The Ford Barn

AnthonyG · 10-23-2015, 04:02 PM

Barner gave me a heads up 90 psi was probably too much pressure during cleaning of Holley 94 and I might have blown the PV. Was wondering how if possible to verify the PV is good or bad for sure? Thought it was PV causing rough engine but not sure now. Changed PV runs rough after warming up under load now. I didn't throw the other power valve away and was wondering how if possible to verify good or bad for sure? Also how do to tell what size the power valve is as don't see any marking and know different sizes exist for leaner or richer shot?
In the mean time to be sure it isn't anything else in the carb I have removed the top of the carb verified clean, took bottom off, pulled jets out and insured clean verified all looked good so don't think it's coming from the carb.
Thinking it was always multiple issues. Pretty sure the original debris I cleaned out of sloppily rebuilt carb helped and was one issue. Thought it might be the power valve as it still ran rough after cleaning debris. Now thinking possibly the coil. I've had them start to act that way when going bad?

oj · 10-23-2015, 04:14 PM

You need a little fixture to test the PV in, easier and cheaper to replace it. the power valve value or rating is written in one of two places: if on the face there'll be like a 6 and it'll be right side up at 3 o'clock the number below it can be a 5 so it is a 6.5; the other place is on the flat of the hex nut that you tighten it with, it'll have the whole 6.5.
Its easy to test the 94, hold it up level and 1/2 fill the bowl. If fuel dribble out below the throttle plates the PV is leaking.

dmsfrr · 10-23-2015, 04:24 PM

Quote:

Originally Posted by AnthonyG

........ Now thinking possibly the coil. I had them start to act that way when going bad?

What engine, battery voltage and ignition system do you have?

AnthonyG · 10-23-2015, 04:40 PM

Sorry guys, screwed up and put thread on late V8 s/b early.
Thx for the PV tips OJ, good any where.
It's a '49 Flatty with 12V and an e-distributor dmsfr.

dmsfrr · 10-23-2015, 11:32 PM

Quote:

Originally Posted by AnthonyG

...... It's a '49 Flatty with 12V and an e-distributor dmsfr.

Most(?) electronic distributors use 12v power. Many ignition systems have a ballast resistor (or resistor wire) to the '+' wire on the coil that reduces the 'running' voltage but is bypassed for starting. Check that your set-up exactly matches the Mfr. wiring diagram for your e-distributor system.

If it uses a resistor check that the resistor connections aren't loose or corroded and that the voltage at the '+' coil terminal is 8 to 10 volts.

oj · 10-25-2015, 08:56 AM

Sponsored Links (Register now to hide all advertisements)

When you say 'e-distr' if you speak of pertronix then you best have their coil to match circuit resistance and do not use ballast resister, they want full voltage (not necessary to reduce voltage because they don't have points).

frank long island · 10-25-2015, 03:47 PM

ck the magnets on the piece that goes on shaft if its a pertronics I've had them come off
went threw 2 sets and went back to points no problems

AnthonyG · 10-25-2015, 04:11 PM

Mallory with supplied ballast Resistor, Did a vac. PV test and it was shot. Having a new Daytona 5.5 being sent with modified seal from a fellow Barner who rebuilds 94's.
Thx for the inputs.

10-23-2015, 04:02 PM	#1
AnthonyG Senior Member Join Date: May 2013 Location: Pa. Posts: 2,174	Verify Power Valve is good? Barner gave me a heads up 90 psi was probably too much pressure during cleaning of Holley 94 and I might have blown the PV. Was wondering how if possible to verify the PV is good or bad for sure? Thought it was PV causing rough engine but not sure now. Changed PV runs rough after warming up under load now. I didn't throw the other power valve away and was wondering how if possible to verify good or bad for sure? Also how do to tell what size the power valve is as don't see any marking and know different sizes exist for leaner or richer shot? In the mean time to be sure it isn't anything else in the carb I have removed the top of the carb verified clean, took bottom off, pulled jets out and insured clean verified all looked good so don't think it's coming from the carb. Thinking it was always multiple issues. Pretty sure the original debris I cleaned out of sloppily rebuilt carb helped and was one issue. Thought it might be the power valve as it still ran rough after cleaning debris. Now thinking possibly the coil. I've had them start to act that way when going bad? __________________ Nomad Last edited by AnthonyG; 10-23-2015 at 04:29 PM. Reason: correction

10-23-2015, 04:14 PM	#2
oj Senior Member Join Date: May 2010 Posts: 293	Re: Verify Power Valve is good? You need a little fixture to test the PV in, easier and cheaper to replace it. the power valve value or rating is written in one of two places: if on the face there'll be like a 6 and it'll be right side up at 3 o'clock the number below it can be a 5 so it is a 6.5; the other place is on the flat of the hex nut that you tighten it with, it'll have the whole 6.5. Its easy to test the 94, hold it up level and 1/2 fill the bowl. If fuel dribble out below the throttle plates the PV is leaking.

10-23-2015, 04:40 PM	#4
AnthonyG Senior Member Join Date: May 2013 Location: Pa. Posts: 2,174	Re: Verify Power Valve is good? Sorry guys, screwed up and put thread on late V8 s/b early. Thx for the PV tips OJ, good any where. It's a '49 Flatty with 12V and an e-distributor dmsfr. __________________ Nomad

10-25-2015, 08:56 AM	#6
oj Senior Member Join Date: May 2010 Posts: 293	Re: Verify Power Valve is good? Sponsored Links (Register now to hide all advertisements) When you say 'e-distr' if you speak of pertronix then you best have their coil to match circuit resistance and do not use ballast resister, they want full voltage (not necessary to reduce voltage because they don't have points).

10-25-2015, 03:47 PM	#7
frank long island Senior Member Join Date: May 2010 Location: westbury ny Posts: 854	Re: Verify Power Valve is good? ck the magnets on the piece that goes on shaft if its a pertronics I've had them come off went threw 2 sets and went back to points no problems

10-25-2015, 04:11 PM	#8
AnthonyG Senior Member Join Date: May 2013 Location: Pa. Posts: 2,174	Re: Verify Power Valve is good? Mallory with supplied ballast Resistor, Did a vac. PV test and it was shot. Having a new Daytona 5.5 being sent with modified seal from a fellow Barner who rebuilds 94's. Thx for the inputs. __________________ Nomad