I have a set of AFR 8017 springs, and Patrick G says they're good to .650 lift when shimmed to within .050" of coil bind. Im trying to make sure I can use them with a MS4...

Does shimming them have any ill effects on the springs? Is there any how-to's on shimming springs?

And can I use the stock retainers with the springs?

 

anyone?

 

......

 

the shimming goes under the lower spring seat, just reduces the installed height of the spring by the amount of shim. If you are trying to achieve .050 from coil bind, you need to measure your current installed height (with a valve spring micrometer), subtract off the coil bind height (AFR can tell you this number or you can have a machine shop measure) and then you subtract off the lift of the cam. this number is the amount from coil bind you have.

 

Your other option is to drop in the AFR 8019 springs. If you shim,you need seals as well to remove the spring seats.

Contact Tony Mamo, get his input. I think he will likely recommend the 8019's as well.

 

Well, I picked up a set of 8017s a few months back for $100..I wasnt planning on running a MS4, but I can get it and new prushrods for $300, so i figured what the hell.... and since I already have these springs, I wanted to try and use them.

So, from what vettenuts said, if I use the 8017s and shim them, i need to buy new seals as well?

And as far as spring height goes...is it something that is usually the same from car to car? im just wondering If i have to install the springs, then measure, then order the shim and then put the shim in...or can I just find out what the installed height is from AFR?

 

OK so what you're looking at is the valvetrain that you will be dealing with.

1=The retainer
2=The valve stem
3=The valve seal
4=The guide
5=The spring seat/locator
A=Installed height
B=Retainer-seal clearance

Basically what you do is measure the installed height (A) with a micrometer. You do that by placing the mic over the locator (5) and then put the retainer and locks (1) on top. The mic expands vertically until the valve is tight against the seat and the retainer won't go up anymore. Usually it's gonna be around 1.75"-1.85". That number, minus your cam's net lift (lobe lift X rocker ratio) is going to be your open height. That number needs to be at least .050" larger than coilbind. You can measure coilbind or it will give a less accurate number on the box or somewhere in the manufacturer's catalog or website.

If your open height is, lets say .080" from coilbind, you can put a .030" thick shim under the spring seat/locator (5) to decrease the installed height and open height. You have to remove the seal (3) to put a shim under the locator, and usually a seal isn't reusable. But, you will get more spring pressure and getting closer to coilbind helps dampen harmonics.

So, meausure YOUR installed height and coilbind height, then order shim accordingly. Good luck.

 

I've worked very closely with Patrick on his builds and what he is recommending is true. I do NOT recommend you trying this without testing each spring first to find that individual springs bind height.

Thanks,
Shane

 

I always measure. I set up a spreadsheet and plug in the height measurements and compute open forces, distance to coil bind, seal clearance, etc.

I wouldn't just slap them in there.

 

well, I PM'd Tony and this is what I got:

So, I think I'm going to play it safe and not use the 8017s with a MS4. I might get new springs and use the MS4, or just get a new cam.

KCS, thanks for the awesome info and great pic though!

 

No problem, happy to help.

 

bringing this back for a quick question...

can the stock retainers be reused with the springs? I have the springs and pushrods, and wanna know if i have to order the retainers too..

 

Maybe if it's a beehive like the stock springs. If it's a dual spring, then no. Very doubtful.

 

so with a comp 918 spring you would have to order new retainers? what about locks? comp has a kit for 250 that has 918s steel retainers and steel locks, seems like a good deal.