Do any know the formula for figuring the installed height of springs. What I want to do is set my spring up to be 130-135 seat and 330-335 open, but what height would give me different seat and open pressure. Hopefully someone will provide a wonderful links that will break it down to the lowest level.
Thanks:

Your open height will be determined by CAM lift/rocker ratio and installed height. I'm certainly not Grumpy Jenkins but I think the only thing you can really setup is the installed height. You can change shims under the spring and change to increased height locks to change the installed height.

The way I check spring pressure at the height in question is to set the retainer on the spring mic set at the height you want and bring the spring tester down to that combined (mic and retainer)height and set it's stop there. Now replace the mic with the actual spring(s) and add retainer on top. Then bring your tester down on that assembly to its preset stop and read the pressure.

You could use trial and error to achieve your desired seat pressure and then add in your lift and check to see what the nose pressure is.

Make sure that when you've decide what you want to do, you aren't into a coil bind situation. Typically you want .060 between spring coils at max lift.

Does anyone else have any other tricks?

Troy.

Lets try this:
Here is the specs on the spring part#8033 upgrade that AFR puts on there heads for Flat tappet Solid Cam, so I want to make sure they will work and NOT wipe a lobe.
410 per inch
140 seat @ 1.930
365 open @1.380

Will these springs be ok for a cam w/
280/284F10 247/251@.050 .525/.530 lift 110lobe 106 centerline

Also stated in the description of the spring upgrade "valve upgrade include .100L Rev"
What is That?
Don't want to wipe a cam.....

Those springs should be fine. If you install them at the spec height given, you won't quite reach the open pressure they give you but it's close. You should be about right where you are looking to be 335#.

How high are you looking to spin this baby? I would think the valve train should be good to at least 6500 or 7000 with those springs.

Harold would be the one to give you the definitive answer.

If they are a double spring, you should still break in the cam with the outers only.

Hope that helps,

Troy.

I've go an excel spreadsheet with formulas for getting your installed springs height (and some other stuff) if you want it.

I wouldn't mind seeing that myself.

tgotschall@cfifl.com

Thanks,

Troy.

Casey,

I would be interested in that also. Would you mind sending it along, or posting it.

Thanks.

Robert.Bragg@fisher-price.com

I'll post it...
Here it is (http://www.goprp.com/extra/cams.xls)

There's 2 sections... camshaft specs and spring specs.

At the bottom of each section are 2 "new" fields. Fill in the blanks in those fields and the rest will fill in for you.

The sheet is protected so that none of the formulas can be changed, but it's not password protected so you can change the formulas or unlock cells if you want by unprotecting the sheet.

Have fun!

graemlins/beers.gif

here's my 2 cent's. :rolleyes:

Like was said, once you own the spring and assuming it's correct for the cam, about the only variable you have to control is the closed spring height. One tool you should buy, to do this at home is a "valve spring height micrometer". It's a great tool for setting the spring recommend height. Crane 66902 about $50. You use spring shim to get the height correct. The spring spec will tell you the "coil bind" number. You know your cam lift, after the rocker. If you set your spring height correct, subtract the coil bind from the installed height and the results is the most lift you could run with 0 margin. If it's a solid, than the hot lash is also margin. Before you do anything you should do this basic math for your parts. If you do not have the spec's for the spring, than you have to measure the coil bind and than make a reasonable assumption about the installed height for the springs or by the recommended spring. Spring installed height can range from 1.3 to 1.9" for single spring, 1.3 to 2.0" for dual and 1.7 to 2.1" for big triple roller springs. If you want to measure your spring pressure, the cheap way is using one of the pressure tested like Tavia sells they have 3: 0- 300, 600 and 1000psi. You can use this in a vise (use care if it's a strong spring) with a dial indicator to read the height or better using a arbor press and the dial indicator. There are better tools and you can use for this but they are expensive. Or use the service of the local machine shop. I just wanted to provide a way that will work for the do it yourselfer.... graemlins/thumbsup.gif PS most cam cards have the recommended closed and open height and desired pressures for there springs.