Mechanical Over-rev

[Satisaii]

Some fellow in a BMW was brake checking me on the freeway today (multiple times), so I decided to try and get in front of him when I shifted from fifth to second (oops) doing about 65 mph. This caused it to trigger a CEL and to run poorly. I decided that the damage had been done and limped it home (avoid one tow charge.) Now, there have been times when I deserved to be brake checked, but I was behaving myself today. I am a little lost on that one.

When I got home, I immediately pulled the plugs and did not see anything wrong with them, so I did a hot compression test (195, 195, 200, 200.) At that point I pulled the codes (p0339 I think, but my memory is poor for those things), reset the computer and restarted it. The supercharger was really noisy, so I cut the belt and that killed the noises except for a small squeak that seems to be coming from the harmonic balancer/crank pulley area. After that I went around the block and it seems to run well. I can't really remember how it ran before the S/C install, but it felt like it was running good.

I am going to take it in for a check-up. What should I tell them to look for specifically relating to the over-rev? I will go ahead and have all of the fluids changed while it is there.

2004
Vortech S/C (I think I will send it back, because it is way too noisy. Wish me luck on good customer service)
~26,000 miles

Thanks,
John

[ninja]

valve retainer damage

edit: if your motor is otherwise fine, you should get the retainers replaced anyway

[Satisaii]

That is something that I did not consider. Which is why I asked the question in the first place.

Thanks!

[repiv]

from fifth to second (oops) doing about 65 mphIf this is accurate, then your engine could have revved as high as 9200 rpm. This, in itself is not a big deal as the same valvetrain in an AP1 can easily handle this rpm. However, what the AP1 motor doesn't experience at this rpm is the piston speed and crankshaft loads. There's no telling if the lower end components have been overstressed. Additionally, it is important the rate at which the revs climbed. An over-rev like this can produce an increase in engine speed far quicker than what is normally seen. It is this high rate of increase that can cause valve retainer damage.

PS. What is "brake checking" anyway and why would you deserve it?

[Satisaii]

I might have been going faster, but I was not looking. It did throw a CEL(and ran poorly until the ECU reset), but I hear no funny sounds coming from it.

Brake checking is when somebody hits their brakes in such a way to force another driver to hit the brakes: ie checking to make sure the other car's brakes are working.

When I was younger and more pissed off, I can see why somebody would do that to me. But this time I was not speeding, had been courteous of other drivers, signaling, etc. Minding my own business, not in a rush... all I can think of is I or another S2000 driver got to him recently and I was the outlet for his pent-up rage. Sure was not the way I was driving at the time.

Bottom end stuff is difficult for me to check out. I figure I will get it in to a dealership, but I don't want to be robbed in the process. I am sure they would be happy to sell me a new engine, but I don't want to buy one if it is not needed. I will get them to do all of the fluids, and was thinking maybe a timing chain. The valve retainers are cheap insurance, since a cracked one may not show up for a while. I will get it back on a dyno after is it all done to see if there has been a change in the performance in the last 2 years.

Is there anything else I should have the dealership look into?

[repiv]

It did throw a CEL(and ran poorly until the ECU reset), but I hear no funny sounds coming from it.An over-rev won't always result in any audible irregularities. The fact that you got a momentary CEL might indicate some sort of interruption in the combustion process (floated valves, loss of compression, etc.). You would be better off getting a leak down test to see if any valves are bent. If there are, then you need to suspect possible piston damage.

I will get them to do all of the fluidsUnless it's actually time to do these, there's no point. Changing fluids won't do much for a mechanical over-rev.

maybe a timing chainThis, too, would be pointless and a waste of money. An over-rev won't hurt the chain. Perhaps have a good inspection of the tensioner. Even this isn't likely to have been affected.

Spend your time and money on inspecting all the retainers and having all the valves adjusted. Not that you necessarily need it, but since they'd be exposed, may as well.
A dyno now may not tell you anything useful that is relevant to this situation. Dynos 2 years apart won't be the same anyway, since your car isn't exactly the same now as it was 2 years ago.

