Moving on from an old 1.6
 

So, here I am again, I've been driving around with my turbo'd 1.6 NA for a while now, despite it having its fair share of problems. I've recently made a new manifold and now I decided I need a new engine. The problem is that the engine has almost driven 270k kms with no service history before I had it, it has pulley wobble (despite having checked the keyway, which looked good, and installing new hardware), it blows the dipstick out under half a bar of boost from my gt2554r and smokes like a chimney on (really) cold starts. I feel like it's nearing its end, sadly.

I've been looking at options for a new engine, but as long as this one still starts and runs, I want to rebuild the "new" engine. Plan is to install all new bearings and piston rings, at least get forged rods, make sure nothing is leaking and get a BE oil pump. I'm aiming to max out this turbo (I guess that will happen at around 250whp, drive it around for a while and maybe upgrade the turbo when I need more power. I don't think I'll ever go over 350whp with a Miata drivetrain (including the engine). My options are:

- 1.6 NB engine for about €200, live with the slightly slower spool and power, have a somewhat safer CR and be able to use my current manifold and downpipe.
- 1.8 VVT engine for about €500, have to get an MS3X and fabricate a new manifold and downpipe.

Fabricating a new manifold and downpipe is not that much of a problem, I've already done that myself and I could do it again if I want. Because I can make it myself it's also not stupidly expensive to get the turbo working on the 1.8.

Now what exaclty do I want to know? Well, I want to know if it's realistic to get a VVT engine and boost it with the stock 10:1 pistons and forged rods. Will I be able to reliably get to the mentioned 350whp (with another turbo) on these pistons? (I know a good tune on pump gas is necessary to get good reliability and power figures but this is purely about what is possible with these pistons) Also, do I need an ATI super damper or equivalent aftermarket damper when using the BE oil pump gears?

What I'm after? (TL;DR)
I want a new, preferably NB engine that can reliably handle 250-350whp. I know I'm gonna need rods for that but what are other things I need to take into consideration? Forged low compression pistons are quite expensive and I don't want to have to buy them if it's not really necessary.

All depends on your budget I guess.
What ECU do you use now?

Cheapest option would be to use a 1.6NB engine and throw in rods, new bearings and rings and be done.
Obviously spool and power would not be as good as using the 1.8, but it will be significantly cheaper.

If you go the 1.8 route you can also decide to use the 99-00 1.8, that might save you some money on the ECU part.
Also if you go the 1.8 route you can also throw in NA pistons: https://www.autolinkmx5.com/piston--...sed-8837-p.asp
Having the higher compression makes you knock limited.
Oil pump gears are not really needed if you retain the stock redline in my opinion, same applies to the damper.

I currently use the DIYPNP. I do have a budget, but it can be stretched if necessary. I'll be doing most of the work myself except for honing.

I am afraid I'm going to regret going the "1.6 with rods" route when I inevitably want more power. Also I can't really find a non-vvt 1.8 for a reasonable price, so that leaves me with the VVT option.
I'm mostly interested in people with experience with turbo'd VVTs with rods and what their opinion is on the slightly higher CR. I don't need 300whp instantly, but I want the headroom to upgrade at a later point in time.

I'm not sure if I want to run used pistons from an older engine, so the only other option is to buy them new, at which point forged pistons aren't really that much more expensive.
As for the BE oil pump gears, I want to reliably make power without having to constantly check everything to see if it still works properly. (It got old the second time I did it) The oil pump is one of these components I absolutely do not want to fail on me, especially if I have a built engine.

Buy a NB 1.6 in good shape to run in the mean time and build a BP4W/VVT engine/ kit over time and enjoy a car in the mean time?

Jay,
I'm glad you're hanging in there. Are you still at University there in the Netherlands?
I would agree with the idea of purchasing a 99 or 2000 1.8. Save the money by retaining your existing ECU. Use that money to purchase low compression forged pistons and forged rods. Our engines are detonation limited when it comes to boost and timing with pump gas. You will be able to make far more power and make it more reliably with a low compression engine. You will also have the benefit of stronger Pistons if you go forged.

I agree with this as well. Huge benefit to saving on ecu because youll probably run into little issues that will cost money which will add up. I did VVT and if I stayed with 99-00 would have saved tons of money.

Just FYI, you may be blowing the dipstick out by pressurizing the PCV system. Try disconnecting the PCV from the IM and see if it helps, it may not be blowby.

I'm in the same boat as you, and have been researching it for a while. From what I've read, I can probably do rods, bearings, new rings on stock pistons and a billet oil pump gear on a BP4W and support around 250hp. To get to 350 requires forged low compression pistons and an aftermarket damper. I've been gathering parts for my build for over a year now.

I have an nb2 with 1.8L vvt engine.
picked up a 94 block with a bent rod, took it apart, brought to machine shop to hone and clean. Then threw Ebay rods, used same 94 pistons (8.8cr) that came in the block, new rings, bearings, seals. Slapped my vvt head on with stock 99 nb1 mazda headgasket (because have coolant reroute).
Stock nb2 oil pump and crank pulley.

5000 miles, 15-16psi 275-300hp, 2 track days + autox later it still runs beautifully.

Damn, apparently I'm not getting any mails anymore for these forum posts, but thanks for all the replies. I have made a list of components I need and I've been able to knock that down to about €2000,- (including the engine itself). Adding forged pistons into the mix adds about 600-700€ to that. Also, I might be a cheapskate, but does anyone have any experience with "Maxspeedingrods" forged H-beam rods? They're cheap and as far as I understood there are a couple of people in the UK that have gotten them to the better side of 350whp.

