samnavy

iTrader: (7)

I've been looking for hours and here's what I've discovered.

My longtime goal of 220whp is totally do-able with my current T25/MS at around 12-13psi. The car will be daily driven @wastegate 8psi and a dash switch to engage EBC a couple times per week. I would love to get 100k+ miles out of an engine. I've just purchased a complete used motor (high miles but babied) I'll be running in the meantime. I'm going to purchase parts and what not over the next 6-8months and need something just a little better "more reliable" than stock. I know that guys run mild boost on stock motors for 100k miles or more... but I don't mind spending a little extra money to get a lot better reliability.

Pistons: Stock w/ceramic on the doam, dry-film skirt, bottom coat.

Rods: Stock

Rings: Brand... seems to be quite a few w/several different metals and treatment options. What to buy and what to treat them with

Head Rebuild: I see the FM spring kit... used w/stock valves? Is there another "kit" out there and do I need better than OEM. Nobody seems to have many head issues on moderate boost like I'm running. I'm going to keep the stock 7200rpm redline... or maybe even lower it a little for the street.

Head Porting: just inquiring as to cost vs. gain and will a port job require oversized valves?

Manifold: Is there anything to be gained in porting/working the intake manifold... cost vs. gain?

Gaskets/Bearings/EngineRebuildKit: http://www.rpmmachine.com/engine-reb...ts-mazda.shtml I see this and think that it's a pretty good deal. Obviously I want all new seals and bearings and ****, but it even comes w/pistons, only doesn't come with rods. What kind of quality is offered in "kits" like this.

Re-Using what I've got: What's wrong with having my current pistons/rods/rings/crank removed, treated/cleaned/whatever and reinstalling them with all new seals/bearings? What am I going to need done to the block itself? I can dismantle everything, but I want someone else to do the build.

What other little bullshit pieces am I not mentioning?

I think this thread can be a good read for a lot of people. I need the gurus to really spell it out for me. What is really needed, and what is it gonna cost? What are the little "hangups" during a build and what do I need to be wary of when talking to a shop.

Shawn has recommended a good shop in town that he trusts, so I'm gonna talk to them. I just want to be well armed with the lingo.

Thanks for reading the whole post if you did... -Sam

Braineack

iTrader: (62)

if you want the cheapest, get new pistons "oem type" $31ea. then a better ring set $110. get the walls honed. reuse the rods and call it a day. If you are really feeling like you need more buy a set of belfab rods. Reused the head gasket you just installed.

http://www.importperformanceparts.net/ (topline pistsons, toga rings)

Ben

iTrader: (33)

Sam, if you are going to disassemble and build a motor, you may as well do it correctly once. Going with a set of inexpensive forged rods and oversize pistons will cost you about $500 or so more than staying with stock stuff. At minimum, I'd go with the forged rods. You're probably looking at $2000 or so on a mild shortblock with budget forged internals and machine shop labor, with your own assembly.

Braineack

iTrader: (62)

this is why i opted to find a cheap *** good block. even if I invested the bare minimum on parts, it was more than i wanted to spend just getting it back on the road.

i mean, if you still just get forged pistons (weicos $510 stock bore w/rings) and belfab or ETD rod ($350 or $530), you're close to 1k or over in parts alone. getting it honed won't cost too much. however, your power goal still isn't one to justify it, imho. The weak link are the ring/ringland, next the rods. I have yet to see a rod go, it's always the rings and ringlands.

If it were me I'd either get it running again on the cheap, or I'd do a mild rebuild on your existing block and try to do something about the rings and call it a day.

