92 GSX Revved to 9800rpm on accidental 3-2 misshift...@75mph

[SpoOLxExO]

So now it makes a rapping noise near the front cover. The two weird things about this noise:

1. The oil pressure fluctuates day to day, somedays it has BUTT oil pressure (Near bottom line), and somedays its healthy.

2.The noise at idle can be cancelled out by pressing the clutch in (Reused throwout bearing after 8 months storage, even thought the act2600 was installed and only ran 300miles.) But when you rev it, it makes the noise, kinda like a small v-twin motorcycle when you twist the throttle.

This is on a:

-Fresh 1g rebuilt head with stainless valves (Springs and retainers coming soon!)
-Low mile JDM GVR4 shortblock (Stock front cover, but with 92 oil pump gears)
-Compression is 150-150-150-138
-Balance shaft removal done via VFAQ method, and kit.

Car still runs, but I'm scared to drive it even.

What do you say?

 

[Lordpaxin]

Ok.

I may be wrong, but isnt there a rev limiter.
i dont see how it is possible to rev that high.

 

[Jebus[tuning]]

Originally posted by Lordpaxin
Ok.

I may be wrong, but isnt there a rev limiter.
i dont see how it is possible to rev that high.

Seconded.

Unless you were redlining in third, this is impossible.

 

[kpt4321]

No, it is possible. He was in third gear, and he accidentally downshifted into second, he probably was trying to get into fourth.

The ECU cut fuel and spark (rev limiter), but that doesn't matter when the motor is connected to the wheels spinning at 75 mph, through the tranny.

 

[CR95GST]

, this is definitely possible. My friend downshifted his Prelude from 5th to second at 85MPH. The calculated RPM was like 11,500 RPM. Funny, all he did was kill the valvetrain. No engine damage at all (lucky non-interference motors )

As for the probable noise, if it was a spun rod bearing, it's pretty loud. Internet diagnosis is virtually impossible. Especially when noises are a symptom. Get it checked out. ANY abnormal noise is not good no matter what it is.

 

[Defiant]

Originally posted by Lordpaxin
Ok.

I may be wrong, but isnt there a rev limiter.
i dont see how it is possible to rev that high.

You may not be able to _rev_ it that high, but if you bang the wrong gear you can certainly _drive_ it that high with the weight of the car and the speed of the road.

 

[SpoOLxExO]

Maybe I should have added to the fact that I'm running a TMO chip with a 8500rpm limit, either way KPT is correct.

Its because of the wheels driving through the trans @75mph, and forcing it to buzz to 9krpm+

At any rate it doesnt matter what it is now, because my stainless valves are toast.

The crank timing pully bolt, backed out. Thats probably what the noise was to begin with, but either way it backed out enough to let the timing slip under boost. Shouldnt have done it but looks like I got meself a winter project...

I'm gunna rip it all out and build myself a 95 piston big rod motor. My buddy has invested in a torque plate for a guy who builds engines in his own machinery.
I just racked up at least a grand damage for this one, but boost is soo addictive, you know the story....

Oh well, I'll be out for the spring anyways.

Thanks for the responses!

 

[billdo_83]

Originally posted by kpt4321
No, it is possible. He was in third gear, and he accidentally downshifted into second, he probably was trying to get into fourth.

The ECU cut fuel and spark (rev limiter), but that doesn't matter when the motor is connected to the wheels spinning at 75 mph, through the tranny.

Exactly.

I did the exact same thing that you did but I was going 90 when I shifted into second.
I was very lucky. My TRE tranny took the shock of it and my motor did for the most part.

I had the rapping noise that you are complaining of and thought that I was going to have to rebuild the whole thing but I just ended up needing to do the top-end.
Its possible that you just bent some valves and your pistons are okay and if that is the case then you just need to rebuild the top-end like I did. I went with Titanium Springs and retainers and then SS valves from RRE.

 

[Megags]

Originally posted by Jebus[tuning]
Seconded.

Unless you were redlining in third, this is impossible.

Try it, it really does work I've done it 4 times now. once up to 9200rpms, the other 3 I didn't see how high it went.

Everything is still ok...so it seems...

 

[Norcalrallyist]

Originally posted by CR95GST
, this is definitely possible. My friend downshifted his Prelude from 5th to second at 85MPH. The calculated RPM was like 11,500 RPM. Funny, all he did was kill the valvetrain. No engine damage at all (lucky non-interference motors )

As for the probable noise, if it was a spun rod bearing, it's pretty loud. Internet diagnosis is virtually impossible. Especially when noises are a symptom. Get it checked out. ANY abnormal noise is not good no matter what it is.

I second the spun main bearing.