@sixshooter I'm not at university anymore, I graduated last month (which means I'm now officially an automotive engineer asking mt.net for info :P)
Thanks for the suggestion, the only thing that keeps me leaning towards the VVT is that I can get it cheaper than most regular 1.8s. Also, are there any low compression forged pistons that have the same diameter as the stock pistons? (I can't seem to find them and I don't really want to bore the block unless completely necessary :P) If there aren't I'll probably go for the >84mm pistons possible for the extra street cred (lol)

@sixshooter & ysleem Can I not keep the VVT disconnected and run a VVT engine without it until I have an MS3? (I would still really like an MS3 at some point) Plus I can solder the things myself so I can save a bit of money by not buying the PNP version(s).

@Schroedinger I know, but that combined with the leaky valve seals and the pulley wobble makes me want to swap this engine for a newer, fresher one. This car is my daily so I want it to be as reliable as possible, but I still want "big"-ish power. I might make a simple catch can setup to make this engine last as long as it can.

@borka Good to know, what eBay rods have you installed and were they any good?

Also, am I missing stuff regarding building the block? I know I'll need to buy some ridiculously accurate measuring equipment and something to install the pistons into the block with, but what about for example filing piston rings? (don't actually know when that is necessary so some info on what it's for would be appreciated)

Sooner than later I'll at least take the step to buy an engine block and disassemble it to keep me busy and get the ball rolling.

I believe JE and Mahle make 83mm pistons. For me it was cheaper to buy Weisco 83.5 and get the block bored than it was to get those. So I did that.

I am currently running 2 VVT swaps with the VVT unplugged until I get around to wiring them in. So yes it will work

Okay good to know! I've also seen the JE and Mahle pistons but they are so astronomically expensive that it is indeed cheaper to bore the block and get different sized Wiseco or Supertech pistons.

Get the block bored. You don't know if it's going to be in spec and youre better off spending the same amount and getting things machined and getting forged Pistons a hair over stock size.

Good luck!

maxpeedingrods is what i have, fit fine, no complaints. plenty of people running them with over 300hp.
if your block is in good shape with no visible scoring or gouges that you can feel with your fingernail, then all you need is standard size bearings, and stock size pistons after a hone.

to fit pistons into block, all you need is a spring compressor and a wood handle hammer to stuff them in.

search youtube for "the car passion channel" and watch is motor disassembly and assembly videos. you will get a good feel of what needs to be done and what tools are needed.

rings normally come pre gapped to factory spec. which can be measured with a feeler gauge. if need to widen, you can buy a ring filing tool or have machine shop file them.
I put in the rings with stock gaps, i didn't file them. i remembering measuring the gaps and they were in factory spec.

technically people can run a vvt engine with vvt not connected, but i dont think you can do that on a stock NA ecu. VVT engine has cam/crank sensors instead of a CAS at the back of the block. so i dont see how the stock ECU will run this newer engine.

Good to know, I guess I can save some money by using them :)

Luckily I know this much and if I don't know anything I'll most likely be able to find it on "the internets"

Good to know, I hope the Wiseco pistons & rings combo come with the right size gapped piston rings, although I'll be able to handle myself if they won't.
Also, I'm running a DIYPNP, so I can control anything that's related to an nb engine except for the alternator (which I will take from an NA 1.8 when the time comes).

By the way, while we are on the subject of forged pistons, which ones are the go-to pistons? I'll have to decide between the Supertech pistons or the Wiseco pistons. I've heard bad stories about both, as far as I understood the Supertechs have a tendency to break a little easier than Wisecos because of the softer material used. However the material used for the Supertechs has a lower thermal expansion coefficient, so the Wiseco's suffer from piston slap when the engine is cold, right? Is that the tradeoff for one or the other or can you solve the piston slap with (for example) tighter piston ring clearances?

Honestly, I don't want to have to buy the "custom" wisecos from Flyin' Miata because I'd like to buy as many parts at the same store, especially when it's in the US because of import duties and shipping costs.

"Break a little easier" is relative. ANY forged piston will support more power than the rest of the Miata driveline will handle. :)

Wisecos "suffering" from piston slap is... well i'm not sure what it is. I've run Wisecos and JEs in a few cars, and have never experienced the fabled piston slap. That said, Supertech makes the magic unicorn feel good warm fuzzy tummy 8.6:1 pistons that are the gold standard for pump gas builds, so there's not much downside to using those. :)

Agreed, I have used Wisecos in 3 different builds and I dont get piston slap.

I stopped reading thread after "350wph" and then "forged pistons for Miata are expensive" and then "budget"

good luck lol

And why is that? I've heard some people running stock pistons with forged rods, so I don't think my question was all that strange. Obviously forged internals are more expensive than keeping stock internals, but I just wanted to know if the stock stuff could be reliable at such power levels. I now know that it won't be.
Also, I've not mentioned that I'm on a strict budget anywhere (the only thing that hints towards having a budget is running an MS2 before going to MS3X), again, just wanted to know what the limits would be of stock VVT pistons and if I would need them. I know this will easily cost me around €3000 if I want fully build an engine. Apart from that, what's wrong with a maximum of 350whp, of course I'm not hitting anywhere near that with my current gearbox, turbo and fuelling setup, but that's not what this thread was about.

I'm always eager to learn, I don't have a lot of experience yet with engine internals, but that's what I'm here for.

Thanks for the input! I wanted to steer away from the Wisecos because of the stories about piston slap, but since they are cheaper to get over here than Supertechs I kind of wanted to buy the Wisecos. (Import duties, shipping and taxes are killing the prices of anything from the US over here)