eb02z06

iTrader: (18)

Hi guys-I was wondering if I can just drop in a set of the new PAC 1521 Springs using my Patriot Ti Retainers, locks and seats?

Thanks!

mvvette97

iTrader: (18)

won't work, the Pac spring is a beehive spring that requires the smaller retainer. You can use the stock retainers though

mvvette97

iTrader: (18)

I don't even see a 1521 spring. Do you mean 1520?

eb02z06

iTrader: (18)

The 1521 is a dual, the 1221 is the Beehive. It's not listed in the catalogue yet but there are a few out there that have them.

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both 1521 and 1221 are dual springs

the 1221 springs have been the PAC LS1 .650" dual spring for quite a few years, you can use Comp Cams 754-16 or REV makes a retainer that will fit them. Comp's new lightweight tool steel LS retainers could perhaps fit.

If the 1521 carries over same spring dimensions the comp cams 754-16 retainers are fine.

WKMCD

iTrader: (2)

I run the PAC 1521's with Comp 921 retainers. They are dual springs. Nitrited for longer life. I think these are probably the best drop-in's available plus they are good for .700 lift.

Yeahdoug

THe Patriot retainers are very close to fitting. You need to take .003-.005" off for the ID to fit properly. The spring is meant to fit the Comp 921 retainer and I believe it fits the Ferrea as well.

KennethS

Ferrea E11020

eb02z06

iTrader: (18)

So the Comp 921 retainers work but the Patriot's need some machining. What about the spring bases for either the Comp's or the Patriots.

Thanks for all the help guys-I'm wondering why more people don't use these?

WKMCD

iTrader: (2)

921 hardware top and bottom. More people don't run them because the are new, hard to get and people think the cheaper springs will work fine. I've never run anything less than 921's - but that's just me.

Old SStroker

Where have I heard that before?

eb02z06

iTrader: (18)

Here are the specs from PAC:

160 lbs@ 1.800
435 lbs @ 1.150
408 lbs/in Spring Rate
1.080 Coil Bind
1.300 OD or Outer
0.895 ID of Outer
0.655 ID of Inner

Max lift - 0.700 inches with a tall install or tight coil bind clearance

These are perfect spring for FI build, I'll be switching over a couple of cars to these.

However there not cheap-about triple the price of the Patriot Extremes.

I know of only one guy that my have them.

99blancoSS

iTrader: (115)

depends on where you get them from

Grendel

iTrader: (27)

Dumb question time:

Scoggin Dickey didn't send me locks when they sent me retainers with the PAC1521 springs.
We put the Patriot retainers and locks onto the PAC springs. It seems to work???

Like they fit really well?

So, the dumb question: Did you try it?

Beau@SDPC

iTrader: (14)

We did not send comp cams anything except the pushrod checker. We send the AFR retainer as it does fit and is less $$$ than alot of the others.

This is the first I have heard of the patriot parts fitting the PAC springs, but the main part is, do they fit to within Pacs recommendations? Or at that point, well enough to not move at all when both springs are engaged on the retainer. And the seat as well. The seat is not just there as a shim. It is supposed to locate the ID of the inner spring also.

Grendel

iTrader: (27)

Thanks for the correction.

Correct, I didn't receive the seats or locks and ended up using Patriot seats, retainers and locks. I'll post a video, as the motor's together. There is no coil bind or spring movement. From the post above, you need to trim the Patriot retainers down to fit the PAC1521 springs... I had to do no such thing and they fit tightly. Not interference tight, but less than 1MM difference with calipers.

Also, it seems that it took stock push rods just fine.

Beau@SDPC

iTrader: (14)

No problem. It is definitely a good alternative if in fact it does turn out!

Grendel

iTrader: (27)

John, do me a favor, take one Patriot retainer and one PAC 1521 spring (we know you have both, since I got both from SDPC) and snap some shots of them together, please? Or at least some measurements?

I am second guessing myself here and can't get empirical evidence without disassembling my motor... and I don't want to void the machine shop warranty, considering they did all this assembly.

Beau@SDPC

iTrader: (14)

I will try to get on that here in a bit. I will update with what I find.

Grendel

iTrader: (27)

How's that going, John?