F4 Springs

[FlightMedic938]

The mainspring is 5/16” wide and 4 1/2” long. The valve spring is a little wider at 3/8” and it’s 3 1/16” long. I’ve tried springs from Spyder kits and they are too wide. I did change one spring but I can’t remember which one unfortunately. You guys know any springs that fit the bill? Really want to try a lighter valve spring and lighter striker spring

This one has been on the back burner for awhile but I’m getting around to it. I’m not sure I’ll keep it because I’m selling off some stuff in the next couple months. Gonna keep a couple 98s, Pro Carbine, Crossover, and Mini GS. Probably gonna sell this one, a 68 Carbine, Pro-Lite, and maybe a pretty unique Tippmann Raider once I get it working right.

So far I’ve ported the vasa air passages, replaced the stock vasa bolt with a gas thru bolt, polished the valve, volume chamber, polished the striker, removed the internal striker guide (it’s pretty heavy), and put in a ACI Venturi bolt with the choke wide open (I polished the bolt too and polished the internal air channels on the Venturi face). Shooting paint through a 12” Deadlywinds.

I had a gas thru on but just swapped to an Air America Vigilante I rebuilt. I chrono’d yesterday and was shooting 270-280 fps very consistently at 750psi. The thing though was I had to back out the rear velocity adjuster almost completely. It was hanging by a thread literally. I want it at least flush for safety reasons but I was shooting like 320-330 fps with it flush. Super tiny paint too. Like .678

I want to tinker with some springs so any help would be much appreciated.

[Toestr]

Almost as niche but not quite; I think springs from the Maxtact/Scarab Arms TGR series would fit as it is heavily influenced by the illustrator. Each gun came with a spring set as that was the only way to adjust the velocity.

Edit: He ya go: https://mcsus.com/products/scarab-arms-spring-kit

[FlightMedic938]

Only thing left to do is to try a different valve or mod the stock one. The valve measures 9/16 but I remember trying a cheap Delrin cocker 9/16 valve and the fit was TIGHT even after carefully filing away some problem areas. Ended up breaking that valve

[Toestr]

I don't think a cocker valve would work. A 9/16 cocker valve body seals between the back of the valve and a shoulder on the body. The illustrator valve seals between the OD of the valve and ID of the body.

[FlightMedic938]

Toestr Thanks for the info. I honestly think I’ll mess around with the springs a little but I’m going to leave the valve alone because I might sell it. I have way too many now and starting to get heat from the wife. I figure if I sell 4 or 5 she’ll be cool with me picking up one of those Meteor Ghosts when they drop.

I got it shooting 270-280fps yesterday The gauge I had on it wasn’t working right but the RVA was turned about halfway in and there were 5 threads showing on the Vigilante adjuster. So I know it was shooting great under 750psi. Probably around 500-600psi if I had to guess.

[Nish]

BE Raptor should fit if I remember right.

[FlightMedic938]

The spring kit that Toestr suggested works perfect. I haven’t tried any out yet but they all work when dry firing with no air. The stock F4 striker spring has no business being 4 1/2” long. It’s kinda light but under a lot of tension. A 3” spring has no problems engaging the sear and making full contact with the valve pin/face. The F4 RVA has a very large range to tune any spring, even short ones.

I picked up a Griffin off EBay just to see if any of the parts are compatible. Only the grip frame. Everything in the lower tube is 11/16” and the F4 is 9/16”. The Griffin bolt is 3 1/2” long if I remember right. Either 3” or 3 1/2”. I tried putting in a AKA bolt for a Spyder but it’s too long. I think by like 1”. I think a 11/16 Spyder valve would work though. The stock one is made of brass which was a surprise. I’m not sure how I feel about that. A brass valve being punished by a hardened steel hammer? Doesn’t sound good. It would be super easy to dremel out though because the brass is soft.

The grip frame is the same though. It had the “upgraded” .45 frame which is easily identified by a brass pin on the side. What ACI did was they added a trigger slide on the back of the trigger for the sear. It looks like a small metal cube with a spring behind it. The sear itself has a different look to it as well. Subtle changes but noticeable. The trigger also is roller bearing and rides on that brass pin you see on the side of the frame. The F4 brass pin is push in but the Griffin is threaded. Interesting finding though, if you take all the upgraded parts out of the double trigger frame and put it in a single trigger frame the trigger pull is 100% better. It removes most of the pre travel and a good bit of the post travel of the trigger pull.

The biggest upgrade so far is the hollow VASA bolt. The stock VASA is incredibly restrictive. Built for CO2. I opened up the 2 tiny inlets on both sides of the bolt a very small amount but the hollow bolt flows more air then both of those inlets combined plus some. The bolt came with TechT Optimus gauge adapter I bought years ago. I had to shorten it a bit. I decided to “upgrade” the bolt by purchasing two hollow WGP vasa bolts from ATTKTX…. The bolts I got look nothing like the picture on the website. Too long and the air inlet is tiny. I contacted them and was told the picture was for custom short high flow ones they made for Mozak. Wish that was in the description lol.

[FlightMedic938]

Autococker trigger shoes fit the F4 and Griffin trigger. Thought I’d share that too.

[FlightMedic938]

I gotta touch up the black pieces, dial in the springs, and a couple other things and she’ll be good to go