Turned supercharged NA6 into TRUBO! rawwwwr....
 

Rather than posting noob questions in the forums and getting flamed, I figured I'd start a build thread and let you guys ruin me in my own noob quarantine area. There are other "noob" threads where people are welding and fabbing custom parts... this will not be one of those. At least for a while.

Before everyone jumps to "screw 1.6L, screw SC... 1.8 swap and turbo"- understand that I know fuq-all about tuning. I've been doing searches and researching Megasquirt for months, and I'm going to start where I'm at and learn this shi+. Possibly this thread will end like the other build threads: VVT swap, honkin turbo, big wheels and tires, crash into deer or tree, start over.

This is the car when I got it last March, pretty much exactly the way it rolled off the production line. 1992 base model 1.6L, 132k miles. No PS, AC. Pretty good engine compression, 170 on cylinder 3 and 180 on the others. Just out of emissions here in GA.
https://cimg1.ibsrv.net/gimg/www.mia...0e491854d.jpeg

Stuff happened:
- full maintenance baseline
- stock Daisies with Yoko S.Drive tires
- Roadstersport 3 catback exhaust
- suspension. NB B6 Bilsteins, FM springs, NB top hats, FCM bump stops
- Innovate LC-2 WBO2, AFR and boost gauges
- Torsen 4.1 swap
- Jackson Racing M45 kit, AFPR, JR Boost Timing controller. Makes 6-7 psi, good AFR's, drives great.

The car now:
https://cimg1.ibsrv.net/gimg/www.mia...81edd8f452.jpg
https://cimg2.ibsrv.net/gimg/www.mia...3b4495b68d.jpg

Car is great. My local MT.net friends who have gone all the way down this rabbit hole tell me to leave it this way and drive the hell out of it. I'm stubborn and not very smart.

So I bought one of these and started hording associate stuff.
https://cimg2.ibsrv.net/gimg/www.mia...fe699d32d3.jpg

Here is my action plan- I could use some feedback and recommendations.

1) remove AFPR, timing box. Wire SC bypass open to prevent boost.
2) Install MSPNP2 per instructions using stock narrowband O2, run base map. Get the hang of tuning for a couple of weeks.
3) Connect WBO2, adjust MS settings accordingly (question- is it better to wire the WBO2 into the stock O2 harness, or use the accessory pin 21 on the MS? Do I need to pull the WB jumper inside the case?)
4) Build variable TPS using a stock TPS that I scavenged from another 1.6L, and a Wells TPS201. Install, tune startup, idle and accel enrichments.
5) Install IAT sensor, delete AFM. (Question: better to install IAT in the dummy throttle body or the crossover pipe to avoid heat soak? I checked hot engine temps of both with an IR thermometer, they were the same. I figure the crossover pipe has less thermal mass, so may be better?) Should I just intercool at this stage with the CX Racing kit, or perhaps the Vibrant 12800, and put the IAT in the recommended down-low position?)
6) Unwire SC bypass, tune for boost, hope the 1.6L injectors can keep up at stock fuel pressures and 6 lbs of boost (calculations say that they can, but barely). Drive and autotune fuel.
7) Install FlowForce 640cc injectors (already have them), wrestle with dead times, and pretty much re-do the entire tune.
8) Dyno tune and get the spark map right. Drive the hell out of the car for a while, maybe forever.
9) Get bored... VVT 1.8 swap, rippin turbo, blow money on bigger wheels and tires, crash into tree.

Thinking this through more carefully... maybe it would be best to put the intercooler in before Step 5 (IAT/AFM delete). That way I can get the IAT in the best location to start with. It will cool the charge and drop boost a bit (maybe 5 psi instead of 6), minimizing the likelihood that I go lean because of the small injectors and detonate.

I could reverse steps 6 and 7 and put the FF640 injectors in before I boost. However, some of the threads I'm reading have me convinced that these things are going to be a bitch to tune. Still not sure I made the best decision in buying them...

Swap 6 and 7. Just do the FF injectors before boosting. No reason to press your luck.

The IAT in the AFM heat soaks like a MOFO. My GM IAT in the dummy throttle body does the same. Can't say about crossover pipe, I am putting in an intercooler and gonna stick it in the end tank.

Skip the narrow band and just wire up the wide band first thing. I tied my wideband into the stock wiring by cutting the wire right off the narrow band sensor and tieing in there.

Also, I have had zero issues making the car drive and respond better than stock even without a variable TPS and doing everything off mapdot. Though I am tossing in a vTPS over the winter cause I have one.

On the subject of TPS. The stock 1.6 one, being switches, shorts out the MS V-Ref to ground and makes it very angry. Dissconect it, though plugging it in makes a great anti-theft device.

