Tuning TX200 Vortek PG3 Steel 12ftlb install issue: Resolved.

[Sqwirl57]

So I'm attempting to install a 12fpe kit into my TX200 but have run into an issue. With one spacer installed, I am getting 10.5fpe with FTT 8.64gr and closer to 11 with AA 10.6gr pellets. When I add another spacer to bring it up some, the piston rod won't latch on the sear. Everything is bottoming out on the trigger assembly so its safe to assume the added spacers are making the piston rod just a bit to short to work properly. Any advice or am I possibly (probably) doing something wrong? 

Side notes, the original top hat has been removed and the safety wasn't engaging properly with just the single spacer either. With no spacers and the spring in the highest position in its seat, I'm getting just over 10ftlbs.

Edit: Am I supposed to unscrew the latch rod some to compensate?

Edit #2: the spring guide does not fit completely into the piston with spacers installed. Will reduce spring guide length by 0.25" (depth of spacer x2) unless someone has a better answer.

Edit #3: Issue resolved

Here is a picture of how the guide fits into the piston with no shims/spacers for preload. Perfectly flush.

With a single shim installed the gap was slight but hardly noticeable. In this picture, both shims are installed and the gap is quite noticeable.

With the stock off and cocking the action with no shims installed I noticed that I could both hear and feel the sear and safety engaging just as the piston bottomed out on the base of the guide. With the gap seen in the picture above, the piston rod wasn't able to fully engage the sear.

Solution: I measured both spacers and got a total depth of just under 0.25". Using a small tubing cutter, I cut off 5/16 of an inch from the guide to compensate for the shims it was contacting and thus preventing the piston rod to go all the way rearward into the trigger assembly.

Using a bench grinder, I then added a small taper around the end of the guide to help ease it into the piston when cocking. I finally gave it a quick polish with 180 and 800 grit sandpaper to smooth it out. It works flawlessly.

With both shims installed I threw a quick 50 shots down range to allow things to settle in after reassembly. I am now sitting at a comfortable 11.6fpe from my TX200. Now to just break it all in some and recheck my numbers in a tin or two.

5 shots, 50yds, JSB 8.44gr

 

[Lewis]

I'm not sure which kit you have, but with some, the spacers are intended to go on the butt end of the spring and others go on the muzzle end. Do you know if the spring is binding? Are all the coils touching each other preventing the latch rod from seating completely?

Do NOT unscrew the latch rod to make it longer.

Are you also replacing the piston seal? If so, it may need to be sized. This caused me fits recently with a Vortek parachute-style seal. Also, you mentioned removing the top hat. Is the spring end flat, dressed, and polished, or just cut off? The hat serves an important function to allow smooth rotation of the spring.

just 2 cents.

 

[EMrider]

My guess would be that your piston seal needs to be resized a bit. Assuming that you used the Vortek seal, I have found those to be a bit snug. If you do resize the seal, use fine grit sandpaper and adjust in VERY small increments. Good luck.

R

 

[Sqwirl57]

My guess would be that your piston seal needs to be resized a bit. Assuming that you used the Vortek seal, I have found those to be a bit snug. If you do resize the seal, use fine grit sandpaper and adjust in VERY small increments. Good luck.

R

The seal is a good fit. I'm like 95% sure now that the guide is too long which is preventing the rod from moving far enough back when the spacers are added.

Guide sits flush with piston with no spacers.

Guide is gapped with spacers.

 

[Sqwirl57]

I'm not sure which kit you have, but with some, the spacers are intended to go on the butt end of the spring and others go on the muzzle end. Do you know if the spring is binding? Are all the coils touching each other preventing the latch rod from seating completely?

Do NOT unscrew the latch rod to make it longer.

Are you also replacing the piston seal? If so, it may need to be sized. This caused me fits recently with a Vortek parachute-style seal. Also, you mentioned removing the top hat. Is the spring end flat, dressed, and polished, or just cut off? The hat serves an important function to allow smooth rotation of the spring.

just 2 cents.

The hat that I'm talking about is the factory hat that likes to get stuck in the piston. The hat which came with the PG3 Steel kit is installed. I added some pictures to a previous comment of my suspected issue.

 

[DualMagMike]

ALWAYS check with the maker, they should know best. Secondly as far as I have ever heard Vortek kits are not designed to work with spacers or piston sleeves so likely the spring is coil bound. Remember each gun is going to be different power wise and will perform differently with pellet used. If you are looking for a little more power have you made sure the top hat is turned to its proper notch for max power and not the lower power? Lastly the 12fpe kits are designed to be 12fpe MAX! Although 11 may be a little on the low side for you if you changed the seal and the old seal is intact try it back in there to see what happens. I don't think I have had a Vortek seal that did not need to be sized down a bit. 

 

[Sqwirl57]

ALWAYS check with the maker, they should know best. Secondly as far as I have ever heard Vortek kits are not designed to work with spacers or piston sleeves so likely the spring is coil bound. Remember each gun is going to be different power wise and will perform differently with pellet used. If you are looking for a little more power have you made sure the top hat is turned to its proper notch for max power and not the lower power? Lastly the 12fpe kits are designed to be 12fpe MAX! Although 11 may be a little on the low side for you if you changed the seal and the old seal is intact try it back in there to see what happens. I don't think I have had a Vortek seal that did not need to be sized down a bit.

I contacted Vortek well before making this post. Its the weekend so I doubt I'll hear anything back from them until next week. As far as the piston seal goes, if anything it is a little looser feeling in the compression tube than the factory seal is. The fit is good and holds vacuum if I cover the port with my finger and pull back on the piston. As far as the washers/spacers go, they actually come with the 12fpe kits from Vortek to bring them up to the 12ftlbs. There is 100% something funky going on here as all pellets are sitting at 10fpe or lower with no spacers installed. Pellets tried: JSB 8.44gr, AA 10.3gr, FTT 8.64gr, Baracuda Match 10.65gr, Baracuda Hunter 9.57gr, a variety of CPs.

 

[DualMagMike]

Is the top hat set to the high power notch, did you try the old seal and check the breech seals? Also is it an older MKI or MKII TX? The older MK's have a shorter stroke and will not make the power of the new TX's.

 

[Sqwirl57]

Is the top hat set to the high power notch, did you try the old seal and check the breech seals? Also is it an older MKI or MKII TX? The older MK's have a smaller piston and will not make the power of the new TX's.

Top hat is set on high and it is the MK3 piston. With the factory seal I lose 35fps and end up at 9fpe.

 

[AirShot]

From the picture you have an fac piston which will work for 12 ft lb but...you will have a long lock time..the time it takes for the piston to travel its length. A much better solution is to go with the longer stem ( short stroke) 12 ft lb piston. Much quicker lock time and better firing behavior with the 12 ft lb spring. If your interested, I still have a couple 12 ft lb pistons left over from my springer tuning days. Send me a pm if you are interested.

 

[Sqwirl57]

Issue resolved and original post edited for clarity. Hopefully this will help someone in the future.