Zabac

iTrader: (39)

Sam, i am in a similar boat as you, except my build is planned for late next year/early 2009...no hurry for me since im doing it on a spare motor i have laying around with bad rings...
My plans include rods, pistons/rings, oil pump gear (i hope loki hooks it up), knife edged crank, full valve train with 1mm over sized valves, a proper head job, etc.
my goal for said motor is north of 300 whp revving to 8K or so (undecided), the key to make my build possible is the fact that im gathering the parts over a prolonged time and once i have everything i need/can afford i will be taking it to a well known shop for the work on the block/crank/head and assembly
i hope this helps you in your vision...

samnavy

iTrader: (7)

^Brain, That's kinda the route I was looking at.
Just get stock treated pistons, and "upgraded" treated rings... then an otherwise OEM rebuild.

^Whaam... I like it, but I'm shooting for a lower power goal. What does "knife-edging" a crank entail? How much do you buy $$ vs. power with a valve job. Are we talking about top-end/spool/response? Am I even in the arena for larger valves? I don't think I need much more than pistons/rings and a rebuild.

My biggest concern is buying a brand that turns out to be junk. $31 for a piston seems crazy! I never new they cost so little.

If I bought 4 pistons like that, and had them treated... looks like only $25per piston/pin for the tri-coat: http://performancecoatings.com/prices.html It looks like we're only talking about just $275 total including shipping. Those pistons come with rings... but I'd opt for the Toga rings at $109.

The Toga rings say this:
Top Piston Ring: is Plasma Moly inlaid for long life and quick seating. Rings are ductile and can be twisted without fracturing. Thin ring to conform to flexing bores.
Second Piston Ring: are cast iron torsional twist, and offer good ware resistance and shaped to encourage downward oil scraping.
Oil Ring: three piece circumferential type made of stainless steel with two chromium plated carbon steel rails. Extra narrow rails are made to conform to the shape of distorted bores.
Do I have to do anything to them, or is this better than OEM already?

Ben, I hear what you're saying, but I don't really think I need the rods. I'd love the Belfabs... but if I've gotta keep some sort of budget, I think this is an area where I can.

Then I can buy one of the "rebuild" kits that comes with all the gaskets/seals/etc... and call it a day for the bottom end right?

NOW, what about the HEAD? Is there anything to be gained in my application w/going to higher quality parts? I know the aforementioned local shop can do the work and get parts, but is it better to rebuild or buy rebuilt? Valve coating is also $7.50per... so were talking about $120 to do them all... worth it?

LASTLY (maybe): Can I buy all these parts, send the block out to be honed/cleaned/etc... and put the whole thing back together myself? You guys know my skills... pretty decent with all the right tools. Is it more than I want to mess with. Parts aside, how much $$ am I talking about to get somebody to ready the block and put it all together?

Stealth97

iTrader: (5)

dont crack open a block unless you are going to at least put in decent rods, JMHO

Newbsauce

iTrader: (2)

I don't feel like reading what sam just said above because it was entirely too long. My only qualm was the fact that @300 bucks you might as well put in belfab rods.

Zabac

iTrader: (39)

in a nutshell, doing head work will improve spool especially with bigger turbo aps.
the valve train is there to allow for the higher revs

Ben

iTrader: (33)

Sam, we're all on budgets. What is your budget? What is your goal? From reading your equipment list, I'd assume that your goal is more oriented to quick/immediate spool and gobs o torque down low.

Now, let's look at the common failures associated with boosting a motor. From what I see, in order of most common to least
1. piston failure, at the ringland. typical cause: detonation
2. head gasket failure. typical cause: incorrect hardware torque or overheat
3. pretzelized rods. typical cause: high rpm or nasty detonation

Solutions:
1. Why spend $300 on OEM type pistons when you can get oversized forged pistons (with rings) starting in the mid $400s? The forged pistons will be MUCH stronger in the event of detonation and won't come apart.
2. Use ARP hardware, and check torque after the first drive
3. Forged Rods are only $300 at the low end

Between 1&3, we're talking around $450 extra for the hard parts plus whatever your machine shop charges to bore your cylinders. The benefits will be a virtually indestructable motor and the bigger jugs will spool the snail sooner and offer more power, or equivelent power at less boost.