Otherwise, it sounds like a very solid plan.

If you intercool, I reccomend looking into dual throttle bodies.

The FF injectors are easy to tune for driving. Exactly the same as the stock ones. Only issues I had were idle, but I bought an un matched set of ford injectors off ebay and that may be my issue. Worst case, just get the sequential injection modual and wire for full sequential. Once I did that it was cake.

Other option is to leave the AFPR and just use the stock injectors. That will work just as well.

You will be amazed how smoothly the car runs on the MS compared to stock.

combine 2+3. Wire the wbo2 into the harness in the car, simple job doing it that way.

Thanks for the advice guys. Some very encouraging stuff here. I really don't want to get down the road of intercoolers and dual throttle bodies to manage 6 psi of boost, simply to solve the IAT heat soak problem. Might just try the crossover pipe and see if I can get away with it. Maybe I can get a little creative with heat shields to keep the radiator heat away from the IAT.

I had planned to put the MS in this weekend. After doing another week's research, I'm pretty overwhelmed and I started procrastinating with other projects that I've had laying around in the garage. So I got started with these...
https://cimg6.ibsrv.net/gimg/www.mia...9866c825eb.jpg

I had the seats out, so I finally got around to doing this...
https://cimg4.ibsrv.net/gimg/www.mia...7513866203.jpg

... and then I figured with the seats out and the carpet pulled up, I'd go up under the dash and run the WBO2 signal wire to the ECU bay. But while I was up there, I thought about my rattling speedometer cable. So I figured why not replace that as well? Of course, that involved removing the coil pack and CAS, at which point I was looking directly at the back of the engine block. So after the speedo cable, I got started on this...
https://cimg0.ibsrv.net/gimg/www.mia...f728e41ab6.jpg

Man, what a PITA to get that thing bolted to the back of the block. I have everything assembled but didn't have any coolant; will fill it up, get it off the jack stands and drive it around.

I'm running out of excuses to NOT put the MS in...

Yeah, that is why I am pulling the engine for clutch and rerout. I just can't be arsed to deal with the mess back there.

Get the wideband working with the stock ecu for a few days and watch what is going on. (It has a narrow band output somewhere, where depends on which one you have).

After that, set it up so you can just switch betweem the MS and the stock ecu easilly. I did that for about three days while fiddling with idle and start up, then after that, never had to switch back again.

In retrospect, it would have been easier to just pull the motor- especially considering that I have a new clutch and flywheel sitting in my garage waiting to go in. Total work time for the reroute was about 3 hours; at least 2 of those were spent dealing with the back of the block, which would have taken about 15 minutes out of the car.

That's a good idea about setting up to run either ECU for a while. I still have the stock O2 sensor running to the stock ECU, and was going to run the wideband into the accessory port Pin 21 on the MS. That would make it easy to switch back and forth between the two.

My one friend said the same thing about doing the rerout. And his leaks now, and he is ignoring it.

The LC-2 shpuld have both a wideband and a narrow band output. So you can hook the narrow band to the stock pin and the wide band to the extea one. Then you just move the connectors over and unplug or plug in the TPS to switch.

I appreciate your good advice about unplugging the stock TPS with the MS.

So to make sure I'm abundantly clear on what you're saying- run the narrowband output from the LC2 to the ECU harness, cutting in at Pin 2N:

https://cimg1.ibsrv.net/gimg/www.mia...1348ae98b2.jpg

And run the LC2 Wideband output to the accessory port pin.

I assume that TS has a setting that lets me choose whether to use the ECU pin or the Accessory pin for the O2 input?

I keep bringing up the tps because Inkept forgetting and wondering what the hell was wrong all the sudden.

Yeah, narrow band goes to pin 2N, although I would patch it in right at the O2 sensor. Since that has a connector, no nees to cut into the stock harness.

It should have a setting in tunerstudio, duno where it would be though. I have only ever worked with my MS3x, would need to poke around.

Been traveling like a fool; gone for 18 of the last 20 days. This job is really getting in the way of me working on my crapbucket Miata.

