JayL

iTrader: (12)

Had a discussion earlier about how different people are building their motors. The conversation was exactly what you would expect when it comes to pistons, rods, etc. What really stumped me was which would be the best way to start if you were starting with nothing. I'm curious if finding a blown motor for cheap, unknown condition junkyard motor that runs, spending more money to get a good runner, or something I'm not even thinking of would be best. So, if you were starting to do a build today with nothing, which route would be best and why all while trying to do this on a minimal budget?

wes65

iTrader: (7)

I, personally, started with a junkyard motor. I was told it was in running condition. I paid $300 for it.

magnamx-5

iTrader: (7)

find a junk yard motor pull the plugs etc and inspect the block before delivery for big ****** holes etc and go from there. These babys are pretty stout short of the extra ventilation like what wes and others have done nothing is gonna get screwed up that you where gonna keep anyway.

Jeff_Ciesielski

iTrader: (10)

Last time I built one, I started with a tired old running motor from my parts car. Blown motor on the cheap means you can run into unforseen problems like needing a new/reground crank if the bearing were too trashed or being unsalvagable due to excessive cylinder wall damage. Buying good running motors is a safe bet, but tends to be a little pricy for me if its just going to serve as a core anyway.

SKMetalworks

iTrader: (7)

I have a few questions about this because i just so happend to be in the market for something.

1. What do you check first in a motor to know if its good?
A. Cam caps- If the cam caps have some scoring how much would it cost to get them micro
B. Oil- Can there be anything in here that would turn you away? Rust particles or major shavings?
C. Turn the crank to verify that it moves- If it doesnt move then the motor is obviously siezed right?

What else do you look for in the head to check if its bad?

Anything else you would add?

samnavy

iTrader: (7)

POWER GOAL?
USE?

No junkyard is going to let you do more than (MAYBE IF YOU SHOW CASH) pull the valve cover to let you inspect an engine. There's only so much you can tell by looking down the spark plug holes too.

I rememeber reading that 94-95 engines were preferable for some reason (maybe lower compression) and obviously a '99-00 head is the only way to go. I can't think of any "special" years for blocks or cranks that would make one year better than another.

Find a machine shop in your local area and go down there and talk to the guys, get a feel for their competence and have a look at the shop. A clean shop that looks safe and is well organized is a good bet... although sometimes the best work is done in a place you wouldn't let your dog sleep.

Hustler will chime in here I'm sure with some good advice. I think he says that a full balance is worth every penny.

For the 300whp range and stock rev limit, a 99-00 low mileage head that's been checked good by a mechanic... bolt it in stock and be happy. I'd love to see some flow charts of a regular 1.8 head that's got a p&p, oversized valves, 5-angle, etc... vs. a stock 99-00 to see exactly what your extra $1500 buys you. Above that power and RPM, it starts making sense to spend the extra money on head-parts (your budget is probably bigger too)... but I'd still start with the better flowing head.

JayL

iTrader: (12)

This project isn't one of my own (yet, but it's getting me interested in doing something like this), but for a local guy. I have a couple engines sitting in my garage that I would like to get rid of. He might be interested in one of them, but I don't want him to buy something that won't be in his best interest. If one of them would be a good starting point for his project I want to be able to share this information with him so he can make an educated decision. If not, then I want to be able to point in in the right direction.

This would pretty much be a budget build to put in a track car. Around 300 or so at the wheels would be the power goal.

Engine one sitting in my garage: 01 engine with 22K and has had a turbo on it since pretty much day one. VVT head is not something that he wants and the fact that he would be paying for a running motor makes me think this isn't a good choice.

Engine two sitting in my garage: 99 engine with unknown mileage. It quit while driving and when the previous owner brought it to a shop was told it had seized and required replacement. It turns over just fine so I don't think this to be the case, but nobody knows. The oil is dirty and the previous owner definitely didn't take maintenance seriously. I think this would be a good candidate since he will be taking everything apart and building it. What's a fair price for this motor if he was to go this way?

Or keep looking for something else (what and why?).

Any help would be appreciated.

levnubhin

iTrader: (30)

I built the motor that was in my car. If he has another car to drive then that's the best way imo.
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hustler

iTrader: (6)

I'd go with the 99 just so you don't have to jack with VVT. Just take a look at the cam journals. If those are fine then it is a good candidate for a rebuild (unless there's a hole in the block or something). Its easier to deal with line-boring the crank than the head...supposedly. Crack it open and check for scoring.

If all wear items are replaced, then either motor works. I'd say $400 is fair...not a smoking deal, but fair for a motor that came out with the symptoms you described. Now, if you crack it open and check for scoring on friction surfaces and verify that it looks good, then you can ask for $500 or so. An engine that only needs a valve-job and a cylinder bore is worth more than one that might need line-boring on 3-shafts.

