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[Twism_23]

Are the stock CVO 110" valve stem 7mm or 5/16"? I'm looking to switch my valve springs to AV&V Beehives but need to know whether to buy the 7mm or 5/16 version of springs.
Thanks a lot!

[mcflyer]

They are 5/!6 or 8 mm and unbelievably heavy.

[GMR-PERFORMANCE]

5/16 is stock CVO. I would say if you are that far a great bump on that head is to install a 2.120 ( MVA intake)  great upgrade . If cam is under 610 lift the AVV 600 spring will work fine.

Stock 2.080 valve weighs 112 grams. But with the lighter top retainer you are reducing mass .

[Twism_23]

Thank you, how much more work is required to change to the 2.120? I was going to cut my pushrods to change the cam, but after reading about all the pressure from the original springs I decided to pull the heads and change to a .030 hg and change the springs. I can do everything myself but change the springs. If I were to go to the 2.120, I am assuming I would be changing the guides as well if I changed the valve? Also, who sells these MVA valves. Thanks in advance, I really appreciate the info! Thanks for the point about the lift as well, my new cam has a lift of .575 so the 600 it will be!

[mcflyer]

I understand the beehives as I have them too and love 'em.  I question why the 2.120 intake valve? The stock intake valve is more than large enough and the bigger valve will just be heavier.  You will get a better valve seat taper into the port but the damn ports are way to big anyway.  If you think the bigger valve will make a lot more HP I doubt it will as a .575 lift cam is done by 5500-6000 RPM.  If you are leaving the motor a 110 then you will need to enlarge the valve relief in the pistons too.

[TorqueInc]

I understand the beehives as I have them too and love 'em.  I question why the 2.120 intake valve? The stock intake valve is more than large enough and the bigger valve will just be heavier.  You will get a better valve seat taper into the port but the damn ports are way to big anyway.  If you think the bigger valve will make a lot more HP I doubt it will as a .575 lift cam is done by 5500-6000 RPM.  If you are leaving the motor a 110 then you will need to enlarge the valve relief in the pistons too.

  Steve,Myself and others have tested this and at a minimum a 2.10 valve or the 2.12 valve works and works well.

  Has very little to do with valve size or port size its the throat ID of the seat that is the problem with the 110 heads.

  The ID of the seat is too large for the 2.08 valve,Can you port the heads and increase airflow ? yes you can but you will not see the gains from the increased airflow incrementally because of the large ID of the seat.

  You can also by using a larger OD valve that is the right length get a better seat profile as well as get the valve stem protrusion back to where it should be as you would have to sink the valve a little to do a valvejob using the stock diameter valve.

    You can get the MVA 2.12 valves from the dealership...I do not have the part number in front of me...just have the parts dude breakdown a MVA head

  This has been tested enough that I am having my own valves made to my own specs for this application.

and FWIW @ .575 lift the 2.12 valves will clear the 110 valve pockets ...no sweat

   

[HD Street Performance]

2.08" and 1.623"

[mcflyer]

That's what i meant about the "taper into the seat"

[HILLSIDECYCLE.COM]

..............and extensive testing here has shown that AV&V's 2.150", with it's tulip shape, to help with the overly large throat diameter, dramatically increases the the flow thoughout the range from .100" lift on up thru, not signing off until .800" lift.
Scott

[GMR-PERFORMANCE]

TQ nailed it..

The 2.120 and the 2.130 works well and has shown to hold its own against the larger valve size that others use  in a head that has not been welded.  The larger valve above the 2.130  has shown to work,... Tman runs a 2.170 but that port is fully welded first. Those are some very nice heads. And the cost reflex's that as well..  As well running a valve larger than a 2.130 should have a new seat in it. Some may not install it but we and most other shops agree that above that a new seat should be installed. Thus you have another price increase. Add that up and you are running a 110 113 or even a 117 the added cost per extra gain is getting mighty small just like your wallet  Piston pocket, what cam for vs valve to valve. etc . But if the build is set up and you have the extra coin do it the rewards are there.

Not to say that I am against the larger valve we have not found a need for it on the main stream builds.  Below is just one example of that very basic mod on the head. With only a 243 low lift cam in use. Think if you added say 5 more * of duration solid 130/130 + set up. If you wanted more hp.

[TorqueInc]

 Sticking to this

   VALVE / BORE Ratio

The valve to bore ratio should be:
52-52.5% of the bore for Wedge heads.
53-53.5% for Canted valve, rotated canted valve (Mopar P/S hemi) and true Hemi.
If you decrease intake exhaust ratio down to 70-71% you can move both intake and
exhaust valves over to the exhaust side and increase intake valve size by .5-1%.

