Building Bottom end for FMII, seeking advice
 

Hi all,
I installed an FMII Hydra kit into my '94 last july. At the same time, I also installed a bunch of other FM parts onto the car, incl:
Supersize clutch kit
2.5" single exhaust
Hi-Flow Cat
Aluminum race radiator w/twin Spals

In addition, I did a NB head swap at the same time with a 2000 head, had an aluminum head shop go over the head before installing. They planed the surface, and worked a few of the valves to seal up right.

One week after I had everything installed on the car, I got an unwanted phone call. It was a one month notice that I was being deployed.

During the last month, I also installed a set of 225/45 RS2s on Nickel 15x8 6ULs

Since being deployed, the car has been sent from my home in Columbus, OH. to FMs Exhaust producer out in Lancaster, CA to help them fabricate their 3" NA turbo exhaust. I got a free 3" upgrade out of the deal with no "miata downtime" to me, and an excuse for a cross country road trip as soon as I finish this deployment!

The car runs great except for one exception: Heavy oil burn, especially under boost. Since being deployed, Ive been weighing the options in my mind, and as is my nature, I've been over-researching everything at the same time. Since the car is now at 120,000 miles, I've decided it's time for a full rebuild, and because I don't want to rebuild it twice, It's gotta be done right the first time.

My current power goal is 300hp at the rear wheels on 93 octane - whether I'll reach it or not is a different story, it is just a goal after all. I was never able to get the car on a dyno to see it's current power: My priorities changed quickly when i got the deployment phone call. The following is a list of expenses that ive put together:

Pistons(84.0 mm)/Rods - Belfab/Supertech 389+439= $830
Bearings/Gaskets - FM Engine Rebuild Kit -$600
Oil Pump - $40
Already has a farily new water pump - $0
M-Tuned Coolant Reroute - $300
Fuel Pump - Walbro 255 - $140
Shop Work, incl. cylinder boring / balance rotating assembly - 600???



Total - $2500 + incidentals

For the actual engine build, my questions are:

What compression ratio would suit me best? I see these pistons offered in 8.7, 9.0, and 9.5:1 I am currently leaning towards the 9.0:1 CR, but I am definitely not against 8.7:1 ratio, It is closer to stock on the 94 IIRC. I'm probably not dead set against the 9.5:1, but I think I would need some convincing to go that direction. Is there any reason to chose a piston such as FMs 9:1 Wisecos, +$200?

My selection of the super expensive FM rebuild kit is based on an unfounded fear of getting an incomplete kit, a kit with inferior components, or a kit that assumes I'm doing an OEM style rebuild. I am also not a fan of going the e-bay route for engine internals. It's a long discussion of sociology and economics that I won't get into with this post. Certainly, there are some of you who have rebuilt for hundreds less? What are your experiences with bearings/gaskets/kits?

I've read discussion on crank scrapers but can't seem to pull it up with a search lately. IIRC, it is a simple bolt-in upgrade found stock in later model Miatae. Does anyone have a part number? Valid points against?

Shop work: I've seen prices ranging between $200 - $1200 and higher. I will find something competitively priced and within my means, for the quality of work that I expect will be done. What I am more worried about is what shop work I'll need to have done that I can't do myself. Boring the cylinders, of course, and balancing the rotating assembly, are the two jobs that I plan to send to a shop. The shop I am looking at using is AIM Tuning out of Indy. Other work that I'll be trying to learn more about is knife-edging, and line boring.

Is the fuel pump necessary at 300rwhp? Im currently running the RC550 injectors.

I suspect I may have to add a WI system to safely reach the 300hp mark. Has anyone reached the 300hp mark at stock displacement w/o WI? Safely?

Do I install valve stem seals myself into the stock 99 head, and call it a day, or send it to a shop for a rebuild?

Extras: I fully expect to grenade the stock 5-speed transmission if I dont upgrade it at the same time. I expect to have one by the time the build is complete, and maybe even a 3.636 rear to go with it. I'll also be throwing on a FCM suspension as soon as I get home.

What are your thoughts/opinions? What have I forgotten, or what should I add to my list? Does anyone have shop recommendations? Should I start from scratch and build a street legal F1 style car?

I know paul has 300 whp on his internally stock 99 motor. Not sure if he has WI or not.