Only had an hour or two to goof around with the car today. Continued my quest for better cooling; removed the front airbag sensor and installed a radiator shroud.

https://cimg8.ibsrv.net/gimg/www.mia...f30a9000a9.jpg

There are two rattles behind the dash that drive me CRAZY- one behind the instrument cluster, and one behind the glove box. I thought the speedometer cable would fix the instrument cluster, but no dice. I think I might need to replace the rubber grommets for my heater core pipes. When I took down the glove box and started whacking stuff with a rubber mallet, I figured out that the rattle was coming from the engine bay. Turns out it was the cruise control actuator, which hasn't had a purpose since I moved the throttle body before the supercharger and disconnected the cable. Out it came...
https://cimg1.ibsrv.net/gimg/www.mia...791fad940a.jpg

The M45 supercharger was making a little noise while running... a very light metallic dragging sound. Did the research, figured out that the nose coupler probably needs to be replaced. Ordered a rebuild kit from Superchargers Online.
https://cimg8.ibsrv.net/gimg/www.mia...2d6a7a0b98.jpg

I figured that I would just remove the nose cone of the supercharger and swap the coupler, easy peasy. Wrong. The mounting bracket that holds the SC to the engine block sandwiches the two halves of the SC together, so the SC must be removed. No problem, just need to loosen the two bracket bolts and remove everything, right?
https://cimg8.ibsrv.net/gimg/www.mia...7cf3e8b381.jpg

Wrong. Bolts are frozen solid, and I rounded the gotdam heads trying to loosen them. Now I need to remove the bolts that hold the SC to the bracket and take it off that way, so I can use a proper socket and impact to remove the block bolts. Except the one black SC/bracket bolt interferes with the head, as shown in the picture. So now I'm Dremeling off the bolt flange so I can get it past the head and get this bitch off.

THEN I looked below the SC, and saw this:
https://cimg6.ibsrv.net/gimg/www.mia...f84a9d0ee1.jpg

The power steering bracket that holds the lower mounting point of the supercharger is cracked. MOTHER... FOKKER.

So I have to remove all this shite. At this point I'm thinking about revising my whole plan. New plan goes:

- remove and sell JRSC M45 supercharger kit. Put engine back to stock
- install MS-PNP2, play with it, learn to tune.
- order MS-3X kit, take my time building it. When complete, sell off MS-PNP2.
- remove 1.6L motor and sell or sink to bottom of lake. VVT swap this bitch per the awesome thread here, end up with same power as 1.6L SC but N/A.

So yeah, I should have followed the steps laid out in the FAQ's and stickies when I first read them a year ago. That's what I get for ignoring good advice.

Well, after I cooled off I got back to following the original plan. I finished dremelling the hell out of the mounting bolts, Took out supercharger, opened it up and replaced nose coupler.
https://cimg1.ibsrv.net/gimg/www.mia...1e4389096d.jpg

After all this, it looked like the nose coupler had already been replaced, and recently. The one that came out looked brand new, no play at all.

So the metallic sound I was hearing was coming from the broken power steering bracket. I determined that the original bracket had broken because the SC mounting bracket wasn't square between the SC and the PS bracket, and was applying a torque to the PS bracket. Only a matter of time before the cast iron fatigued. I replaced the PS bracket, and this time I shimmed it with washers so that it was square.

https://cimg0.ibsrv.net/gimg/www.mia...d0087ca2d1.jpg

I had to replace the bolts that mount the SC to the head. The originals were 10x1.25, 20mm long, with a low profile head. Closest I could find locally was 10x1.25, 25mm long with a standard head. Few minutes on the bench grinder, the new ones were close enough to use.

So I'm back to my 6-7psi of boost, which feels pretty good.

Well, I finally hit my limit with random buzzes behind the dash. Its' terrible between 3-4k RPM, there are loud buzzes on both sides of the dash. I started pulling things... glove box, steering panel, tombstone... next thing I knew, here I was.
https://cimg6.ibsrv.net/gimg/www.mia...7c1c657366.jpg

https://cimg2.ibsrv.net/gimg/www.mia...cbe9a11c6a.jpg

https://cimg4.ibsrv.net/gimg/www.mia...724b520242.jpg

It's cathartic having that dash off. I can now undo 25 years worth of janky-ass wiring for security systems, stereos, etc. I can re-do my wiring for the WBO2, using proper crimp connectors instead of solder connections. I can clean out 25 years of nasty that resides in there. I can zip-tie and foam tape everything to death. Might as well replace the heater core and grommets while I'm in there.

Ironically, I still haven't found what was causing the buzzes.

Those buzzes kill me too. I think a lot of it has to deal with the quality of materials, age, and weight of the car.

Been a long time since I updated this thread. Started a new job, very busy.

So after spending a few months pulling the dash and doing all sorts of other stuff to get rid of the vibration, I noticed this on top of the supercharger last week:
https://cimg3.ibsrv.net/gimg/www.mia...4e90ab4c96.jpg

Which is a perfect match for this spot on the hood:
https://cimg8.ibsrv.net/gimg/www.mia...2728906c98.jpg

Problem solved. When I fixed the broken power steering bracket that was holding the supercharger up, I installed the supercharger too far towards the front of the car. The hood was vibrating against the supercharger.

