"91 Miata

[rashley]

I recently acquired a nice 65,000 mile '91 Miata that will become my daughter's first car in about a year (yes, I'm making her learn on a manual transmission!).

The engine appears to have been well maintained, runs well and has no leaks. Although I'm partial to synthetics based on my racing experiences, I wonder if an older engine like this ... although not what I'd call "high mileage" might be better off with one of the high mileage oils to keep the seals in good shape.

I'd appreciate any opinions (other than those referring to my sexual prefernces and heritage, that is).

 

[Quest]

AutoRx once and then if you want to go with synthetic, by all means.

For this vesion of Miata(1.6L, bottom part is basically from B6 block), watch out when it's due for timing belt replacement. PM me if you need to know..

Q.

 

[The_Jeff]

Those cars are awesome and your daughter is 1 in 1000 lucky. IDK about any stigma, Miatas hold their value way better than many other vehicles. So maybe even more stigma would be a good idea?

Hopefully the car sitting in the garage will serve as motivation for her to do well in school and everything you ask of her.

Will she be driving year round in this thing or taking the bus when it snows?

 

[UncleS2]

My 97 Neon has over 187,000 miles on it now & has never seen any of the "high mileage" oils. Most (all?) of the high mileage oils have seal swellers, some more than others I suspect: might stop a tiny leak, but if you stop using the high mileage oil, the seals will probably shrink, & then it begins to leak oil again, & maybe worse than before. So, for *some* cars, high mileage oil may be a one-way atreet- once you start using it, you're kinda stuck with it.

You say it doesn't leak now. If I had any concerns about giving it a "seal treatment" I'd probably give it a dose of Auto-RX, using conventional oil for both clean & rinse phases. In fact, that might be a good "General Principles" thing to do for its first two oil changes, then run whatever motor oil you like. There are a lot of oils out there producing great used oil analysis these days. In my little high-revving engine, the best results have been with Schaeffer 7000 Syn Blend, though a badly overextended interval with plain old Pennzoil 5w30 recently also produced very good results. JMO, your decisions may vary.

Too slow, Quest beat me to the Auto-RX suggestion! I guess it's true: "Great minds run in the same gutter..."

(or something like that!)

 

[OMCWankel]

My '91 Miata had 240,000 on it when I sold it to a co-worker. It is still running at 260,000. Quest is correct, watch out for the timing belt, although I went 100,000 with the belt still like new. Use a quality synthetic in the transmission and rear end, as the rear end is the weak link in the drive train.

I used Mobil 1 15W-50 at 5000 mile OCI, but I live in the tropical swamp of Houston, and Miata's run hot (small radiator/small front grill). I still believe the Miata is a great economy car in disguise, and currently own a ‘97 with 125,000 trouble free miles. A big thumbs up

on your purchase, and your daughter is one lucky young woman!

 

[ARB1977]

Off topic but those miatas are pretty cool i went for a ride in a 91 miata at a thunderhill raceway in norther california with the stock suspension and slick tires those things are way fun.

 

[ex_MGB]

I run Mobil 1 Extended Performance 5w30 in my 2001SE BRG Miata with Redline MT-90 in the transmission and Redline 75W-90 in my Torsen rear end.

65k miles on that iron block oil sprayed piston cooling '91 is nothing. Engine is same as the turbo 323, so it's heck for stout in NA application.

Engine is non interference so if timing belt breaks you are only stranded. You should check your shifter turrent oil level.

My experience is this engine as well as my P5 really enjoys new plugs every 15k or so. Snap to change with that huge old fashioned valve cover with plugs going straight down to the top of the cylinder.

Finally, this car was designed to be driven at the limits. Need to take the keys from your daughter every now and then and blow out the carbon with a relentless high rpm thrashing and red line shifts. The car will love you for it as the little bugger actually thinks it's a sportscar rather than a rwd economy car in disguise.

 

[rashley]

I've PM'd everybody I could, but I also "thanks" also to the rest of you for your thoughts. fortunately the timing belt was changed on this car just before we got her and I've already changed the transmission and rear end to synthetic.

The turret oil is on the "to do" list and a little regular carbon removal (and sanity check) by this used to be racer remains a regularly scheduled item. Once it becomes a daily driver, it'll probaly be a year 'round car ... so a set of snow wheels and tires are on the agenda.

I too have a P5 and agree about the plugs at early intervals. So easy to get at, I just throw in another set of cheapo copper plugs.

Thanks again guys.