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 FAQ Rewrite #2 
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Joined: May 09 2004, 2:01 AM
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Location: Blacklick, Ohio
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Post FAQ Rewrite #2
Engine swap information for the V6 originally posted by David Coleman. Also, I edited out some of the mundane information. If you want to see the complete posts, check out the respective author's webpages.

From Sean Matthews page

Engine Swap!

I've been saying it for over a year now: "I'm going to swap the engine, I'm going to swap the engine..."

So, now it's happening for real. As it happens, I'll update these pages with tons of pictures and text.

Step 1: Finding the right engine

Jan 22nd 1999: I start the hunt for a 2.5L KL-ZE, the Japanese 195hp version of the V6 found in the 626 and MX-6 overseas. This motor is not easy to find.

Jan 25th 1999: Found what was supposed to be a KL-ZE for $1400cdn, ordered it into the shop and it turned out to be a regular 2.5L Probe GT engine.

Jan 27th 1999: Found the real thing, a true KL-ZE engine for $1200USD. Exactly what I was looking for. Only problem is that it's in southern USA, which would mean I have to import it and pay taxes & duties and all that stuff. I promised myself if I don't find a Canadian distributor by the 1st of the month, I'm ordering this engine regardless. Got another lead on a KL-ZE in Toronto, which is being looking into by a friend on the 29th.

Jan 29th 1999: It's a done deal. The KL-ZE from Toronto is the real McKoy. Steve ("Tekguy" from the MX-3 Mailing List) who lives in Toronto did me a huge favor and actually went down to physically inspect this engine and ensure that it was indeed what we were looking for. The problem had been that almost every engine importer I've talked to had been trying to pass off KF-ZE (the Mazda 2.0L V6) as a replacement for the north american 2.5L version. This is likely due to the cost difference between the two. Anyways, Steve checked it out, and they did indeed have a KL engine (/w id stamped into the block) with the telltale squared off intakes and the oddly positioned VRIS compared to the standard north american 2.5L V6 (the KL-03). There are (unfortunately) many different versions of this KL engine, even among japanese versions. I have now seen 3 different intake manifolds on the KL-ZE engine, and Steve noted that the one that I bought is not like any of the others we have seen. It has the final portion on the manifold right by the throttlebody aimed more towards the front of the car and not so much straight out and towards the drivers side like the photos above. Stay tuned for the next stage, the actual removal of the 1.8L and installation of the 2.5L.

Feb 5th 1999: The engine from Toronto showed up, and had too much damage to the rear portion to risk installing. Damn it. It was the correct J-spec engine from the MS8, but the oil pan was crushed and there was no way of knowing if the internal components were safe or not. Engine mounts were also broken off. So, we're 0 for 2 on engines so far. Now I have to try to get my money back out of the Toronto shop. Learn from my mistakes, always pay with a Mastercard in case the engine supplier turns out to be less than reputable. I paid by certified cheque that was promptly cashed before the engine even arrived. I smelled a rat when they insisted that they couldn't take credit cards over the phone, but I was too horny for this engine to let my common sense prevail. Be warned. Always use plastic for major purchases from companies that you haven't dealt with before.

Feb 11th 1999: Remember the great looking engine from Jan 27th? Well, I decided to bite the bullet and order it regardless of import taxes and our weak dollar. Only problem is that in thinking that the other engine was ok, I informed the Ford Probe mailing list of the availability of the KL-ZE in North Carolina. Guess what? Within two days, one of the guys from that list that asked me about it bought it. Good for him, bad for me. However, Eric from Japan Direct (1-888-518-7341) who sent me the original photos above mentioned that he did have another one coming in from Japan, that is to arrive in mid-March. It's literally on the slow boat from China, and I didn't waste any time in giving him my credit card # to secure first crack at this engine when it arrives. So, the KL-ZE project is on hold for about a month until the motor hits north america. Stay tuned....

March 17th 1999: This has got to be the longest step 1 ever, eh? Well after more than a month of waiting, my engine finally arrived in North Carolina late last week. Here is a picture of the new engine. Yes, it's the right one again, with all the tell tale signs of the j-spec intake (straight before the throttlebody, squared off tubing, different VRIS placement, etc). It looks fantastic even if I do say so myself! It's going to be shipped out tomorrow, and is likely to arrive early next week when the real fun begins.

Oh, btw, I did get a full refund back from JK Auto parts (the engine importer in toronto with the damaged 2nd engine). An honorable orginization, couldn't get the engine I needed fast enough. I was quite concerned that I might not get my cash back, but they did come through.

March 27th 1999: Well, the engine swap project (yes, still step 1) got much more real today, since the engine actually showed up at the shop where we're going to be working on the swap. To be honest, it was almost laughable. After more than a year of trying to find a motor, rejecting other ones, and shipping things half way around the world, my initial reaction when I was shown the motor was "damn, it's kinda small". Maybe I just built it up in my mind over all this time, but yes, it's just a 250 pound hunk of metal when it gets right down to it...
So maybe the engine won't be in by the end of the month, but the old one will be out of the car as soon as tomorrow. However, we don't have a clutch yet, and the flywheel will have to be machined down to about 13-14 pounds, so the next steps might take a week or two while we wait for these things to happen.

