Good Stuff Reubs, I believe the stock B6 engine doesnt have halve of the things you are going for but all good if you are.
There needs to be the water passage at the front of that head like on the RWD B6 engines that will help with plumbing from your radiator rather than have water coming from the back of the head with messy pipes.
 
Dont go for the isotropic polishing, if crank wears out eventually you can get another but normal linishing will be fine.
Look at spending that on maybe a custom ebay inlet manifold rather than the ugly one atm.
The head is exactly as on the Ford Capri which is what I saw the other day.
 
Surpringly the 8v sohc late ford festiva mazda B engine had roler rockers

http://www.ebay.com.au/itm/Kinugawa-Turbo-Exhaust-Manifold-Ford-MVP-MAZDA-323-FS-FP-T25-Flange/271531500244?_trksid=p2050601.c100103.m2451&_trkparms=aid%3D111001%26algo%3DREC.SEED%26ao%3D1%26asc%3D20140211150826%26meid%3D8262813530528536904%26pid%3D100103%26prg%3D20140211150826%26rkt%3D4%26clkid%3D8262816743979617071&_qi=RTM1714243
 
Any opinions on this?

http://mx5cartalk.com/forum/viewtopic.php?f=57&t=49039&start=345
 
interisting thread about cooling system setup.
 
it seems that moving the cooling from the front of the head is the prefered method!

On further thought today, Im going reverse flow for my twin cammer early A12 with A14 crank and 81mm bores

Youve made me rethink the whole process Reubs and on looking at how the original radiator works, the reverse flow idea used by some A series racers is fine as their pumps are not used for long periods of time in a race so can expect good durability unlike the streeters.
 
It will be easier and better for the e-pump to use the original flow design of the A series, even with the twin cam head its easier to make sure the headgasket holes are biased correctly to suit flow like on the A series head.
 
The headgasket determines alot of this so no need to worry whether it flows from the back or the front of the head, for me I just dont want that extra plumbing for the back of the head when you can have it like on the MX5 setup from the front.
 
On the A series head I expected there are more water holes biased from the rear to make sure water runs across from the bottom front of the block up to the bores where the first cms of combustion take place then up through the back of the head then flows out towards the front.

http://www.miataturbo.net/engine-performance-56/purpose-coolant-reroute-64305/
 
more on the coolant reroute
 
http://www.miataturbo.net/engine-performance-56/very-different-coolant-reroute-40479/
 
D This is a thread about reverse cooling just like you have been thinking
 
http://www.miataturbo.net/diy-turbo-discussion-14/what-you-think-his-coolant-reroute-52203/
and another setup
 
http://www.miataturbo.net/general-miata-chat-9/beginning-my-spacerless-coolant-reroute-12027/
a setup not using a spacer at the back of the head! Good for the crampted engine bay of the 1000!

It seems that re-routing the coolant in various ways is the prefered method.

D
 
As for actual HP atw, I dot really know what to expect. I dont have a HP figure in mind as such. I guess if I had to put a number on it, im aiming for around 130-150 atw, but If I get more than that without major modifications, then ill take it. Im not modifing the head at all. Im planning of running stock stuff where I can as aftermarket items just seem way to pricey. Running the t25 (300zx) with efi and intercooler  should hit the 150hp mark I feel with realibility. 150hp atw in a dat will be enough... at least to start with!!
 
The recurring theme with the coolant reroute that the mazda nuts speak about is the uneven cooling that they get with the B6 motor. No4 seems to get too hot and cause them problems.
It seems that in the stock form, that it isnt much of a problem, just once you modify that the re-route is a reccommended modification.
 
Is there any benefit from running from the front instead of the back?
With the fancy timing cover, to run from the front, means that I will have to cut a hole for the pipe, which I am not keen to do. It also means that it has to be a custom thermostat housing as nothing std will fit with that plate there.
 
As Im yet to fix the head to the block (hopefully in the next few weeks if paychecks permits) Ill post up some pics of the situation.
 
The more I think about it, the more Im thinking that Ill need to run from the back as I dont want to cut into the front of the timing cover. The benefit of even cooling is just a bonus, and the kia sephia/chevy excalade pipe setup looks very tidy

Hmm very true.

Since the motor is not yet in the car yet, I can let this rest for the meantime. I'm kinda leaning towards the front setup since it would be easier for plumbing though.

Now onto the next topic...

what about modification to the head?
Porting?
Bigger valves?
Double valve springs?
Roller rockers?

Since I am going to be ceramic coating the head in places (chamber, valves, ports) it would seem like before coating is the best time to do mods, else the coatings are a waste of time.

Should I just be happy with the std head setup and not get too greedy?

Since the vast majority of power in a motor is mostly developed in good head design and modifications/charactistics, I feel that I should focus my efforts there.

Since the block that I am planning to use is only bored to 77mm, which should clear the valves, going to bigger valves would mean I might have to notch the block or bore out again, which is starting to sound like its getting out of hand.

Thanks D

I was originally going to keep the head std, but then had crazy ideas about performance blah blah blah.

Yeah, just get the head machined flat, valves re-seated and seals. make sure the springs are even tension (replace as required) and debur the ports/smooth out. The get the coatings done.

Picked up a complete MX5 intake manifold yesterday cheap cheap, so stoked with that.
Looking at the aftermarket intakes, they all look ugly, "very" basic in design and take up more room in the engine bay.

The std MX5 intake manifold has nice long runners wrapped up (bunch-o-bananas style) with a forward pointing throttle body that points slightly down (about 22.5deg). Perfect for hook-up to the intercooler on that side!

As for the exhaust side, I'm still undecided on weather to go Cast or stainless. The designs of both are essentially the same. Very basic with the 4 exhaust runners coming straight out into a 4 into1 log type setup.

Both are as compact as each other.
The stainless one is cheaper.
$260 stainless
http://cgi.ebay.com.au/ws/eBayISAPI.dll?ViewItem&item=201117542767
lighter
shiny!
should be wrapped to keep heat in (not shiny anymore )

$300 cast
http://cgi.ebay.com.au/ws/eBayISAPI.dll?ViewItem&item=331268143671
cope with heat better
more durable
no wrapping needed
heavy mofo!

opinions?

Update on progress

Was discussing with a local wrecker about the head that I have here. When I described it to him, he seemed confused about what model it could be from. He reckons that all the B6 motors have a rocker cover that fits over the timing wheels. Mine doesn't.
Looking at pics on the interwebs, it seems my head is from a Mazda BF 323. I've got to look for a head casting number to help him out identify which head to ensure what bits will fit correctly

Now, I've been thinking about the accessories needed for this head.

I reckon a CAS from an mx5 is the way to go. It bolts to the back of the head and is fairly low profile, so shouldn't foul on the firewall. Certainly no worse than a right angle distributer setup.

Since I am running with the std intake and injection setup, coil packs and CAS, I'm starting to think that I might be able to use a mx5 wiring harness and computer to run the show.

I was going to use a delco 808 or similar and program it myself (my brother is a bit of a guru. He just did his VR commodore), and this still might be the way forward as you can set an 808 to deal with boost. not sure about a mx5 computer.