Could Oil may have *somewhat* prevented this?

[The_Oz]

From the vague posts, it seemed that this K20 engine was downshifted to 2nd at a very highspeed of 75mph. I'm even surprised the ECU let the motor rev up to 12000RPM for that matter.

Anyway, thinking that how 5W20 seems to be the recommended factory oil for the RSX, would it have prevented the number 3 piston from destroying itself? OR is that a design flaw?

Comments?

Oz

[ February 04, 2003, 06:47 AM: Message edited by: ED P. ]

 

[ShootingStar]

quote:

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Originally posted by The_Oz:
I'm even surprised the ECU let the motor rev up to 12000RPM for that matter. Oz

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People get confused about the idea behind a "rev limiter". It cuts off the fuel flow and keeps you from doing something really stupid on your way UP through the gears, but it can't save your a$$ from a bad downshift. You could have removed the fuel pump and thrown it out the window just before the now infamous downshift, and you'd`still hit 12K!

 

[mph]

quote:

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Originally posted by The_Oz:
From the vague posts, it seemed that this K20 engine was downshifted to 2nd at a very highspeed of 75mph. I'm even surprised the ECU let the motor rev up to 12000RPM for that matter.

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The ECU has no choice in the matter, if you overrev the engine due to downshifting. The ECU enforces the rev limit by cutting off fuel. If you're going 75+ mph, put it in second, and drop the clutch, the engine is spun up by the wheels, and it doesn't matter if you're feeding it gas or not.

 

[mph]

Since my comment turned out to be redundant, I'll try adding something more relevant...

In many cases, the rev limit is chosen to avoid damage due to valve float. The idea is that it takes a certain amount of time for the valves to close, regardless of how fast you turn the camshaft, because the spring is not totally stiff. At high engine speeds, the valve may not finish closing before the piston occupies the same space, and they will collide. If this happens, I don't think it matters what oil you are using.

 

[HOndaGuy]

thats just plain dumb, i would never downshift to 2nd gear at that kind of speed. If anything, he shoulda downshifted to 5th or 4th. Kinda wonder how the heck he decided to do that?

 

[MolaKule]

I dunno, I have stupidly misshifted but caught it in time; I guess I have been lucky.

Inertia placed a force on the con rod bolts or caps that exceeded the tension or shear forces.

No oil can stop that.

 

[Patman]

When I had my 6 speed 98 Formula I missed a few shifts at the dragstrip before. Usually the 2-3 shift, and I'd grab first instead. Sure the rev limiter cuts off the fuel, but mechanically the engine was still overrevved to 9000rpm! (rev limit is 6250 on the LS1!)

I was lucky all I did was break a set of rear end gears. But I didn't bend any pushrods (which is what usually happens on the LS1 when someone does what I did)

And no oil will help a situation like this.

 

[Idrinkmotoroil]

there is no oil or fluid in the world that can keep a piston from smashing into a valve at astronomic speeds - your talking Formula One piston speeds on a street car - yikes !.

sometimes the best equipment can't protect a stupid mistake. It's amazing how many RSX owners are going back to their dealers asking Honda to warranty mis-shift engine damage. Some of them are actualy getting coverage from Honda believe it or not depending on how much the dealer likes you, they really don't deserve any warranty coverage for that kind of mistake IMO.

Just for your information, the RSX-S uses 5w-30 oil from the factory, they recommend 5w-20 for the base RSX and Civic Si K20's, which lends support to the idea that 5w-20 is meant for fuel economy not engine protection.

 

[The_Oz]

quote:

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Originally posted by HOndaGuy:
thats just plain dumb, i would never downshift to 2nd gear at that kind of speed. If anything, he shoulda downshifted to 5th or 4th. Kinda wonder how the heck he decided to do that?

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I believe the guy wanted to shift to 4th and accidentally caught 2nd. It seems that this will be a common occurence to affordable 6-speed cars since the general public doesn't know how to shift to 6th (saw a vid where a *ahem* kid misshifted and caught 4th instead of 6th).

Regards,

Oz

 

[The_Oz]

quote:

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Originally posted by JSIR:
Just for your information, the RSX-S uses 5w-30 oil from the factory, they recommend 5w-20 for the base RSX and Civic Si K20's, which lends support to the idea that 5w-20 is meant for fuel economy not engine protection.

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Thanks for the clarification JSIR (that's twice now

)

Oz

 

[impala_sc]

Hell, I managed to misshift on a 4speed a few times.

Fortunately I had a strange feeling something wasn't right before letting the clutch out.

quote:

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I was lucky all I did was break a set of rear end gears

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Hey, that's a good idea! Design the rear-end to kamakazi to save the motor. I should patent that...

 

[Patman]

Actually, what normally happens on an LS1 when you misshift, is that the weak pushrods will bend. People get mad about it, but I tell them it's a cheap easy fix that is much better than a piston getting ruined or a valve getting bent. You can buy 16 new pushrods from GM for under $150 and it only takes 3 hours to change them.

 

[Soma07]

quote:

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Originally posted by Patman:
You can buy 16 new pushrods from GM for under $150 and it only takes 3 hours to change them.

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Ouch! Is there anything special about LS1 pushrods that make them so $$$? Normal run of the mill hardened pushrods only run ~$20-30 a set. For that much you could get some awesome chromemoly, one piece SBC pushrods (custom length if need be) and still have enough left over for a 6 pack

Sometimes I'm glad I have an LT1

 

[MolaKule]

Patman,

"You can buy 16 new pushrods from GM for under $150 and it only takes 3 hours to change them. "

I would assume that one would "re-bearing" at the same time. Bearings would probably be out of spec with those forces encountered.

 

[Patman]

I could be wrong on the pricing on those pushrods, this was the price a few years ago and they could also cost more in Canada. I bought them thinking some of mine were bent, but in the end the ticking noise I heard was my rear end about to let go (one of the teeth must have been sheared off when I missed the shift, then the rest followed a few weeks later)

AFAIK, when people bend their pushrods, all they change is the pushrods and nothing else. That's all I was planning on doing. I wish I took some digital pics to show how clean the top end of my engine looked after using Mobil 1 all that time.

 

[sprintman]

impala_Sc
a company did. They are called General Motors. after destroying numerous 10-bolt Salisburys and a couple of Saginaw g'boxes in my 1970 Holden 350 Monaro I understand why 90% or more hot chevs here have Ford Toploaders and 9-bolt diffs in them. Also explains why a GM Nascar is nearly all Ford based from the floor pan to diff/g'box and from memory suspension and axle design.

 

[S2000driver]

Manufacturers could easily implement a solenoid-based downshift lockout if your ground speed is too high for a given gear. But they don't.

Many high-revving Honda/Acura owners are getting stiffed on engine warranty claims because the dealerships are quick to assume the owner probably did a downshift overrev.

links to other forums are not allowed

[ February 04, 2003, 06:53 AM: Message edited by: ED P. ]

 

[eldawg4100]

come to think of it, i work at a dealer that sells honda as well as many others... we have had 3 nearly new s2000's with blown engines needing replacments.. i know about one for sure, i heard something about 1st gear, and 75 mph lol... people also try to get it under warranty... the 75mph finally admitted it...