Hot Rod Forum : Hotrodders Bulletin Board - View Single Post - New Engine Combo - Your Opinions
View Single Post
  #7 (permalink)  
Old 01-10-2008, 10:04 AM
F-BIRD'88's Avatar
F-BIRD'88 F-BIRD'88 is offline
Yada Yada Yada
Last photo:
Join Date: Oct 2005
Location: Ontario, Canada
Posts: 9,211
Wiki Edits: 0

Thanks: 5
Thanked 389 Times in 383 Posts
Originally Posted by 300Deluxe

I've been under the impression that the springs that came with the heads are too aggressive for my cam (see my other thread on valvesprings). I don't know the specs right off hand, but I do remember the tag on the springs mention a roller cam (I'm running hydraulic).

Sounds like you're familiar with these heads. Will the springs be suitable for my cam?
These heads come with a 1.47" dual coil valve spring suitable for a Hyd roller cam and a aggressive flat tappet cam. They are not for a solid roller tappet cam unless the max rpm is kept to a point that the springs can handle. Mild street solid roller cams with easy opeing and closing ramps and modrate rpm are ok up to .575" lift and under 6500rpm. No race rollers. If you don't understand this, don't play. A roller tappet and camshaft can easily be damaged by "valvetrain crash" if you float the valves/lifters from exceeding the rpm capility of the springs.
This spring is the max you'd want to use on a Hyd flat tappet cam.
For easy break in wether hyd or solid flat tappet on any dual type valve spring it is highly recomended that you first run the motor using the outer springs only until the cam lobe and lifter face get nice and friendly (break in). Break in the cam and motor in for a good week of driving and then if you want maximum rpm limit capability out of your hyd cam reinstall the inner valve springs using compresseed air to keep the valves closed and a simple lever type valve compressor tool to compress the retainers.
For initial cam break in (on the outer springs only) muck up the cam lobes and lifter bottoms good with Isky rev lube. (moly disilfide grease). Add 1 bottle of GM EOS + 1 can of Moly lube to the oil and be sure to keep the rpm up on the motor above 2500rpm for the first 1/2 hours of running. Do not excessivly crank over the motor and do not idle. if the motor is not right, shut it off and fix the problem and then restart, again keep the rpm up.
Drive the car around for a good week with the mixture of break in stiff in the oil. Do not let the engine idle for long periods and do not try to exceed 5000 rpm until the motor is fully broken in and stabilized, You've changed the oil and filter, reinstalled the inner valve springs and reset the valve train adjustment. Continue to add GM EOS to every oil change and the cam will live a very long happy life and rpm to its full potential. If max rpm capability is not a priority just run the outer valve springs only. Should be good for 5500 5800rpm . If thats all you need for max rpm then running just the outer springs are fine.
Remove the valve covers and look at the pushrods while the motor is idleing ( after its all broke in.) If all the pushrods are spinning,the cam and lifters are properly broke in and the cam will live a long life. If the pushrods will not spin even when you rev the motor, you got troubles and the cam and lifters will soon fail or are already failing.
The extra pressure of these 1.47" "Hyd roller/flat tappet type dual springs" is only a issue during the critical initial break in period. Sometimes in some situations, I use a stock SBC springs without shims when breaking in a new motor's flat tappet camshaft. On cams up to .510" lift.
During flat tappet cam/lifter intiial break-in, less (spring pressure) is definatly better.

You can read about Moly engine oil supplement and break in lube
here. It does much more for your motor than help ensure easy cam break in.
Its best to premix the Moly break in lube first with the engine oil, then add it all to the oil pan so its instantly ready to go to work when you first fire the motor ,eliminating metal on metal scuffing, reducing friction and aiding successful engine break in.

Last edited by F-BIRD'88; 01-10-2008 at 10:37 AM.
Reply With Quote