ORX-626 - My Mazda 626 13B Turbo

L10B · **Posted:** Mon Apr 25, 2011 12:22 am

1998 was a year I really got to enjoy my efforts and in June I took her to FF&R Jamboree at Willowbank. Seen here parked with another rotary powered 626 from NSW.

In October ORX-626 finally made it to print in Fast Fours and Rotaries magazine

. Here's the story.....

...and here with my wife's (then girfriend) Series 2 RX-7....

I continued on throughout 1998 getting to Lakeside Raceway as much as possible. Here's a short video from an event...back in the day before anti-shake technology! :oops:

http://www.youtube.com/watch?v=olo7FMYT1oM

Various shots with a 3/5" floppy digital camera!

Obligatory modification plates! :tu:

Custom adjustable camber/castor strut top plates I knocked up...IIRC just over 2 degs negative camber and 4 degrees of castor.

New in car entertainment - Pioneer CD Head Unit

Momo Shadow Carbon gear knob

Real time air/fuel ratio gauge - Wolf unit IIRC

In December 1998 a friend had a deal fall through on a series 5 RX-7 front cut with 70k km on it....hmmmm

Yum 13B turbo powered 626....I like the sound of that! :wink:

Now the fun was really about to begin!

Cheers,
Danny

ewokracing · **Posted:** Tue Apr 26, 2011 3:51 am

Somewhere, in a box, probably either water damaged, lost or given away, I have that issue of FF&R, I even remember that article only because the artwork and background pictures rarely changed in FF&R at the time and it was nice to see a 626 instead of the usual Gemini, Suzuki Swift GTi, RX-3 etc.

:tu:

L10B · **Posted:** Sun Nov 04, 2012 12:02 am

Good news!

The thread is back from the dead as the image file size restriction has been lifted! :tu:

Now where were we....

Instead of having my 626 off the road for an unknown amount of time as I installed the new drivetrain I purchased another series 2 shell to work out the "installation kit." The main outcome I wanted was if the engine ever expired, I could just drop another series 5 RX-7 engine with minimal changes to the engine. Most 626 rotary conversions (like my first one) use a front mounting arrangement, however I wanted to maintain the side mounting arrangement of the Series 5 RX-7 13B turbo. Further, I did not want to change the position of the turbo and fabricate to new exhaust manifold. So the first thing to do was to remove the broken MA 2-litre drivetrain and see how the 13BT fitted best around the standard 626 steering and suspension components.

April 1999

It was pretty obvious that to retain the side mounting arrangement of the 13BT the standard 626 front crossmember needed to be remanufactured. If I went to a front mount arrangement I'd have to change the sump for an early model 13B anyway. This was the best solution...the cut the straight centre section out of the crossmember after jigging the outboard lower arm pick-up points, and fabricate a new section that wraps around the sump. The material used was schedule 80 50NB pipe...plenty strong and moreso, plenty stiff...I also added a locating ring for safe jacking of the car. Here's the result...

May 1999

I couldn't use the factory series 5 RX-7 mounts as the chassis rails were too close together on the 626...so I made my own engine mount brackets for the engine. IIRC I used a pair of new Ford V8 engine mounts in opposing orientations, hence the different brackets on the modified front cross-member.

So with the engine sitting on place the next thing to do was to sort out the cooling system (radiator & intercooler). I really wanted to use as much of the standard series 5 RX-7 items as possible....or at worst modify them to fit (along as it was cheaper than making a completely new item).

July 1999

To get the shift lifter in the best position I did the usual remote shifter housing shortening mod...

August 1999

Here's the engine trimmed down to the bare essentials and a nice little dump pipe stubthat clears the steering box...

Here's a recored series 5 RX-7 oil cooler (shorter but still has the thermostat)....

September 1999

By the end of September 1999 it was starting to come together with all the ancillary components finding a home. The wiring was also underway as I was also using the factory computer (this was necessary for compliance).

The wiring took many weeks to sort out....especially when I could only work on the car for a few hours every Saturday morning...getting engaged might have had a bit to do with that as well! :mrgreen:

.

