Use either 10/40 syn or 5/40 syn only.
[/quote]


^ This, you can use any brand you like, I do like Red Line 5w40 or 10w40, Mobil1 makes a great 0w40 as does Amsoil, but something like that is what I would suggest.

 

Hey LeonV, I got a chance to read through your thread here and I'm sorry you're having this issue. From what I read you've been through your entire valve train multiple times and quite thoroughly. I think you may have been onto something with the LMA's though which is a shame since you had removed them, measured them and determined that they were fine based on free length...

I was researching the issue and ran across a thread on a different forum. Now granted, this isn't an S2000, it is a B16 DOHC VTEC Honda engine so it's surprisingly similar in its construction.

This guy in the other thread mentions that the issue with the LMA's is known (on that engine) and that they fail not in free length when measured, but a weakened spring rate over time. Now I'm just speculating here but it sounds like its possible you have the same issue. He also mentions that Honda "fixed" the issue by updating the LMA's so you'd think that the S2000 shouldn't have the issue, but all metal fatigues over time so I wouldn't count it out completely. Also keep in mind that the metal would have less spring rate as temperature rises. Just another reason I'm connecting the two in my mind... Obviously I can't be sure and I'm only offering this info based on research and not real world experience, so take it as you will.

If you have a method of measuring the spring rate it might be worth your time to do so(or simply replace them anyway since you said they were cheap). The thread I was reading was a success story like you mentioned you hadn't seen yet. It was also a relatively thorough DIY, although some steps would be slightly different due to the fact its a slightly different engine.

When the job was done he states "The new LMA's made the engine so smooth. Not only was the tapping noise gone, but the engine reved smoother. I am very pleased with the results."

The link is below. Have a read through it if you have time and let me know what you think. Hopefully this helps you out.

http://honda-tech.com/forums/honda-c...d-lma-2536305/

 

Definitely not injectors. Its mechanical like you say. Sounds like a TCT issue itself, or timing chain related as in a lose chain guide possibly, but that wouldn't really coincide with the more intermittent nature. Or piston slap. Or excessive valve lash on one or multiple valves. Not much else it could be. But id still lean heavy on the TCT being its not a totally turn key/off key consistent issue, which tells me there could be some hydraulic/oil influence. Have you replaced the TCT recently?

 

Does sound like timing chain tensioner with maybe a bit of accessory belt issues.

 

Thanks for that! I've definitely seen success stories with the B-series engines since they came with the old-style hydraulic LMAs. The S2000 F-series engines use the updated coil spring LMAs. If those springs were to fatigue, they'd either crack or sag. I noticed neither which is why I decided not to replace them.

Anybody have an accurate (measured with good caliper or mic) free-length measurement of a new LMA?

I've not touched the TCT, it's original. From what I can tell by listening to TCT failure videos as well as having an S2000 owner that has had a TCT failure listen to my engine, it doesn't sound like the TCT. I'm not ruling it out but it just doesn't seem to match the sound or symptoms that others have experienced.

It's 100% not accessory belt related since it still makes the noise with the belt removed.

 

Use either 10/40 syn or 5/40 syn only.
[/quote]


^ This, you can use any brand you like, I do like Red Line 5w40 or 10w40, Mobil1 makes a great 0w40 as does Amsoil, but something like that is what I would suggest.
[/quote]
I was considering 0W-40 as I just got a bunch for my Volvo. Used Mobil1 for my last oil change but have 15qt of GC 0W-40 coming next week. I have a fresh fill of Amsoil 10W-30 in the S2000 so I don't want to dump it just yet.

 

In my experience on my car and others, the TCT failures aren't all the same, its not a clockwork failure. For me, I had 2 that started acting up by a TC rattle at first start up in the morning and would then go away after 1-2 sec after the tensioner re primed itself with oil. Many other report problems such as yours to where its a full out failure where the Tensioner never primes, and what you here is the chain slapping against the guides, because the tensioner isn't picking up the slack. Some report symptoms of the TCT acting up after the oil temp gets high and then goes away when it cools down, oil viscosity makes a difference. Usually it seems my experience is what happens in first stages, before it just never primes anymore, and you have a situation like yours. IF thats what it is. Again, not much else that makes that kind of racket on the engine. Maybe try the ol metal stick trick, putting your ear to one end and the other placed in key areas on the motor to listen for culprit location. If it is the TCT, I would expect the loudest noise coming from the front of the engine at the timing cover.

 

I've been using a screwdriver as my stethoscope and have probed around, probably not enough. I'm out of town this weekend but I'll give it another listen on Monday. I have a track day on 9/11 so I'm considering just buying the Billman TCT as a might-as-well do it kind of thing...

 

Just replace the TCT with Billmans and eliminate that possibility, especially if yours is OEM. To me that very much sounds like TCT

 

Use either 10/40 syn or 5/40 syn only.
[/quote]


^ This, you can use any brand you like, I do like Red Line 5w40 or 10w40, Mobil1 makes a great 0w40 as does Amsoil, but something like that is what I would suggest.
[/quote]
I was considering 0W-40 as I just got a bunch for my Volvo. Used Mobil1 for my last oil change but have 15qt of GC 0W-40 coming next week. I have a fresh fill of Amsoil 10W-30 in the S2000 so I don't want to dump it just yet.
[/quote]


That will work fine too, lots of good choices out there, see how that works for you.

I also agree with the recommendations listed above for a Billman TCT swap, I had a TCT issue that was unlike what most other owners reported, the Billman TCT solved it immediately, just like Junky stated. One more thing to cross of the list of potential culprits and it isn't that expensive, and eventually you will need one given the high failure rate of the oem Honda parts. Worth a try.