Ford Mustang Forums banner

1 - 4 of 4 Posts

·
Registered
Joined
·
2 Posts
Discussion Starter #1
Hi all,
I'm new to all of this, which is why I've chosen the budget build route that I'm going. I have a 1999 Ford Explorer GT40P engine that I'm going to carb. I purchased a Ford Racing E303 cam, and Crane's 44308-1 spring kit. I have seen on several forums that this is a known working combination and the springs that Crane recommends for the E303 cam. I am using stock 1.6 rockers, stock gt40p heads, stock lifters and stock pushrods for now. I plan on aluminum heads at a later date.

I am having trouble determining what my installed height should be. I purchased a valve spring mic from summit as well. The crane kit says 1.950 install height for ford roller engines. Ford Racing website says 1.820 installed height for the E303 cam.

What installed height should I be using?

Thanks for any help!
 

·
Registered
Joined
·
302 Posts
Start with the required seat pressure when closed and at max lift. Combine that with your spring rate and free length and you can find the necessary installed height.

The Crane springs are 457 lb/in. Per Crane, at 1.95" installed height, they provide 118lbs of seat pressure.

The E303 cam needs, per Ford, "120 lbs valve seat pressure minimum 295 lbs open." The E303 cam has 0.498" of lift with a 1.6 rocker.

0.498" * 457lb/in + 118lb seat pressure = 345lb at max lift.

So go with the Crane-recommended installed height. If you're using stock valves, you'll need to make sure that your retainers and locks give you correct installed height. If I remember correctly, the GT40P valves have their locks at different heights and use different retainers because of that.

I know you said you already bought the springs, but did you consider a kit from Alex's Parts, like this one? It's designed for GT40P heads so it has staggered retainers already. It has 135lb closed seat pressure and 322lb at 0.500" lift, which would pair well with the E cam. If you don't want to pay extra for the beehives, they have a dual spring kit that's 133lb closed and 298lb at 0.500" for $125.

Even if you're planning on keeping the stock rockers and pushrods, it would still be a good idea to check the pattern of the rocker tip on the valve head to make sure it's not doing anything too crazy.
 

·
Registered
Joined
·
2 Posts
Discussion Starter #3
Wow thank you so much for the information! I appreciate it. I have decided to purchase a kit from Alex, who I called to discuss this with. Great service. I'll be sending the crane springs back. Thanks for the explanations, much appreciated.


Start with the required seat pressure when closed and at max lift. Combine that with your spring rate and free length and you can find the necessary installed height.

The Crane springs are 457 lb/in. Per Crane, at 1.95" installed height, they provide 118lbs of seat pressure.

The E303 cam needs, per Ford, "120 lbs valve seat pressure minimum 295 lbs open." The E303 cam has 0.498" of lift with a 1.6 rocker.

0.498" * 457lb/in + 118lb seat pressure = 345lb at max lift.

So go with the Crane-recommended installed height. If you're using stock valves, you'll need to make sure that your retainers and locks give you correct installed height. If I remember correctly, the GT40P valves have their locks at different heights and use different retainers because of that.

I know you said you already bought the springs, but did you consider a kit from Alex's Parts, like this one? It's designed for GT40P heads so it has staggered retainers already. It has 135lb closed seat pressure and 322lb at 0.500" lift, which would pair well with the E cam. If you don't want to pay extra for the beehives, they have a dual spring kit that's 133lb closed and 298lb at 0.500" for $125.

Even if you're planning on keeping the stock rockers and pushrods, it would still be a good idea to check the pattern of the rocker tip on the valve head to make sure it's not doing anything too crazy.
 

·
Premium Member
Joined
·
1,240 Posts
Wow thank you so much for the information! I appreciate it. I have decided to purchase a kit from Alex, who I called to discuss this with. Great service. I'll be sending the crane springs back. Thanks for the explanations, much appreciated.
what kit did Alex recommend you to get? or which did you get?
 
1 - 4 of 4 Posts
Top