I have a MK 2 with the new power plenum. And I was having trouble not getting enough hammer spring force to overcome the pressure in regulator... to push a 25 cal slug efficiently (I figure around 965 fps will do... I'm at 950 when I start losing power if I up the regulator with Maximum hammer spring applied. So I ordered and exchanged the new 16mm hammer spring adjuster and the notched cup it attaches to. Still not enough hammer spring adjustment. So I ordered a HUMA Air hammer spring replacement (reported as more powerful). When I replaced the spring I noted that the valve seat in the rear did not fit flush. To get it to fit flush I had to back off the hammer adjustment way lose. The problem from what I can see is when C1 is screwed down, it was hitting the hammer, and sucking in the rear valve.. lifting it off the seat. So I measured the C1 extrusion and it is 4.89mm. I think most videos on YouTube state it should be 6 to 6.5mm. Yes I measured correctly. I don't know how to adjust it other than unscrewing C1.. which is already a pain to keep solid, not sure how that is even possible with 1.25mm less thread engagement. Also don't like the idea of the hammer slamming thru threaded portion of the rod. Are these rods too short? Is there another adjustment? Any suggestions would help. Thanks.. Joe
Valve Rod Length C1 Length
- Thread starter Virginia_Joe
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Thanks cfs916 for the info. Last time I used blue Loctite, the installers (FX USA) used copious amounts of red, and it was very difficult to get off. I learned all about heat and Loctite and Chlorinated brake fluid. I trust blue when all the way screwed on. I have not buttoned it up yet, so I will look into the power wheel at 1 and get a reading. I have C1 on right now (not Loctite), and it's not touching the hammer, but I also am way back on the hammer adjustment. My fear is I will be adjusting, and as soon as I send the preloaded hammer too far (which isn't far) I will unseat the back. i.e. it appears I have all the adjustment in the world... but I don't. I do have three springs and three hammer weights... currently the HUMA Air beefy 56.5mm spring (which feels the same as the 57mm original spring), and I have the 52mm Power Plenum spring (and their weight). I have two HUMA Air brass weights which are 20 and 30 percent increases from the steel Power Plenum weight. Not quite the unobtainable Tungsten... point being is I have some adjustability. Perhaps when this is back outdoors and tuned in (hopefully) I will report my findings for the rest of the AN.
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As long as the hammer isn't preloaded to the c1 you can leave the power alone I found out I seated the valve and assembled everything adjued the c1 and my power wheel was on max and there was still Freeplay at 6 mm setting I also tried original hammer but haver the 2 huma hammer weights I think I'm going to take it back apart and install the heavy huma hammer weight I also adjusted c1 with blue locktite
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You can set max adjustment of hammer spring tension whether the power wheel is on 1 or 16 (min or max). Ideally it should be set on max power wheel adjustment so you can can actually have quick detuning function of the wheel.
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