Anytime you increase valve size over the above stated Valve/Bore ratio you will see
a small gain in CFM but the discharge coefficient drops and takes your power with it.
An over shrouded valve instills a host of nasty scenario's, the two worst being
decreased discharge coefficient and increased reversion below and above intake
tuned power band.
(according to Darin Morgan)

 Combined with a low port entry the situation gets worse....much worse

   That said 

Stock 4" bore 2.12" valve

         4.06"  bore 2.14-2.15 MAX

         4.125" bore  2.17-2.18 MAX

[Snakebyte]

Sticking to this

   VALVE / BORE Ratio

The valve to bore ratio should be:
52-52.5% of the bore for Wedge heads.
53-53.5% for Canted valve, rotated canted valve (Mopar P/S hemi) and true Hemi.
If you decrease intake exhaust ratio down to 70-71% you can move both intake and
exhaust valves over to the exhaust side and increase intake valve size by .5-1%.

Anytime you increase valve size over the above stated Valve/Bore ratio you will see
a small gain in CFM but the discharge coefficient drops and takes your power with it.
An over shrouded valve instills a host of nasty scenario's, the two worst being
decreased discharge coefficient and increased reversion below and above intake
tuned power band.
(according to Darin Morgan)

 Combined with a low port entry the situation gets worse....much worse

   That said 

Stock 4" bore 2.12" valve

         4.06"  bore 2.14-2.15 MAX

         4.125" bore  2.17-2.18 MAX

What stroke? Looks like 4 3/8?

[TorqueInc]

This is referring to strictly bore size.....stroke rod/stroke ratio and rod length are an entire OTHER subject

[HILLSIDECYCLE.COM]

TQ nailed it..

The 2.120 and the 2.130 works well and has shown to hold its own against the larger valve size that others use  in a head that has not been welded.  The larger valve above the 2.130  has shown to work,... Tman runs a 2.170 but that port is fully welded first. Those are some very nice heads. And the cost reflex's that as well..  As well running a valve larger than a 2.130 should have a new seat in it. Some may not install it but we and most other shops agree that above that a new seat should be installed. Thus you have another price increase. Add that up and you are running a 110 113 or even a 117 the added cost per extra gain is getting mighty small just like your wallet  Piston pocket, what cam for vs valve to valve. etc . But if the build is set up and you have the extra coin do it the rewards are there.

Not to say that I am against the larger valve we have not found a need for it on the main stream builds.  Below is just one example of that very basic mod on the head. With only a 243 low lift cam in use. Think if you added say 5 more * of duration solid 130/130 + set up. If you wanted more hp.

Wrong answer..................no seat replacement needed whatsoever, with a 2.150" valve......

[GMR-PERFORMANCE]

Read the post  palmer.. Did I state your shop?? NO!!

I could post solid facts apon facts and you would still state I am wrong.
 
So lets get to the point .

 It is very clear what you are trying to do ,.. dis crediting our shop  as everyone can see that. If its not us its Jamie at Fuel moto, or the next shop.

 I was not directing my post at you our your shop. If you took it that way well thats your problem. This is a open forum not your private place to tell me or anyone what is wrong or not.

Most shops do swap the seat at that point if you feel its fine then so be it.  Its how you feel you want to do it in YOUR shop . Many shops such  T man, Dan B, TQ , WFO,  John Sachs , Bob Wright,  Us  would not cut the stock seat that far.

You are taking .070 out of the stock seat.. Would you take a stock t/c head and put a 1.940 valve on it?? that's only .065 . At this point you are well under the recommend spec on valve seat ( width /thickness )OD vs ID.

To state its wrong is really funny.. You have your way and others will have theirs. SO if one shop wants to ensure that the customer never has an issue with a valve seat coming loose, and they opt to take the extra step. Nothing wrong with that at all.  A shop can never know what un forseen circumstances may come up with the end user. In direct reference to  heat,   traffic jam, etc.. Better to make sure that the seat will never be able to come loose.

To correct your post it should have read something like this

"no seat replacement needed in our shop whatsoever, with a 2.150 valve......"

But again in the end its your shop and your OPINION nothing more as you cannot back up YOUR opinion  on this topic with facts , as other shops can.  Keep up the good work


For those of you who are not understanding this or would like validation feel free to reach out to other well know ports such as I listed.