I wouldn't get my bearings out of a kit. I'd let my machinist size and reccomend the bearings. FYI, my crank needed signifigant turning and polishing.

Changing out the valve stem seals is going to mean tearing down the head (pull cams, shims/buckets, springs), and rebuilding. This isn't hard to do w/ basic tools, a spring compressor, and a set of feeler gauges, but it's time consuming.

Miatas have nitrided cranks and should not be turned, iirc.

Edit: I believe that was Joe Perez that I heard that from...

did you look here first. Racing Mazda b series engine. they have some good deals and build many fast miatas. the cost is not so bad.

Don't listen to anything this person says. RM is a shitty shop.

BenR, good advice. I suspect that a good shop is going to know their shit a hell of a lot better than I ever would.

Fluke, thanks. I know it's time consuming and a bitch to tear down a head. Before I found the 99 head, I took apart my 94 head, cleaned out all the HLAs, cleaned up the valves, and put it all back together. I think I spent an entire saturday working with that thing. After I got to about the 6th HLA, I was thinking "what the hell did I get myself into?" But it wasn't terrible overall. I just dont know how easy the seals are going to be to pull out and replace, what sort of accuracy/precision/tolerance will i need to get them in? I'm assuming you dont just set them in, and then hit them with the blunt end of a tool. But hey, if that's all it takes, then it should be an easy task!

Six, I'll definitely look into if there's any truth behind this.

locomonkey, i'll look into this shop

sav, sometimes I can't tell if you're being serious or sarcastic, but I know that you know your shit, and definitely value your input. TY

True about the nitriding, but the treating is pretty deep. The factory provides for some amount of turning. Mine was cut but, only to the next bearing size up, they did full hardness testing of the journal surfaces. I trust my machinist, they do this all day, and were building fast cars before I was born.

Good info, I'm assuming i wouldnt need to worry about reduced bearing surface area. i.e. stock should be more than sufficient?

You never really know untill you see and measure it. You can guess and probably be ok. I don't like guessing with that.

Well, no HLA's to deal w/ but you will have to check the clearances and possibly replace shims. Stem seals just pop off, new ones pop on; really easy.

After 170,000 km and valve lapping, I didn't have to replace a single shim in the head, springs were good too.

Assembly (after lapping) took ~ 3hrs, 1hr to check clearance. I spent about a day rebuilding the head with a good buzz on.

Do a full head check while you're at it (guide bushings, springs, etc...), get the engine rebuilding manual. I scanned mine and have that in PDF if you don't have it. Will the admins freak out about that?

First off, where are you finding a $40 oil pump? IIRC, new OEM pumps run about $150.

Anyway, some '94s had 8.8:1 CR and '94.5+ had 9:1 CR. Honestly, never really been able to tell a difference when driving either in OEM form. With my own build I went 9:1. It's responsive out of boost and in boost.

You can find the Walbro pumps all day long for $100/shipped on eBay, there's one seller that regularly lists them for our cars, has 100% feedback, etc. I know someone on here posted his UserID on here at one point in time, but I can't find it. Anyway, you want the 190 lb/h HP because the 255 is known for overloading the FPR on 90-97 Miatas.

Main Bearing Support Plates were offered on later Miatas, however, scrapers were not OEM to my knowledge. MiataRoadster.com offers the scrapers and I believe the site hints on what's required for the installation.

If you buy your rebuild kit from a good supplier, they'll ask you what size bearings you want :) You really should measure the crank to know if it's going to need machining. Most don't, but...

I thought I recalled seeing an oil pump for $39 on one of the vendor sites - just the gears. But cant seem to pull it up. Never had the oil pump out so didnt know what it entailed. After a quick check, your numbers are more inline with reality at about $150.

Regarding the FPR, I had an AFPR in my list some time ago, it must have slipped off somewhere.

Thats probably why I couldn't find the "crank scraper" anywhere. Indeed, you're right. It was the MBSP that I recall being a "bolt on" upgrade!

Thanks Keith, I know you've got different bearing options in your kits at FM, but the numbers never really made sense to me. It's all starting to come together now...

yes, let the builder decide which bearings you need.

Ah. I was interested to know because I was about to be mad that I got ripped on mine. lol Definitely get a new pump though, it's not worth it to get everything in and then have it fail. Ask me and ZX-Tex how we know. Having a stupid $0.50 plunger and spring fail (relief valve) is not cool after a long build.

