G8MikeGXP
G8MikeGXP New Reader
2/8/18 10:06 p.m.

I've been looking for an NA Miata for a while.  I'm trying to buy something pretty close to challenge price.  I'm looking for something to work on with my kids, autocross a little bit and generally bomb around in.  This does not have to get me to work.

I found a 1990, and the price is right.  When I went to look at it, the battery was dead.  Seller said he hadn't run it in 6ish weeks.  We jumped it, and there seemed to be a lot of racket coming from the top end on start up.  It ran for several minutes and didn't ever really quiet down.  It idled high, almost 2k, but the idle dropped to just above 1k when I hit the clutch.  There was a little squeak when I hit the clutch, could it be the throwout bearing?  There was also some oil on the ground under the rear of the oil pan.  The bottom of the transmission was pretty well glazed.  This got me to wondering if the rear main was leaking enough to slime up the clutch and flywheel.  The clutch pedal seemed to not have as much travel as it should have.

So, does any of this sound catastrophic?  Or more like something that I can use to negotiate the price down and fix relatively easily?  I'm not against tearing into it, but I'd rather not buy something that requires the engine to come out as soon as I get it home.

Thoughts?

NickD
NickD UltraDork
2/9/18 5:28 a.m.

Dead battery wouldn't worry me.

Top end noise is likely hydraulic lifter rattle. Might be from sitting for 6 weeks or might just be that the lifters are worn out. How many miles? My 1990 has also developed some piston slap when first started as well.

The squeak when you hit the clutch could be a throwout bearing. I also know that sometimes it's just the slave cylinder pushrod on the clutch fork and a dab of white lithium grease will fix that, so its worth trying that.

The oil leak very well could be the rear main seal. If it does need a clutch, then you can slap a rear main seal in it while you are in there. Could also be the oil pan seal leaking. Unfortunately an oil pan leak requires pulling the engine to reseal the pan. My 1.6L has leaked since I got it 5 years ago and I've never fixed it, because if that engine comes out, something else is going in.

All in all, doesn't sound terrible for a car that's pushing 30 years old. They are cheap and easy to work on and all the parts are available. As long as the top is intact and the car isn't rusted out, I'd say go for it

G8MikeGXP
G8MikeGXP New Reader
2/9/18 7:00 a.m.

Thanks, Nick. 

The car has 105,000 miles.  It's in Tucson, AZ, so the paint is fried but there's no rust.

Blaise
Blaise HalfDork
2/9/18 7:06 a.m.

It's a miata. Everything is fixable.

Idle dropping with clutch in is quite strange though (assuming clutch, out of gear).

There's a screw for idle adjustment. I'd start there, but doesn't sound like a big deal. Top end racket should quiet down though. How's the oil pressure? The gauge on the 90-93s is a real gauge.

We are all friends here. How 'right' is the price? Hows the soft top? Hard top? Even for bombing around, IMO the 90-93 isn't ideal as it doesn't have a proper diff, which makes a world of difference.

G8MikeGXP
G8MikeGXP New Reader
2/9/18 7:22 a.m.

The oil pressure was just over 30 at the high idle. 

He's asking $2200.  I don't plan to pay more than $1900.  It has some janky coilovers and a set of 15x8, zero offset wheels from eBay.  The window in the soft top is ripped.  The seats are in much better shape than I expected.  No rips, no smooshed bolsters.  The dash has a small crack, but that seems to be the tradeoff down here for not having to deal with rust. 

KevinLG
KevinLG New Reader
2/9/18 7:26 a.m.

Take a look at the frame rails underneath and see what sort of condition they're in, they get pretty beat up on some lowered cars. Doesn't bother some people, but it definitely bothers me.

NickD
NickD UltraDork
2/9/18 7:30 a.m.
Blaise said:

Even for bombing around, IMO the 90-93 isn't ideal as it doesn't have a proper diff, which makes a world of difference.

As an owner of a 1.6L car, I agree that you might want to hold out for a '94-'97 (if you like the first-generation body style) or the even better 1999-2000 (if you aren't hung up on pop-up headlights). The '90-'93 cars have less power, smaller brakes and a wimpier rear differential that only had a viscous LSD with a ~25% lockup rate.

On the flipside, if you do buy it, I have a 1990 VLSD as well as a Racing Beat header and a high-flow cat and a larger rear sway bar I'd be willing to sell, now that I am plucking the 1.6L from my car.

Blaise
Blaise HalfDork
2/9/18 8:31 a.m.

^ How much for the RB header and rear sway?

Yeah, I put a 4.3 torsen from a '99 in my '92.

I'd hold out for a '94-97. A beat up '90 (short nose) with crap coilvers, 0ET 15x8s and a ripped top is not a deal, at least in my book. I paid $2800 for my '97 bone stock WITH hard top but a bad soft top window.

Stampie
Stampie UltraDork
2/9/18 8:36 a.m.
G8MikeGXP said:

The oil pressure was just over 30 at the high idle. 

He's asking $2200.  I don't plan to pay more than $1900.  It has some janky coilovers and a set of 15x8, zero offset wheels from eBay.  The window in the soft top is ripped.  The seats are in much better shape than I expected.  No rips, no smooshed bolsters.  The dash has a small crack, but that seems to be the tradeoff down here for not having to deal with rust. 

If you buy it then I might be interested in those zero offset wheels for another car.

NickD
NickD UltraDork
2/9/18 1:17 p.m.
Blaise said:

^ How much for the RB header and rear sway?

The header isn't warped or cracked or dented or been welded up, some discoloration from being on the car for 3 years. I'd say $250 + shipping.

