Holdsy''s Innova

Hello every peeps, it's that time again. Time for a blog on another .22 Sharp Innova, this time it's gonna be completely stripped, resealed, overhauled to make it efficient as possible, and lovingly put back together.  Whilst not working on it in a sterilized enviroment, it shall be laid to rest on a bed of crushed velvet.

And this i had too collect from the Post Office as i was still asleep at 8.20 am when parcel force knocked on our door.

The reason for doing this is that it belongs too a fine chap who goes by the monicker of Holdsy, he lives in the flat lands of east England and had posted the action and two different sets of replacement seals for me to work with.

After unwrapping tape , box, and bubble wrap, this is what i would need.

Holdsy's Innova looked in excellent condition but had a few niggling problems with it,these were that it  took 10 pumps to reach the 12 ft/lb mark, the loading bolt had the wrong O ring seal and would not shoot back when the catch was released,\ after it had been left standing for a while.

Stripped Innova and tools used.

So seeing as i was sort these problems and reseal the exhaust valve i decided to strip his Innova right down, just to be on the safe side if you know what i mean.

One fat over sized rubber O ring replacing the original double set.

 This was just as well, as i found the front sight unit that holds inner and outer barrel, compression tube, and pump arm in place had one of its jaws broken clean off.

The front end cap that had the broken jaw, now as good as new...ish.

 However i managed to clean it in white spirit and glue it back in place, using a quality super glue made it as good as new, almost (i wouldn't go testing it with a hammer any time soon, but it will withstand the contant strain produced from the pump arm working).

Holdsy's .22 Sharp Innova stripped right on down, coulda gon further but it wouldn't all fit in the picture.

Holdsy had supplied me with both the T R Robb valve repair kit and the J Knibbs valve repair kit, i decided to use the T R Robb kit for the valve which has a firing pin and spring with it. As well as some silicone grease and bottle of lubing oil this in my opinion is the better of the two valve repair kits, this one i used on Holdsy's Innova valve

J R Robb Sharp Innova seal kit.

The J Knibbs kitt has a spare buffer plate and two sets of O rings for the loading bolt, i have seen at least three slight variations in bolt design on the Innova. Holdsy's Innova had one oversized O ring at the tip of the loading bolt, this was causing it to stick when the bolt catch was released.

T R Rob kit on the left, and J Knibbs kit on the right.

Two sets of two O rings of slightly differing dimensions should give you a set that would seal and not let it stick, the thinner of the two sets sealed perectly and stopped the bolt from sticking.

Loading bolt, bodge job O ring (that did seal well, too well), and the two sets of double O rings that came wih the J Knibbs kit.

I reckon the forward assist spring for the bolt was on the weak side, but seemed to be working fine now it was back in the reciever block.

A .22 Sharp innova with all original parts should give you roughly 12 ft/lb when the pump head is adjusted so the face of the pump head and inlet valve touch at the end of a stroke, this took 10 pump strokes to reach 12 ft/lb. So the first thing to do is adjust the pump head assembly to top out at 12 ft/lb, first releasing the bigger brass locking nut,

Unlocking the brass lock nut so the air release valve housing can be removed.

Then i removed the release valve outer body too check on the inner spring and blow off seal.

That spring holds back a lot of Pressure

All seemed hunky dory there so i screwed it back in place, and set to adjusting the rod assembly length so pump and valve touched ( 217 mm).

The air release valve housing about to be locked in place with the brass locking nut.

Working out the the length took a hell of a lot of tiny adjustments but once it was found the rest was easier.

Silver lock nut holds the air release valve securely in place.

Once the blow off valve was set to ones desired muzzle energy, the silver lock nut on the rod could be loosened and the newly adjusted release valve unit could be moved so the whole assembly reached the magic 217mm. 

However something was amiss, Holdsy's Innova would only reach 12 ft/lb after six pump strokes. This would be more noticable if one wanted to go FAC which would take 20 instead of 12 pump strokes to reach 20 ft/lb (pellet dependant).

I took it apart again to make sure the firing pin was well clear of the transfer port, i took the compression tube out to make sure the air inlet hole in the barrel was properly aligned with the transfer port in the breach block, i even took loads of measurements with the vernier calipers to make sure everthing internal was in the right place. I was stumped, i hadn't a clue  what was up.

So i looked at the trigger, for change is as good as a break after all. It's a lovely trigger because it's the first Innova trigger that still had it's first stage  adjustment screw still in place, 

The trigger adjustment screw does make a difference.

Just one more thing that makes Holdsy's Sharp Innova so nice, Triggers that release an exhaust valve get stiffer the more pump strokes one adds, so adjusting the first stage shorter is a lot of help and therefore a little easier.