So... time to take everything apart again. Except this time, when I had the crossover tube off, I installed the IAT sensor:
https://cimg7.ibsrv.net/gimg/www.mia...3c38eac72d.jpg

Don't need no stinkin' IAC hose across my engine bay. Check valve/ air filter dongle idea courtesy of x_25.
https://cimg4.ibsrv.net/gimg/www.mia...3dabfdf0e6.jpg

And said buh-bye to the AFM. Decided to keep the DDM Works cold air intake where it's at.
https://cimg6.ibsrv.net/gimg/www.mia...41936d5dd3.jpg

I had already run the wire from the Innovate LC-2 wideband into the engine bay when I pulled the dash, so I spliced it into the harness. I pulled the Jackson Racing boost timing controller, fixed the wiring around the ECU harness, and:

https://cimg7.ibsrv.net/gimg/www.mia...c1825778c6.jpg

Boom. Megasquirt installed at about midnight last night.

This morning I hooked the computer up, loaded the basemap, changed all the necessary settings, and cranked it. Started right up, and idled beautifully. Set the timing, and took it for a little drive. It runs really well. It's pretty rich in most areas; upgrading my TunerStudio tonight, and I'll do some VEAL autotuning. When it warmed up the idle was hunting around, so I switched it to open loop; dead stable at 900 rpm now, I think I'm just going to leave it open loop.

It does go lean on hot restarts, which I'm assuming is heat soak of the IAT sensor, but it's pretty manageable, around AFR 15. No detonation or anything. If it doesn't get any worse, I'll probably just live with the IAT where it's at.

I'm fired up. It only took me five months to get this done, but my car is running and I'm on the road to power.

I love that tiny little filter, its like a wittle baby kitten....:party:

Rocinante got some new shoes.
https://cimg9.ibsrv.net/gimg/www.mia...f4d113415b.jpg
https://cimg4.ibsrv.net/gimg/www.mia...a43c6f03a8.jpg

Konig Dial-In 15x8's. Local deal that I couldn't pass up. I'll have to roll the fenders a bit in the back.

Finally got around do doing some autotuning yesterday. Dead easy, and really improved how the car ran.

Today I did some searching for AFR target maps, and picked one that looked like it would suit my needs. Loaded it up, and autotuned. Holy cow- major improvement. I think I finally realized the benefits of deleting the stock airflow meter.

I've had my SC bypass zip-tied open, because I haven't replaced the stock 1.6L injectors with the FF610's yet. However, I still have the rising rate fuel pressure regulator installed, so I figured why not give it a whirl. Cut the bypass zip tie and did some more autotuning in boost- wow, huge improvement in power. I'm still fine tuning idle, but I'm already overjoyed at the improvement in the car.

Next step- install FF610 injectors and re-tune. Also need to get a roll bar in this thing.

https://cimg5.ibsrv.net/gimg/www.mia...0c3f742bb9.jpg

Hard Dog Hardcore x braced. I like it, the rear view is much better than the double diagonal in my friend's car.

Maiden voyage on the track is Wednesday night.

Car is coming along nicely...fine work sir.

Signed up for my first event, SCCA Track Night in America at Atlanta Motorsports Park. The event was last night. Chronology:

- came down with a vicious cold on Monday

- drove up to the track yesterday afternoon in a biblical summer rainstorm. My no-A/C car reached approximately 150 degrees interior.

- got to the security gate at the track. As I'm pulling up, I hear a violent flapping noise from the engine bay, and the car stalls. Won't crank. I get out, push the car to the side, and wave through the Viper and new Vette that were behind me. My first point-by.

- spend the next hour in the now-blazing sun, working over a hot engine, unwinding my shredded supercharger belt from the crank pulley. Lose about 10 pounds.

- wire the supercharger bypass open, drive home.

Lessons learned: When someone is sending you signs, listen to the signs. Always carry a spare supercharger belt. Or get rid of the damned supercharger. I considered running the event anyway, but a non-rotating supercharger makes about the worst air intake in the world.

Finally got around to making a variable TPS. I had scrounged the metal mounting plate from a junkyard car, and got the Wells 201 off of Amazon. Mounted it up:

https://cimg9.ibsrv.net/gimg/www.mia...9b5f6d66b3.jpg

Hooked it all up, jumpered the VTPS in my MSPNP2, and stole the acceleration enrichment settings from the 94-95 basemap. Took it for a drive tonight; TPSdot rocks. The hesitation when stepping on the gas pedal is gone, and the transition in and out of overrun cut is much, much smoother. The only thing is that if I'm already rolling and I get on the throttle hard, the engine stumbles. Looking at the log, when TPSdot cranks up, it goes way too rich- like in the 9's. I need to figure out how to tune it.