The rear sway bar is an FM adjustable unit. $60 + shipping. I'll even toss in a set of stock end links with polyurethane bushings pressed in.

Sorry to threadjack.

Rodan
Rodan Reader
2/9/18 5:15 p.m.
G8MikeGXP said:

He's asking $2200.  I don't plan to pay more than $1900.  It has some janky coilovers and a set of 15x8, zero offset wheels from eBay.  The window in the soft top is ripped.  The seats are in much better shape than I expected.  No rips, no smooshed bolsters.  The dash has a small crack, but that seems to be the tradeoff down here for not having to deal with rust. 

In the ~$2k price range here in AZ you should be able to find a higher mile early NB (99-05) in at least equivalent condition.  I would pass on an NA6 at that price point.

Rodan
Rodan Reader
2/9/18 5:20 p.m.

Have you looked at this one:

97 Miata w/ bad transmission

At ~$1k, that could be a decent fixer...

Or this is more what I was talking about:

99 Miata

There's a couple others in Phx that could be decent project candidates...  I really shouldn't be looking at this stuff.  It gives me ideas, and I really don't need a 5th Miata... cheeky

G8MikeGXP
G8MikeGXP New Reader
2/9/18 7:42 p.m.

Rodan, I've been looking at both of those listings.  I'd prefer an NA, so the 97 has me interested.  I thought the transmissions were plenty strong to handle 1.8 litres of power.  Any chance it's a quick fix?

I decided to pass on the other one. 

goingnowherefast
goingnowherefast New Reader
2/9/18 7:48 p.m.

To add on to what everyone else said, as an HPDE car, the Miata gets better with every generation/refresh. I would suggest holding out for a 1.8L car. 

Rodan
Rodan Reader
2/10/18 5:47 a.m.

Even if the trans is not a "quick fix", 5sp transmissions are not that expensive, and were essentially the same from 90-05, so finding a replacement should be easy.  Failures are uncommon at stock power levels, though, which has to make you wonder if it was run dry or something.  That's the only issue with these cars... they're so reliable that they're often neglected by non-enthusiast owners because they just keep running.

R&Ring the trans is about as easy as it gets on modern vehicles.  And it would provide an opportunity to check the rear main and clutch while you're in there.  That particular '97 does look to need quite a bit more than just the trans, though.

As goingnowherefast said, the later the car, the better base it will be for HPDE.  Bigger engine, better brakes, stiffer chassis, etc.  I have an NA track car, and I love it, but knowing what I know now I would have tried to start with an NB2.

If it were me, I'd go have a look at that '99 in person...  

einy
einy HalfDork
2/10/18 9:55 a.m.

Minor threadjack ... sorry.  

Nick, how much are you looking to get for the VLSD, shipped to company loading dock in Mason, OH?  Assuming that would bolt right in to a 1991 that currently has an open diff without needing a different driveshaft or axle shafts? 

John

Jaynen
Jaynen SuperDork
2/10/18 9:42 p.m.
Rodan said:

Even if the trans is not a "quick fix", 5sp transmissions are not that expensive, and were essentially the same from 90-05, so finding a replacement should be easy.  Failures are uncommon at stock power levels, though, which has to make you wonder if it was run dry or something.  That's the only issue with these cars... they're so reliable that they're often neglected by non-enthusiast owners because they just keep running.

R&Ring the trans is about as easy as it gets on modern vehicles.  And it would provide an opportunity to check the rear main and clutch while you're in there.  That particular '97 does look to need quite a bit more than just the trans, though.

As goingnowherefast said, the later the car, the better base it will be for HPDE.  Bigger engine, better brakes, stiffer chassis, etc.  I have an NA track car, and I love it, but knowing what I know now I would have tried to start with an NB2.

If it were me, I'd go have a look at that '99 in person...  

It looks pretty similar to the one I got off copart with less body damage than mine. I had a NA6 and while I do love the "original" I wanted a NB this time especially after my kids managed to break my popup lights from pressing the manual up down button too much.

 

The good news is the "newer" miatas are still dirt simple to work on so you can work on a NB just as easy as an NA with your kids. I do like the fact that my NB has power windows because then I don't have window cranks hitting my knee, and I can put the passenger side down without laying across the car.

 

G8MikeGXP
G8MikeGXP New Reader
2/11/18 8:39 p.m.

Still looking...  If I expand the search out to Albuquerque and San Diego, and everything in between, there are some interesting options in the $3k range.  If anyone has an NA8 they are looking to part with, let me know. 

Keith Tanner
Keith Tanner MegaDork
2/11/18 9:58 p.m.

To answer some questions from the initial post:

-oil on the pan is most likely a leaky cam angle sensor o-ring. It drools down the back of the block, into the bellhousing and proceeds to do an imitation of a rear main seal leak. Rear main seal leaks on Miatas are actually quite rare, CAS o-rings are quite common. They take minutes to fix.

- change in idle behavior when you press the clutch probably means the neutral switch on the trans is not plugged in. If it had a clutch done, I'm guessing someone screwed up. For fun, check to see if the reverse lights work. That's the OTHER sensor that needs to be plugged in. Quick fix when you're underneath.

- lifter rattle tends to develop on a car that's been started and stopped and started and stopped, like moving in and out of a garage. You can swap in replacement lifters from a Kia, they're not expensive these days - but first, drive it at high rpm on fresh oil for a while. It may heal itself.

- chirp chirp chirp that goes away with touching the clutch pedal is usually fixed with a bit of grease on the end of the slave. Quick job when you're underneath. Squeak as you depress the pedal may actually be the pedal itself, I've seen them start to make noise at the pivot.

 

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