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Discussion Starter · #1 ·
Hi guys, not sure how active this forum is these days but can't seem to find any other decent ones.
I have a GV 626 with an F2 that has died beyond economical repair.
I am getting hold of an F2T (partly because a bit more power would be nice but mostly because it's the only engine I could find for sale in the whole country).

Question is - what is required to get it up and running with the F2T?
It doesn't include an ECU but I've found an F252 ECU for sale, but this thread makes me not super confident it will work properly:
f252 ecu swap with f2h3 ??? | Mazda MX-6 Forum (mx6.com)

Any advice would be great.
 

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Well the injectors would not be an issue, they can be interchanged between aspec (88-89) and bspec (90+).
You haven't mentioned what year F2T you are getting.

You will need the Engine Harness and ECU for the spec of F2T you buy. The coil and igniter, distributor for that spec also.

Physically both a and b spec blocks are the same, with the exception of the coolant sensor threads in the rear housing of the head. (and an extra coolant path in the intake manifold, this can be capped or run ...).

Much of the stuff on the block stayed the same, the EGR valve, TPS, Idle control valve, throttle closed valve, oil pressure switch, knock sensor and O2 sensor all work with and connect to both A and B harnesses.
The injectors have different connectors between specs but are rated to flow the same.
The distributors have different connectors but could be interchangeable with some wiring.
The tstat housing sensors are different connectors and may put out different signals between specs, but both spec sensors use the same tstat housing.
The 2 coolant sensors in the rear housing (behind the T-stat) may also have different connectors and put out different signals, the Bspect holes can be threaded to accept a spec sensors but not the other way around, however the rear head housing on you F2 can be bolted to the F2T head...

Your your planning to run the f2t transmission you will need more parts.
 

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Discussion Starter · #3 ·
Thanks for the info!
At this stage I haven't actually picked up the F2T yet so not 100% what year it is or what it includes in terms of loom/harness etc but I didn't really know about the a/b spec differences so thanks for explaining that.

If it turns out it doesn't include the harness would it be possible to adapt the one from the F2 to make it work? I don't think I'm going to be able to find one for sale unless someone overseas has one.
It sounds like if I did something like that it wouldn't necessarily matter whether the ECU was from an a or b spec as long as I found a way to use all the correct sensors etc?

The F2T has an auto on it but my car is already manual so will just be using the F2 manual box, I believe they're not particularly strong but I think it'll be the easiest option.

My other big concern is around connecting up all the vacuum lines, which even on the NA motor seem way more complicated than they need to be.
 

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The a spec and b spec ECU's use different connectors, the F2T ecu always uses 3 but some F2's have only 2 connectors on the harness.

If the specs match and you run a 3 connector harness you will need to add pins and wires to the harness and get the proper connectors or rewire the f2t components...

There is hope however, you can run the N/A tune stuff and boost or you can run the F2T motor N/A and make less than f2 power. attaching all the factory shit, ecu to sensors is as much work as or more than running stand alone engine management.

There are write ups on here about how to run the f2t on F2 dissi, ecu and harness.

You need a wideband gauge/sensor.
You need to upgrade your clutch while swapping engines, maybe it's strong enough maybe it can handle the torque but once it slips it only gets worse and you have to remove the transmission to swap the clutch, a six puck disk or high pressure plate will yield the necessary clamping force to hold 190-200 ft-lb torque. Are you running factory f2t intercooling and pipes? or aftermarket, This will change your hpr and tuning requirements.

If you don't get the harness and have to buy a GT ecu, coil and firewall sensors to run a stock F2T you might as well start with standalone and set-up your car with more potential at less cost and more work. It's money or time. Time is learning money is time spent working.

If your expectations are low than run GT on N/A everything except injectors.
 

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Discussion Starter · #5 ·
So you're saying it's possible to just keep the NA ECU, wiring etc, and adapt it to be able to run the F2T? I'll have a look to see if I can find threads about this, if you have links that would be awesome.
Do you lose much performance doing it this way?
Also what do you mean by firewall sensors?

I'm not against running a standalone engine management system but the goal with this car is to keep everything as cheap as possible, I already have a heavily modified daily so this is more about getting the car running again now that the engine's blown and ideally give it a little more power in the process. That being said if you know of particular standlone ECU options that are good for these motors I'm happy to look into it.

Would you recommend upgrading the clutch even if keeping the F2T at stock power levels?

Sorry for all the questions, I'm just completely new to Mazda/Ford so this is a big help.
 

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Yes people run the f2t block and injectors on the NA harness, ecu and distributor.
You don't loose performance .

The firewall holds an egr control valve and 2 vaccum solenoid valves.

