Are 98s with RT worthwhile?

[Trbo323]

That goo is what remains of the o rings if I had to bet

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[Calvin]

What made them degrade that way? They usually just dry up and start to crumble. Never seen green goo from a urethane oring.

[Magmoormaster]

Agreed, almost gauranteed. Should come off after soaking it. I usually just use Dawn.

[Myrkul]

I've seen green goo from "o" rings before. Not as much as I used to, it's pulled back a lot. I'm not really sure what causes it. I suspect a cheap "handy" fix like WD-40? Petroleum based lubricants do absolutely horrible things to "o" rings over time, but they will get you through a day if the issue was a dry marker.

Kids these days don't really work on things much. I definitely remember a buddy in junior high hitting his old tippmann with break cleaner then WD40 and he was able to finish the day out with no issues. There is a zero percent chance that marker is still functional now, BUT it got him through the day back then and that is what mattered at the time.

It should clean up fine. Lots of really hot water and dish soap, rubbing alcohol, q-tips, tooth picks, paper towel, toilet paper. Just clean it up and slap some new "o" rings on it with the correct silicone based lubricant, I believe the tippmann manuel recommends hoppies #9, but personally I always just use "Super lube" (because that's what ICD always recommended.)

https://www.amazon.com/Super-Lube-12...0617982&sr=8-1

It's a silicone based lube. It will get the job done AND it won't eat your "o" rings into a corrosive mess.

[Myrkul]

This.

To me, setting up the whole marker right takes some doing. To preface this, I'm not a huge fan of tippmann. I work on a ton of them buying and selling and fixing though.

The RT for the most part works as advertised, each marker is a little different though so I've had some that will only do about 10bps and others that didn't want to do anything lower than 20. I'm sure I could dial them in in either case but it gets to a point of does it really matter for my situation.

Get the rt working and then you need to make sure and have a fast hopper, rotor is a good choice, but on the 98c the wobble from the feedneck annoys the crap out of me, got to fix that, then the trigger has extra play, got to fix that. Then because you took it apart now the RT doesn't want to cycle at the same speed or it's not recocking properly. If you have a A5 the cyclone doesn't want to keep up.

Imo there's always something that leaves you wanting with a tippmann rt, but, like I said for the most part they do work as advertised

Now, if you want an actually good rt system, automag

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Absolutely this.

It takes a LOT of doing. The tippmann 68/Pro-carbine was THE peak of the platform and everything else tippmann has done since then has been produced en-mass for the hordes.

There is absolutely always something that leaves you wanting with a tippmann R/T. That's why I built mine with the option to shut it off. I actually managed to shatter the stock plastic trigger before. It broke along the pins because the rt was too strong.

I recommend a large "01x" "o" ring over the base of the feedneck on a 98 to correct the hopper wobble. If done right it helps with blowback and eliminates the "wobble". They dry out pretty quick though so expect to replace them frequently.

The power feed actually seems to help a lot, as do polished/modified internals and springs. The cyclones are just a hard no for anything over 6-7 BPS. Cyclones suck, especially with modern paint.

An automag R/T is a wildly different system I've never actually had the pleasure of using. I don't doubt that they can be done correctly, I absolutely adore my automags, but in today's world of 10.5, it seems like over kill on steroids. That and there are very few people left who can actually set up a level 10 correctly....

[FlightMedic938]

Just a suggestion Calvin…. But one of your Pro Carbines would like that response trigger a whole lot more than that 98….

[Calvin]

I will not assault the two nice ones in that distasteful way. Perhaps one of the junker carbines could feel the tender caresses needed for such a project.

I did get my hands on another old 98 with a low pressure kit. I figured people would like some pics of the valve parts for posterity so the differences from a standard 98 valve could be noted.

The top valve body is from the low pressure kit. The stem hole is identical at 3.5 mm, as are the cuts for bolt reset gasses. It appears that the hole for the gas release chamber around the the valve has been bored out larger to give greater volume. The gas channels down the side of the valve body are the same width and placement, but have been cut deeper into the body for more volume as well.


All the parts inside the valve are custom. The hole through the lower seal disc is considerably larger. They also used a much longer and lighter spring, which clearly needed a spring guide. I find that pretty interesting thing when thinking about springing down a valve in the future. A longer spring like this with a printed guide to match may be needed. I wish I had a stock valve stem out for comparison, but the one from this standard valve was badly bent, and I already chucked it. A new one is on the way.

The seals specced on these internal valve seals are white urethane. Makes sense due to the CO2 use they were originally meant for. Since I never plan to use CO2 again, can I swap these out for buna o-rings? They don't appear to move in any way once installed. I think the buna would last longer, and definitely be cheaper. The same synthetic air tool oil I use on Mags is all I plan on using with these, so I don't think there will be a chemical attack on the buna.

[FlightMedic938]

Great job. I ran a GTA LPK on 2 separate occasions and while it did a good job I started to notice little things that were not allowing the marker to run at its full potential, in my opinion, because I didn’t chrono anything. With the LPK I couldn’t get my Tippmanns to operate under 450psi. Everytime I tried to go lower they would jackhammer from lack of blowback.

These are just my thoughts and I could be wrong but the valve plug with the stem just takes up way too much space inside the valve reducing volume. A trick I learned here was using a CN27 valve plug for a Pro Carbine. Half the size of the the stock valve plug. It doesn’t seem like much but it’ll let the valve hold a good amount more volume. One thing though is you’ll have to use a 1” valve spring IF your stock valve has a 3/4” spring and a size 12 o ring inbetween the valve retaining ring and valve plug. This gets the spring to the correct length so the cup seal can seal internally against the valve seat. TechT sells 1” lightened valve springs.

I did find a spring that was perfect in length but it requires using a dremel to reduce the OD of the valve stem base and the valve plug guide. It’s a green CCI Phantom valve spring. It’s light and strong too, great spring.

How long is that LPK spring? I never measured it. It could be worth it to ditch the valve plug with guide and use a CN27 but I do remember the LPK spring being super light so it could bind without the guide.

The valve stem is much thicker and a little shorter than stock. The thickness is to reduce blowback which allow more air to travel down the channels to the paintball. I just think it’s too thick and reduces blowback too much. The shorter length reduces the mechanical dwell as well so the valve isn’t going to be open as long. I like the stock stem better.

The valve body itself is perfect though. I polished the channels to smooth out airflow but nothing else needed to be done. It’s great.

The vertical adapter though is a little restrictive with a rough finish inside. It also feeds air above the volumizer and below the valve. That’s really bad placement. It should feed from the bottom of the volumizer or at least 1-2” below the valve from the side. Having it feed from the top like that causes a lot of turbulence. Air is jetting across the top of the volumizer which isn’t going to let it do its job to its best potential.

The volumizer itself is great. I can’t remember completely but I do think I ported the inlet/oulet to increase air flow.

The hammer weighs 118g and the spring is really nice. I think its design with the spring having a full length guide is great. It keeps the hammer very concentric which should improve consistency. I never tested that with a chrono but it just made sense to me.