I gotcha, you might still want to consider the 190 though, it is able to outflow the 255 at higher pressures. (Read the Turbo DIY FAQ on here if you haven't yet, it will start sparking ideas while you're considering your list.)

You may also want to consider a set of ARP head and main studs as well.

I think you should go with the low compression. At 15psi I hit MBT well before detonation. I made 252wtq at 27* advance, with over 30* on the dyno with no detonation. I also recommend a bigger compressor housing although this forum doesn't agree. I've opened up the exhaust a bit since and added cops. I have no doubt that I'm over 300whp on a dynojet, probably around 290whp and 285+wtq on a dynodynamics (man's dyno). John Day built my motor with a reasonably "loose" bore and it has zero blow-by problems, its not loud, and the motor is incredibly strong at 6k miles and 2-hours of track time.

I showed up with pistons/rings/pins, rods, ARP mains, and ARP headstuds. I handed over $1200 and he did a bore, blueprint/balance on the rotating, cleaned-up the castings and port matched the 99 head, and assembled it too. That guy has put together a ton of FI miata motors and everyone I've spoken to is happy with him in the miata world and outside. I searched for a long time before I selected my machinist, I recommend you do the same.

hustler, are you running that power on WI, or without?

your builder sourced all the bearings/gaskets/etc himself?

rotornut, after looking at the FAQ again, I think I've been convinced to go the 190 HP route. Thanks!

To be honest, I just got done building my shortblock and I wouldn't do it again myself. If I had to do it again, I'd send the motor to John Day in Texas and pick it up 3 weeks later. You'll spend a couple hundred bucks more, but it will be done totally right and you'll know it. You can't build it yourself without some specialty tools anyway (bore gauges, micrometer, etc).

Seems like this John Day fella is pretty popular. I think I'm going to have to have a talk with him. Anyone have contact info for him? I can't seem to google him :(

no on the water; yes on everything else.

972.235.7405, tell him Trey Rozelle sent you.

I don't know why he became so popular here but I selected him because he's put together several FI miata motors that have seen hundreds of sessions on the track. I can also think of 5 engines built by other people with "issues" large and small. He does tons and tons of machine work for professional teams, shipping stuff all over the nation. Like I said earlier, I've talked to a lot of people and no one had anything bad to say about him other than it taking too long. :) He's one of the few machinists I know of that I would trust to assemble an engine, and not pull a "switcheroo" on using parts other than requested which seems to be a major issue with a few machine shops around town.

Hi Fooger. Thanks for volunteering your car for the 3" NA prototype. I just had the production unit installed on my car and I am extremely pleased with the results. Peak torque occurs 1,200 rpm earlier and drivability is vastly improved over the 2.5" unit I had before. Best of all, it sounds absolutely fantastic. Not boy-racerish at all, but producing a mellow, deep sound that encourages me to turn the stereo off around town. The best part is an intoxicating burble on the over-run. I think you'll be very pleased with it indeed.

I'm not sure what ECU you plan on using, but if it's a Hydra, I really recommend the Hydramist. It works hand-in-fist with the ECU to maximize performance and safety - something that can't be said for standard WI units. I'm able to run high boost (20+ psi) on 91 octane Colorado "squirrel piss" and my intake temps actually decrease during a dyno run!

One other component to consider is the ATI Harmonic Damper (Flyin' Miata 1 800 FLY MX5s). It not only helps prevent your oil pump from shattering at high power levels, but it makes your engine almost as smooth as a V6 (I'm not kidding - the typical 4 cylinder vibration is almost eliminated).

R.e. the transmission: One big bucks option is the Quaife gearset, but the cheaper route is a 6 speed from an NB. It doesn't shift as nicely though and you will need a longer ratio rear-end to give you usable gearing.

Finally, if you want the best available (IMHO) Miata suspension for street and track, consider the AFCO system that FM offers. It performs like a champ and the extra travel designed into it allows it to work much better on real-world roads.

Good luck with your build. The results will be worth it (I get a grin every time I drive my car).

Another Texas Miata engine builder is John Long ( John Long's Automotive Specialists - Auto Repair, Maintenance, Performance - Round Rock, Georgetown, TX ). He is a former Mazda Master Mechanic who focuses on Miatas and RX's in conjunction with his commercial autoshop. His service manager is Dan Pedroza an SCCA Miata driver. - They are the shop I used to build my engine prior to taking it to Corky for the HE-X build.