Stand alone. It is a suggestion or alternative to having to gather all the f2t parts needed to run the engine factory, depending on what's available/ you can find that's the right spec for the f2t it would be the same effort with better results.
Stand alone engine management is universal, don't look for what's commonly used on your engine, look for what the people who will be tuning it like to work with.

Your other option is to run a piggyback extra injector controller operated by boost and rpm and use the NA injectors in the fuel rail. With two f2t injectors as extras.

Yes upgrade the clutch, you will be making 60+ ft-lb torque over NA at the same rpm, there is a 99.5% chance you will need to pull the transmission and upgrade the clutch within the first few months. The F2T clutch also slips when running a chip and higher boost but when the clutch and transmission are already on the car is called taking a chance. When you have to install the clutch and transmission it's called a missed opportunity.

You will need an NA 5speed pilot bearing to install in the crank, auto's dont run a pilot bearing but it's the same crank.

What do you mean Mazda/Ford? Ford has nothing to do with these engines, they made their contribution to this generation by means of the 3.0l v6 Vulcan boat anchor they installed in some of the probes in 90 and 91.
My dislike of the Vulcan stems from the fact they where often listed as GTs so you drive really far to look at one open the hood and leave, or buy one site unseen, get it delivered, open the hood and send it to the scrap yard.
One lady didn't know what engine was in the car but it's really fast she said, my shop partner and I where intrigued and confused, no stock factory engine options where even mildly quick. To her 168 hp NA auto v6 was really fast. At least the F2T has the potential to be mildly quick with a bigger turbo and lots of boost on the factory engine.

The really fast bar keeps moving farther and farther away with 2000+ hp street builds and 1600hp hybrid hypercars, leaving the rest of us to feel like kids playing in a sandbox.
 

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Discussion Starter · #7 ·
So F2T with the NA harness/distributor/ECU sounds like the easiest option then? I was just asking about potential performance loss since you said "if your expectations are low" in your previous post.

If I understand correctly the firewall EGR valve and vacuum solenoid valves are different or not present on the NA setup, so even if I kept the NA ECU etc I'd have to find those parts?

I did find out the engine I'm getting is from an 88 model, so I guess the ideal scenario is that the engine comes with the harness as there is someone local selling a pre 90 ECU - sorry if I've missed something but I assume that would work even though the car is post 90?

Thanks for the advice on the clutch.

In Australia (where I am) we had a bunch of models sold as both Mazda and Ford including the 626 which is the same as the Ford Telstar (as well as the Mazda 323 and Ford Laser which are the same, and the Mazda Bravo/Ford Courier utes) which is why I said Mazda/Ford. It doesn't really matter who made the engines guess, my point was just that I'm unfamiliar with the platform.
 

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I meant with the N/A harness and ecu you're pushing it if you run 2X factory boost on the factory turbo. With the F2T ECU, a chip, a larger turbo and fuel management you can run 3X stock boost. (For me that's the only reason to bother running an F2T).

Use the F2 vacuum rail, throttle body and firewall sensors.

The ECU harness also connects to the dash harness, if the connector is different 88-89 to 90+ you will have to pin out and connect the wire at those connections.

I know fords run these engines my point is if ford designed these engines they would be unreliable pieces of crap with very little potential in stock form and I wouldn't drive them. Or they would be fords and not worth driving.
 

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Discussion Starter · #9 ·
Thanks for the info and sorry for the late reply.
Sounds like the easiest option will be making the NA harness work, given it's a pre 90 motor but a post 90 car.

Forgot to ask before but can I use the old NA flywheel?
Also would something like this be ok for the clutch or would you suggest a higher rated one? (Noting that the car probably won't make more than stock F2T power but might get launched hard sometimes)
Ford Telstar (1990-1992) 2.2 Ltr Turbo OEM PHC V1011N Clutch Kit – Clutch Direct
 

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You will have to use the N/A flywheel and a performance N/A clutch, the F2T clutch and flywheel are bigger and can not be used with the N/A transmission.
 

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Glad I checked, I would probably have ended buying an F2T clutch.
So something like this would be ok?
Mazda 626 (1990-1993) 2.2 Ltr 313Nm PHC Heavy Duty V1046NHD Clutch Kit – Clutch Direct
I would say no.
It's peak peak torque capacity is 313Nm = 230 ft-lb.
It's recommended torque capacity is 250Nm = 184ft-lb.
Remember these are ratings at the flywheel not the wheels.
The F2T puts out 190 ft-lb torque at the wheel = 257Nm at the wheels.
If we give it a conservative 15% drivetrain loss that would be 218.5ft-lb torque at the flywheel = 296Nm.
The F2T exceeds the recommended torque and is a slow spool in 4th gear on a cold night away (11.5ft-lb) from reaching and exceeding the peak torque capacity.

