98 Protege 1.8 Swap
 

Hi all,

Few questions I have about this. I've done a little bit of reading but still unclear on a few things. I've posted on other forums and gotten no feedback. Since this is a "turbo" forum, I'm willing to bet there's a bit more engine knowledge than miata.net and clubroadster

I have the opportunity to buy a low mileage 1.8 protege engine with auto trans from a 1998 to swap into my 1990 NA with manual. Please deal with me I'm a n00b to engines.

From what I gather, everything I need to do is exactly the same as a normal 1.8 swap, except take flywheel from 1.6 engine and put it on the 1.8? Also since its same 1.8 engine as 94-97, that I'll need an EGR cap?

Now call me stupid if it is for asking, but are the 1.8 manifold, cat converter, injectors, motor mount brackets, thermostat housing, alternator and intake tube coming off the protege all interchangable with the Miata, or are all specific to the 1.8 Miata?

If not this swap might cause me a headache for sourcing all these parts

Thanks

Is the Protege transverse? If so, then nothing is going to fit except the block itself and the head. You are correct that the 1.6 clutch and flywheel can be used on the 1.8, lots of guys do that as a cheat for a low mass clutch.

I just googled the 98 Protege and it has a distributor on the "back" of the head. I can tell you right now that's not going to fit. I have no idea on the interchange for the CAS on the 1.6 so you might get lucky with that... or not. Does the 98 Protege use the 99/00 Miata BP4W style engine or the earlier 94-97 Miata style 1.8? Because that will make a difference as well.

These are all Miata specific parts you will probably need:

• Intake Manifold
• Throttle Body
• Exhaust Manifold
• Downpipe
• Engine Mount Brackets
• Intake Plumbing
• Fuel Rail w/regulator
• Oil Pan
• Oil Pickup
• Alternator Mounting Bracket
• Coolant block off w/heater core feed for "rear" of head
• Miata coolant neck and thermostat at "front" of head
• Front coolant mixing manifold
• Probably a starter

Some of these parts may interchange between the 1.6 and 1.8 in the Miata world, but I couldn't tell you exactly. If you have PS or AC you will obviously need Miata mounts and such to make those work as well.

It's going to be a very long list, this probably isn't even the half of it. FM makes a 1.8 into 1.6 kit Flyin' Miata : Engine conversions : 1.8 conversion : 1.8 conversion kit and that's a good start, but that assumes you are starting with a Miata 1.8 so there is a lot of stuff not on that list. You are going to need to source all the Miata specific parts to make this work. I'd recommend looking at the Miata specific wreckers; I've used ThePartsGroup.com for a bunch of stuff and never had an issue. Tom generally knows exactly what you are talking about and his prices are reasonable. There is also FM Salvage, Panic Motorsports, BTDT, and a host of other guys out there as well.

make sure the 1.8 is a BP first. Technically speaking for the north american market th 98' proteges had a 1.8FP motor which is different and will NOT work.

If it is in fact a BP, pretty much read what is written in the post before this.

EO2K, thank you for that. Seriously, you laid it into perspective! That is exactly what I needed to know.
And, from what I gather, it is the same 1.8 shared with 94-97 Miata.

To manage and locate all those parts it would cost me an arm and a leg being on a cold island in Canada.

I now have to seriously debate a 1.6 rebuild.. I think my engine is nearing its last breath at 190k miles

Thanks guys

No worries, glad I could help.

If you had a burned/blown up 1.8 Miata engine this wouldn't be that bad a swap, but sourcing all the bits and pieces to complete a project like this with no local resources is going to add up with a quickness.

Stick around and enjoy the forum, go make an intro thread: Meet and Greet - Miata Turbo Forum - Turbo Kitten is watching you test compression. Tell us about your car, yourself, your mechanical abilities, your plans for the car and your cat. We are very visual people and love pics (provided they don't suck :giggle:) so figure out how to make that happen.

If you were swapping a blown 1.8 engine, then a Protege BP engine is much easier swap since you already have all the parts necessary, just reuse block and head and swap over everything else.

Whereas if you were swapping a 1.6 to 1.8, it be way way easier getting a Miata engine.

The BP Protege swap can be done, but involves sourcing a fair few parts, in which will probably negate the cost savings (if any) by the end of it.

FYI, The BP Protege engine uses a BP05 head, same as the NA8s. Whereas the turbo versions (BPD on the Familia GTR and GTX) uses a BP26 head, they are quite restrictive due to their port shape which is designed to reduce flow but increase velocity by tapering the intake ports. Not so good for NA applications, turbo can be debatable but I personally don't see the point.

Also useful info is that the GTR (iirc) uses sodium filled exhaust valves.