SPFSkyline

So after a couple weeks of some odd bog and hesitation I finally threw a CEL and the S2k started running like a lawn mower. After getting tested by Honda they think I have some valvetrain issues and want to tear the head off. I opted to take the car and I will try and see what I can get done. From what I have researched it is not uncommon to have some valvetrain issues. I'm not sure why it happened as it occurred out of the blue one day and I have not over revved the thing. Honda tried to adjust the valves with no luck so they would have seen the springs and retainers if that were the issue? What is the likelyhood that a 2001 with 70k miles would bend or burn up a valve? My major worry is that it could be piston rings? Looking for any help or suggestions as to where to move from here. I'm researching and planning on pulling the head, but don't want to if not needed.

toekneeg

I'm assuming you or Honda did a compression test? If not went even further and did a leak down.

I have an 01 as well. I recently had problems idling and slow minimal throttle starts (ie traffic). I replaced my 02 sensor and my car ran better. Changed at 70k miles btw.

Only reason why I mention the 02 sensor is because it sounded and felt like a lawn mower.

SPFSkyline

Ya I have 25% leakage from 2 and 3. 5% from 1 and 4. Throws misfire codes 24/7 and you can light the exhaust on fire a little. They did a leakdown, but I didn't get to talk with the mechanic. The Rep didn't have any info as far as Intake, Exhaust sides. They were pretty convinced it was not bottom end on a S2000 with 70k.

9kFever

They wouldn't have necessarily seen a cracked retainer when doing a valve adjustment. Did you ever mis-shift or overrev the car? Doesnt even have to be recent. Could have been an overrev from a year ago.

SPFSkyline

I know there has never been an over rev caused by me misshifting. However, I have bounced off the redline in 1st before. I wouldn't think that would be the same since the engine has a rev limiter. Would a cracked retainer cause the car to run like crap or would it just help cause a valve to go bad?

busaboy

Pull the valve cover and check for cracked retainers immediately. Don't drive the car till till you do this! If the retainers are cracked you will drop a valve and blow the engine. I know because I've done it. The debris will go into every other cylinder and wipe out the FRM bores, and the block and head will be useless.

However, I don't think a cracked retainer will cause leakdown, it's probably a burnt valve in #2 cylinder.

Pull the PCV valve on the valve cover. Start the car and look for smoke and fumes coming out the breather hole. Some is normal, a lot and you have bad piston rings. Quite often you can tell what is leaking by where the hissing sound is coming from during the leakdown test.

If a valve is burnt you shouldn't drive the car much more because the valve seat will get damaged and it will be difficult to repair. Not as dangerous a situation as a cracked retainer or worn valve keepers though

S2oooNvegas

Start with cracked retainer inspection. If they are all good, you have wasted guides. happens all the time. guides get sloppy then the valves trash the seats. check my "daves garage" thread on the vegas section. late in the thread youll see a friends car that the retainers were cracked on. I took some good pics that will help you. The guides failing is so common, my roomates s2k had that issue. We just had his head rebuilt with all new shiz and ap2 retainers and keepers. Its bulletproof now.
if you dont have a good head shop nearby, let me know. My machinist rules.

SPFSkyline

Thanks for the help. I need to get my garage cleaned out and get the thing pulled apart. Once I figure out the issue what are some good parts to go with? Is OEM Ap2 the way to go or aftermarket (Feerea, Skunk2, Laskey)? Also does a port and polish do anything on the S2k, I have read there is not a lot of improvments that can be made to the head?

ABCVTEC

I wouldn't worry about improvements as far as flow goes. I'd just get the thing up and running.

wholeo

As S2oooNvegas stated your valve guide would be one thing to look into. You can't pin point a problem untill you really get in there.

When I had bogging, hesitation and shut off problems. My spark plug groumets messed up and my spark plug(s) were covered in oil. I just replaced all of them. This happend six months ago.

also (recently)

I kept getting numerous multiple/random misfires (CEL). Especially in cylinder four. The reason was worn out valve guides; and the carbon build up didn't help. I took it to Laskey/Portflow and rebuild my head (stage 2). No problem....

If you are planning on upgrading your valvetrain; you might want to do it all at once so you dont pay twice the labor.

Good Luck, I hope everything works out.