On another note, I figured out Virtual Dyno. Did a pull tonight, looks like I'm running about 137hp and 117 ft-lbs. I'm not terribly disappointed with this considering I haven't touched the timing map yet. It feels faster than that- possibly because of the smooth torque curve. It pulls pretty nicely from 3500rpm up.

https://cimg8.ibsrv.net/gimg/www.mia...ab392a286e.jpg

So it's been an interesting week. On a lark I listed the supercharger kit for sale locally, and within a day or two I got a good offer for not only the SC but the entire 1.6 motor. Buyer is supposed to formally commit tonight. Looks like I'm headed to Swapville.

In other news, I learned that it's possible to haul a Miata motor in the back of a minivan without spontaneously sprouting a vagina.

https://cimg8.ibsrv.net/gimg/www.mia...9a48fcd9b5.jpg

I had been thinking about swapping in a VVT motor. Then I was thinking that I'd probably do a coolant re-route. Then I was thinking that I would need a different head gasket to do it right. Then I was thinking that while the head was off, I'd replace valve springs and seals. But while I'm in there, why not forged rods? And onward down the slippery slope.

Then I found this on Craigslist, a running BP4W for $200. I called the guy, he seemed legit, and I figured it was worth a shot as it's probably worth at least that in parts alone. Here's what I know about it:

- The guy and his wife are retired, and were really cool. The guy seems pretty handy and had a workshop with an engine lift, I think he likes to work on bikes. The car it came from is single owner '99 NB with 132k that they still baby and drive all the time. They gave me a bunch of service records with the motor, which include a TB/WP, seals, and an oil pump replacement (?) in the last 10k miles.
- The motor was replaced by a mechanic in May 2017. Sounds like it lost compression; still ran, no rod knock or anything, but was significantly down on power.
- To the best of their knowledge, it had never overheated or been run dry of oil. That oil pump replacement has me wondering though...

I'm gathering up my plans for the rebuild/swap. I have to pull my 1.6L this weekend, so I'll have a non-running car until I get it figured out. First I'm going to tear down the motor to have a look at what's going on in there; I'm not sure if the compression loss is piston rings or valves/seals. Depending on what I find, I may do one of two things:
- if it's not bad (top end only), I may do a more-or-less stock rebuild and get it back in the car quick.
- if it needs more than that (top and bottom), I may find another running VVT motor that I can drop in without opening. Then I'll take my time with this one and do a bad-azz, no expense spared turbo build over time.

The owners of this motor lived in Key West for 3 years, and the motor looks like it. Lots of surface rust and rusty bolts.

I started messing around with it. Pulled off the valve cover- pleasantly surprised. Everything looks well-oiled, no signs of unusual wear or corrosion.

https://cimg0.ibsrv.net/gimg/www.mia...3f58b14453.jpg

So I pulled the spark plugs. Cylinders #1 and 4 looked normal. Cylinders #2 and 3 were filled with watery coolant. Oddly, the coolant was both above the plugs and below them in the combustion chamber. I' assuming it's a head gasket issue.

https://cimg8.ibsrv.net/gimg/www.mia...292db2c753.jpg

I proceeded to do a leakdown test, because I wanted to see if the valves and pistons were sealing correctly (independent of the head gasket issue). It's the first time I've done a leakdown, so I followed the instructions:
- Exhaust unobstructed, throttle blocked open. Oil dipstick pulled.
- cylinder being tested at TDC on compression stroke (all valves closed)

The motor was obviously cold, but from everything I've read a cold test is a worst-case test because everything would seal better at operating temp.

Here's where it gets weird. All cylinders were very good in leakdown- around 6-8% on all cylinders, on a stone cold motor. Not believing the result, I intentionally tested a cylinder at TDC of the exhaust stroke, with the exhaust valves open. >60% leakdown; it appears that the tool is working correctly.

Here's where I need help from anyone who cares to answer. Tell me if the following statements are correct or incorrect:

- I didn't make some newb mistake with the leakdown test, and the good results are meaningful.
- The head gasket leak is small enough that it's beneath the sensitivity of the leakdown test, or was an intermittent problem that happens when the engine heats up.
- The valves and piston rings are indeed sealing correctly.
- If I pull the head and the mating head/block surfaces are still within flatness spec, it may only require a head gasket to get this motor back to good health.

Thanks in advance to anyone who can provide guidance.

