valve spring recommendation

[NewFalconOwner]

I got a custom cam off from a member of the fordfe forum, and im looking for valve spring recommendations. I got a copy of the cam card but it doesn't list valve springs on it..

will be using C4AE-G heads with 2.09/1.66 valves, stock adjust rockers, if that matters.

heres the cams specs sent from Paul, and they match the comp cams card.

Intake lobe: Compcams 270XTQ

Exhaust lobe: Compcams TL276

270/276 degrees @ 0.020"

240/246 degrees @ 0.050"

108 degree lobe separation angle

Gross lift .598"/.608" with 1.76 rockers

ive looked around comp cams site, and the 294s cam is close and recommend the 924s or 930s, but when I ask they want to know seat load,installed height,etcc and I have no idea what it should be..




thanx for any help

Rick

[afret]

Those are pretty aggressive lobes.  What seat and open pressure was Paul running?  The 924 is probably too weak and springs like the 930 or Isky 8005 series work well with most off the shelf solid cams but if these lobes are really radical you might need more spring.

Best thing is to talk to someone knowledgeable at Comp like Chris Padgett and get his recommendations on what spring pressure is needed with your cam and valvetrain.  If it requires a lot of open pressure, hopefully the cam is nitrided and tool steel lifters might be a good idea.

[NewFalconOwner]

thanx,, I will try and get a hold of them this week.

[plovett]

Just FYI.   It's been a long time so my memory is a little fuzzy, but I believe I started with Crane 99893's with that cam.   I think I used .050" under keepers, but still wasn't happy.   Valve float around 6200-6300?    I can do the math if you want but I think the spring pressure was around 140 lbs closed and 390 lbs open.

Then I went to Crane 99895's with titanium retainers and it worked good past 6500 rpm.   Later I found some broken inner springs with this setup.  After sending them to Crane and discussing it we decided it had some sort of harmonic issue going on.   Tore up the titanium retainers too.   Seems like the pressure was about 150 lbs closed and 400 lbs. open.

Ended up going with Crane 96879's with standard keepers and new titanium retainers.  Pressure is about 150 closed and 405 lbs open.  I also got some stiffer pushrods in case they were causing or contributing to the harmonic issue.   And I swapped cams at this time.   Went with a bigger one, 252/260 degrees @0.050", but with <I think> slightly mellower ramps and about the same total lift.   Now it works past 7000 rpm no problem.

Sooo, that cam will require some care to work well.   If I remember your combo correctly it sounded like you might be turning fewer rpms than mine did.  In my 428 it peaked at 6200 and I shifted around 6500 rpm.  I'm guessing your combo will be a few hundred rpm below that which will help greatly. 

paulie

[NewFalconOwner]

yeah, im not really going to spin it to the moon.. just scare people lol. thanx a lot Paul.

Rick

[plovett]

I think it'll scare everybody within a half mile when you hit the gas in that light little Falcon, Rick.   

I highly recommend titanium or at least tool steel retainers.   Makes a big difference in valve control and/or can let you use less valve spring pressure. 

paulie

[plovett]

One other thing.   I remember you were thinking of making a 445 cube FE.  That and different cylinder heads was why I was thinking your rpms would be significantly lower than in my 428.   If it's going in a 390 for now I would recommend advancing the cam a bit more than you might otherwise.   At least within reason, and piston to valve clearance and compression ratio permitting.   Maybe something like a 102 degree intake centerline? 

Just a thought,

paulie

[NewFalconOwner]

thanx a lot Paul

[bluef100fe]

I run the comp 930-16 springs at 1.900 installed height with that lobe family.... edm lifters HD shafts and Harland sharp rockers with end stands and good pushrods. Good luck

[NewFalconOwner]

thanx