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So my NA8 engine went boom.. and I found lots of pretty shavings and shrapnel in my bottom end. Instead of rebuilding i purchased a NB8A Engine for decent price which gives me the good old BP4W head. This is a racecar, not registered or streetable.. for now at least. The engine will probably remain fairly standard. I have exhaust and intake done.

Few questions just to make sure I have got all bases covered.. more of a sanity check.
I have swapped over the CAS, Coils and Alternator from the NA8 engine already.

Adjustable Cam Gears - The NA8 engine has adjustable cam gears, is it worth swapping these over as well. The engine will most likely stay standard internally for now. They are Flyin Miata ones that where on the car when I purchased it.

Throttle Body Should I leave the 99 TB on. Research tells me I think I need to find a 99 throttle cable no matter which TB I use, but if I use the 99 I will have to swap some of the wiring around for it to work with the ECU. what about purchasing a Skunk2 or similar? Much benefit?

ECU I have a Wolf V500 installed, which in its day was a pretty good ECU. Is this still up to standard, or should i be looking at trying to source a megasquirt or similar. I dont want to be buying things just for the hell of it if they aren't really needed. I'm not sure how long i will keep the car.

Coolant Reroute The car has no heater core. So the old engine had one of the coolant mixing manifold port blocked off and then the coolant return line went into a T piece in the upper radiator hose before the thermostat. Should i simply pull the blocked up mixing manifold off my old engine and swap it onto the 99 engine and replicate the same setup?

Fuel Rail I know there is differences in the 97 and 99 fuel systems, so do I simply swap the fuel pressure reg off the old rail and put it on the end of the new one where the damper is? And then where does the fuel line go? Just back to my fuel return line?

Sensors What sensors do i need to swap over. For whatever reason, the previous owner just removed the temperature sensor at the back of the head and the fans are wired to a switch on the dash. Do i need to use the 97 oil pressure sensor? What other sensors should I swap.. specially before i drop the engine into the car.

Coils I have swapped the coils back to the 97 ones, but they appear to have a different order in terms of which coil goes to which plug. Should I use the 97 order or 99 order? Or am i imagining things and they are the same?

Clutch I didn't really want to spend $500 on a new clutch, but maybe it is best that I just bite the bullet and do it? Has anyone machined their flywheel to remove some weight on it as well as cleaning it up? Rather than purchasing a lightened flywheel.

I know i still need to control the VICS somehow, but I can work that out later.. Im sure I have forgotten stuff, do have some photos of various bits and pieces if needed for clarity

Soo.. any help would be appreciated.. and what else am i missing?

This is about 1/4 of the shrapnel I found in the bottom

Thrown some notes below in red.

frog_a_lot wrote:So my NA8 engine went boom.. and I found lots of pretty shavings and shrapnel in my bottom end. Instead of rebuilding i purchased a NB8A Engine for decent price which gives me the good old BP4W head. This is a racecar, not registered or streetable.. for now at least. The engine will probably remain fairly standard. I have exhaust and intake done.

Few questions just to make sure I have got all bases covered.. more of a sanity check.
I have swapped over the CAS, Coils and Alternator from the NA8 engine already.

Adjustable Cam Gears - The NA8 engine has adjustable cam gears, is it worth swapping these over as well. The engine will most likely stay standard internally for now. They are Flyin Miata ones that where on the car when I purchased it.
Are you running a standard ECU? or an aftermarket? if standard there's no real need for adjustable gears, since the ECU wont know what to do once you adjust them anyway

Edit: saw you have an ecu. the gears will allow you to shift the power around, but normally wont make a big difference to peak power/torque.

Throttle Body Should I leave the 99 TB on. Research tells me I think I need to find a 99 throttle cable no matter which TB I use, but if I use the 99 I will have to swap some of the wiring around for it to work with the ECU. what about purchasing a Skunk2 or similar? Much benefit?
Skunk ones are mainly a reliability thing than a power thing. Since in some cases the OEM throttle lets the bolts back out and get sucked into the engine. On a standard engine, with standard ECU, there wont be any real change to power with either throttle.

ECU I have a Wolf V500 installed, which in its day was a pretty good ECU. Is this still up to standard, or should i be looking at trying to source a megasquirt or similar. I dont want to be buying things just for the hell of it if they aren't really needed. I'm not sure how long i will keep the car.
If it's working well, and you know how to tune it well etc, leave it. Only really consider changing to a new ECU if it has features that you really desire

Coolant Reroute The car has no heater core. So the old engine had one of the coolant mixing manifold port blocked off and then the coolant return line went into a T piece in the upper radiator hose before the thermostat. Should i simply pull the blocked up mixing manifold off my old engine and swap it onto the 99 engine and replicate the same setup?
I'd just do a normal reroute (ie: move water outlet to back of head) without a heater you can probably avoid even needing a spacer and can just use a front thermo cover and stick the thermostat directly into the head

Sensors What sensors do i need to swap over. For whatever reason, the previous owner just removed the temperature sensor at the back of the head and the fans are wired to a switch on the dash. Do i need to use the 97 oil pressure sensor? What other sensors should I swap.. specially before i drop the engine into the car.

