911vet

I would ask this on the Miata forums, but they aren't half as useful as Rennlist.

I bought a 96 Miata, haven't got it on the track yet. It's smoking badly from the tailpipe. The theory is bad valve guides. 130K on the engine. Haven't done a leak down but the PVC pressure is good and the mechanic thinks the rings are ok. Smoke is primarily on acceleration.

It's smoking so much I'm guessing I'd be black flagged.

Mechanics are telling me to go after a used engine. But it seems I'd be risking getting another that needs a rebuild. Doesn't it make more sense to rebuild? Obviously, I don't know what all the engine will need... so exact cost isn't known. But it's definitely cheaper to get a used Miata engine than do a rebuild.

Thoughts?

Thanks.

LDadrenaline

well seeing as you can get a new crate motor for a few grand, used cant be that expensive. I personally already have a primary and backup motor so I dont need to buy anymore... But I went and bought a new one to be safe.

aj986s

AFAIK, SpecMiata motors are readily available, and relatively affordable, including new factory crate motors. I would consider getting a new or rebuilt crate motor, and then have your existing motor gone over, to use as a backup.

911vet

Thanks for the input. I've heard I can get a pretty cheap engine from Mazdaspeed. I may look into that.

Also, a good buddy here on Rennlist sent me a PM to remind me the car has sat for the last 2 months. Maybe it's just some seepage from sitting. I haven't really got the rpms up... so I think I'm gonna change from synthetic oil to some real Brad Penn stuff... take it out and run the snot out of it... and see if the smoke clears.

Wish me luck!

PedalFaster

SpecMiata.com and SpecMiataClassifieds.com are both filled with knowledgeable people.

mooty

no one rebuilds miata motors. it's much cheaper just to pick up a junker motor or crate motor.

PedalFaster

Au contraire, rebuilds are very common in the Spec Miata world since crate motors don't have all the tricks a fully build race motor does. Full race rebuilds are pretty pricey (budget $4k+ from a well known builder), but a local shop should be able to do a track day-appropriate rebuild for significantly less than the price of a crate.

p-cardriver

http://www.monstermiata.com/

http://www.flyinmiata.com/V8/configurator.php

Go big or go home!

Gary R.

"Pretty pricey" and "$4K+"......... remember what forum this is!

PedalFaster

True, true.

mooty

i am talking about "regular" motors.
if you want a "blue printed" motors, yes rebello and many many others have tricks up their sleeve. i was referring to cheap motors.
and 4K is very very low end of "built" SM motors.

d15b7

hi. i've raced a miata several times. and i race two other japanese cars. before you go out and buy a new motor, i'd do the following:

change the oil and filter. i don't think i'd use Brad Penn. just use a good quality synthetic (mobil 1, or redline, or castrol). i typically run 5w-30 or 10w-30 oil in my jap motors. (my mazda motored car, a ford probe (KL V6 2.5 liter mazda motor) has over 40k track miles on it; never been apart or rebuilt in any way. i change the oil and filter every 5 race weekends. i almost always run 5w-30 mobil 1 in it). anyway, change the oil and filter with a good synthetic. change the spark plus and wires (notorious on a miata). change the air filter and pcv valve. and then take it out on the street and STAND ON IT for at least a full tank of gas (put in some TechTron fuel injection cleaner, too). run it 'one gear down'; by that i mean if you normally would be in 4th, keep it in 3rd. if you normally were going to be in 5th, keep it in 4th. try and keep the revs up above 5k rpm all the time.

keep an eye on the oil level. after that tank of gas, change the oil and filter again. drive the car a bit (normally, now). how does it sound? is it excessively 'tappy'? the mazda motors sometimes have lifter problems, especially if they are sludged up. the top end will make lots of 'tappy' sounds when it does this. (if it taps for a couple of seconds on startup, dont worry. lots of the miatas do this. it should quiet right down in less than 5 secs). if yours is 'tappy', i have some redneck backyard fixes that really work wonders on the mazdas......

after all that, how's the oil burning? a little blue smoke isn't bad (my Probe smokes like crazy on startup, but hardly smokes at all once its hot and turning high rpms. and it set a track record at its last race, so its still going well!).

don't buy a new motor yet; give that one a chance. good luck!

todd
ReidSpeed

LDadrenaline

too true

PedalFaster

So am I. A competent machine shop should be able to do a track day-appropriate rebuild of a Miata motor for less than a new crate motor, let alone the price of a race motor.

Gary R.

Somehow I think "appropriate" in the *Spec Miata* world is as much of a joke as "inexpensive" is in the "Stock" class of PCA is..