I saw this thread on S2K I about the timing chain auto tensioner. Some of the owners on there were complaining about a "playing card in bicycle spokes" type noise upon startup and sometimes at idle, or various point in the rpm band. My S2000 had this noise occasionally (mostly at startup), so I figured I'd go ahead and give this a shot.
So while I was changing the oil this afternoon, figured I'd go ahead and do a little write up on this as well... I bought a new auto tensioner from hardtopguy.com for about $130 shipped. Two days, and it was here. Great guy to deal with, I'd say. Anywho, the new tensioner came in it's Honda factory sealed parts thingy... and was obviously of great quality. Here's a picture:
Parts you're going to need:
- 5/16 (T50) Hex key
- 10mm socket
- Ratchet and small extension
- Needle Nose Pliers or similar
First things first, the tensioner is located under the VTEC solenoid, attached to the head. There are only two 10mm bolts holding it in place, and the T50 Hex maintenance plug, which will need to be removed in order to complete installation. Keep in mind, that I did this after first draining the engine oil. So if it's full, there might be a lot more oil spilling out when you remove the tensioner. Mine, on the other hand, was somewhat clean. You're also going to want to do this on a somewhat cool engine... as the tensioner is going to be hot as fuck.
Remove the maintenance plug first. It's not that tight and doesn't need to be torqued a lot when reinstalling it. Once it's gone, set it aside as it will be the last thing you reinstall. Here's a picture of it's location, circled in red.
Next you'll remove the two 10mm bolts holding the tensioner to the head. The ones you're looking for are the brass colored ones, not the silver. They are circled in red in the photo below:
Now the tensioner should just slide right out. Be careful, considering that there won't be any tension on the parts, and they could all fall out or remain inside your engine... who knows what kind of damage that could do. Here's an exploded view of the tensioner, and it's internal parts.
and a view of the old tensioner (top) with the new tensioner (bottom) so you can see the piston travel
Now that it's out, make sure you've got all the peices... and slide the new tensioner in place. It should pop in pretty easy, being that it's already compressed. Dont force anything. Tighten the two 10mm bolts in place.
Now you will need to remove the cotter pin from the new tensioner piston. You'll access this peice through the maintenance hole. Make sure you didn't put the tensioner in backwards (I'm pretty sure there's only one way for it to go in anyway) and you'll be able to see the tip of the cotten pin through the hole. Grab your set of needle nose pliers, and pull it out. Once it's out, you'll hear a pop of the piston tensioning the timing chain. Be extra careful not to drop this pin inside the maintenance hole. Getting that out would require a complete head removal, I'm sure... so be sure not to drop it.
In order to get the pliers into the maintenance hole, I had to remove my stock airbox. Those of you with aftermarket intakes probably won't have this problem. It was simple enough though, as there are only three 10mm bolts holding the bottom tray, and once those were out I could manuver it enough to access the maintenance plug properly. I didn't feel the need to take any photos, as it is simple enough.
Once you've removed the pin and the tensioner is doing it's job... replace the maintenance plug. Fill her back up with oil if you drained it, and you're all set!!
For 20 minutes worth of work... I'd say it was well worth it. My engine is noticeably quieter, and the "playing card in bicycle spokes" noise hasn't returned. I mean, every S2000 I've heard has some valvetrain noise, but with the new tensioner in there, it's noticeably quieter.