Cam Questions

[Russ Pottenger]

Al,

Summit stocks those springs and at $36.00 for a set of springs, not a bad deal if your not running a lot
of camshaft lift.

Keep in mind these Jeep engines don't need a lot of spring pressure.
My LS valve race engines are only seeing 110lbs on the seat with a spring rate of just 35 lbs/in,
and seeing 6000 to 7000 rpm's

[jeepxj3]

Keep in mind these Jeep engines don't need a lot of spring pressure.
My LS valve race engines are only seeing 110lbs on the seat with a spring rate of just 35 lbs/in,and seeing 6000 to 7000 rpm's

I hope that is a typo.

[Russ Pottenger]

Keep in mind these Jeep engines don't need a lot of spring pressure.
My LS valve race engines are only seeing 110lbs on the seat with a spring rate of just 35 lbs/in,and seeing 6000 to 7000 rpm's

I hope that is a typo.

It wasn't a typo.

Lets say for example you are going to run your engine with a camshaft that had a gross
valve lift of .450
With my valve spring you would have 110lbs. seat pressure and 267lbs. open spring pressure.

Russ

[jeepxj3]

Is that 110 at 1.64" installed height?

Thanks for sharing.

[Retlaw01XJ]

You mean 350 lbs/inch.....

[Russ Pottenger]

Is that 110 at 1.64" installed height?

Thanks for sharing.

110 @ 1.700

It's a Chevy LS spring that I use with the LS valve upgrade
I use a spring set cutter to lower the spring seat and therefore increase the install ht.
and at the same time creating a proper ID fit for the new spring.

[Russ Pottenger]

You mean 350 lbs/inch.....

The valve spring manufactures usually give you at least 5 key specifications to help the
engine builder evaluate and choose a valve spring.

1. The ID and OD of the spring or springs.
2. The seat load or pressure, and at what installed height.
3. The open pressure. That is the compressed measurement that is the most ideal for the spring.
4. Coil bind. Depending on the spring, you usually are going to run your open pressure measurement
to within .050 to .100 of coil bind.
5. Spring progression rate. Going back to our spring example. If you install it at 1.700 you get 110lbs
closed pressure. If you have a spring rate of 35lbs. You pressure increase of 35lbs for every .100 compression
of the valve spring. To know the spring rate is key to calculating the open pressure you'll have based on the
gross valve lift of your camshaft.


Russ

[bigal389]

Thanks Russ. I read about them on a couple of other forums but wanted to get some first hand info. I think I'm going to go with the Mopar 229 cam and the 1456 springs. Then add a mild port job and polish the cambers and a bigger throttle body and see what it feels like.
Thanks, Al