Drop the idea of an oil scraper and knife-edge the crank...

- L

https://www.miataturbo.net/forum/t35744/

We just started the group buy at $299 for our Rods. They even come with ARP 2000 bolts now :)

Hardly. Robispec > fatcat > AFCO Look at the shock dynos and championships.

I love "engine build" threads... I learn something new every time. Fooger, there's a thread you should read. Search under my username for a thread titled "Pricing a mild build"... good info.

Just to throw some extra stuff out there (I'm going to babble for a minute because I've got the time)... there are a few '99-'00 stock longblocks out there that have been running 300whp with an acceptable amount of reliability. A big turbo will get you there fairly easily on 93octane and some good tune... 15psi on a GT30 and you're there.

I'd really like to be able to do it in the 15psi range on a GT2560, with a big fat torque curve and full boost by about 3500rpm. I think with a 2.0 stroker, lotsa headwork, cams, custom IM, WI (for the shit-ton of timing), 3" dump, tubular mani, EW, etc... should be in the cards... but I'm on a mortal budget (as in, if I exceed the budget, the wife will find out and kill me) so all of that shit is out.

We're right on the edge of efficiency with the GT2560 at that power, so heat is a big factor and the BP isn't known for it's flow-ability.

3" exhaust and a straight-through muffler are mandatory... external wastegate will help tremendously with boost control, but cost is factor, so having the internal wastegate ported and using closed-loop EBC is my route.

Aftermarket cams are too expensive, but an exhintake swap and some adjustble cam-gears have shown to make very impressive gains on NA cars, I'm hoping the FI gains offer the same ratio with some tuning. Protege valve cover=BLING!

There is a big movement right now towards custom intake manifolds. Emilio at 949 broke it down for me one afternoon about the flaws of the '99 manifold wrt packaging constraints for incoporating the VICS system. Some guys have gutted the stock '99 mani various ways with good results on the top-end and little to no loss through the midrange... low power suffers a little, but boost is a cure. At a minimum, I'm going to be modifying the stock IM to achieve a bigger plenum and possibly removing the VICS. I'M HOPING that somebody will have a direct PnP turbo application IM for a reasonable price (w/a bigger TB that will utilize the stock throttle cable) before I'm ready to buy in about 6-7 months.

A nice big intercooler that fills the whole nose... probably in the 27x10x3 size range w/around the radiator pipng and a Forge BOV mounted on the coldside using a 1" t-coupler. 2.5" piping is a favorite around here although Corky says all the time that 2" is plenty big enough for 300whp. Plus, 2" is a lot easier for routing the hot-side... and if you're going with a big radiator and fat swaybars, 2" make A LOT of sense. I have no need for AC/PS, so my options are less limited... but WITH AC/PS, any DIY guy up to 300whp should stick with 2" IC pipes to eliminate a lot of headaches.

So far the Godspeed and Mishimoto's are holding up well enough that I'm convinced. If you're going to the track, maybe a Koyo is worth the peace of mind, but I'm on a Godspeed budget. For bling, I'll probably go with the 12" ebay fan special, but the dual stock fans are a good design and work well enough. Combine a larger radiator with a good re-route, and you're set for 300whp on the street. The BEGi S4 mani/dp setup is a no-brainer for the price and reputation. I'll get the 3" option and have a couple extra bungs welded on. I've got local connections and a 3" exhaust will be cheap and well made. I'd love the Savington-style polished duals, but it's not in the budget.

I'm also hoping DIY has a PnP MS for 99's ready early next year... and it has onboard wideband and dual-map EBC. I've got a great idea for installing a pushbutton switch on the shift-knob for mometary high-boost activation (remember the "Go-Baby" switch from "Gone in 60 seconds")... on a Voodoo Magnum knob should be easy.

OK, planes are landing, gotta go.

samnavy's Kaczinski diatribe ftw!

I can put down 300whp at 15psi on my gt2860rs.


If you ever plan on tracking this car, even once, get v-bands on everything. I'm pretty pissed about my hardware loosening right now.

