Canada1

I am planning on using dual valve springs on my CVH 1.9 build.
I am not sure what to use for valve stem seals.
The Ford valve stem seals/seats have an inner step, which a single valve
spring is located.
What does one use with a dual spring set up?

The Kent catalog says their S71 valve seal/seat will work with dual springs.
Is the Kent valve seal/seat different dimensions than the Ford seal?

Has anyone measured the valve seal/seat unner step diameter?
The Ford seal/seat inner step I have measures 23mm diameter.

Your help is greatly appreciated.

Cheers

Christian and Beccy

iTrader: (14)

The one-piece stem seals should do it, you have those?

You sure you need dual springs? Mine doesn't (didn't) run them.

Canada1

Hi Christian,

I already have 2 different sets of dual springs - both slightly different diameters
and pressure.
I would like to know if you could measure the inner step diameter on the one piece
stem seals you have used - it may be different than the Canadian ones.

I am using a hydraulic roller lifter camshaft - which requires slightly more pressure
than a regular flat tappet type.
I am setting up the springs with 118 to 125 lbs of closed pressure, and 220 - 230 lbs
pressure at 0.440" valve lift.
With 15 psi boost I have been told to increase the factory spec'd seat pressure of
95 lbs. This is a result of boost pressure against the valve reducing actual seating pressure.

Do you remember what closed pressure your single springs were set to?


Regards,

Perry

DazC

iTrader: (1)

i think standard rs turbo springs where 195 lb and the uprated ones in cam kits are usualy around 220. I have newman springs on mine and at 50 psi inlet pressure, the valves remained closed.

DazC

iTrader: (1)

you'll need the old type stem seals with double valve springs. They are just a push on type and they used to come off and travel up and down with the valve. Thats why the top hat seals came about.

Canada1

Hi Dac,

Thank you for your information.
Why would you set up your valve springs to 50 psi closed?
At this pressure you would have very little valve control.
Was this recommended by a shop - or Newman Cams?

In North America, boosted applications call for an increased valve seat (closed) pressure.
The CVH has a heavy valve, and rocker arm thus requires more valve spring pressures
than a Pinto 2L.
Speedtalk.com is a great technical site, and valve spring pressures and valve control is
a topic much discussed. There are several top racing persons who post on that site.

I had some email correspondance with Dave Baker at Puma Racing and he was shocked that
the so called "uprated" springs had lower pressure than the factory Ford single spring.
We discussed 115 to 120 lbs of valve presure closed.

Cheers

DazC

iTrader: (1)

I pressurised the inlet with 50psi of air pressure purely as a test to see if they would lift off the seat with that amount of pressure pushing down on the valve head. I am unsure what tension from the spring is on them at the point of closure to be honest, but having checked they are rated at 190lb. Newman's double springs combined are rated at 200lb and their uprated non turbo springs are rated at 160lb.

DazC

iTrader: (1)

These are the type of seals you need for double valve springs...

http://cgi.ebay.co.uk/FORD-PINTO-CVH...item19a4586bd2

And these are the type we normally fit...

http://cgi.ebay.co.uk/FORD-CVH-TOP-H...item2ea864f3d5