Competition bigger valves for 24v heads?

[KSmid]

Who sells them? whats the biggest you can fit? change guide size to 5/16 to get a more common valve? Anyone done flow bench work before and after valve changes? Found some shops that put bigger ones in but will not sell just the valves. (ATS,Piers,Shieds) ANY info here?

 

[COMP461]

You can go to a 5 mm valve stem, it flows more , but unless you bore the block the valves are close now. This is the primary reason to bore a block. Ray will send you valves, but there in no secret to them, all the above mention get them from valves makers,Manley , Dell and REV and these sources are available to anyone. Just changing valves will not gain you much, there is an enormous amount of flow to be gained by valve angles, and seat angles, , but unless the head porter has, a flow bench ,and has the knowledge to find these gains they are just grinding metal blind.

 

[Forrest Nearing]

agreed, on a factory casting, you'll gain far more from real portwork than just bigger valves... and as Greg stated, w/ the 24v heads, you're pretty shrouded as it is... bigger valves only exagerates it...

 

[RacinDuallie]

A contact for the question.....

If your serious with the bigger valves contact John Russin at Buddha Power . I believe he has all the geomotry worked out with the rocker arms too, when installing larger valves. He has some pretty trick 12 and 24 valve cylinder heads. And will be better to explain the benifits of each mod he has done... ... ...

 

[BAnsley]

watch out for valve schrouding. Boring the block will help but i have seen a lot of great numbers come from a flowbench with larger valves with no consideration for the diameter of the cylinder. I guess this would be great if ya brag about your flowbench numbers and not how much better your truck runs after a lot of hard earned money and time is wasted. just be shure if you have this done make shure the shop uses bore sized tubes under there heads to simulate acctual conditions. good luck, Brian

 

[RacinDuallie]

Most professionally run flowbenches are operated with this consideration of bore size... ...

And experience... ... ...

 

[COMP461]

Ray uses bore tubes in sizes ranging from 3. 5 to 4. 7. The 4 valve is not as susceptible to bore shrouding as a 2 valve motor, the reason I was talking about bore size is that the valve is close to the bore on a stock bore. In reality, the amount that can be done before you change to bigger valves is a significant. I have a lot of time on the flow bench with the 24 valve, and next step is not cheep. The high end heads now from RayMac or Buddha is $10,000 and up. A good Street head is about half that .

 

[Timebomb]

Maxflow In Va. uses bore plates,test pipes on exh,runner cc,s. You Almost have to have these key pieces to the puzzle to get actual flow data. I would say anyone using a flow bench would be doing this. Or at least I hope so.

 

[NoSeeUm]

Off topic sorry... .



This is the advantage of the hemi head, less shrouding?



Jim

 

[Forrest Nearing]

that and the exhaust stroke can help draw the intake charge in during overlap... not really as big an issue w/ a turbocharged application w/ high back pressure

 

[CRiggan]

Comp, need your help pls give me a ring at 919 369 1621. thanx