Im getting ready to install a 228r cam and PAC 1518 springs. The springs are going into 241 heads. Does anyone know the height I should install them too?

 

Max lift should be .075 to .050 from coil bind depending on rpms.

 

lets say 7200 rpm, what height?

 

at 72 I would stay under .060 from coil bind. Beehives are much more stable the closer you get em to coil bind.

 

Ok here comes a complete newb question. How do I determine coil bind? This is my first time ever doing a cam swap so please forgive me for the dumb question.

 

No dumb questions when it comes to any engine measurement. It is the height of the spring compressed solid. Must remember every spring is slightly different. Its not a bad idea to measure each one.

 

So if im understanding correctly, when i install the springs ill compress them completely and back off until the height it.075 to .050? The car should have stock shift points until i get is tuned (the trans is a 4l60e and is getting a shift kit installed). What would be the correct height to adjust them to with these specs?

 

No the numbers are from your max lift point.
What total lift are you running?

At your max lift you want to obtain .050 to .075 from coil bind. If you do not know what you are doing I would keep it further. I would suggest help from someone who has experience setting up valve train.

 

Its a TSP 228r cam. I dont have the numbers in front of me but i believe the lift is .588

 

You need a spring height checker to determine how the spring sets up on your head. It has nothing to do with the spring itself but rather the head its going onto. Its a lot like a sock going on a foot, the sock doesn't determine the size it will be when stretched, the foot does. I got a proform spring height checker, one like this:

http://www.amazon.com/dp/B000CCFK9M/...M&linkCode=asn

You need to have one in the range of 1.800 bc thats where the GM heads like to set-up. Mine went from like 1.6 to 2.2.

How you figure your height that you need to be is simply this

Coilbind-----Let's say its 1.100
Add your safety net-----0.060++
---------------------------------------
--------->>>>>>>>>>1.160<<<
The max you want to compress your spring

So we take your installed height of say 1.800
Subtract your cams lift, say------------- .595
--------------------------------------------------
That gives you>>>>>>>>>>>>>>>1.205
This is what you are actually compressing your spring to. So to get to your first figure you would need to shim.

So ----1.205
Minus 1.160
--------------------
>>>>0.045 shim.

You have now set your springs up at max lift to be .060 away from coil bind.

 

ok thanks for breaking that down. I couldnt find any stickies with that info. Hopefully Im understanding it correctly. I have a spring height tool so i should be good to go.

The PAC 1518 springs I believe are 1.080 at coilbind. So the max compress would be 1.140 when measure with the height checker, correct?

If the install height is 1.8 and the lift on my cam is .588 then max lift on the spring would be 1.212, correct?

All this would equal out to needing a .072 shim when installing the springs?

 

YES that is correct. Bet remember you do need to check every springs solid height because they will not all be exactly the same.


Thank you 01ss for the break down. I don't think to well in the wee hours of the night.

 

Ok now that I got that understood a couple more questions lol. The OD on the 1518 sprigns is 1.290 and the shim needed is .072.

Im assuming the OD on these are too small to work? http://www.jegs.com/i/Comp-Cams/249/...oductId=773417

So these would be the correct size? http://www.jegs.com/i/Comp-Cams/249/...oductId=773417

Im not sure what the ID needs to be. Also my last question (i think) all shims ive seen some in .015, .030, and .060. Since I need .072 shims to be exact (i know i need to measure each spring individually) but in theory lets say the .072 is what i need. Since no shims I've found would allow that exact measurement, Im assuming it would be better to shim .072 and below than to .072 and above? It seems I would have to shim to .075 or .060 since theres not really an in between. Unless someone knows where I can purchase a different range of shims.

 

The shim iself will sit under the seat/cup. The ID depends on the size of your guide OD.

We offer shims in .015 .020 .030 and. 050. You can use multiple shims to reach your closest point. The amount of shim really depends on your setup. You may want to be tighter or looser depending on you engine building skills, RPM, valvetrain weight, ect.

 

from what I understand, you want to measure them all, then pick a range that is attainable. IE: lets just use these numbers for example. Lets say your range of attainable numbers is between .050-.060

that would mean that you would want all your valve springs to be between .050-.060 from coil bind. (thats just an example number)

 

That is a correct assumption.

 

Well I've learned a lot and here I was thinking the spring install was going to be the easiest part lol. Turbo do you have a link to the shim selection you offer? I went to the PAC site and didn't find any.

And since the springs are essentially the last thing to be installed. I'm assuming I can just install them, measure, order the shims and go back and install shims. I was hoping to do it all at once but since this my first time I guess this is the best way.

 

Here is the website to our online catalog http://racingsprings.com/RS2010CAT/RS2010CAT.html

Pretty much yeah that is what you need to do. If you have an idea what total lift is you can ball park shims to a close number still within specs.