Valvespring poundage

[frederick]

Hi,

I am changing the valvesprings on my 440source heads because of inadequate clearance with some of the original stamped rockers.

New springs are comp beehive #26918.
Camshaft is a lunati 60302, 220-226deg 0.475"-0.495"
Lunati recommend the 73815 springs with this cam.

With an installed height of 1.820" the lunati springs would give:
seat pressure              120lbs
inlet nose pressure       282lbs
exhaust nose pressure  289lbs

With the beehive springs I have several options;
Match the nose pressures, raising the seat pressure.
1. Install at 1.79" to get
seat pressure of          132lbs
inlet nose pressure       282lbs
exhaust nose pressure  287lbs

2. Install at 1.83" to get
Match the seat pressure, lowering the nose pressures.
seat pressure of          120lbs
inlet nose pressure       269lbs
exhaust nose pressure  275lbs

3. install at a different height.

You probably see my question coming now: What installed height do I choose with the new springs.
I have read some articles about the beehives that suggest you can lower the nosepressures because of the lower mass of the beehives and valve retainers.

This is a street only car, probably wont ever go above 5.5k rpm.

Thanks,

Frederick

[frederick]

I thought about it some more and have decided to play it safe and go with option 1.
This means I will match the recomended nose pressures and raise the seat pressure from 120 to 132lbs.

Frederick

[firefighter3931]

I thought about it some more and have decided to play it safe and go with option 1.
This means I will match the recomended nose pressures and raise the seat pressure from 120 to 132lbs.

Frederick

That should work just fine.

Just make sure you have enough lifter preload with that installed height.



Ron

[frederick]

Hi Ron,

Not sure what you mean, because the tip of the valve remains at the same height whatever the installed height of the spring.
Or am I missing something?

Frederick

[firefighter3931]

Not sure what you mean, because the tip of the valve remains at the same height whatever the installed height of the spring.
Or am I missing something?

Frederick

Frederick, as long as there was no work done to the valves or seats then you are correct....the valve tip height will remain the same regardless of the spring installed height.

Nothing i use is run out of the box. Valvejobs and seat grinding are the norm for me so as a rule of thumb i allways verify lifter preload just to make sure. It's a good practice to get into anyway....just gives you peace of mind. Never assume anything is correct....you'll sleep better at night. 



Ron

[frederick]

Ron,

You are correct of course, I was speaking of my situation.
Even different locks and retainers can give a different installed height, you would think there would be some standard for this.
I've got 4 sets of retainers and locks now, each giving a different installed height.

It's a good practice to get into anyway....just gives you peace of mind. Never assume anything is correct....you'll sleep better at night.  Wink

This engine is giving me a real headache, almost everything I check is not ok and needs adjustment and more $$ correcting it.
Just like the rest of the car.

Frederick