Now, assume you go with oem pistons and rods, and a ringland comes apart, or detonation takes out a rod. What's it going to cost you (time and money) to pull the motor back out?

That's why I say you might as well do it right once.

I don't think you need to touch the head for your goals. There's no need to get into the springs and lifters at stockish rev limits. However, some DIY porting (like what Brian did for Scott) will tremendously help spool. I would not get into OS valves, however I would unshround and do a valve job. Save the OS valve money and put it towards the block or to adjustable cam gears.

On top of the other stuff you've listed, you'll need a multitude of bearings, an oil pump, a water pump + guides and tensioners, an ARP hardware set. You'll also want to have the crank checked for trueness, and if not lightened, at minimum filmed to shed oil (reduces windage losses).

Yeah, you probably can do the assembly work yourself. Just take lots of pics and notes. But it's only a little 4 cyl, so it's not too tough.

My .02 x 2

hustler

iTrader: (6)

I am spending $1100 with a respected SM builder who's put together a handfull of FI cars that are famously reliable around here. I'm getting a bore on a plate, line bore / turning the crank if necessary, bearings, valve guides, balancing the rotating mass, and assembly since I don't have precision tools. It will be cheaper if the crank is ok. Its more than I wanted to spend considering I already dropped $800 on rods and pistons, but I can live with the cash because I'm fairly confident that it will be a strong motor. I'm still undecided on piston coatings.

Zabac

iTrader: (39)

thats what i was thinking for myself, to do the assembly on my own and then take it to the shop with flywheel and clutch assembled and have the whole unit balanced...
or do you do this balancing with crank out of clock? im a little confeused

fmowry

iTrader: (8)

Hell at that goal if you can maintain a good tune that's knock free you don't even need to open the motor. I probably got 35K miles on my bone stock '90 1.6 FMII that made 220whp that started with 110K miles and ended at about 145K miles when I jacked the boost up to 16 psi, sprayed a 50 shot, and went lean and shot a rod through the block at the dragstrip. That was with the original FMII Link with a few improvements.

Frank

hustler

iTrader: (6)

balance is outside the block.

Braineack

iTrader: (62)

the problem is sam's engine needs work. so while it's all apart and while he may need new rings anyways he looking to do a mild build.

hustler

iTrader: (6)

I'd rather build a cast motor with ETD rods and ceramic coated pistons including the machine work rather than throw a crap motor in and do the labor twice. I'm lazy.

Braineack

iTrader: (62)

My car has been running for the last few months with my $200 block.....Now I have a spare head and block sitting on the floor of my garage....the day I feel the need to start pushing over 12-14psi is the day ill drop it off to get bore out and start collecting parts.

samnavy

iTrader: (7)

Ben, I'm with you on the "only $500 more to do it right"... and then I run into a post like this: http://forum.miata.net/vb/showpost.p...98&postcount=9 I've seen the same thing said about forged pistons before (problems with expansion during the heat) and that a lot of guys will say they're too many possible problems for the strength benefit... especially for my modest goals.

I totally love the idea of new rods now though... so if there's a set of those you've got for sale reserved for me (Paypal can be on the way today), then consider a set sold. If they're already spoken for, then I guess it's Belfabs... maybe a group-buy will pop up.

And I'm gonna leave the head alone as far as hardware but will have it rebuild/unshrouded/etc.

It looks like the going price for a head/main ARP stud set is gonna be around $250... but some guys quote shops being able to get the stuff for much less.

I'm learning more and more with every post, everybody thanks for your time posting in this thread!!!

Markp

Sam, the weakest part of the stock motor is the rods. Get the Belfabs. Cheap insurance. Finally, if the rings are shot but the bores are good, just get new rings. The pistons may or may not be hosed but a set of stock pistons are easy enough to come across.

Mark

Mach929

iTrader: (3)

does anyone make hypereutectic pistons for the miata, from the reading i've done these would bridge the gap between stock cast pistons and fancy loose fitting forged ones.