mechanical overrev, whos done it? what broke?

[MyBeatGSX]

I had my first one today. My tranny hates going into 4th after being shifted hard into 2nd and 3rd. So I banged it hard and bounced off into 2nd. Thankfully I was on the brakes at this point and only hit ~8400rpm (according to the SAFC). I quickly put the clutch back in before it was even out all the way and thankfully nothing seems broken. Anything I should check or keep an eye on now?

Who else has done it, how, and what (if any) damage did it do?

 

[talon96tsi]

I have downshifted accidently from 3rd to second when i meant to shift into 4th, the car still runs mechanically sound, and as far as i know nothing is broken as a result.

 

[weith1111]

Have you done the BS elimination?

If not those bearings saw almost 17k rpm, and are probably very unhappy.

 

[andymoraitis]

Have you done the BS elimination?

If not those bearings saw almost 17k rpm, and are probably very unhappy.

I've actually done the same thing at the track on the old 2.0 with the motor spinning to 8700 RPM. It spun the BS bearings and took out the rod bearings within the next 6 months. I did have the same thing happen on the 2.3, but this motor has no balance shafts. About the only thing it did was partially shred the alternator belt and rip up the oil pressure sender wires. Draining the oil and dragging a magnet in the pan showed that everything was still in one piece thankfully.

 

[MyBeatGSX]

No the balance shafts are gone thankfully. No belts appear to be damaged, the motor runs same as it did before.

Andy, how long was it at that RPM? Did you like solidly let the clutch out? I let it 60% of the way for just a split second and felt the car lurch forward and immediately slammed it back down. That's exactly what I'm worried about is no problems now but something being damaged and then fully breaking very soon.

 

[CanadianTSi]

About a year ago I grabbed 2nd going for fourth from the top of 3rd...S-AFC saw 9450rpms. No damage done...

I routinly see over 8000 on mis-shifts even though I still have the stocxk 7500 rev limiter.

Stock 7bolt with 223,000kms FTW.

 

[andymoraitis]

Andy, how long was it at that RPM? Did you like solidly let the clutch out?

Probably close to a second with the clutch close to fully out during which time I crapped my pants. Here I am hauling the mail at close to 95 mph down the track and bam! Just to be safe, you can drain the oil and drag a magnet through it. It seems like Ty dodged a bullet so hopefully you did as well.

 

[MyBeatGSX]

Yea Ty, I figured 8400rpm wasn't way way out there for this motor and it saw that for probably <1/2 a second.

My friend did the same thing to his Redline last summer. Those things have some very tall gears so it burried that tach at like 9,000rpm (6,500 limiter) and was there for a good amount of time before he put the clutch in. No apparent damage a year later, so I guess some people are fortunate.

So now I just thank God it didn't break anything and hope nothing decides to break in the next few days.

 

[99gst_racer]

I've never done it in a DSM, but my buddy did it in his B18C power car that I helped build. It wasn't pretty. http://www.dsmtuners.com/forums/showthread.php?t=109117

 

[Kevin Jewer]

At 8400 you should be fine, as stated earlier. But the most common problem to come of over revs is loose flywheel bolts. It's almost guaranteed. Of course I'm talking 10k rpm plus. I personally went over 10k twice in a couple week period and my bolts loosened up. When you get up around 12k you can usually count on bad rod bearings too at the least.

 

[Apeximprt2nr]

I've done it twice so far. Mis-shift 3rd -2nd when racing trying to get to 4th. I hit about 8k RPM's. Still runs fine as far as I know. It scared the crap out of me though . Why does the rev limiter not stop it? Does it not have time to react?

 

[Kevin Jewer]

The rev limiters can only cut fuel or spark so the engine can not increase in speed on it's own. Forcing the motor to rev faster mechanically (tires turning the transmission and turning the motor) can not be stopped.

 

[BISHILVR]

The bearing material is not magnetic, so I dont think a magnet check will do you much good. If you find anything on a magnet it is way to late at that point. Drain the oil and check for sparkleys in the sun, and if you want cut the oil filter open and check it for glitter. Good luck

 

[bob123131]

He's right if you actually find metal shreds your screwed and start saving money. Check for a light sparkle in your oil. Also remmeber a red line is set there for your safety, but that does not mean your engine will blow up or aotmatically be damaged. Yes it is very possible, but its one of those things we hear about alot liek vapor lock, but in all reality is rare. We have all probably brought our cars above 8k one time or another half of us probably ###### didint even know we did. Check for glitter if anyone else gives some good tips do it otherwise forget about it. If somethign did go most lickely by time you relise it wil be to late. I highly doubt anything did though so just relax and move on to the next thing.

 

[slipstream808]

I second the flywheel bolts! Check 'em.

 

[andymoraitis]

The bearing material is not magnetic, so I dont think a magnet check will do you much good. If you find anything on a magnet it is way to late at that point. Drain the oil and check for sparkleys in the sun, and if you want cut the oil filter open and check it for glitter. Good luck

That's a very good point. Thankfully, I had no glitter with the episode on the stroker, but I didn't drain and check the oil and filter when it happened on the 2.0

 

[sunflashx]

I did the 2-3-2 shift on a 2.0L. Shredded the balance shaft belt and busted the flywheel loose. No idea what rpm I hit.

6 new flywheel bolts and a belt later she was good as new.

 

[NOSLO2PT0]

I've done the 2-3-2 shift more than once. One time, it happened at about 103mph, 8100rpm in 3rd gear. For those that really need to know, that's 10,400rpm on HKS 272's and a stock valvetrain. I bent a few valves and had some flywheel bolts come loose. After changing the flywheel, the car still ran 11.70's with the bent valves. Only took me 30psi with a 3065 to do it though

 

[MyBeatGSX]

How does overreving loosen flywheel bolts?WTF

 

[Kevin Jewer]

I'm assuming it's because the flywheel distorts under the immense pressure. Mine had the bolt holes elongated towards the outside edge of the flywheel. If the flywheel has any imperfections it can come apart, usually the car is a total loss when that happens. So I never used that flywheel again, just to be safe.

 

[silvah_gsx]

Can the bolts come loose without being over-revved or can that not happen in normal driving?

 

[NOSLO2PT0]

Can the bolts come loose without being over-revved or can that not happen in normal driving?

Of course it can happen with normal driving. That's why you ALWAYS use loc-tite RED + 100ft/lbs of torque on flywheel bolts. Basically, if you don't want a nut/bolt to come loose, use some form of loctite.

 

[sunflashx]

Of course it can happen with normal driving. That's why you ALWAYS use loc-tite RED + 100ft/lbs of torque on flywheel bolts. Basically, if you don't want a nut/bolt to come loose, use some form of loctite.

I drilled all my new bolts and ran safety wire through the heads in addition to the loc-tite.

 

[Caithness]

I drilled all my new bolts and ran safety wire through the heads in addition to the loc-tite.

How the hell did you drill through the grade-11 flywheel bolts? I took my grade 11 turbo bolts to a machine shop (though not a very good one) and they broke two bits unsuccessfully trying to drill through them with a drill press. I really want to safety wire my turbo, flywheel, and a couple of other things but I haven't found a way to get holes through super-high-grade bolts.

 

[bastarddsm]

Id bet that cromemolly fly wheel bolts and some other stainless hradware form ARP would be a possiblility if enought interest was shown.