So I got a little bit of 2nd gear instead of the intended 4th gear during a "scca track night" event this evening in my 95 Miata. I think I got the clutch back in pretty quickly, but the engine definitely spun way past redline. It seemed to run fine for the rest of the session and made the 1 hour drive home with no complaints. Is there anything I should/can check/watch out for/do? Or can we conclude that I dodged a bullet?
The old adage on how to tell if you overreved your engine was that it loosely fit in a 5 gallon bucket. Since yours is still running, you may have dodged that bullet.
Properly executed money shifts will provide immediate feedback... boom
I would do a compression test but otherwise call it bullet dodged
Your good, the oil pump gear is usually what busts when you over rev a miata motor so if you still have oil pressure id call it golden. Still paranoid then send an oil sample off to blackstone
Compression and leakdown test. But should be OK.
Sometimes you'll spin a bearing, but if it handled another hour of track driving, it's probably OK.
If it's not fine, there's not a lot you can do for it right now anyway. Continue as normal.
ssswitch has it - there's not much you can do, unless you choose to tear it down now and save the block. I'm not of the "if it didn't blow immediately, you're okay" camp, as I have seen them blow the session after an overrev.
Keith Tanner wrote: ssswitch has it - there's not much you can do, unless you choose to tear it down now and save the block. I'm not of the "if it didn't blow immediately, you're okay" camp, as I have seen them blow the session after an overrev.
Yeah, and not just the session afterwards. I've seen a number of people report rod failures in the weeks following an overrev, often when just driving around on the street. The theory seems to be that the overrev weakened the rod and it then fatigued out some time later.
So yeah, if the other components in the engine are expensive, there might be value in tearing it down to inspect it and prevent damage to a stroker crank or a P&P head or the like. If it's just a stock motor then the cheapest approach is probably to just run it and swap it out for junkyard motor if/when it blows.
Did the same thing with Toyota 4ag decades ago. A month later I was replacing a head gasket due to some exterior weeping.
Keep a close eye on everything and follow-up with all the advice offered in this thread.
I remember blowing up a BP motor in the Escort GT at VIR the weekend after the big over-rev at Road Atlanta. There's a piece of the cap and bearing lying on my "racing memories" shelf here at the office.
Many moons ago I intentionally set my rev limiter about 300rpms too high for my engine... It effectively used a series of small over-revs to coax the rods into growing until they could no longer be contained by the block. It was an experiment in how not to safely get a little more power from an engine without spending any money.
Compression/leakdown to check for bent valves. Bore scope can help look for nicks in the piston.
You won't be able to determine slightly stretched rods or fatigued pins but often the bottom end is way more capable than the valve springs so you can often get away with a head job if there is damage.
Oh, bad luck.
I have done similar things to motors and lived to tell the tale. If I wanted some $25 reassurance, I would do an oil change and send a sample to Blackstone, and he will at least be able to tell if there are is high contamination of copper (bearings) or iron (steel), or coolant (head gasket). If the numbers come back high, he will usually tell me to change the oil again in 1K miles and send him a sample of that. It lets me plan whether to start looking for another motor.
I've done the same on my 99 Miata coming out of 17 at Sebring a few years back at my first track day. No issue since. My dad even had a minor one last night at PBIR. Still ticking.
Out of curiosity, what do you consider way past redline?
A friend did the exact same thing in his MSM. It started rod knocking some time later. It all worked out ok though, it makes over 300HP at the wheels now.
Of course, it took a pretty heavy Flyin Miata intervention.....
I think on a BP, i'd be less worried about oil content from a short overrev, and more worried about some S-shaped rods. I doubt oil content will show anything.
Keith Tanner wrote: ssswitch has it - there's not much you can do, unless you choose to tear it down now and save the block. I'm not of the "if it didn't blow immediately, you're okay" camp, as I have seen them blow the session after an overrev.
Paging EvanB...
In reply to Jamey_from_Legal:
WIX/NAPA does it for $14, NAPA P/N FIL 4077. That includes TBN.
In my IT Neon, I have hit first instead of third at turn 3 in Calgary. The first time I did it, I thought I'd broken the tach, because it never dropped off the pin while I was in the process of pulling it out of first, then back into first again, then finally finding third. Never even spit a rocker. The next time I did it, I knew better.
There's times I hate good synchros. I always hate having to shift mid corner.
Kenny_McCormic wrote: In reply to Jamey_from_Legal: WIX/NAPA does it for $14, NAPA P/N FIL 4077. That includes TBN.
Someone had a sense of humor about the numbering process 
Knurled wrote:Keith Tanner wrote: ssswitch has it - there's not much you can do, unless you choose to tear it down now and save the block. I'm not of the "if it didn't blow immediately, you're okay" camp, as I have seen them blow the session after an overrev.Paging EvanB...
Mine was fine...until it blew the event after.
Sell it to me cheap!
In reply to Knurled:
I don't get it, HOLL? LLOH? The CMOS XNOR gate chip?
Streetwiseguy wrote: In my IT Neon, I have hit first instead of third at turn 3 in Calgary. The first time I did it, I thought I'd broken the tach, because it never dropped off the pin while I was in the process of pulling it out of first, then back into first again, then finally finding third. Never even spit a rocker. The next time I did it, I knew better. There's times I hate good synchros. I always hate having to shift mid corner.
Shifting mid-corner is usually not a good idea. 
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