A clutches ability to hold torque is based on two things, the clutch disk material and the pressure plates clamping force. You can run a pressure plate with 2 or 3 times the clamping force that is a sprung system with needle bearings, the pedal will be no stiffer than stock and the drive ability and engagement points will be the same but when your foot is off the clutch pedal the pressure plate will apply 2 or 3 times the clamping force to the clutch disk against the flywheel.

The clutch disk material changes the engagement of the clutch and the temperature it needs to be at to grab, how much temperature it can handle and plays a role in how much torque the clutch can hold but weather it's kevlar, ceramic, organic, sintered steel, feramic, carbon... if the pressure plates clamping force isn't strong enough to keep the disk from slipping once it's starts slipping it only gets worse, the steel flywheel and pressure plate faces overheat due to friction and harden reducing bite against the disk, some disk materials will also harden and others will burn, crack, break or shatter.

I have a stage 3 6puck kevlar clutch (400 ft-lb torque) a stage 4 6puck sintered steel clutch (550 ft-lb toque) and a stage 4/5 6puck race cut sintered steel clutch with stage 5 pressure plate (700 ft-lb toque) (Full stage 5 is a 3puck disk, they aren't very streetable, the pressure plate is so heavy that with a 10lb aluminum flywheel the clutch assembly is as heavy as the stage 3 or 4 assemblies with lightened flywheels, 10-12lbs of steel removed from the back side).
All 3 are sprung with needle bearings, the pedal is not stiff and the same for all 3, the engagement is the same for all 3.
Aside from the fact the kevlar disk needs a break in period and the sintered steel doesn't there is no noticeable difference between the 3, I wouldn't be able to tell the difference between the three from driving with one of them at random. They all transfer crank torsion to the transmission without slipping.
The only difference between them is how much torque they can hold without slipping when your foot is not on the pedal. Something you'll never notice, can't feel or measure until you exceed the torque rating of the clutch, it slips, it's ruined and wont hold as much torque and now you have to spend the price of the first clutch again + the cost to step up to the next stage and remove the transmission to change the clutch.

I say always go 100fl-lb or more toque capacity over the most torque you ever plan to make. Make 200ft-lb run a 300ft-lb clutch, make 400 run 550...

Although clutch directs prices are super low, the clamping force of their clutches is pretty low, the Turbo heavy duty clutch is rated for a max torque of 392Nm = 289ft-lb
And recommended for a torque of 313Nm = 231ft-lb, and F2T bone stock with a chipped ECU running 15psi will make a lot more than 231ft-lb torque at the flywheel. The fact the heavy duty clutch recommended rating is only 12.5 ft-lb flywheel torque over the conservative factory flywheel torque at 15% drivetrain loss doesn't sound like a clutch that leaves any performance potential room.
They don't mention torque specs for the factory spec Turbo clutch but with the heavy duty clutch having such low numbers it sounds like the factory spec turbo clutch would be 4 or 5psi away from slipping.

At 125$ you might get lucky and the clutch never slips or you might have to buy a more expensive clutch and replace it.
 

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Discussion Starter · #13 ·
I see what you mean.
The hardest thing really is actually finding a higher rated NA clutch, obviously most of the ones out there are for the turbo.
The best one I've been able to find has been a 6 Puck Ceramic clutch from RockAuto which is apparently rated at 25-50% more torque than standard (compared to 20% more for the 313Nm one that I linked to before).

I picked up the F2T engine so now ready to start getting it ready to go in.
Any suggestions on essential parts that should be changed before the engine goes in?
Since I have to put a clutch on would you suggest doing the rear main seal, or just leave it if it's not leaking?
 

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Rear main seal, you know what I would do. Do you want to spend 10$ on a seal and 5 minutes to install it now or possibly have to spend 10$ on the seal and 5hours changing it later.
Do the oil pump crank seal and head gasket (Use Felpro) before dropping the engine in. (I also recommend doing the valve stem seals).
Although it's much easier to just drop in a 30year old engine than to change gaskets, it's still much easier to change gaskets before there is a problem than repairing parts and changing them after theirs a problem.
 

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Discussion Starter · #15 ·
I'm happy to do seals etc but would rather not do the head gasket - I know where you're coming from and that is exactly what I would do with a daily driver, but this is not a performance build, it's just a cheap car that we want to get on the road.
That being said I guess if I was going to do the head gasket I could pull the head and just see what the engine looks like inside before buying the clutch and other parts, on the off chance that it's stuffed.