So I've had these used Flow Force 610cc injectors sitting around for a few months. I've read about people having idle and tuning issues with big injectors and small motors, so I was a little reluctant to put them in. I thought the AFPR was working pretty decent, and I wasn't in a big rush. But the last few months I've gotten more comfortable with tuning my MS2, and I've gotten better at reading data logs. I realized that with the AFPR, my AFR's were pretty unpredictable in boost. I also realized that at full boost (7psi), even with the AFPR my stock 1.6L injectors were at 90%+ pulsewidth trying to keep up. I realized it's time to install the FF's, and ordered the necessary seals and o-rings.

Put them in the car tonight. Easy job.

https://cimg1.ibsrv.net/gimg/www.mia...6333e510f1.jpg

Changed Req Fuel, dead time and voltage compensation per the instructions on the website. Crossed my fingers and started it up.

Result? Perfect idle right away, AFR was pretty much dead on. Drove around and autotuned for 30 minutes, no issues at all. A few more tweaks in the idle cells and the tune is pretty much perfect. I'll work on my enrichments tomorrow, but the car's running great with no AE at all.

One thing I learned about tuning idle. If you watch the VE map at idle and you see any oscillation, set all the cells in that region to the same VE value. Oscillation goes away, and anything remaining you can dial out with idle PID settings.

Overall, very easy and very good result.

Good on FF Injector change-out.

Thanks, it was a good upgrade.

This build thread is becoming one of those movies where you have two intersecting storylines. In story #2 (the '99 1.8 motor), I was encouraged by the good results in the leakdown test. The previous owner complained of the motor stuttering and losing power. As I've been taking things apart, I noticed this:

https://cimg4.ibsrv.net/gimg/www.mia...2128d4303f.jpg

https://cimg9.ibsrv.net/gimg/www.mia...5aa357d61d.jpg

I think I've solved the mystery of the poorly running motor- the crank nose bolt came loose, and all the bits are worn out. The timing gear probably has 10-15 degrees of wiggle on the crankshaft. The pulley boss is worn eccentrically and the pulley wobbles. Most unfortunate is that the keyway on the crank nose is pretty worn. If I was just trying to get this thing back on the road, it would probably be a good candidate for the Loctite fix. However, I was going to take it all down and build it back with forged rods and new bearings, so I might as well just go ahead and replace the crank.

On a positive note, now that I know why the motor was running like poo, it gives me hope that the head is probably fine. Going to pull it tonight to inspect.

I can't seem to track down a decent BP crank for less than $200. But I found another orphan motor on CL for $100. This one is a '95 with 100k on it; it was over-revved and the valve springs are shot, but supposedly the bottom end is solid. So depending how good the bottom is, I may just run the '95 bottom end and the '99 top, or I may transplant the '95 crank into the '99 block. My garage is going to be full of motor parts, and my wife is going to kick my ass.

Pretty much an every day thing for me lately, I feel your pain

My garage is so far from the house that my wife almost never goes in there. Only if she needs me and I don't answer my phone.

You truly are a man who has life on lock. Bravo sir.

I wouldn't go that far, it helps that my wife is exceptionally cool. What I wouldn't give for a nicer garage though.

A year and a half of work, only to end up back where I started- with a stock 1.6L motor.

https://cimg1.ibsrv.net/gimg/www.mia...9a23ca96b6.jpg

Found a buyer for the Jackson M45 supercharger kit, and sold it for the same amount that I bought it for.

Not to fear, power is on the way. I now have a grand total of $300 invested in two 1.8L motors. The subjects:

https://cimg4.ibsrv.net/gimg/www.mia...b56293579d.jpg

On the left, a 1995 motor with 100k that I bought from a mechanic. Supposedly has a good bottom end (with the lower 8.8 compression pistons) and a bad valvetrain. On the right, a 2000 motor with 135k and a good head and VICS manifold, and a trashed keyway on the crankshaft.

This week I pull them apart. If the 2000 head and the 95 bottom check out OK and have good flat surfaces, I'm going to get a head gasket and some ARP studs, slam them together and do the transplant. Then an MKTURBO setup from Lars, and I should be sitting at 220 whp. I'll then take my time building the 2000 bottom end with forged stuff for future shenanigans.

^ Sounds great. I was already thinking, "What is all this SC stuff, I thought Schroedinger was a sensible guy."

The head is off of the '95 motor. In case any of you want to see what happens when you rev a stock motor to 9k:

https://cimg6.ibsrv.net/gimg/www.mia...197b7bd306.jpg

A bunch of bent valves, mostly exhaust, some intake. As expected from what the PO told me. No worries, I knew the head had issues. Now onto the bottom end:

https://cimg7.ibsrv.net/gimg/www.mia...707ee1b8f3.jpg

https://cimg0.ibsrv.net/gimg/www.mia...b43e566774.jpg

... and after 5 minutes with a brass brush:

https://cimg2.ibsrv.net/gimg/www.mia...d137308492.jpg

Things are looking really good down there. The pistons and bores look great, no scoring at all and the cross-hatching looks good. Checked flatness of the deck with a precision straightedge and feeler gauges (all the tools from my other hobby as a luthier are coming in handy). I can't get a 0.001 feeler gauge under the straightedge anywhere, the deck is almost perfectly flat.

