Im kinda new to the whole car thing, but i have been doing a lot of reading and studying lately, and i came across a question i was really curious about. Im going to probally start head work pretty soon. I have a friend who has a turbo cav, and he is going to help me install stuff (mostly him putting in the parts, and me learning, lol) but i was wondering does a 3 or 5 angle valve job do the same thing as getting over size valves? I mean correct me if im wrong, but the purpose of a valve job, being 3 or 5, is to open up the flow of air and create more volumetric efficency, right? Well, wouldnt oversize valves do the same thing, or do they open it up to a higher extent? I have done a lot of searching, but came up with nothing. I know this might be a stupid question, but i would really like to know. Also, if i got 1mm oversize valves, can i still get a valve job to gain even more power, or does that defeat the purpose? Any input is greatly appreciated.

a valve job is so the valve closes tight all the way around while trying to be as flow friendly as possible... no matter how nice of a transition it is ground the edges a 5mm hole will not flow as much as a 6 mm hole ( leaving out port design and flow, not even using realistic numbers, just braking it down very simply)

bigger hole = ability to flow more air (doesn't mean it will, means it can)

If im not mistaken in order to install larger valves you need a valve job done anyway to accommodate for the larger valves.

If you could only afford to do one set would you do the exhaust or intake?

exhaust.....


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** Flat Broke Racing Inc.**

Zs Z wrote:If im not mistaken in order to install larger valves you need a valve job done anyway to accommodate for the larger valves.

+1

If you've got it apart... it's better to save up and do the whole works at one time, than have to tear it apart and do the other half. Exhaust valves are small on the 2.4L.. going 1mm oversize, you can still use the stock valve seats assuming they're in good shape. You will need a valve job with the new valves to seat them properly.

...j