Hi there, I searched NRV Removal the other day, and got an old thread by Jan-Willem of the Netherlands. He had pictures and a description of removing a rounded off NRV with an "easy-out" or screw extractor., and pre drilling the NRV with a 3mm drill, so that he could get the extractor into the hole. So, I just copied him. Thanks, Jan-Willem, you saved me a LOT of grief. Here's the half fettled Optimus 48 with the REALLY stuck and rounded NRV I had to file the flats on the easy out to get a 12mm socket to fit onto the back of it. The socket was then hammered onto the easy out, and thus kept it centered on the NRV...sorry for the fuzzy picture...cell phone camera Just like Jan-Willem said in his posts, it gave an aching groan, and then popped unstuck, and unscrewed easily from there on out... The easy out was made for a 1/2 inch socket, but only a 12mm would fit down the pump tube. So, I had to hand fit it. The easy out and drill came from McMaster-Carr, in the USA easy out, is part number57195A511 Shallow Grip Screw Extractor, Drill bit is Part Number 88455A37 Extra-Long Twist Drill Bit, 3.00 mm drill size, by 160mm long with 100 mm flute Thanks CCS, Best Regards, Al
Gary, I had previously tried soaking in Kerosene, and WD-40. But, when I used these tools, I was afraid of having too little friction, so I did it dry. Kerophile warned me about using too much aggression, and accidentally expanding the NRV, so it was easy does it. I have to find a similar set up that will fit into the pump of a Primus 96 stove. This one just closely fits the 45-48 size pumps. Man, was I scared!! I'm fresh out of NRVs. I just made an order with Base Camp. Can't wait. Thanks for the kind words. I get a lot of encouragement from Kerophile, and man does it help me go ahead and try. Thanks, George. EDIT: Just added this...Stole an NRV from my Opti 45, and made coffee. Best, Al
Hi Al, Great result! I am so glad that you got the old NRV out without having to remove the whole pump tube from the tank....although that would have been the fall-back position. It is likely that the offending NRV is the original, and has been in the tank since the 1960s. The photos, that you showed me, of the tarry deposits on the outside of the tank suggest that a full tank of fuel had been allowed to evaporate leaving varnish-type deposits behind. You can also see green corrosion deposits on the NRV that you have removed. Well Done, Don't forget to fit a thin lead washer on the NRV when you re-assemble it. We all look forward to seeing photos of the stove in operation, Best Regards, Kerophile.
Well done Al, I can imagine the relief when it came free I've had success with stuck NRV's by filling the tank and the pump tube with boiling water, which helps move things about a bit as well as providing lubrication. Gardening gloves required !
Keith, The tool was such a close fit to the inside of the pump tube, that I couldn't tell if I had unscrewed the NRV or not, til I removed it from the outside end of the tube. I can't describe the relief that came over me. I tend to tense up "a little". The real truth is, that I value my stoves so much, emotionally, that I tense up every time I take a tool to one, and I have to tell myself to lighten up. If I can't relax, I have to stop work until I do. It's a function of the fact that I have no experience, except for twisting the spindle arm off the vaporizer tube on my 1970 Svea 123. That's how I started collecting...I wrecked my stove, and needed another. I didn't know about eBay having Svea 123s. Imagine my surprise when I found out about that! Party time! LOL Best, Al
Nicely done! I was so happy it was out too. But I would never do it again this way, only as a very last resort. Not because of the destruction of the nrv, not because it was much work, the way I did it it was just nerve wrecking to drill the hole in the nrv. But I did not have a long enough drill bit to do it properly. Ah well it is nice to see another stove working after many years!
Jan-Willem, My 3 mm drill bit, is 160 mm long. I was able to actually place it into the little hole in the NRV by looking down into the pump before I connected it to the drill. Then, my wife held the bit in place while I tightened the drill onto the end of it. The actual drilling, took about 0.5 seconds. No kidding! Then I blew out the shavings from the pump tube with a 115 pound pressure air hose. Bingo. Done. However, before I did it the right way, I tried it several times with a different power drill, and the bit was slipping in the drill chuck. I couldn't see it slipping, and it would start to spin, then get stuck in the NRV then slip in the drill chuck. I thought that was the hardest Brass NRV I had ever seen. I also thought it was going to be impossible to complete. Once I determined that the bit was slipping in the drill, I changed to another drill, and was finished immediately. I included the part number for the drill bit in the other post. It makes all the difference, and didn't cost much. With the 160 mm bit, the job was fast and very easy. Still Scary, though . Kind of a desperate situation too, as I've no knowledge of soldering at all. Best, Al
Gary, In the last picture where the 48 is burning, the stove has greasy hand prints all over it. Before I fixed the NRV I had cleaned it using Kerophile's Citric Acid and wallpaper Paste concoction. Before I started, it was really really bad, and the results were almost a forehead slapper. I had never dreamed it would be so easy, and work so extremely well. Kerophile is the Master Fettler. It doesn't hurt that he's smart, either, to develop a method like this The nice part of using the paste, is that you can spot treat stubborn areas, without turning the whole tank Pink. I had planned on spending hours and hours trying to get all that junk off the tank, and it just disappeared before my eyes. Thanks for the compliment. You made my afternoon. You too, Jan-Willem. Best, Al
