72 Mazda b1600 rotary swap
 

Friend bought this cool little truck and wants me to do 13b swap in it..so let the fun begin!or should I say drama haha...

Truck pics when purchased from Arizona

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And here it is sitting in my yard ready for action

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Motor is already built.its a s4 turbo 4port block,streetport,s4 n/a rotating assembly with all new seals and springs.he wants to run it all motor but we did modify the front cover for a turbo oil return line in case he decides to go turbo in the future.going to use a fc rx7 stock Ecu.here some pics of the motor during the build.

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Clearancing and fitting side seals to .001

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And random pics of measuring end play and pressure testing coolant seals

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Will be using a turbo II transmission.tomorrow going to shorten the shifter housing about 5".
I will post more pics as I go.

Cool project!

looking nice

We pulled the motor out yesterday.gotta plasma cut the old piston mounts of that crossmember..

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Looks more narrow than a repu and measured and confirmed it's actually right around 3" narrow.so probably need to fab up a header for it.

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Neat little truck, good color too. Nice work on the motor. Wouldn't a rotary bellhousing fit onto the B1600 ribcase?

^drivefast I was hoping it was a ribcase trans because I have seen you can swap out the bellhousing but it's not,it is a 4speed non removable bellhousing .we are trying to make this truck as much possible like a repu,we already installed repu front disk brakes on it and even the brake booster which I didn't take pictures of:(

I managed to plasma cut the piston mounts of today and will grind them down a bit another day.

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Sweet project!

please don't scrap that piston engine...I think that is similar if not the same as the 1.6 that came in the very early 626's. Many parts on there I need

^ what you need?
The head was rebuilt and new timing chain and guides put on.but never ran right.so it's why we got the rotary transplant going on lol..

Intake and exhaust manifold as well as cylinder head and valve cover and carb. Let me know.

Alright let me hit up my friend and see what he wants to do.

Shortened the transmission remote shifter by 5 1/4" here's before and after pics

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wow looking real good , great job and I'm liking that pick up !

I assembled a engine together with no internals to use as a mock up while doing the engine and trans mounts
I got a hold of an rx3 crossmember and modified a bit so it fit the truck.worked out pretty good I think.

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But damn it's going to be some tight space for the header.

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the usual trick with rx3/rx4 cross member in the oz cars
( when fitting a turbo manifold to clear steering )

is to take about 75 mm off one side of the rx4 crossmember , and weld it to the other end
then redrill the cut side and remount
( unsure if you welded that one in.. in the rx2,3,4 they mount to sway bar holes )

this will shift the motor over like the rx7 s1/2/3 does and provide room for the extractors

^yea we welded it to the frame rails.it is shifted over a bit more to drivers side so it gives me more room for the header.

I was able to fab up the transmission mount but after doing that it turns out motor was sitting a little high up front so I cut the engine bracket and dropped it about an 1" and it sits level now with good clearance to trucks crossmember.

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Just got to weld it up and reinforce it a bit.

Thanks for ideas Dave and Bumpstart. Good topic.

That truck looks sweet- never knew they had a piston version. I know Ford had the Currier but never new Mazda had a piston version. I like the looks better than the Repu

This is Mazda's version of the ford courier.almost everything is identical besides the front grill .this is the second truck like this I have seen in my whole life,might be more rare than the repu..maybe...

as a side note,, when i built one of these ( b2000 with turbo LPG RESI engine with tall port centreplate )

i used 2 x FC spark side metal engine brackets welded to the chassis where i needed them
( cut shut gearbox shifter position 103mm )
and dropped the s1/2/3 engine bracket onto s1 rx7 rubber mounts

an exact fit,, with inbuilt offset rx7 engine bracket

Bumpstart never really thought of that and might have worked also.were they welded to the frame?im guessing they would have to be upside down (compared to how they mount on the fc's iron)in order for that to work right?

yes welded , and upside down so the slots for rubber mount are turned up

oh, and PS

if the rear of the gearbox has ended up in the stock location then you can choose 2 piece tailshafts from the b2600 range which use a piston adaption of the t2 gearbox

if things have changed and you need a custom tailshaft then you may also wish to install a t2 diff head
as this is long nose and shortens the need for the two piece tailshaft
( when it is over a certain length, mazda chose the two piece to avoid the limits of tailshaft critical speed )

with the long nose " tq tube " diff setup then you can get a decent single shaft
( 3 inch thickwall with 1310 or equiv mopar uni joint )
made up that will be much cheaper than making a double
( and safer than modifying your current double )

the trick with using the t2 diff in the semi floater diff tube is to weld washers onto the end of the axles to make up for the change in lengths
now that the new t2 diff lacks the support in the middle of the 'rubbing block' found on the old b1600 diff spider pinion shaft

ie.. the axles are supposed to rub on the spider gear pinion shaft "rubbing block" in the b1600 diff
so as to share the weight load across the two opposed taper bearings at each axle end

when you put in the t2 diff ( ex IRS )
.. it lacks the rubbing block width
and so makes setting the endfloat for axles impossible
till you add washers to axle ends so that they rub on the t2 spider gear pinion shaft

the trouble is worth it,, as it brings the option for LSD
,, and much simplifies the fabrication and cost to a single piece tailshaft

Got to do some work on the truck yesterday.cleaned and sanded down the chassis and got it painted.

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And installed it's new heart ��

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Managed to get some more work done to it.i had a 86-91 rx7 13b header that I modified so it fits the tight engine bay on the truck.also got a fd upper intake manifold ported so it bolts up directly to the s4 turbo lower intake manifold.got some dual radiator fans mounted also.heres some pics

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3 row rx7 Radiator was a tight fit but got it in there.also had a radiator shop change the bottom outlet and also put the heater hose outlet on driver side.

Looking good Dave. Just saw one of these for sale up here. If I didn't have the REPU already. I loved to have one.

It's getting there slowly.
Wired up the rx7 ecu onto the b1600 and just need to finish little things here and there and it should be ready to fire up soon
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damn...not sure how i missed this thread...sweet truck and now its going to be even sweeter once TurboDave is done with it.

Updates also on this
Truck is up and running
Just need to do the exhaust
Doing 2.5" stainless steel pipe,racing beat universal pre silencer and racing beat universal muffler out back.
Here's A video of first start up

Nice job, how's it looking now?

mazda b 1600
 

c'est un beau projet bonne continuation
ou est ce que je peux trouver le pare prise pour ma camionnette sur le net

Translation:"it's a nice project good luck or is it that I can find the spark plug for my van on the net"

www.rockauto.com

Really nice truck. Anything to update with it?

Turbo_dave I have been following you on instagram for about a year now. You do a ton of old school rotary stuff, I love it way more than bolting shit on FDs as you normally see on social media.

Keep up the good work!

Really sorry to dig this thread up, but i was wondering if i could pick your brain a bit about this project, Dave.