List of BP swap gotchas

[LongJohn]

I'm going to post a list of gotchas here so others can avoid the same mistakes. I'll edit in more as I finish. Many of these will be obvious to the more talented, but for those like me...

Doing an Escort BP into a 93 MX-3:

1. The fuel lines are different. The return from the fuel regulator requires a special Ford o-ring based connector that you no longer can buy from Ford. It is also on the passenger side of the fuel rail. Solution: hack saw off the connector, but leave a small flange so the hose clamp has something to grip (grind it very smooth). Run about 1/2 meter of rubber fuel line back to the metal return line that goes to the tank.

2. Passenger-side motor mount is different. The large bracket that mounts to the engine (and also holds the alternator adjustment bracket) is slightly shorter on the BP to make up for the longer engine block. Solution: you must use one from a BP engine, not the one from your SOHC.

3. You cannot remove the alternator without first removing all those air valves on the passenger side of the intake manifold. Solution: make sure you have a good alternator before installing the engine, and mount it first.

4. The metal bracket that mounts to the engine and manifold and holds the backside of the starter is different. Solution: make sure you get one of these. I didn't have time, so I made a bracket, but I don't have the back of the starter bolted to it. I sure hope the starter doesn't rip itself out without it.

5. Clutch is different. This is well documented already, but here are details. The Escort clutch plate fits the splined shaft of a "G" series MT. Your stock "F" series shaft is different, so you have to use a clutch assembly for that, but that assembly doesn't fit the BP flywheel, so you have to use the flywheel from the SOHC as well.

[atlantamx3]

Originally posted by John Long:
5. Clutch is different. This is well documented already, but here are details. The Escort clutch plate fits the splined shaft of a "G" series MT. Your stock "F" series shaft is different, so you have to use a clutch assembly for that, but that assembly doesn't fit the BP flywheel, so you have to use the flywheel from the SOHC as well.

If you use the SOHC tranny-- you use the clutch AND FLYWHEEL for it. If you use the BP Tranny-- use the clutch and flywheel fot it.

Also-- I noted the Fuel line difference while i was pulling some injectors off of a Escort GT-- they ARE weird metal lines.

Also-- Not sure why you couldn't remove the alterntator without removing the VICS lines... THATs strange too.

Everyone should save themselves the trouble and get a Protege LX BP! LOL

[Shady469]

i ran into the same issues with the fuel lines on my EGT BP. I'm pretty sure you can just swap the pro lx fuel rail over, but i just used a long hose like john did. I used the SOHC MX-3 disty, alternator (involves swapping over the pulley and finding the correct size belt), and wiring harness (the injector harness is very easy to modify). i agree with perry that you shouldn't need to mess with any of the VICS stuff to put in the alternator. to wire up VICS i spliced into the common hot in the injector harness for the purge control valve(the white/red wire) and ran the other wire through the fire wall and to the ECU. i also used the mx-3 starter and got it to fit by cutting off the two gold screw things that stuck out of the back of it.

<small>[ November 28, 2004, 07:13 PM: Message edited by: Shady469 ]</small>

[LongJohn]

What I meant with the alternator is that the engine is so close to the fender that there is no room to pull it up and out without clearing some space.

Regarding the VICS wiring, my wiring harness doesn't have the pin where it is supposed to on the ECU connector. Can you buy those from Mazda?

[Typhoonk]

Originally posted by John Long:

Regarding the VICS wiring, my wiring harness doesn't have the pin where it is supposed to on the ECU connector. Can you buy those from Mazda?

Just go to the wreckers and take a mazda ecu plug from a mx-3 92-93, ford probe, escort 91-93. You can just flip up the plastic holder on the plug then just pull out the wire. Or just grab the hole plug.

Then just slide the wire and pin into your connector and close the plastic holder.
Done.

[Joe Carlson]

In swaping my EGT BP motor in, I used my protege LX fuel rail and have had no problems there. It was pretty simple to do, took me about 15min at most, and works great.

[LongJohn]

JoeC, it's good you had an LX fuel rail to use. I just ohmed my cable, and I have an interesting problem that wouldn't exactly be fixed with such a rail. It turns out my 93 has some similarities to a 94 in it's wiring.

For instance, every injector is separate.

If you hold the fuel rail connector so the tab is on top and you are looking into the pins (wires on the back), and you number them like this:

2468
1357

Then my SOHC connector is as follows:

1 = W/R Common
2 = Y/B Injector 2
3 = G/O PRVC valve (connects to pressure regulator)
4 = Y Injector 1
5 = B/O Green temp sensor
6 = G/W Green temp sensor
7 = O/G Injector 3
8 = O/B Injector 4

My Escort fuel rail is like this:

1 = W/R Common
2 = Y/B Injector 2/4
3 = B/O Engine temp sensor (single pin dude under distributor)
4 = Y Injector 1/3
5 = B/R Green temp sensor
6 = G/W Green temp sensor
7 = B/R VICS
8 = DKG/O PRVC

So, I was going to modify the fuel rail wires, but I can't do everything that way, so I'm going to modify the harness at the ECU conn. I need to:

1. Trace pin 7 back to the ECU and move it to the VICS pin (and solve the VICS that way).
2. Trace pin 3 and 8 to the ECU and swap them (or just leave the O/B wire disconnected).

Everything else should be fine. The single pin engine temp sensor is not part of this conn in my wiring harness, so I'll just hook up the conn that was used with the SOHC.

As a note, the 93 wiring diagram in the Chilton's manual do not match my car. I wonder what's up with that? I would appreciate it if someone who did the BP swap into a 93 could check and see if their injectors are all separate and are still working? I'm wondering if the Escort ECU has some hope of supporting this. I'll probably still make the above mods, but I would like to know...

[What]

I agree on the mounts... I took all 4 and compared them. The EGT BP mount is little over an inch shorter. However the block is only 3/4" longer. Just using the BP passenger side mount allows enough room to drop in the other three, but it's still not perfect. To be perfect you should be using the G series rear mount as it is also displaced. I have pictures and such I'll post up if I can find the time.

I used the EGT fuel rail, an easy fix with some pushlok hose, and a quick slightly modified $6 adapter for each fuel line side. It's not steel throughout EGT line, it's plastic and can come off.

The bracket on the intake manifold that attaches to the block is for support of the intake manifold. Attaching it to the starter is overkill by Mazda IMHO, and the starter 'should' be quite fine without being bolted to that bracket. A lot of 4 cylinders have this rear intake bracket just to the block at any rate.

Now the only other problem I have is with the wiring harness, I used the EGT engine harness and ECU (not the one that goes to the starter).... some wires are different color and it seems there are more differences than 'two wires to the VICS' and the injector harness. I haven't tried to start the vehicle yet, but I did notice a faint smell inside the cabin familiar of hot electrical components. To which I disconnected battery and came on here to ask people what harnesses they've used with no problems (engine one and seperate 'starter' harness?)