[Alacrity]

Not to be the young punk in this thread- but I brake checked a guy today in a minivan. I was doing 65 in a 55 and he came up on my butt and sat 4 feet off my bumper for a mile or so. He was on his cell phone and I had the top down so I collected myself, turned my head and stared him straight in the eyes as I applied my brakes and clutch. He uh, backed off.

and yeah, i felt dumb a few miles down the road...

[Satisaii]

It is about time to do the fluids, and I would strain them to look for large chunks. Not that I really expect to see anything.

As for the dyno thing, I find it helpful to be able to stand outside the car and listen for odd sounds while it is under load. Plus my butt-dyno is not sensitive enough to pick up 20 hp changes. A good example of this is my Miata. It felt fast and pulled strong, but when we put it on the dyno it was clear that something was wrong. The curve looked typical supercharged Miata up to 5500 rpm, but then fell off. We found that the exhaust cam was retarded one tooth, and fixing that picked me up 20 hp. We never would have looked for that based on the way the car ran, with good compression and leakdown numbers.

If what you would recommend doing is the leakdown test followed by a valve train overhual, then I might just go buy the tools to do it myself. Been a couple of decades since I have done it, but maybe I still have it in me. I need to take a peek at a service manual first.

I am kinda surprised about the chain and tensioner. I seemed to remember chains stretching under high loads. But my experience is with old V8's, and maybe Hondas are better designed than 70's AMC products.

[SondraS2k]

John, what a bummer! :( I hope everything is ok...

[alvanderp]

All compression testing gauges are somewhat different, but those numbers seem abnormally low for an S2k. Mine specs over 260 on all 4 cylinders on 3 different brand testers that I have had it on. The fact that the numbers are all within 5psi of each other leads me to believe that the gauge may just read low.

Totally agree with repiv - get a leakdown test done. If the leakdown specs out ok(most low mileage S2k's are sub 5% leak on all 4), pull the valve cover and have a look at the retainers. If none of them are cracked, you probably got away with it.

[Satisaii]

The Honda service tech gave it a clean bill of health. They also quoted me +$1000 to do the retainers. They say it requires pulling the head, but I have done it on a AMC V8 using compressed air to hold the valves during the process. Has anyone done this on this car, and are there special tools required? He also recommended aftermarket springs and retainers. Anyone have any experience with the various offerings, or should I keep it stock?

The S/C has been returned to Vortech with a RMA. I was amazed at how much NHV that sucker added to the car. If they tell me that this is normal operation and this blower is within operating specs, I will not be putting it back on the car. I can hear now that the sounds of the car running at idle all came from the S/C.

[repiv]

The Honda service tech gave it a clean bill of health.It looks like you dodged the bullet, but then, many Honda techs wouldn't know a bad retainer if one flew up their nose. I hope this is not the case with you.

They also quoted me +$1000 to do the retainers.B.S. Billman on Long Island is an S2000 mechanic. I think he charges a couple hundred and he knows how to find sunken or cracked retainers.

They say it requires pulling the head, but I have done it on a AMC V8 using compressed air to hold the valves during the process.B.S. You can do them the same way on an S.

He also recommended aftermarket springs and retainers.You can always look into titanium retainers, but these haven't proven to be any better than stock ones or a good bang for the buck. The stock springs and retainers on this car have lasted well over 100,000 miles. There is no reason to get aftermarket parts here unless you want bragging rights or something.

I can hear now that the sounds of the car running at idle all came from the S/C. Can you be sure you weren't just hearing the typical supercharger whine? I love that sound and I would think I was short changed if it didn't make that noise. You may have removed a perfectly operating supercharger.

[Satisaii]

Thanks for the help.

I know they did not look at the retainers. They just did a hot leak down and compression test, which they told me came well within normal specs. It also drives very nicely with no abnormal engine noises. I will get the numbers tomorrow when I get the car.

My SC feels and sounds like it is crushing rocks at idle and low speeds. I don't remember it doing that when I had it installed. There also seemed to be a fair amount of resistance and noise when I was turning it by hand. It started out only doing it when cold and has been working up to being continuous ever since.

It was something that had been growing and you don't realize how bad it is until it is gone.

[RacingEmotions]

EEEE. Good luck findin out what it is. could it also just be your imagination. maybe you never really paid much attention to it until you saw the CEL. iuno