The Ford Barn

Tinker · 08-22-2019, 02:49 AM

vacuum should drop to near zero at open throttle but never zero. going from 17 to 13 is not correct. maybe the vacuum is not in the right area. pv wouldn't open on the carbs.

from that video the vacuum is steady. hard to tell from the pictures. being its just armchairing it on the web.

flatjack9 · 08-22-2019, 09:52 AM

The drop in vacuum is totally dependent on how much the throttle is opened.

FortyNiner · 08-22-2019, 01:21 PM

Quote:

Originally Posted by flatjack9

The drop in vacuum is totally dependent on how much the throttle is opened.

Any suggestions?

flatjack9 · 08-22-2019, 05:29 PM

No, I was just noting that Tinker said a 17 to 13 drop was not correct. It is impossible to say what the drop would be since it totally depends on how far you punch the pedal down. Are you flooring the pedal when you get the 17 to 13 drop?

tubman · 08-22-2019, 08:46 PM

Listen to Jack.

FortyNiner · 08-22-2019, 11:49 PM

Sponsored Links (Register now to hide all advertisements)

Quote:

Originally Posted by flatjack9

No, I was just noting that Tinker said a 17 to 13 drop was not correct. It is impossible to say what the drop would be since it totally depends on how far you punch the pedal down. Are you flooring the pedal when you get the 17 to 13 drop?

Not floored. Maybe about halfish throttle.

flatjack9 · 08-23-2019, 08:23 AM

That would account for a smaller drop.

Tinker · 08-23-2019, 07:06 PM

Quote:

Originally Posted by Tinker

vacuum should drop to near zero at open throttle but never zero."

Is it okay to quote myself?

FortyNiner · 08-23-2019, 07:19 PM

So do I need to rerun the check at full throttle to have meaningful results?

Tinker · 08-23-2019, 07:22 PM

How are you checking your vacuum?

Yes you can goose the throttle to the floor and check what the vacuum does. Don't leave it to the floor at idle. But it needs to open fully.

17 is still a bit low. you can bring it up to around 19 with the idle/air adjustment screws.

Being that the vacuum is steady at 17 idle is a good thing. Just bring it up to 19ish.

Set your vacuum with your air clear on too.... its how you are driving the car.

.

FortyNiner · 08-23-2019, 07:33 PM

The video shows that I'm manually moving the throttle while watching the gauge. I'll also adjust the mixture screws.

Thanks for the comments. I appreciate it.

Brendan · 08-25-2019, 04:36 PM

i have a 36 pickup with a 21 stud . its all stock, i had the orignal air cleaner on it. i changed it to one of he little chrome air cleaners, with a K and N filter element.
i could tell the difference as soon as i started to crank over the engine, you could hear it breathe, while cranking. and it ran so much better

FortyNiner · 08-25-2019, 08:28 PM

As others have mentioned, the original style air filters can be clogged for any number of reasons. Glad you found a solution that meets your needs.

08-22-2019, 09:52 AM	#22
flatjack9 Senior Member Join Date: May 2010 Location: Oshkosh, Wi Posts: 4,526	Re: The Case of the Gasping Flathead The drop in vacuum is totally dependent on how much the throttle is opened.

08-22-2019, 05:29 PM	#24
flatjack9 Senior Member Join Date: May 2010 Location: Oshkosh, Wi Posts: 4,526	Re: The Case of the Gasping Flathead No, I was just noting that Tinker said a 17 to 13 drop was not correct. It is impossible to say what the drop would be since it totally depends on how far you punch the pedal down. Are you flooring the pedal when you get the 17 to 13 drop?

08-22-2019, 08:46 PM	#25
tubman Senior Member Join Date: Dec 2013 Location: Minnesota, Florida Keys Posts: 10,304	Re: The Case of the Gasping Flathead Listen to Jack.

08-23-2019, 08:23 AM	#27
flatjack9 Senior Member Join Date: May 2010 Location: Oshkosh, Wi Posts: 4,526	Re: The Case of the Gasping Flathead That would account for a smaller drop.

08-23-2019, 07:19 PM	#29
FortyNiner Senior Member Join Date: May 2012 Location: u-rah-rah-Wisconsin Posts: 1,136	Re: The Case of the Gasping Flathead So do I need to rerun the check at full throttle to have meaningful results? __________________ 19 and 49 F1 - jes' like Henry II built 1946 Deluxe - as Henry built it

08-23-2019, 07:22 PM	#30
Tinker Senior Member Join Date: May 2010 Location: MN Posts: 7,053	Re: The Case of the Gasping Flathead How are you checking your vacuum? Yes you can goose the throttle to the floor and check what the vacuum does. Don't leave it to the floor at idle. But it needs to open fully. 17 is still a bit low. you can bring it up to around 19 with the idle/air adjustment screws. Being that the vacuum is steady at 17 idle is a good thing. Just bring it up to 19ish. Set your vacuum with your air clear on too.... its how you are driving the car. . Last edited by Tinker; 08-23-2019 at 07:55 PM.

08-23-2019, 07:33 PM	#31
FortyNiner Senior Member Join Date: May 2012 Location: u-rah-rah-Wisconsin Posts: 1,136	Re: The Case of the Gasping Flathead The video shows that I'm manually moving the throttle while watching the gauge. I'll also adjust the mixture screws. Thanks for the comments. I appreciate it. __________________ 19 and 49 F1 - jes' like Henry II built 1946 Deluxe - as Henry built it

08-25-2019, 04:36 PM	#32
Brendan Senior Member Join Date: May 2010 Location: At my kitchen table in Santa Rosa, Ca Posts: 2,903	Re: The Case of the Gasping Flathead i have a 36 pickup with a 21 stud . its all stock, i had the orignal air cleaner on it. i changed it to one of he little chrome air cleaners, with a K and N filter element. i could tell the difference as soon as i started to crank over the engine, you could hear it breathe, while cranking. and it ran so much better __________________ If it would have been a snake it would have bit ya! i can't spell my way out of a paper bag!

08-25-2019, 08:28 PM	#33
FortyNiner Senior Member Join Date: May 2012 Location: u-rah-rah-Wisconsin Posts: 1,136	Re: The Case of the Gasping Flathead As others have mentioned, the original style air filters can be clogged for any number of reasons. Glad you found a solution that meets your needs. __________________ 19 and 49 F1 - jes' like Henry II built 1946 Deluxe - as Henry built it