Also - I'm guessing it might be a pain with wiring etc but how easy would it be to try running the engine on a stand, i.e. before we put it in the car? Obviously I'd be much happier to spend money on it knowing that it actually runs ok.
 

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The head gasket is probably original, they are pretty easy to change on these engines. Unlike N/A engines if the head gasket goes on a forced induction motor the head warps and the pistons surfer burning and pitting.

How easy would it be to get the engine running on a stand, it would not be easy at all, just to run a compression test in your case would be a pain, you would need to install your flywheel and transmission and starter just to turn it over. Nether of which put the engine under load and truly verify it's condition.

You can swap the head gasket in far less time and inspect the engine parts, better yet, pull the pan, remove the pistons, clean them and the rings and reinstall them, check for cracks and odd wear. After that it's like running a new engine in the car, no seized rings or potential problems.

You can tell the condition of the engine by looking at the pistons and rod bearings, I understand it's a cheap build just to drive but you bought the engine, you will have to buy a clutch, you have to install the engine and get everything running, give yourself a fighting chance at success, for me everything I suggested would take about 8 hours with my experience, for you maybe 16 hours, although time is free it's the only thing in life we get, you can sell it (work) or spend it learning and doing things for yourself. The world is geared so that salaries don't work out 1:1, if you take your car to a mechanic you have to work 2 3 or 4 hours to pay for 1 hour of his work, because taxes, you get taxed on what you make and he gets taxed on what he charges... If you did make enough after taxes to afford garage rates at a 1:1 ratio after taxes you wouldn't be driving an N/A 626 or swapping your own engine. Life is money or time but for most of us money is time, If it takes more time to earn the cash and pay someone else to do the job than the time it takes doing it yourself ... It's all your decision.
If this was a lady driven auto GT and never revved above 3500 rpm it won't like 6000 rpm much, there will be seized rings and possibly a ridge at the top of the cylinders. Free the rings, rent buy or borrow a ridge reamer and the engine will be fine and handle red line cut off all the time.
 

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Discussion Starter · #17 ·
Interesting what you say about if it has been gently driven its whole life. That adds up to what happened with the old NA motor - I bought it off a lady who bought the car new and only ever drove the car very gently. And then when I got it I drove it, let's say, less gently. It ended up overheating and causing major damage.
I doubt that was the case with the F2T though as it came out of an MX6 which isn't really an old lady car (compared to 626 at least).

If you're talking about potentially siezed rings though, is removing the pistons and cleaning the rings going to be enough? I just feel like it's easy to end up saying, might as well get new rings and/or oversized pistons if there is wear in the cylinders, etc etc, at which point it's turning into a fair bit of work and cost. Plus the cost of extra tool, eg ridge reamer.

If I'm changing the head gasket can I get away with not getting the head machined, assuming the engine hasn't overheated? Or would you get a shop to check it out just in case?
 

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Sounds like the head gasket failed on your N/A motor.
I've got an 89 MX6 GT 5speed, single owner, lady driven, low millage. I could feel the rings hit the ridge in the cylinders above 4500rpm.

Yes cleaning the rings will be enough, rings don't wear down cylinder walls do.
Personally I prefer using blocks with warn cylinder walls. I clean the pistons and rings, hone the cylinders (remove the ridge when needed) use the old rings and bearings with new seals and gaskets. Then run 3 or 4 times factory boost on much larger turbos with zero engine issues. In stock set up if the engine is torn down, cleaned and and all the gaskets changed every 15years I bet that engine would last long enough for your grandson to pass the car on to his son.
My 89mx6 GT is running an auto block, it had 9 seized rings out of 12, the cylinders had a huge ridge at the top. I cut the ridge, cleaned everything and the engine runs great, doesn't burn oil, has no exhaust blowby

I would not get a shop to check the head, I would check it myself, you need a feller gauge and something dead straight and flat. Hold the dead straight flat thing against the head surface and use the feeler gauge to check if the head is true.

If it wasn't true I would shave it myself using angle iron and sand paper. I try at all cost to avoid having heads shaved, machine shops act like it's a good thing but it fu*ks up engine compression by making the combustion chamber smaller, reducing the size of :1 and therefore the compression ratio increases because cylinder displacement now fills :1 more times.
Fun with math- The F2T is 2184ml / cc it has 4 cylinders 2184 / 4 = 546ml per cylinder, It has a factory compression ratio of 7.8:1 so 546/7.8 = 70 CC that is the value of :1 in 7.8:1 I know the F2 head has a 50CC combustion chamber therefore the F2T pistons have a 20CC/ml dish.
The N/A 8.6:1 block 546ml /8.6 = 63.48ml/cc the combustion chamber is 50cc therefore the piston dish is 13.48ml/cc

Lets pretend we take a head to a machine shop to have it shaved, they are shaving away the largest diameter of the combustion chamber as soon as they start. Lets say the combustion chambers are now 46CC/ml each when the head is done. We know cylinder displacement is 546 and we know the F2T piston dish is 20cc so what is the new compression ratio? 46+20 = 66. 546/66 = 8.27:1.

