Need some advice on 3 angle valve job. (Civic vx)

[MetroMPG]

Can you share what numbers you're currently seeing on your worn out lean-burn motor?

Post some more info in your intro thread and I'll add it to the project library.

http://ecomodder.com/forum/showthrea...sota-9198.html

[robertwb70]

If you're not into high RPM performance then 30 degree valve seats could show measurable improvement. (you can still have the 3 angles, just the seat/ contact point is 30 instead of 45)

[Frank Lee]

Originally Posted by robertwb70

If you're not into high RPM performance then 30 degree valve seats could show measurable improvement. (you can still have the 3 angles, just the seat/ contact point is 30 instead of 45)

"Could" being the key word, as my understanding of it is that strategy can't be universally applied; some port/valve/chambers work better with 30 and some work better with 45. I personally wouldn't change any of my heads from one to the other unless there was an impressive body of work by accomplished cyl head guys that proves it to be a good move for my application.

[robertwb70]

Well it depends on what/ how you look at "better", if you look at peak flow numbers 30 is usually worse. Peak lift only happens one time per cycle though, all points less than peak happen twice, it's all about the area under the curve. The 30 degree seat provides more curtain area at lower lifts in any engine, if I could I would do it to all my engines since I don't own any pure race vehicles the benefits far outweigh the drawbacks.

[turbovolkswagen]

I found a good read about 3 angle valve jobs, check it out:

1320network.com/2010/05/should-i-street-this-episode-1-3-angle-valve-jobs

He basically says it isn't worth it for street vehicles, and your money is spent better elsewhere.

[zhillz]

I though the air flow 'swirled' on the lean burn engines? Would this effect it?