Some information on this engine:

The neck portion of the intake manifold looks like it is going to cause some minor/major problems. The neck, for lack of a better term, is perfectly straight out and parallel to the engine, unlike the 1.8L V6 which has a severe bend (maybe 60 degree) towards the front of the car, or even the 2.5L north american model which has maybe a 45 degree bend. This means that it's going to run right into the brake fluid resevoir, unless we relocate it somewhere else. Shouldn't be a big deal, just an unexpected problem.

If you look into the throttlebody, you should be able to see how the intake is immediately split into two chambers, presumable one for the rear bank an one for the front bank. It's cut in half top to bottom, right behind the plate on the throttlebody. I'll measure the opening on the tb, but I believe it's the same diameter as the north american 2.5L which is 60mm if I remember corectly.

Step 2: Relocating the Battery

April 5th 1999: My mid to long range plans for the car are to make a straight line accelerator, not a track racing machine. Since the MX-3 is front wheel drive (duh), it would be ideal to have the battery remain over the front wheels for more traction on takeoff. Drag racing cars want as much weight as possible over the drive wheels, while track racing cars want an even weight distribution so they usually relocate the battery to the rear passanger side to help balance the car out for more even handling (offsetting the weight of the driver). There was a pretty good article in the April 1999 edition of Sport Compact Car where they were working on a Subaru I believe.

However, due to the position of the intake on the new 2.5L, the rubber elbow from the throttlebody to the VAF would need to run right through where the battery now sits. So, the battery is getting a new home in the trunk, even though I'd love to keep it up front. Also, if I ever decide to go ahead and add a turbo (idea on backburner until next year at least) there will be room under the hood.

For the complete process on the battery, click here:

Step 3: Still dragging our feet...

April 17th 1999: I have the good forture of having Vaughn Nishimura (MX-3 Mailing List Manager, 2.5L MX-3 Owner, & Mazda Guru) make the drive in to Ottawa from Montreal on Saturday night to give me a hand with double checking the ZE against my current stock 1.8L and his 2.5L. Most of the info on this update are pulled from the mental notes I tried to absorb while chatting with Vaughn for most of the night. If you're and MX-3 fanatic and you don't know who Vaughn is yet, you must live under a rock.
Start here:
He's probably forgotten more about our cars that I'll ever know...

Anyways, the old engine was supposed to come out today, but there were a few snags. I had a chance to take a really good look at the ZE parked right next to the K8 last night, and there looks to be what we could call a major problem. As expected, there are no hookups for the EGR sensors on the exhaust manifolds (doesn't matter we're using the 1.8L exhaust manifolds), and the distributor is completely different. It came with a KF distributor with external coil, we are planning to use KL distributor off the 1.8L.

The other thing that we found out is that the front exhaust manifold is different than the one used in North America. Apparently, on the MX-3 the manifolds used are K8 on front and rear (makes sense) and on the 626/MX-6/PGT they used the K8 in front and a KL in the rear (K8 & KL). That's why if you notice on Vaughn's swap when he used both manifolds off of the 626 engine he had to modify the rear on to get it to lineup to the y-pipe, but when Luc St. Pierre did his 2.5L swap (see he used the manifold from the existing 1.8L (K8 & K and it bolted up no problems.
To make a long story short, if I were to keep the exhaust manifolds that came on the ZE (KL & KL) I would have to re-weld both to get them to line up. So we're using both exhaust manifolds from the 1.8L and it should bolt up no problem with no welding required.
Sorry if the above seems confusing, all I was really trying to say if the front manifold that shipped with the ZE (presumably from a MX-6 or Capella) is different from what we are used to seeing. Notice there is no EGR plumbing.

We have run into what we might call a major snag. The MX-6 style intake manifold shown above just won't fit. From the measurements I was able to do, it looks like the neck of the intake manifold more specifically the throttle body) is going to touch the master brake cylinder. On Luc's web page he mentions that there is only about 8 mm clearance for the KL-03, but the neck on the ZE is longer and straighter. So, now the question is what can be done about it (I'm assuming the cylinder can't be moved back further into the firewall, correct?).

The best solution would be to find one of those MS8 intake manifolds like the one Michel (PGT list) had on his page ( That version has the nice curve in it, but sourcing one of those would probably be next to impossible (not to mention incredibly expensive). Another idea is cutting an inch of so off the actual manifold and re-welding it back together, but this would be quite ugly and god knows how it would affect the air flow and/or sensors that measure it. Other bad ideas include inserting an rubber 'elbow' before the tb (not after) to bend around the problem area.

April 18th 1999: For a temporary solution we will probably take the 1.8L intake manifold and throttlebody and use them on the 2.5L ZE. There is now a good chance I'll get my hands on a MS8 intake manifold and throttlebody in a straight swap for the MX-6 versions of both.