Coils I have swapped the coils back to the 97 ones, but they appear to have a different order in terms of which coil goes to which plug. Should I use the 97 order or 99 order? Or am i imagining things and they are the same?
MX5s are wasted spark, so as long as cyls 1-4 are on one coil, and 2-3 are on the other, it doesnt matter which way the leads are. Wasted spark just means that you have two coils, and each one just fires a spark off to 2 leads at once. so long as they're paired as 1+4 and 2+3 it works fine.

Clutch I didn't really want to spend $500 on a new clutch, but maybe it is best that I just bite the bullet and do it? Has anyone machined their flywheel to remove some weight on it as well as cleaning it up? Rather than purchasing a lightened flywheel.
if the engine is out, replace the clutch (unless the old one is only a few months old)

The NB8A inlet manifold with VICS is shyte. Either use your NA8 one with an adapter plate (best option) or get an NB8B flat top. Either way you'll get better performance through the range and you won't have to reprogram for the VICS.

I'm running a BP4W with all NA8 sensors and accessories, TB, inlet manifold and loom. It's the easiest way to go and pulls like a train.

You must use a BP4W fuel rail with a BP4W head. The BP05 rail doesn't fit.

It's pretty common practice to machine the outer lip off the flywheel at the same time as the clutch surface is machined. Costs an extra $10 or so and significantly improves response in lower gears while maintaining good tractability around town.

Cheers,
At least the intake manifold I can still play around with after i've dropped the engine in. As long as i have all the other stuff sorted so i dont need to pull it back out . Might investigate Skunk2 Intake and TB.

Will get new clutch and machine flywheel and leave the ECU alone for now.

In terms of sensors.. there is coolant temp sensor at back of head, oil pressure sensor on side of block.. what else is there that needs to be swapped? Any?

frog_a_lot wrote:Cheers,
At least the intake manifold I can still play around with after i've dropped the engine in. As long as i have all the other stuff sorted so i dont need to pull it back out . Might investigate Skunk2 Intake and TB.

Will get new clutch and machine flywheel and leave the ECU alone for now.

In terms of sensors.. there is coolant temp sensor at back of head, oil pressure sensor on side of block.. what else is there that needs to be swapped? Any?

It's much easier to fit the manifold while the engine's still out of the car, especially if you're using an adaptor plate. This is mainly because it's wiser to retain the manifold support bracket with an adaptor plate and the position of bracket has to be moved out an amount equivalent to the thickness of the plate.

The output curves of the NA8 and NB8A MAFs are very different. If you're still using a MAF then using the NA8 one means no reprogramming. On the other hand the NB8A MAF offers less flow restriction but you do have to substitute the NB8A values for it.

As I recall the NA8 IAT is integral to the MAF but the NB8A IAT and MAF are separate, with different plugs. I've used so many MAFs that I'm confused about which was which now.

I think the NA8 throttle body is tougher, but not 100% sure of that. Nor do I know whether or not the NA8 and NB8A curves are the same. For safety I'd use the NA8 TPS.

The NA8 has no crank position sensor. The NB8A does. I just used the NA8 cam position sensor mounted in the BP4W head exactly as it was on the NA8 (you can do that easily) and ignored the crank sensor.

manga_blue wrote:The output curves of the NA8 and NB8A MAFs are very different. If you're still using a MAF then using the NA8 one means no reprogramming. On the other hand the NB8A MAF offers less flow restriction but you do have to substitute the NB8A values for it.

As I recall the NA8 IAT is integral to the MAF but the NB8A IAT and MAF are separate, with different plugs. I've used so many MAFs that I'm confused about which was which now.

NB one is the separate temp sensor.
It's a bulb ended plastic probe that is pushed into the lid of the airbox.

Make it stupidly easy to change it when running an aftermarket ECU, since you just take off the OEM one and make an adapter lead to fit the plug on the new sensor.

hks_kansei wrote:NB one is the separate temp sensor.
It's a bulb ended plastic probe that is pushed into the lid of the airbox.

Make it stupidly easy to change it when running an aftermarket ECU, since you just take off the OEM one and make an adapter lead to fit the plug on the new sensor.

... and add an IAT and connector.

Also forgot to say that if you use the NA8 cam position sensor at the back of the exhaust cam then it makes more sense to use the NA8 cam cover as well.

manga_blue wrote:

hks_kansei wrote:NB one is the separate temp sensor.
It's a bulb ended plastic probe that is pushed into the lid of the airbox.

Make it stupidly easy to change it when running an aftermarket ECU, since you just take off the OEM one and make an adapter lead to fit the plug on the new sensor.

... and add an IAT and connector.

Also forgot to say that if you use the NA8 cam position sensor at the back of the exhaust cam then it makes more sense to use the NA8 cam cover as well.

They are a direct swap aren't they?
The boyracer in me does love exposed Cam gears.. just need to repaint the cover.

I was originally going to ditch the intake manifold brace, but it weights nothing so I will just leave it in.

Cam covers are a direct swap. The NA8 one just doesn't have the mount for the NB8B sensor at the front of the intake cam.

Intake manifold brace is optional if you're just bolting a manifold up to the head but necessary (at least I think so) if you're using an adaptor plate for an NA8 manifold.