November 1999

I can't exactly remember when I got it running in the donor shell... but I'm pretty sure it was before the turn of the millenium!!! :lol:

Cheers,
Danny

gypsy · **Posted:** Sun Nov 04, 2012 4:55 pm

Nice update, still reading though it. Your 626 is a more epic build than my Rx3, you've been at for well over 10 years, I'm only approaching the 7 or 8 year mark. I find it best if I don't keep tabs on the time I've spent working on it :lol:

A couple of questions I have, did you end up TIG welding the worlds longest intercooler piping ? :lol:

Also who recored your oil cooler ? I asked a couple of places years ago (10+) and I was told they couldn't do it, which I couldn't understand. After seeing that you managed to do it I'll call around again, most oil coolers today have a fair bit damage from years of use. Makes sense to recore an original and have it look and perform like new again. I know you can buy aftermarket ones pretty cheap these days but it's not the same, they look completely different.

L10B · **Posted:** Mon Nov 05, 2012 2:02 am

gypsy wrote:

Nice update, still reading though it. Your 626 is a more epic build than my Rx3, you've been at for well over 10 years, I'm only approaching the 7 or 8 year mark. I find it best if I don't keep tabs on the time I've spent working on it :lol:

Hi gypsy, yeah Rome wasn't built in a day was it! :mrgreen:

Yeah the build as you will see (as I get time to populate the thread), extended right to 2005 with only minor improvements and general maintenance after that. I've now owned the 626 for 21 years next month.

gypsy wrote:

A couple of questions I have, did you end up TIG welding the worlds longest intercooler piping ? :lol:

Yes, the intercooler pipe work was TIG welded.

gypsy wrote:

Also who recored your oil cooler ? I asked a couple of places years ago (10+) and I was told they couldn't do it, which I couldn't understand. After seeing that you managed to do it I'll call around again, most oil coolers today have a fair bit damage from years of use. Makes sense to recore an original and have it look and perform like new again. I know you can buy aftermarket ones pretty cheap these days but it's not the same, they look completely different.

Yes, it takes someone with a lot of skill and patience to cut the tanks off without losing too much tank volume. From 1999 through to 2004 I did a fair bit of R&D work (on the side) for Aluminium Radiators and Engineering (ARE) here in Brisbane so I was able to get Richard Anderson (owner) to re-core the series 5 RX-7 oil cooler and modify the intercooler for me as remuneration. I'm sure he has done it since and could do it again.

Cheers,
Danny

rx7s2 · **Posted:** Mon Nov 05, 2012 5:39 am

Nice I was really turning blue holding my breath waiting for this to kick off again.

mazdajon · **Posted:** Mon Nov 05, 2012 1:17 pm

rx7s2 wrote:

Nice I was really turning blue holding my breath waiting for this to kick off again.

You would look like a Smurf then Marek, nice. :lol:

L10B · **Posted:** Sun Nov 18, 2012 3:47 am

Time to take another breath Marek!

The year 2000 brought some pretty big life changes for me...mind you they were self inflicted! :wink:

So not a lot of work on the 13BT conversion was completed...especially as the 626 had a starring role as my wedding car! :mrgreen:

In early 2000 I just cleaned the engine up in preparation for when I could take the 626 off the road.

In late 2000 everything fell into place and I got the green light to start the swap...

This is the new crossmember bolted in place.

The old engine and crossmember in the corner waiting for a new owner...

The new engine in waiting...

Some ancillary components in place...

The start of the FC RX-7 brake upgrade...ceramic coated calipers! :twisted:

Cheers,
Danny

rx7s2 · **Posted:** Tue Nov 20, 2012 5:53 am

Breathing for now, thanks Danny. :tu:

L10B · **Posted:** Sat Dec 15, 2012 7:03 pm

The year 2001 saw plenty of progress and with the advent of the digital camera so did the quantity of photos that documented the progress. :tu:

This is the in-line (top radiator hose) cooling system fill point.