ZX-Tex

iTrader: (15)

If you know a REPUTABLE machine shop you plan to use for your build, then you might ask them if they deal with a good boneyard for parts. They could get a motor for you, then if they tear it down and it is junk, then they could deal with their buddy at the boneyard to find another one. This gets you out of the middle of the finger pointing process.

JayL

iTrader: (12)

I'll pull a few more cam caps and take some pictures later today or tomorrow. We pulled a couple of them last night and there appeared to be some signs of wear to my untrained eyes. Probably from the lack of oil changes. I've only looked at stuff that was new so I'll let the pictures do the talking.

Laur3ns

So does a full 99 engine, drop in a 94 chassis without issues or do you need to mess with oil pressure senders, starters, alternators, PS, etc? If it's a drop in, I might be tempted to bite on a deal for a 99 engine and build it for when I blow my current engine. If it's a larger project than dropping in a 94 engine, I will just do that.

hustler

iTrader: (6)

If you can feel scoring, you have problems. If the car overheated and stalled...then just go ahead and melt it down because its over.

My buddy's shop had a car show up that overheated so bad that the cams snapped. lol

SKMetalworks

iTrader: (7)

What are the signs of a overheated head? Anything else you can check for besides head warpage and cam cap scoring?

miatamania

iTrader: (9)

Why is everyone here afraid of VVT? Get an EMS that can control it and enjoy the extra power down low.

Freaking Y8s dyno should be enough to point that out.

hustler

iTrader: (6)

what compuer controls it? I was under the impression that y8s upped boost at high rpm to compensate for the valve timing.

hustler

iTrader: (6)

well, you can look at the valves for uneven coloration / burning indicating leakage thorugh the valves.

neogenesis2004

iTrader: (12)

He had Hydra which controlled it, and now has adaptronic which can control it. You should really check his dyno thread again where he shows the effects of vvt on tq curve. Its pretty amazing.

y8s

iTrader: (8)

you must have missed it i guess. probably sitting in the corner shaking wondering if 8.6:1 compression was going to make your car a dog.

anyway, at the same boost level, advancing the intake cam gained me at least 30 ft lbs (max 40ish) from 3k to 4k with positive gains from 2500-4500. similarly retarding the cam at the top end made a difference of 60 hp.

look at the graph again:
http://y8spec.com/dyno/taleoftwoturbos.jpg
green = retarded
red = advanced
both runs are at 9.5 psi. same dyno, same day. mixture was not ideal due to the drastic changes in VE.
basically the VVT allows me to take the tallest curve on each side. red on the left, green on the right.

here's a comparison of the idealized VVT curve from those two graphs and photoshop (though in practice it should be the same) against TurboTim's twins. I forget what boost he was at.
http://y8spec.com/dyno/twins_vs_2876.gif

the_man

Step 1- Find a motor that doesn't have a rod sticking through the block. In the case of Miata engines, this is pretty damn easy, especially for NAs, since they aren't worth much and get totaled without much damage, and therefor the engines have more life than the chassis they're in. That said, going with a junkyard motor, even if it doesn't have any OBVIOUS damage (like the aforementioned rod through the aforementioned block), it could have been severely overheated, etc., you just don't know. You could go to a more reputable recycler, whether Miata-specific or not, many will check the engines over for compression, etc., so you have a better idea what you're getting. Of course this costs more. Balance cost vs. gamble according to your own findings.

Step 2- Determine goals/budget. If you're planning relatively low boost or whatever, don't bother with really expensive components. Then again, if you HONESTLY believe that you'll be going to higher power levels, it's silly to build the motor and then have to build it again. Only you can make this determination. I've seen this go both ways- people having to yank a motor to build it up more after a mild/stock build within only a few months/years as they became bored, and people building fairly exotic motors that are WAY overkill for what they're doing. Then again, if money is no object, then go with the best components money will buy. For the rest of us, we have to determine what will comfortably do what we need to do without breaking the bank.

Step 3- Find good machine shop. For Miatas, spec Miata builders are a good place to start. Ask intelligent questions and see how they respond. Don't go with a shop that doesn't bother to take the time to figure out your needs, but also don't go wasting their time asking a million stupid ******* questions that you could easily Google. Personally I don't worry about clean/organized vs. not- I look to see the results of what they've built. One shop I know of doesn't look like anything, and I think only two of the workers speak English (they're all really nice guys), but they build some of the best rotaries around. Most shops are more than happy to brag of their (customers') accomplishments if you ask- so ask.

Step 4- Figure out how much assembly you're comfortable doing. Building an entire motor by yourself is cool, but not if you **** it up. Then it's just expensive.

Step 5- Spend money and wind up with built motor.



Srsly?