May 21st 1999: Sorry it took so long to get to this next part. Basically as I write this the ZE is installed and working great. Michel "SuperProbe" Fortier generously offered up his intake manifold from the MS8 in exchange for my MX-6 manifold that didn't fit. Once that piece of the puzzle came through, it was just a matter of dropping it in. Easy, right?

Here is the step-by-step to install an engine in your MX-3 V6. First step is GO BUY THE MANUAL. This is a relatively easy installation (from what I was told, it all seems like rocket science to a rookie like me) if you have the instructions it is no different from replacing a blown engine. Everything bolts up where it should, no cutting engine mounts or anything ugly like that. Just grab that wrench set and bolt on about 50% more horse power than stock.

No more MX-3.

Last edited by ScooterBovine on April 19 2005, 3:21 AM, edited 1 time in total.

April 19 2005, 3:06 AM
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Step by Step from Sean's site:

They have all kinds of great drawings that expain the whole procedure step by step. No difference from 1.8L to 2.5L. A truly amazing swap...

1) First things first, find a place with enough room to work and jack up the car at the jack points. Be smart, use more than one set of jack, you don't want to die under your car. I'm paranoid about this, and had double jack, a spare tire and a big log 'just in case' (see #6).

2) Disconnect your battery (positive first).

3) Next, drain all the fluids out of the engine. Oil, transmission fluid and rad coolant. Dispose of them properly (please don't just dump them down the drain).

4) Next yank out the rad/fan assembly. I also removed the overflow canister, but you don't really have to do this in order to get the engine out.

5) Remove the tubing to the rad at the block not at the rad and leave them attached to the rad to save yourself the trouble of putting them back on. They are on damn tight and aren't fun to work with.

6) Remove your battery if it's still under hood, and take out the brakets underneith. If you've still got the factory air box, you'll need to unbolt it first. If it's already gone, disconnect the VAF from the throttlebody and remove it, too.

7) Unclip the throttle cable from the throttlebody and tiestrap it out of the way. It just pulls out of a little guide and then you unbolt it from the intake manifold.

8) Unscrew the steering fluid resevoir and pull it out of the way. You can also now disconnect the vacuum hose from the intake manifold to the cruise control (shiney up-down cable on picture at right) and tuck it aside.

9) There is a bracket holding the power steering pump hose to the block, you need to remove the bracket to remove the engine. It's sort of buried, you'll need an extension on your ratchet.

10) Since they were being replaced anyway due to the underdrive pulley in my case, I cut off all the accessory belts since I needed shorter ones. If you are not replacing your crank pulley it's probably a good time to replace these belts anyways.

11) If you've got A/C, unbolt it from the block and duct tape it to the frame. BE CAREFUL, you don't want to bend any of the piping here or damage the compressor, they are not cheap parts.

12) Pull your spark plug wires out so they don't get damaged.

13) Follow your wiring harness around the engine, label everything and then disconnect them one by one. Remember you have to be able to put everything back together at a later point. And no, you won't remember what goes where so keep detailed notes and use lots of ziplock bags and masking tape to label things.

14) There are two fuel lines you'll need to disconnect under the throttlebody. Have rags ready, it will spray. Leave your gas cap off to relieve pressure in the lines, or else it will continue to spill gas everywhere.

15) At the same time remove the two heater hoses from the block (same general area as the fuel lines) and disconnect the vacuum hose from the back of the block to the brake fluid resevoir.

16) Pull your wheels off (it would have help if you loosened the nuts before jacking the car up). Now here's where things got really ugly.

17) You need to separate the axles from the hub. Problem was one of these things are torqued to hell and my passanger side nut was rusted on really good. Clive, my mechanic, isn't a small guy, and even with a 3 foot breaker bar and a few hundred pounds of Clive bouncing his weight on it, not a thing budged. It had to be cut off with the dremel.
This took almost 3 hours, and it should have been 5 minutes. Once the nuts were off the axles separate from the transmission pretty easily. I replaced both axles as a precautionary measure, since the old ones were worn anyways. Remanufactured axles are about $60 each.

18) Disconnect the y-pipe from the exhaust manifolds. Unbolt the engine mount member AFTER properly supporing the engine with the engine hoist.

19) Remove your hood, you can't get the engine out otherwise. Great time to make hood scoops...

20) Unbolt the engine mount and start gently lifting the engine and transmission out of the car. Careful to check for any remaining hoses, brackets or wiring that might still be attached. Slowly crank it up with the help of a friend.

21) Well, you did it. It's out. Basically, now you just reverse the whole process to get it back in. You'll have to move over some things to the new engine like all the EGR plumbing, and crack the transmission from the engine to change your clutch, but that's basically it.

22) The only non-fitting pieces changing to the 2.5L were already well documented on Luc & Vaughn's pages. The vacuum hose from the cruise needs to be extended by a few feet since the connector on the 2.5L intake manifold is on the other side of the engine, and another foot or so is needed to attach the vacuum hose that goes to the block from the brake fluid resevoir. Those were the only differences I encountered as well.

No more MX-3.

April 19 2005, 3:18 AM
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