ctchrm

I need some advice from all you engine savy guys. I do not know much about car engine design/function (only what I read) or rather have no hands-on experience but I have run into some trouble with my '02 S2000 (48K miles). My CEL came on so I had it diagnosed as random misfiring. I took it to a mechanic and he went through the normal series of tests trying to determine the problem. He went through everything just as I have read described in the normal process of elimination in these S2000 threads...spark plugs, coil. then he checked compression. It was low 20psi on one cylinder. He did the valve tests and the adding oil bit. Turns out to be a broken piston ring.

So, my question is, how could this happen? I do not race or rev it. I use only premium gas. One thing I am worried about is that I haven't used Honda oil filters (I saw that was highly recommended on one of these threads) but always used synthetic shell oil. Could it just be a defective ring? I only recently started driving it a lot so maybe the ring was fragile to begin with but only broke recently due to the amount of increased driving.

Is this common with low mileage S2000/honda engines? Will it likely happen again? Will replacing the ring only put a band-aid over the real "BIG" problem? I have pretty much driven old used high mileage sports cars (mustang, pulsar, firebird, eclipse) before and I never had an engine problem with any of these! So, this makes me angry that I finally get out of grad school, decide to upgrade to what I thought was one of the best engines out there and run into this.

Does anyone have advice/suggestions for me? My mechanic will charge $2800 for everything he's gone through trying to fix the issue plus ring replacement but will have to charge approx $500 more if he needs to bore the cylinder blocks (from what I understand). Is this reasonable? If not, if I were to have him to put everything back on and go somewhere else like Honda service center at dealership, would I be out more $? I called the vandergriff honda service center and they would not offer any price quote or any advice except bring it to them (of course that's what they would say!). Or, should I just trade it in for a new S2000 (ie would the loss in trade-in value be worth it if the '05-'06 models are better cars)? Lastly, if you think I should keep the car (I really love it and want to keep it) is there any advice on what I should make sure my mechanic replaces or checks along with ring replacement and anything I should do differently to prevent other rings from breaking?

Cheers

xviper

You should get a second opinion from someone who has S2000 experience. I don't know what this "valve test" is, but a hung or bent valve could also give you such a result. It would be a shame for him to tear your engine apart only to discover that it's valve work that needs to be done.

Ek9

Cylinder #4?

If you read here, and I hope SlowS2K chimes in, I'm not hearing much about broken rings but, skuffed cylinder bores seems pretty common on the '2k.

From the symptoms, it's not necessarilly a cracked ring. I suspect it's more likely to be something like a skuffed cylinder bore which will require an engine rebuild/ short block replacement. Seems to be a common problem when people don't keep a close eye on the oil levels.

If he has to bore, he'll have to replace the pistons too. If he's offering to bore on only one cylinder, it's a 1/2 assed repair. Maybe he means honing which is simply a cleanup process. Might want to ask if he's ever done this on an FRM block before. The S2000 block is special as are the bores.

My guess is, if you go to honda, they'll want to put a motor in it for from $5000-9000 bucks.

Find out what happens if he gets it apart and finds out it isn't the ring. If I was you, I'd talk to him about installing a shortblock from honda. They're $2100 or so or maybe finding a used one.

You car's probably worth, 19K or so with a good motor? I might be tempted to try trading it in as is and not even mention the motor problems.

ctchrm

I have read about the #4 problems. However, I don't know if it's # 4 or not. When The guy first checked the cylinders, he said 2 and 4 were misfiring. I'm not real sure where along the process, maybe new spark plug and coil, fixed one of the cylinders but the other was still bad.

My problem about trade-in is that the check engine light is still on and needs to be inspected. Therefore, if I take it in to trade at the dealership, they will know something is wrong. Whether they will take the time to check out the problem, I don't know.

Ek9

Reset it before you go in. What I'm suggesting's fairly unethical and might even get you in trouble so, you might not want to attempt it. It depends on whether they ask you if there's anything wrong with the car. If you say the car's fine and they find out you know it's messed up, that's fraud.

I look at it this way, with a broken motor, it's still sellable. Just maybe 5K less than it normally would be worth. You have to decide whether it's worth it to spend that money or maybe try selling it for 14-15K. I'd drive it to a dealer and just see what they offer on it. Can't hurt. They might tell you what's wrong with it for free.

You ought to be able to find someone with the right tools to look into the cylinder without taking the head off. Lighted bore scope or something like that. That would tell you more than anything. I don't know if you mechanic did that or not.

fperra

I doubt if you have a broken piston ring. And I don't know how your "mechanic" could determine that without, at the very least, pulling the head or dropping the oil pan and finding ring bits. You could have a bent valve , a sticking valve, or a badly scuffed cylinder to name a few. My suggestion would be to run some seafoam through the engine, reset the ecu, and see what happens. If this doesn't help, have a competent mechanic pull the head and see what is really going on.

Eluded

Sounds like a strange problem but there are lots of blown engine stories with the S2k0

Ek9

I was just thinking about it. 20 PSI isn't really that much. Might be worth getting a leakdown which is more precise and will let a good tech determine if it's the bore or valves.