll probably struggle to mount the starter engine side on a Vee unless it was designed for it. On mine it had to go super low and even then I
had to cut out some of the sump and relocate a cable exit on the starter.
If I was doing it again I'd probably go gearbox side even if it meant cutting a big chunk of bellhousing away like Claire's done.
You're probably gonna have to cut a little bit out anyway for the nose even if you put it engine side.
About not wanting to chop up your gearbox. It's a nice idea to make it easy to go back to standard, or just do avoid 'damaging' a
standard part, but is it really necessary? Are you really ever going to undo this conversion? Even if you do, how many years will that be? If it
costs you a second hand gearbox (or at least welding your kept cutout back in) is that really a big problem? I'd suggest it's not an issue
worth over-complicating or compromising your current project for. I felt similar trepidation about chopping up my cossie 4x4 bellhousing - I paid 450
quid for it 'brand new' (but 10 yrs old!). Was the right thing to do though and I couldn't care less about having 'ruined'
the part cos it's never going to be used for its original purpose!
Liam
NS Dev - 15/10/08 at 09:49 PM
I'd agree with every word of that Liam
Liam - 15/10/08 at 09:57 PM
quote:
Originally posted by iti_uk
quote:
Originally posted by clairetoo
0 to 60 in................... 0.97 sec Yep , a bit quick ! (oh , and 0-170 in 8.1)
Not bad for home-built and lo-cost
Crumbs. I've experienced a 600hp, 800kg, 4wd, slick-clad Metro 6R4 replica, and that was borderline painful (partially because I wasn't
expecting it - 0-60 in ~2.5s). I can't begin to imagine what 0.97 0-60 (or 0-170 in 8.1) feels like... And while hanging from the handlebars...
Chris
Mmmmmmmmmmmmmmmmmmmmmmmmmmmm
Just been oogling a 6R4 at a work conference at the heritage motor centre today 
. I could even see its front diff - siiiiiiiiiigh. A 600bhp
version?! woah! would that be one of the ones being rally crossed (at least there was when I last saw some rallyX). Awesome car - nicely feeds my
fetish for seeing 4WD and powerful motors crammed into little things that shouldn't rightly have such bits crammed into them. Like Metros. And
Sevens
Liam
Liam - 15/10/08 at 10:02 PM
quote:
Originally posted by NS Dev
I'd agree with every word of that Liam
Great minds, and all that...
P.S: - iti_uk - I found this paper billions of years ago on the net. It's everything you ever wanted to know, and didn't want to know,
about that Mazda V6. You've probably already got a printout by your bedside, but just in case...
iti_uk - 15/10/08 at 10:10 PM
Maybe you're right - after all, I don't plan on selling my car. I should get my grubby mitts on a 6spd asap, and if Claire would be kind
enough to help me with the adapter plate (the 5spd and 6spd are direct bolt-on replacements for each other), and get this done...
So... I've got a disassembled DV6 sitting out back now with nowhere to go... Ah well, I can spend some time having fun re-building it anyway.
Maybe I can sell it for a profit...
There's only one LARGE fundamental problem with going with the KL... I have been planning on calling my car the DureX5 (see the cunning play on
words there...? see my miata.net threads lol). Now I'll have to call it something else... Suggestions on a postcard.
Chris
iti_uk - 15/10/08 at 10:18 PM
quote:
Originally posted by Liam
Mmmmmmmmmmmmmmmmmmmmmmmmmmmm
Just been oogling a 6R4 at a work conference at the heritage motor centre today . I could even see its front diff - siiiiiiiiiigh. A 600bhp
version?! woah! would that be one of the ones being rally crossed (at least there was when I last saw some rallyX). Awesome car - nicely feeds my
fetish for seeing 4WD and powerful motors crammed into little things that shouldn't rightly have such bits crammed into them. Like Metros. And
Sevens
Liam
Ahh, wow, thanks for the document. Good bed-time reading there for sure
Yeah, I've pined after a 6R4 for years. I was a passenger in it, being only 15yrs old, at an airfield rally event. Yeah, the guy normally used it
for rallyX, but was using the tarmac event as a shakedown. It was comically fast round the course.
Thanks again, all.
Chris
locost_bryan - 23/10/08 at 03:57 AM
quote:
Originally posted by iti_uk
I have been planning on calling my car the DureX5 (see the cunning play on words there...? see my miata.net threads lol). Now I'll have to call
it something else... Suggestions on a postcard.
KLit? 
iti_uk - 24/10/08 at 09:03 AM
quote:
KLit?
Lol, that's the spirit!
On the miata.net forums, one name that's been suggested which I quite like is KLMX-5. That's derived from KLiMaX-5. Loving the
tongue-in-cheek nature of these suggestions.
Chris
