21 replies to this topic

[Tom Masiero]

I missed forth and went into second and over revved. Engine still seems to run fine and has the same power. But in the back of my mind I keep thinking what did I hurt. Are any signs of failure I can be looking for as I do maintenance over the winter?
1990 ssm Miata 1.6

[Jim Drago]

Do you have data? How bad was over rev?

 

The bad thing is often they will dyno and run fine after an over rev, then you snap a rod or lose a rod bearing. 

 

Do a leak down and make sure you didnt dink a valve. The rev is either change rod bolts and check rods or chance. If over rev was under 7800 or so, you should be OK

[wheel]

Just my experience.  Same thing except missed the 2nd to 3rd up shift and went into 1st.  Two races later the thin end of a rod snapped off without another over rev.  

[FTodaro]

I have over rev my Stock motor when I first started racing, not sure of the RPM but it was big and did not do a thing to the motor. I have not made that mistake on my pro motor over the last few years but early on you tend to get a little excited. I think i did it twice and since then had it rebuilt and its still kicking.

 

What is nice about our little Miata's is that they can take a beating like most other cars cannot.

[Tom Masiero]

No Data running at the time. Can I get that info off the ECU somehow?

[Keith Andrews]

I'm religious about cutting open oil filters.  It's my understanding that if a rod bearing starts to come apart you will see some metal in your filter.  It's simple to do and no matter where it comes from if you see metal bits in the filter it's time to investigate further. 

[Jim Drago]

I'm religious about cutting open oil filters.  It's my understanding that if a rod bearing starts to come apart you will see some metal in your filter.  It's simple to do and no matter where it comes from if you see metal bits in the filter it's time to investigate further.

I do and advise the same. If you dont do it all the time, it is almost a waste of time. If a rod bearing starts to go, you have to be a little lucky to catch it by cutting the filter. It stems the bleeding, it turns a potential 5000-6000 problem into a 1500 or less problem most times.

[screaming monkey]

Did the same. Bent valves. Went two weekends of racing before the discovery. Engine felt a little flat at RA, but not obvious. Found in leakdown. Could have been worse.

[steveracer]

I did that once. It went to 8510 rpms according to data.

 

Never made any funny noises, lost pressure, or put metal in the filter. Raced it for another year and a half before freshening it.

 

YMMV.

[Bench Racer]

I did that once. It went to 8510 rpms according to data.

 

 

YMMV.

Usually the E & F production car racers check their rods after a time or two above 8,200 rpm's.

[Keith Novak]

If you pull the pistons out, do you have to re-do the rings?  I was thinking that if they weren't in exactly the same orientation they were when the engine broke in, it could result in higher leak-down numbers.

[Bench Racer]

If you pull the pistons out, do you have to re-do the rings?  I was thinking that if they weren't in exactly the same orientation they were when the engine broke in, it could result in higher leak-down numbers.

Within an engine some rings tend to rotate during actual use and some rings tend to stay put. As far as re-using rings, it may be reused if there are no issues and the end gap is to spec. I wouldn't re-use rings because it's a hell of a lot of work to get an unexpected surprise.

[Keith Novak]

That's what I figured.  I've over-reved my engine a few times and it's still running strong but from what I've been told, if the tires are good and hot they'll slide and it's not as bad on the motor.  There are low hours on this motor and I have rods that I could just swap out with some new bearing which is relatively easy <cough> but tearing it down to deglaze the cylinders for new rings adds a fair bit of extra effort.  I may just break in my back-up motor and give some thought to dealing with the questionable one.

[Sphinx]

What's the easiest way to cut open the filter without a filter cutting tool?  I did this guy's method last night http://www.youtube.c...h?v=KFXYN5ZN9S8 on a filter for one of my street cars.  It was a PITA, but worked. 

[Keith Andrews]

That looked like a fairly good way to do it without a filter cutter.   If you decide to buy a cutter this is the one I have.  http://www.jegs.com/...roductId=753437  It has worked well for a number of years.  

[Ron Alan]

I used my wife's can opener...

[Sphinx]

I used my wife's can opener...

 

I tried it, didn't work. 

[steveracer]

Cheap exhaust tubing cutter from any auto parts store.

[James York]

No Data running at the time. Can I get that info off the ECU somehow?

You mean is it stored for download?  No its not.

[Juan Pineda]

I've only had good experiences with over revs. I tried to kill my 1.6 so many times. What finally did it in was leaving the oil cap off and running it low on oil.