downhil

What is the difference between a burnt valve and a bent one (if there is one). I know honda is quick to point the abuse finger at a bent valve, but can a burnt valve even be caused by driver error?

how is a burnt valve caused? and is it always on exhaust valves?

thanks!

xviper

This is probably not the answer you're looking for but based on the way you asked your question .....................
A "burnt" valve results from a chemical/thermodynamic event - usually from a bad valve adjustment and poor valve seating.
A "bent" valve results from a mechanical contact event - usually from a valve hitting a piston.

Slows2k

Valves can also burn from :

being bent in the 1st place, a bent valve won't seal againsdt the seat. It will burn where the margin of the valve isn't in contact.

Inccorrect assembly

recessed valve seats

wrong valve retainers used that contact the rocker arm

rad23racer

Local lemon law investigator was telling me that they have seen a small number of cars (7?) that have valve guides that are about .0005 too small. At high RPM that allows the valve to float ever so slightly and make contact with the piston. Honda dealers want to pass it off as driver error (missed shift, etc.) but the ECU keeps a record of highest RPM. You can pull that information with the PGM scan tool. They have seen this problem with 7000 rpm or less as max rpm.
Please keep in mind that this is a very limited problem but one that you might want to investigate further. If your car is still under warranty in California, PM me and I will get your contact information to him.

Slows2k

A 00 to 03 car will only record RPM at the time a DTC occured, not highest RPM turned. The 04 and newer car will record max RPM if they where mechanically overreved.

Considering how many drivers have botched a shift, bent valves in a S2000 is usually driver error.

xviper

Somebody is being lied to.

downhil

would a car idle and drive fine if there are possibly 2 bent or burnt valves? my car is below leak down %'s in cylinder 1 and 4, but the car idles fine and drives fine. the dealership hasn't given me a for sure answer, but after the leakdown test, the threw those out as possiblities.

any other ideas? if it wasn't for the check engine light, i would not have known that the car needed service...

DaveOnLI

an S2000 that never exceeded 7000 rpm?

Dylan Hunt

are bent valves or burnt valves covered under the honda care extended warranty?

Ludedude

If you caused a bent valve by your own action, would you expect it to be covered under a warranty that guards against manufacturer defects?