Previous owner said it was making good oil pressure when it was pulled, so the oil pump should be in good order. I'm hoping that what I find in the 2000 head looks this good; if so, I'm not going to take things down any further. Get it together and get it in the car.

I learned something. I would have expected the pistons to be toast if the valves were bent.

This is when it's nice to be working on a non-interference motor. The two things I was most worried about were bent rods and broken oil pump gears, but neither of those things appear to be an issue.

I finally got around to pulling the head off of the 2000 motor. The good news:

https://cimg5.ibsrv.net/gimg/www.mia...00b5afcce2.jpg


Deck is completely flat, couldn't get a 0.001" feeler under the straight edge in any direction. So it's a viable head. I can't find any evidence at all of head gasket failure; no leakage pathways, and even carbon deposits on all the piston tops. Not sure why there was liquid in the #2 and 3 spark plug cavities, but I suppose it doesn't matter. Maybe it was left in the rain.

The bad news:

https://cimg9.ibsrv.net/gimg/www.mia...ffaad2bbcf.jpg

A bunch of effed-up valves and/or springs, like on the other head. Obviously this head's going to need a valve job. And obviously my leakdown testing skills suck. Actually I think I know what I did wrong- hooked the tool up to over 100 psi on the compressor and broke it. Should have read directions more carefully. Yay for shitty/cheap Harbor Freight tools.

I'm not building a 9,000 rpm race motor, and I'm running a stock bottom end (at least for a while). I've read Emilio's awesome thread and other good info here, and I'm thinking I should do a mostly OEM rebuild. Three angle valve job, OEM standard sized valves, OEM valve seals, OEM springs and SOB lifters. Somebody please talk me out of my hard earned money and tell me why I need to use fancy-ass Supertech stuff, I can't think of any good reasons.

when I rebuilt my first cam'd engine 18 years ago I learned that not all valves go down at the same time.
Did you turn the cam and the valves stuck up, or are you upset that one cylinders valve is up when you pulled it?

Sorry I don't know your mechanical experience but its hard to know if a pair of valves sitting proud is actually a problem or not.

The reason I ask is because they appear straight and parallel to each other and there is no evidence of contact.

I have ruined some very expensive gauges by over pressurizing them. Not harbor freights shortcoming.

Wow. This may be some epic noobishness that I'm laying down on MT.net. I need to check this when I get home.

Roger that- it's not the fault of the tool, which is pretty good. It is the fault of my own stupidity, which in this case only cost me $35.

.

Well, it looks like I have not learned something. My original expectations again seem the most likely.

OK, so apparently I don't know much about how motors work. I put the timing gear on the camshaft of the 2000 head and gave it a spin, the valves are fine. Chalk that one up to being a newb... this is the first time I've taken apart a motor.

DNMakinson, I tried to repeat this experiment on the 95 head that I thought had bent valves. It is hard to turn the camshafts, feels like something is binding. However, it seems likely that the valves are actually not bent, in which case you are correct- you actually didn't learn anything from me. That shouldn't surprise either of us.

Since pistons 1/4 and 2/3 travel up and down together, I always assumed that the valves on those cylinders opened and closed in sync as well. Turns out that's not the case, all the cylinders's valves do their own thing at their own time. My brain is hurting trying to figure out how motors work again. Gonna need a few days to soak this all in.

Anyway, it seems I have a good 95 bottom end, and a good 2000 head. Got some Mopar combustion chamber cleaner today, I'm going to clean them both up and put them together with my new 94-97 OEM head gasket and ARP head studs, then repeat the leakdown test while trying not to blow up another Harbor Freight tool. If everything seems good, it's time to start gathering things up for the swap.

In other news, the guy that I bought the '95 motor from was moving in a week, and getting rid of all of his stuff. I liberated him from these wheels, which came from the same car as the motor. figured I'd try them out on Rocinante.

https://cimg7.ibsrv.net/gimg/www.mia...7574456656.jpg

They're the 15" BBS wheels from the '95 M Edition, complete with the center caps that I was too lazy to put on. He thought that one of them may have been bent; I took them to the Wheel Wizard today, who found that one was indeed slightly bent and the others were fine. After the repair, I paid less for the whole setup than a set of center caps alone sell for on Ebay. The 15x8 Dial-In's were not a lot of fun to drive around town with manual steering and a +25 offset... I'm going to save those for the track. The BBS wheel/tire combo is 4.8 lbs. lighter per corner than the Dial-In combo, and that's not a little bit. The car drives beautifully with these, and I know opinions vary, but I think these are the dead sexiest wheels ever to appear on a Miata. Need to find a good 195/50/15 tire for the street, thinking about the BFG Sport Comp 2's.

