99 Miata Blown Engine - HELP!

With the oil changes at ~10,000 mile intervals, I'm not too surprised. That's about twice what I'd recommend as a maximum. The dealers price is arguably out of line. What grade and brand of oil were you using? It's remotely possible that you had a #4 bearing failure. I'd suggest you look it up on miata.net There is a faint hope that you may get Mazda to pay for some of the cost.

Alternately, the dealer's total price is in the ballpark if you want to replace the engine with a custom rebuilt engine, and have someone else do the install. As a rough number, I'd likely figure ~$1000 for labor. If the head is OK (doubtful, due to the oil change interval), a "short block" might be used. Flyin Miata (an advertiser on miata.net) deals in custom rebuilds), as do several others.

miataplanet.com lists '99 engines for $1,250... of course you need it shipped and installed... but that is far from $3,700.

$1,250 is definetly better than $3,700 but still, I'm really put off about this. I had a Grand Cherokee I did every 10k mile oil changes and it lasted for about 239k miles. I'll definetly put off about this. I called up the Mazda corporate number and before I explained my problem or disclosed if I was someone who owned a Mazda or was thinking about buying one I asked the guy how long Mazda engines are built to last for. I didn't say how often the oil was changed or anything, the first words out of my mouth were literally "How long is a Mazda engine supposed to last?" The response was firt "7 to 10 years". I asked the guy how many miles? He said 70-100k. That's not too confidence inspiring. To top it all off, they suggested I pay to have the car towed to a dealership, so I could pay them to take it apart so they could tell me they can't do anything for me. After that I recieved a call from the dealer down here saying a "Mechanic there was interested in buying my car" and "Is there a new Mazda I would be interested in?" They're going to try to sell me another car? When the first one didn't last 80k? I don't care if the oil changes weren't frequent enough, my AMERICAN made Jeep went for longer between changes and lasted almost 4 times longer.

I doubt your Jeep turns 4000 rpm at 80 mph, though. 3k miles is a good plan for changing the oil in any small 4-cylinder. Miatas on that sort of maintenance schedule typically pass 200k with no major problems, and often go much farther.

Think of how many oil changes you could buy for $3700...

Hadn't even thought of that. You make an excellent point and you're probably right. I'm still sitting here with a very expensive paper weight at the moment and don't have a clue as to how to get out of this thing.

You should get in touch with that fellow somebody referenced a few weeks ago and have him drop a V8 into your Miata.

I suggest getting at least a second opinion and repair estimate.

How do you know who to trust? Anybody know someone honest in the Boca area? The shop the car is at now is usually pretty good and they're not a car dealer so that raises their credibilaty with me slightly. Has anyone else who reads this blown a Miata engine? I can't be the only one this has ever happened to....

Is there a local miata club, maybe you could find someone thru there to do the swap for you. I've been told it's relatively easy as far as engine swaps go. There are always engines for sale on miata.net , w/o paying for a rebuilt you might get one considerably cheaper (more risk of course). Tons of miatas there in Florida, should be plenty of used engines around.

You could try a long shot and read up on the #4 thrust bearing problem on some 99 and 00 engines. I can't imagine Mazda doing anything for you this far down the line and especially since you didn't follow the maintenance schedule. But at least you may come to realize that the extended service intervals were the cause of death. Maybe that wouldn't be so helpful now.....

Chris

99BBB

Thanks Chris - That's not a bad idea. I'll find where they are and send them an email in a few hours. Somebody has to want this thing. I never really liked the miata when I had it, but now that it's gone I sort of miss that wretched little car. You couldn't hear yourself think over 60 MPH, you could hit a giant bump and tell if it was a nickle or a quarter you had just run over, but there was something really fun about driving that little money sponge.

the miata I4 is widely regarded as exceptionally durable...bulletproof even. which is not to say you can get away with abuse, but is to say that it as reliable/durable as just about anything else out there.

my '99 gets new synthetic motor oil every 8-10k, and a new filter twice as often. it's a rare day that i drive it and don't hit the rev limiter. it is autocrossed at least once a month and tracked 4-6 times per year. and with gas costing what it does, it's been pulling much more daily driver duty. i expect 200k+, easy, and have gotten that and more following the same service regimen with a honda I4 and nissan V6.

your experience is exceptional, to be sure. i suggest a little forensics to determine the reason for the failure. 10k OCI should not result in a catestrophic engine failure at 78k.

