After reading couple incidents about valve failures, i started to think if theres a need to replace all valves/springs/retainers as precaution at some point like 100k miles?

at least this would apply to anyone running higher than stock hp. or does this happen because of tight valve clearance?

any thoughts on this?

 

Well if you can avoid the headache I currently have by replacing the valves early I'd recommend it.

 

i'll probably gonna look into it then.. my car was pushing more hp most of its life.. and 3rd of its life been running boost, still the same head.. i don't adjust them too tight but more on the loose side..

 

hm I have 115k on mine which is like 60% highway, 30% city, and 10% aggressive driving

is the periodical valve adjustment sufficient before I do my rebuild in the next year to come? (I plan to do a few track events including expo this summer)
its still running strong and I haven't come across any big problems yet

id really liek to take precaution if b18c5's come across the above listed problems at high mileage

 

I dunno about replacing the actual valves. Make sure you do your valve adjustments on time, or sooner if your running the car hard. I've seen so many honda engines burn valves because the exhaust side becomes to tight, thus leading to what you have seen recently.

 

yeah as long as you recheck the valve clearance and don't run them to tight because you are afraid of the ticking noise, would the valves last forever

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Dave_B &raquo;</TD></TR><TR><TD CLASS="quote">I dunno about replacing the actual valves. Make sure you do your valve adjustments on time, or sooner if your running the car hard. I've seen so many honda engines burn valves because the exhaust side becomes to tight, thus leading to what you have seen recently. </TD></TR></TABLE>

Why would tight valves lead to burned valves? Can you explain? Thanks.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Petah &raquo;</TD></TR><TR><TD CLASS="quote">

Why would tight valves lead to burned valves? Can you explain? Thanks.</TD></TR></TABLE>

It tightens the valve clearence, causing the valve hang open keeping the valve open and thus burning the valve over time. This happens mostly on exhaust valves as it expands and contracts to the heat of the exhaust temps blowing by it. This is not a it happens all of the sudden thing. It happens over a period of time. When in refernce to the cam, it changes the clearences and on the back of the cam it will be closed, but as the cam turns, the timing of it causes the valve to remain open before TDC.

Basically the exhaust valve clearences change because of the heat, causing it to stick open and over time the hot exhaust gases will burn the valve.

 

bump for more opitnions.. is it simply due to tight valve adjustment? or is there more to it?

 

With the valve lash too tight, the time for the valves to transfer heat to the cylinder head through the valve seat is reduced. This leads to overheating the valves and eventually burning the valve. I think lower end of spec. is fine however wouldn't recommend below spec.