No worries. Remember that a full cycle on a 4-cycle engine is 2 revolutions of the crankshaft, and that the camshafts turn at half speed.

And the lightbulb switches on- thank you.

The difference between information and knowledge. Information is taking a 400 level thermodynamics class and spending the entire semester dissecting the mathematics of the Carnot cycle, while looking at a picture of a single cylinder. Knowledge is what you wrote above.

Well, finally took the 2000 cylinder head apart tonight. Every one of the cam journals and caps has some light scoring. Oddly, the cam bearing surfaces on the head itself look perfect. The scoring looks concentric around the shaft of the cams and the interior of the caps, and I don't see any galling or pitting.

https://cimg8.ibsrv.net/gimg/www.mia...7d1fed25de.jpg
https://cimg9.ibsrv.net/gimg/www.mia...2de82fde9e.jpg

In this thread, Savington explains that the scoring may not be that terrible.

https://www.miataturbo.net/engine-pe...-scored-77521/

The car made it 135,000 miles like this with no related issues; the motor was running fine when pulled except for bad timing due to the trashed crankshaft keyway. There was a good oil film on all of these surfaces. I haven't found any metal in the oil at all.

Alas, I'm taking this to the machine shop in the morning to get their opinions.

Dropped everything off at the machine shop this morning. They don't think the scoring on the cams/caps is any big deal, and are just going to lightly polish them. They quoted me $600 for a valve job (?!?!?) because of the amount of time it takes to set lash correctly with the shims, due to the solid lifters. I told them no thanks- these valves were sealing up really well before I took the head off in the first place. So they're going to do the aforementioned polishing, check the deck for flatness, and clean everything up. Should be ready tomorrow.

In retrospect I should have measured the lifter clearance before I took the cams out. I just ordered a valve spring compressor, lapping tool and compound. I'm going to lap the valves myself as minimally as possible/necessary, and hopefully the clearance will be within spec when I'm done so I don't have to re-do the shims.

Behold the Harbor Freight "brass" brushes. Muthafukkas.

https://cimg7.ibsrv.net/gimg/www.mia...8a8a5ca74b.jpg

Behold the results from the Harbor Freight "brass" brush. Right on the HG sealing surface I believe.

https://cimg0.ibsrv.net/gimg/www.mia...e496bda33d.jpg

Wonderful. I can barely feel the texture with my fingernail. I have some 1200 grit cloth that I use to polish guitar frets, I'm going to try using it gently with a metal surface plate to gently level it.

don't get too carried away with cleaning stuff up (piston tops).
it gets dirty the first few minutes of idling and there is a lot of time to screw something up.


scrape any old gasket off and if the deck is flat, your good to go. any more than that and you will want to do a proper rebuild and decking.

If the pan is still on the engine....broken bristles may have fallen into the pan via six large oil drains.

600 for a valve job is insane. I paid 400 including the install of 8 inconel valves.

Yeah, I need to go easy with the cleaning. My shitpicking meticulous side wants everything to be sparkly clean, but it's not doing any good and might cause harm.

I taped over the oil drain holes to make sure that nothing gets down there. I may still pull the pan to check out the oil pump before I put everything together; might as well get it all done while the engine is out of the car.

I'm busting out all my old luthery tricks. Sharpie marker:

https://cimg4.ibsrv.net/gimg/www.mia...a4fe2a1284.jpg

Then hit the area with a leveling block and very fine abrasive fabric:

https://cimg8.ibsrv.net/gimg/www.mia...424fd4fa9b.jpg

Everything looks flat enough to seal, and the head gasket coverage should be more than adequate to keep coolant away from the scratched area.

https://cimg1.ibsrv.net/gimg/www.mia...d99d220afb.jpg

Got the head back from the machine shop. So clean and pretty.

https://cimg2.ibsrv.net/gimg/www.mia...8efce45107.jpg
https://cimg6.ibsrv.net/gimg/www.mia...fccefdc81e.jpg

Since I didn't indulge in their $600 valve job, I'm going to inspect the valve/seat interfaces, and check the cam/lifter clearances. In the unlikely event that everything is good, I'll be ready to start reassembly. More likely I will be pulling the cams again, then the valves so I can lap them. I'll then see about reshimming the lifters to bring the clearance back to factory spec.