The Ford Barn

CA Victoria · 01-30-2020, 09:04 AM

Found a lot of dialog on seat (spring) pressure for performance cams but nothing on this value for a stock 221 cu in engine.
Anyone out there have this info for our flatheads?
I would also be interested to know how this value is determined?

Thank you!

Mart · 01-30-2020, 09:20 AM

30 - 40 lbs at 2-1/8" test length.

From the repair manual. Official ford publication.

CA Victoria · 01-30-2020, 09:40 AM

Thank you, mine tested at 20# seemed pretty light........need to locate a ford shop manual for my 35’

bobH · 01-30-2020, 12:31 PM

According to the data published in the Motor Manual, c.1943, for 1935-42 vehicles...
Here are the specs....
1935 through 1942, for all 'regular' V8's. (V860 is different)
Valve closed, 37-40 Lb at 2.13 in. Valve open, 76-80 at 1.83
Pretty much the same info as posted by Mart, above.

Ol' Ron · 01-31-2020, 12:15 PM

When actually measuring spring pressure, you have to do it at installed height. Which is determinded by the valve keeper lock. On my street engines I use 50/55 lbs on all cams, except the 400jr at 65. Unless you are actually racing, this is more than enough. amd keeps everybody happy under 5K

bobH · 01-31-2020, 01:41 PM

Sponsored Links (Register now to hide all advertisements)

I'm nit-pickin again, but we (collectively) seem to consistently mistake 'pressure' for 'force'.

01-30-2020, 09:04 AM	#1
CA Victoria Senior Member Join Date: Feb 2011 Posts: 2,111	Stock Valve Seat Pressure Found a lot of dialog on seat (spring) pressure for performance cams but nothing on this value for a stock 221 cu in engine. Anyone out there have this info for our flatheads? I would also be interested to know how this value is determined? Thank you! __________________ Tim Downtown, Ca

01-30-2020, 09:20 AM	#2
Mart Senior Member Join Date: May 2010 Location: Solihull, England. Posts: 8,745	Re: Stock Valve Seat Pressure 30 - 40 lbs at 2-1/8" test length. From the repair manual. Official ford publication.

01-30-2020, 09:40 AM	#3
CA Victoria Senior Member Join Date: Feb 2011 Posts: 2,111	Re: Stock Valve Seat Pressure Thank you, mine tested at 20# seemed pretty light........need to locate a ford shop manual for my 35’ __________________ Tim Downtown, Ca

01-30-2020, 12:31 PM	#4
bobH Senior Member Join Date: May 2010 Location: so cal, placerville, vegas Posts: 1,394	Re: Stock Valve Seat Pressure According to the data published in the Motor Manual, c.1943, for 1935-42 vehicles... Here are the specs.... 1935 through 1942, for all 'regular' V8's. (V860 is different) Valve closed, 37-40 Lb at 2.13 in. Valve open, 76-80 at 1.83 Pretty much the same info as posted by Mart, above.

01-31-2020, 12:15 PM	#5
Ol' Ron Senior Member Join Date: May 2010 Location: Chester Vt Posts: 8,857	Re: Stock Valve Seat Pressure When actually measuring spring pressure, you have to do it at installed height. Which is determinded by the valve keeper lock. On my street engines I use 50/55 lbs on all cams, except the 400jr at 65. Unless you are actually racing, this is more than enough. amd keeps everybody happy under 5K

01-31-2020, 01:41 PM	#6
bobH Senior Member Join Date: May 2010 Location: so cal, placerville, vegas Posts: 1,394	Re: Stock Valve Seat Pressure Sponsored Links (Register now to hide all advertisements) I'm nit-pickin again, but we (collectively) seem to consistently mistake 'pressure' for 'force'.