Deerhunter - glad you like the 3". I cant wait to get home to see how it sounds. If I do a WI, I'm heavily considering the Hydramist, but I do have a budget to work within. If I can get to 290hp safely w/o WI, and my goal is only 300hp, then it's going to have to wait awhile. The same thing goes for the ATI damper. It's a big chunk of change that I can add a few months down the road. The Quaife gearset isn't even in my consideration set right now. I've looked at the AFCOs, and they're not what I'm looking for. This is a 95% DD build that will see 1, maybe 2, autoX per month in the summer, and 1, maybe 2, track days per year. I've spent a lot of money on the motorcycle for track days, so most of my track days will be on two wheels: I value some good "knee time" very highly!

samnavy - I had read your thread probably 3 times before starting this one - indeed, it does have some great info. Let me know how the search for an IM goes. Regarding the radiator, I dropped in the big Koyo unit from FM at the same time I did the FMII install. I threw the FM dual-Spal kit on it 2 weeks later. I love your idea for the maximum boost button on the shifter knob! I think I'm going to keep my button on the right pedal though :P It doesn't make sense to me to have to perform an additional action when I want to go somewhere!

hustler - my non-V-band hardware is already installed. I've seen the prices for those things, and I think I'd rather get off to a bad Michael Jackson photo than redo all of my hardware right now :O If I start to have issues with my current hardware, I'll definitely look into it. It's just not one of those "gotta have it" things right now.

The info in this thread has been INCREDIBLE compared to what I was expecting. It's great to wake up to 10 new good posts. Keep the opinions/experiences/etc. coming! I was half expecting a "use the search, jackass. /thread" post :D Now I'm pissed that I'm still deployed, I wanna go home and tear my engine out! *sigh* 3 more months.

New Questions:

Auxilliary Oil Cooler? Is the water-to-oil cooling block enough when combined with the reroute? I've read complaints that adding an oil cooler makes the oil "too cool", even with a thermostat. Car never sees anything that isnt full synthetic.

Dual Feed fuel rail? I've always been of the opinion that, with a proper fuel pump and FPR, the dual feed rail is simply a gimmick. It seems like a proper set up will leave injectors 1 and 4 within 99.5% of each other, or better. Has anyone lost an engine yet to a single feed fuel rail with a quality fuel pump? It just seems like the money here would be much better spent elsewhere.

I have never seen oil temps so hot that I thought I needed an external cooler, sure the temps go up when driving aggressively or in boost for longer than a quick run, but nothing scary. I also don't like the thought of adding more potential points of failure in what's basically the lifeblood of the engine system. If you plan on tracking the car a lot, you may want to consider it, that beats on the car and heats it up more than on the street. Or, just see how things are without it, and if it's too hot for comfort, add one.

A while back most everyone that had issues were breaking something in cylinder #4, so the thought was that cyl.4 was running lean and that the fuel rail had something to contribute to that. But then the coolant reroute idea took off strong (even though some had been running it for a long time) because there was a lot of heat to alleviate from the back of the engine.
I run a dual feed from M-Tuned because it's honestly not that expensive to do so, I think it still helps equalize everything, but at the same time, a proper reroute will help cure the heat issues that plague the rear cylinders and cause problems.

The fuel rail, if there was an issue, wouldn't be solved w/ either the FPR or line pressure (pump), ppl were under the impression that the flow losses across the length of the rail were large enough to lean out cyl #4.

There was a great thread here where someone actually bench tested various fuel rails at different flow rates, no appreciable difference from cy #1 - #4.

M-tuned rail is nice, and cheap; I didn't bother though, money went elsewhere.

the fuel rail is fine and you only need the oil cooler if you're going on the track.

I think what gets lost in the discussion about various shock combos and their relative merits is this: The AFCOs are designed to be a comfortable (i.e. lots of travel with little chance of bottoming out) street suspension that can hold its own when you autocross or do a track day. Many of the banzai systems that people are in love with are track suspensions that may be (barely) tolerable on a daily driver.

On my recent trip to Texas, I was very pleased with just how well-controlled my suspension is on all kinds of roads. At highway speeds, it's almost plush, but with none of the float that a typical plush suspension offers. Turn-in is razor sharp and I could pick off apexes with surgical precision.

If budget is a concern, you'll get 80-90% of the results (at least for the street) with the FM 2.5 suspension set-up. It's not as controlled during fast transitions and severe bumps, but it's waaaay better than stock.