...and this is the re-cored (shortened) 2nd gen RX-7 oil cooler with the thermostat retained.

A couple of piccies of the 2nd gen top mounted intercooler after being modified to be used as a front mount.

The CB2MS 626's have very shallow noses so there really isn't enough room for an air to air intercooler, an oil cooler and a radiator fitted with a rather larger thermofan. Soooo I mounted it horizontally and low between the radiator and the engine. It was mounted to the engine so that the hoses didn't have to absorb any relative movement that happens when the oil cooler is mounted to the body.

Here's some piccies of the intercooler and it's mounting detail. I added a small thermo-fan that would turn on when either the park brake was on (ignition powered) or when the foot brake was applied; especially when sitting a traffic lights. This was to cool the intercooler unit when there was no ambient air flow. I think the fan motor blocked more air flow when the car was moving than creating any benefit when the car was stationary. :oops:

Oh well, it was an idea that I tested and then discarded!

Here's the 13BT engine mounted in the car...

More updates to come over the Xmas/New Year Period.

Cheers,
Danny

rx7s2 · **Posted:** Sun Dec 23, 2012 3:32 am

Ahhhh my xmas fix!

L10B · **Posted:** Sat Jan 26, 2013 11:26 pm

Well it's not quite the Xmas/New Year break...but a rather wet and windy day with not much else to do!

Circa 2001....time to upgrade the brakes

Sneaky hole as a cold air intake in the front fascia panel which is hidden by the front bumper.

My custom front brake upgrade kit using FC RX-7 rotor and caliper.

Custom caliper bracket

Rebuilt ceramic coated caliper and modified front hub

Caliper bracket fitted to the front upright

Powder coated and re-bushed lower arm

Brake rotor and caliper installed

The other side...

Next was the rear brakes....again I used the FC RX-7 rear caliper and rotor

Caliper bracket template

Trail fitment of the laser cut bracket prior to zinc plating and the addition of studs to the rear axle.

Ceramic coated rear caliper slide bracket

Rear brake rotor painted with hi-temp paint

Custom zinc plated rear caliper bracket installed

Custom cooling system header tank with temperature gauge sender unit and thermo-fan switch. This allowed an modified FC RX-7 radiator top tank to work in an upright position (as they are normally inclinded). This was also the fill point for the cooling system as it was the highest point.

I fabricated the intercooler plumbing from 2" 304 stainless steel tube and had it TIG welded.

From the turbo to the intercooler

From the intercooler to the inlet manifold

Initially I didn't recirculate the blow-off/bypass valve

The turbo dump pipe, catalytic convertor and mid-pipe was next on the agenda....

Cheers,
Danny

L10B · **Posted:** Thu Mar 28, 2013 9:40 pm

The exhaust system was fabricated predominantly from mild steel tube and mandrel bends and then ceramic coated for longevity and exhaust gas heat retention. As you can see in the below photo, the standard series 5 RX-7 turbo is close to the chassis rail but has plenty of clearance for engine rotation under hard acceleration. It is also leaves a reasonable air gap to the steering box.

The dump pipe was made from a 3" mandrel bend that I slotted at 90 degree spacing to reduce it down to the turbo's exhaust housing outlet diameter.

This is how the dump pipe finished up after ceramic coating.

Next in the exhaust system was the catalytic convertor. It has 3" inlet and outlet that I flanged.

After the catalytic convertor the exhaust continued at 3" to the 2.5" front muffler. I used a reducer right at the inlet to the front muffler. So from here the rest of the exhaust system was 2.5" in diameter and uses the same front muffler I had when the engine was naturally aspirated. I manufactured a new straight through rear muffler of the same construction.

The below photos show the rest of the exhaust system.

The dash gained an extra gauge as well! :mrgreen:

So by the end of 2001 the 626 was getting pretty close to hitting road once again.

Cheers,
Danny

Rolo · **Posted:** Tue Apr 09, 2013 12:41 pm

Amazing 626! Love the story too!

ORX-626 - My Mazda 626 13B Turbo

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