$0.02,

dookie

The real key in your case is synthetic oil and an in between filter change. Time will tell.

I tend to agree. Usual problems I have seen from infrequent oil changes are:

1. Premature wear on valve gear, maybe tappet replacement at 80K, Cam & bearings at 150K
2. Premature ring wear, maybe oil consumption & smoke at 150K
3. Tappet noise, particularly on Miatas.
4. A build up of sludge in the engine, particularly the sump.

Maybe a smoking, tapping miata could be explained by infrequent oil changes, but not this. Aggressive driving probably would not do it either, unless you were being silly, and changed down gears to rev beyond 7200.

I suspect this one probably had a weak point somewhere, sometimes steel develops hidden cracks.

Another $0.02, (only being Australian its a little less)

The repair shop said there was a hole in the side of the engine block. What could have done that? I'll take an educated guess from someone before I throw money to a repair shop.

Probably a broken connecting-rod. Why the rod broke is another question.

Usually the cheap way of solving a serious engine problem is to find an used engine (from a wreck) for sale. If the head of your engine is not damaged it might also be possible to find a engine with a damaged head and make a complete engine out of the non-broken parts of the two.

"Miataman" wrote in news: snipped-for-privacy@t31g2000cwb.googlegroups.com:

The engine threw a connecting rod. This is caused by insufficient oil getting to the big end bearing so the bearing is damaged, then the excessive clearance between the connecting rod big end and the crank shaft quickly beats the end of the rod so it breaks. You should have heard it before additional damage was done.

Not a guess, if you have a hole in the side of the block that's almost certainly what happened.

Not always. Could also have been caused by:

1. A dropped valve. A valve breaks or it's retainer lets go, and it falls into the cylinder. As the piston goes up, it pushes the remnants of the valve into the head at great speed, and something breaks at the weakest point.
2. A lot of water in the inlet. If a cylinder gets a lot of water in it, it fills the combustion chamber. Water cannot be compressed like air, so something breaks. AKA as "hydrauliced"
3. A piston damaged by extreme pinging. Pinging puts a lot of stress on piston crowns, if it's real bad, damage can result. Once the piston comes apart, the rest of the motor often follows.
4. A stuck injector. This can fill a combustion chamber with fuel, causing a fuel hydraulic. Usually only happens with oversize injectors.
5. A broken timing belt/chain. Some motors (not standard miatas) will fly apart as the valves are pushed into the piston if the valve timing is out.
6. Something was flawed, and broke. Could be almost anything.

If the damage was due to oil starvation, there shold have been some indication, just before it happened. A) Was the oil low? A leak maybe? Oil pressure switchs/sensors sometimes break & drop all your oil on the ground. I have had 3 cars do this. B) Oil pressure drop to nothing just before it happened? Were you going fast around corners with low oil? C) A whole heap of noise, as oil drained out of the clearances between bearings. This should have been rather obvious.

If you have a conrod through the block, it should be obvious, there will be a gaping hole on one side. The shop shoud be able to point it out to you. The motor is stuffed, and IMHO your best option is either a rebuilt one, or a replacement from the local wreckers. On a miata, if A, B & C were not observed I would be guessing 6 as the most likely cause. Some Miatas were build with a flawed mainbearing, this could well account for it.

Covers the defective mainbearing issue. If your car was one of these, maybe you can hassle Mazda & get somewhere.

Leon