Common Problems - Tight Exhaust Valve Clearances | Honda S2000

Valve Adjustment DIY:    • Valve Adjustment | Honda S2000  

Note: at 1:33 I misspoke. I meant to say "when the piston is on its way back upwards".

Hey everyone. Let’s talk about tight exhaust valve clearances on 2006+ Honda S2000s.

If you have a 2006+ Honda S2000 and you don’t know the last time a valve adjustment was performed on your car there is a good chance that your exhaust valve clearances are way out of spec and are tighter than they should be. As the valves and cylinder head wear it is possible for the valves recede into the head and eventually tighten up the valve clearances.

Now the reason why this is a problem is because tight exhaust valve clearances can lead to burnt exhaust valves, and burnt exhaust valves will lead to misfires and loss of compression. Ultimately you will need to remove the head and get it rebuilt.

If you’re like me and you’re wondering how tight valve clearances can lead to burnt exhaust valves let me make an effort to explain. Valve clearances affect the valve lift, which is another way to say how much the the valves open. If the valve clearance is too tight it is possible for the valve to open early during the combustion stage or even stay slightly open all the time! If this happens, the quality of the valve seat contact is lost and the hot gases created during the combustion stage are forced past the valve which burns the edges of the valve due to the concentration of heat and pressure. Ideally the valve should be completely closed during the combustion stage so that the valve can dissipate heat to the head with the use of conduction through the valve seat. Once combustion is complete and the piston is on its way back upwards the valves should open to expel the exhaust gas.

Sooo. What can you do about this? Well, the best thing you can do to mitigate this is to perform more frequent valve adjustments, for instance every 50k miles instead of the 100k miles instructed by the owner’s manual. You also want to set the valve clearance to the looser setting of .29mm in order to but you some more time before the exhaust valves tighten again. If you’re interested in doing this yourself you can check the description below for a DIY video I made on the process.