So it doesn't mater if you change the piston dish or combustion chamber size they both affect compression ratio's in the exact same way, but every time the head gets shaved the valves get closer to the pistons.

Math is not fun it can be used to figure out what you need to know but I always failed because I made up my own formulas to solve the problems, it was debated with the teachers and the principals because I would get the right answer. If a different calculation was done using both mine and the school systems formula the same answer would be achieved, while the other students couldn't figure out how to use the school systems formula properly to achieve the correct answer, I wrote my own formula to achieve the correct answer. I should have got extra credits.

I understand my suggestions sound like lots of work and money, but had these things been done on the N/A block you wouldn't have bought the GT block. At factory boost 7-8psi the engine is under 1.5X the stress of the N/A tuned set-up.
The GT block is even older than your 626block and so are the gaskets and seals.
If you tare down the block and there is damage than you have a decision to make. You said you want to test the block before you run it, tare it down and find out.
My suggestions are based on the premise you got a running block and are so you keep it a running block.
Most of them are based on learning things the hard way. The engine shop that rebuilt one of my blocks in early 2000 used a top line brand head gasket, at 350km of a 500km no boost break in the head gasket melted and coolant pored out between the head and block everywhere, pulled over the second it happened and shut off the engine but the engine temp gauge just kept climbing even with the engine off and the head warped. Learned to only use Felpro head gaskets...
Watched F2T customers drop junk yard engines in cars with the original head gaskets, we would offer to change the head gasket for 200$ in labor (took us 2 hours to do the headgasket) they refused and the head gaskets would fail. Behind my garage I have a 93 mazda 323, the owner dropped in an 88 F2T engine and transmission and ran 11psi on the factory ECU, He traded the car with my shop partner for a 626GT touring sedan (I hate 323's and hatchbacks and pisspots). My shop partner unplugged the ECU and plugged in a chipped ECU and turned the boost up to 16psi and took the car to the drag track the same day, so the 323 F2T has a blown headgasket.
 

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Discussion Starter · #19 ·
Why would you say my head gasket failed on the NA? Generally I would only expect that to happen if something else caused it to overheat, unless you have a Subaru.
Even your gasket that failed which you say was a top line gasket - you would have to assume that it's just an unlucky 1 in 1000 failure that happened to you if it was a decent brand so how can you be sure the same thing won't happen with Felpro? Surely even the cheapest gasket has to be better than a 30 year old one.

I'll definitely give it some thought, I'm happy to do the work in terms of it being a good learning experience, but I'm also going to end up spending the same amount on parts as the actual car cost.
Yes I guess you could argue that the car was a good deal but the whole point is that it was meant to be a cheap car to have fun with, I already have 2 other cars and don't need a third.
 

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Thanks for the info!
At this stage I haven't actually picked up the F2T yet so not 100% what year it is or what it includes in terms of loom/harness etc but I didn't really know about the a/b spec differences so thanks for explaining that.

If it turns out it doesn't include the harness would it be possible to adapt the one from the F2 to make it work? I don't think I'm going to be able to find one for sale unless someone overseas has one.
It sounds like if I did something like that it wouldn't necessarily matter whether the ECU was from an a or b spec as long as I found a way to use all the correct sensors etc?

The F2T has an auto on it but my car is already manual so will just be using the F2 manual box, I believe they're not particularly strong but I think it'll be the easiest option.

My other big concern is around connecting up all the vacuum lines, which even on the NA motor seem way more complicated than they need to be.
[/QUOTo
Why would you say my head gasket failed on the NA? Generally I would only expect that to happen if something else caused it to overheat, unless you have a Subaru.
Even your gasket that failed which you say was a top line gasket - you would have to assume that it's just an unlucky 1 in 1000 failure that happened to you if it was a decent brand so how can you be sure the same thing won't happen with Felpro? Surely even the cheapest gasket has to be better than a 30 year old one.

I'll definitely give it some thought, I'm happy to do the work in terms of it being a good learning experience, but I'm also going to end up spending the same amount on parts as the actual car cost.
Yes I guess you could argue that the car was a good deal but the whole point is that it was meant to be a cheap car to have fun with, I already have 2 other cars and don't need a third.
my 626 is swapped currently need a new harness
 
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