Go Back   The Ford Barn > General Discussion > Early V8 (1932-53)

Sponsored Links (Register now to hide all advertisements)

Reply
 
Thread Tools Display Modes
Old 02-05-2018, 10:59 PM   #1
elwood
Senior Member
 
elwood's Avatar
 
Join Date: May 2010
Location: Dallas
Posts: 937
Default power valves

Hey guys, Im looking to try using smaller power valves, Im running 2 Holly 2110 carbs, with a 400JR cam, and it seams like the PVs are dumping fuel right off the get go.
Are the power valves the same in Ford 8ba 94s as Holly 2110s ?
And what is the smallest PVs I can get, and where would be a good place to order them from ?
Thanks ...
elwood is offline   Reply With Quote
Old 02-06-2018, 05:40 PM   #2
Bored&Stroked
Senior Member
 
Bored&Stroked's Avatar
 
Join Date: Jan 2011
Location: Central Ohio
Posts: 2,895
Default Re: power valves

In Holleys, it is not about being "smaller" - it is about coming in at the correct vacuum level. When you run multiple carbs and a big cam, you might not have enough vacuum to be using the 'stock ones' - they open too early or all the time (ones supplied with the kits).

The PVs "should" be marked with the vacuum level they open at --> like "6.5" for 6.5". Some of the carb kits have PVs with no markings - so I can't tell you where they open. Guys like 'Charlie NY' (on this board) can probably supply you with good (and tested) power valves . . . it is worth PMing him.

You may also want to contact these guys:

Daytona Parts
386-427-7108

What I can't tell you is whether or not they have the correct sealing surface for the 2110's - ask them. Most of the newer Holley PVs have an incorrect (large) radius and they'll leak gas. I "fix" them on my lathe.

Selecting the right one:

Some Good Tips: If you take CRUISE vacuum, divide it in half and add about 2" you will be close. You want the PV to be closed while running at steady cruise, and open when the load is enough to require more fuel. Idle has nothing to do with it, even if the PV is open at idle the idle feed restriction is so much smaller the open PV will have no significant effect. Much like drinking through a coffee stirrer, it doesn't matter whether it's in a cup or a gallon jug, you will only flow so much through it.

Last edited by Bored&Stroked; 02-06-2018 at 05:55 PM.
Bored&Stroked is offline   Reply With Quote
Sponsored Links (Register now to hide all advertisements)
Old 02-06-2018, 09:00 PM   #3
elwood
Senior Member
 
elwood's Avatar
 
Join Date: May 2010
Location: Dallas
Posts: 937
Default Re: power valves

Thanks for the help Bored&Stroked,
So Im thinking I need to put a vacuum gauge on the intake, below the carb base plates, and see what my cruse idle is..
So since Im running 2 cabs, should I add the PV values together ? I ordered 2 2.5 Power Valves today, so that would be 5, correct ?
So if my cruse vacuum was 6, divide that in half, add 2, Id at 5 ... lol ..
elwood is offline   Reply With Quote
Old 02-06-2018, 09:36 PM   #4
40cpe
Senior Member
 
40cpe's Avatar
 
Join Date: May 2010
Location: Star, MS
Posts: 3,682
Default Re: power valves

You don't add them together. They both see the same manifold vacuum. I'm going out on a limb and predict your cruise vacuum to be about 15-17" judging from what my engine does. This is at about 2000 rpm, unless you have a really high (low numerical) gear ratio.
40cpe is offline   Reply With Quote
Old 02-06-2018, 11:20 PM   #5
elwood
Senior Member
 
elwood's Avatar
 
Join Date: May 2010
Location: Dallas
Posts: 937
Default Re: power valves

Ford 9 inch, 384 ratio, Tremec 6 speed. I try to keep cruise around 2000 also ..
Thanks 40cpe, so lets say 15, devided in half, say 7.5 and add 2 .
I took 8.4s out, and it seamed like the Power Valves where dumping gas right off the get go..
I thought I knew the basic function of power valves, guess im just not getting it, or the big cam is acting so different its confusing me ...
thanks for bearing with me ...
elwood is offline   Reply With Quote
Old 02-07-2018, 09:02 AM   #6
donald1950
Senior Member
 
Join Date: May 2010
Location: san antonio, texas
Posts: 461
Default Re: power valves

Sponsored Links (Register now to hide all advertisements)
when i had two 2110s on my otherwise stock 8BA in my 1941 pick up i had 3.5 PVs and 49 main jets in both carbs. that combination seemed to work very well.
donald1950 is offline   Reply With Quote
Old 02-07-2018, 09:50 AM   #7
Mart
Senior Member
 
Mart's Avatar
 
Join Date: May 2010
Location: Solihull, England.
Posts: 6,897
Default Re: power valves

I run 2 2100s. (not 2110s) on a 4" stroke 3-5/16" motor with a Schneider cam.

I use 54 jets and stock power valves with slightly shortened springs.

94 type carbs can run rich for a lot of reasons. Once you solve all these issues that cause it to be over rich you can then start to fit suitable jets and power valves. Personally my opinion is that if it runs ok on 49 jets it is getting extra fuel from somewhere else. Mine ran bad on 49s.

Best test to see if the mixture is good and you have no leaks is to see if it starts with just the slightest stab of the starter after sitting for 15 minutes. If fuel has leaked in you will have to crank and pump some air through it to get it to fire.

Mart.
Mart is offline   Reply With Quote
Old 02-07-2018, 08:13 PM   #8
Bored&Stroked
Senior Member
 
Bored&Stroked's Avatar
 
Join Date: Jan 2011
Location: Central Ohio
Posts: 2,895
Default Re: power valves

Another place you can order power valves from (and I would think they'd be okay - but have not ran them myself) is from Edelbrock - given they make the "new" 94.

I would imagine that the stock power valves are somewhere between 6.5" and 8". I would probably try a 5.0" power valve (if they make that size). As noted, if you put a quality vacuum gauge in the manifold (beneath the carbs), you'll soon get a good idea as to what type of vacuum profile you're actually generating. As somebody noted above - both carbs will see the same vacuum.
Bored&Stroked is offline   Reply With Quote
Old 02-07-2018, 08:41 PM   #9
38 Ford Guy
Senior Member
 
38 Ford Guy's Avatar
 
Join Date: Jul 2010
Location: Central MN
Posts: 104
Default Re: power valves

I have an Isky 88 two 94's. after lots of testing front carb 3.5 PV back 1.5pV. Sounds goofy but works. Great mileage too. Both dumping at mild acceleration is too much gas.
__________________
"If you always do what you have always done then you will always get what you always got."
Henry Ford
38 Ford Guy is offline   Reply With Quote
Old 02-08-2018, 11:57 AM   #10
Crankster
Senior Member
 
Crankster's Avatar
 
Join Date: Oct 2017
Posts: 284
Default Re: power valves

While I'm no expert I have studied these issues enough to note that each engine & carburetor combination is different, plus gearing, weight, cam selection, add to that variables such as elevation, seasonal variations, fuel quality and it quickly becomes apparent that while "what power valve/jetting/timing are you using" is useful for a starting point, it will be just that. The main thing with power valves (economizer) is to be assured that it is NOT opening at steady, low load cruise. As a power circuit it is tuned independent of the others.

A mechanic's vacuum gauge is VERY useful for engine tuning and diagnostics. I don't know how anyone would get along without it. Wideband O2 sensors are worth your time as well.

Last edited by Crankster; 02-08-2018 at 12:02 PM.
Crankster is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Sponsored Links (Register now to hide all advertisements)


All times are GMT -5. The time now is 06:52 PM.