Another view of thefirst stage trigger adjustment screw.

  
Eventually i realised what the problem was with the needing two extra strokes to make 12 ft/lb was, it was fitted with a later J Knibbs parachute style pump head seal. The outside face of the air inlet valve has a flat surface with the last two mm bevelled backwards at outer circumference, 

This is the shape the pump head seal has too mirror for best results.

the original sharp pump head seal, and even the T R Robb replacement O ring pump head seal sit flush even at the bevelled circumference. There will be trapped air the same PSI that is stored in the exhuast valve body in the V of the parachute pump head seal and the bevelle on the valve.


The orinal Sharp Innova pump head is made from Black delrin type plastic, but when it's damaged the whole thing is junked and is bloody impossible to remove without destroying it.

The T R Robb pump head seal is made from stainless steel with two rubber O rings used to seal it, pretty much the same set up as BSA Meteors and Mercurys use on their piston head seals. You also need to cut an half inch UNF thread into the pump head assembly for it to fit, looks the best though i've never fitted or used one yet. And they don't work on the newer Webley Rebels either.

The J Knibbs pump head seal is made of an  orangey red delrin type plastic and just clips into place, though just like the Innova seal it's a bitch to remove. If you don't mind six/seven pumps per shot they are fine, and half the price of the T R Robb seal

I'm sure there was a lot of fiddling about with this rifle that escapes my mind at the moment, as i had it for about four weeks and tinkered with it most other days. But the seals were changed, the bolt unstuck, overhauled and made as efficient as possible with what parts i had to hand. So that's it for now, and thanks too Holdsy for letting me work on his splendid Sharp Innova.

TTFN

Best wishes, Wing Commander Sir Nigel Tetlington-Smythe. 

 










                                                  

.22 Mk I Sharp Innova, A Restoration Project. Adjusting The Pump Rod And Blow Off Valve

The pump head - when the pump rod is at rest on any multi pump - should ideally just touch the face of the outside of the air inlet valve, inside the pump cylinder. Most leave a little space which, when the rifle is fully pumped, is compressed air and will want to expand, pushing the rod back if the gap is too large. However the length of the pump rod can be adjusted on the Sharp Innova very easily indeed, which my friends is very handy for so many reasons.

To remove the pump rod for adjustment for either stroke length or pressure blow off adjustment, first remove the front sight unit. Knock out the front roll pin, then pin with circlip on it and the unit pulls off the front as well as the pump arm dropping free. 

As I had been removing and refitting the pump arm so much I used a clear plastic bag between punch and pin to avoid the possibility of scratching the blueing.

Next, pull the rod back by the pump arm linkage, and tap the pin holding them together through the same hole the pin and circlip go through; this leaves the pump rod free to be removed out the front of the pump cylinder. Tease the link end out with something, then it just pulls out.

Just used an old bent pair off tweezers to push the pump rod out this time.

The brass unit on which the actual pump head sits is the pressure blow off valve, and the 10mm silver nut behind this is the lock nut which holds the unit in place on the rod. Crack the 10 mm nut loose by supporting the end of the blow off unit with a 14 mm spanner.

If the lock nuts are too tight, use a pair of mole grips on the valve body, it's pretty rare to resort to that though.

With a 10 mm spanner, loosen off the lock nut for the blow off valve unit and pump head.

10 mm lock nut loosened off.

By hand I screwed the blow off unit and pump head about 2 mm outwards to bring the pump head nearer the inlet valve, reducing the amount of pumps needed to make full power. Remember, if it is adjusted too far the rod will bend eventually as it will be too long, so do it in small increments, reassembling and testing each time until you are happy.

The thread on the rod and the thread on the blow off valve run in opposite directions, which does make things a lot easier.

Then tighten the 10 mm lock nut to keep the pump head in place on the rod.

Tighten that lock nut back up.

For adjusting the blow off valve, use a 14 mm spanner to loosen the brass lock nut at the base off the blow off valve unit; the thread runs the opposite way to the thread on the rod so you can use the 10 mm lock nut for leverage.

The lock nut for the blow off valve is actually a ring with two flat edges opposite each other.

If you need to up the ft/lb before the blow off valve kicks in, screw the brass unit inwards, likewise adjust it outwards if you need to lower the full power output. There is a very strong, thick, square section spring holding back the air inlet seal in the blow off valve, so you might need some mole grips or something to adjust the unit inwards.

Screw to the right or inwards to up the power and to the left or outwards to drop the power, it was fine as it was in this case.

I didn't need to adjust the blow off valve this time so I left the valve alone and tightened the brass lock nut back up.

And retighten the blow off valve lock nut to keep the power where it is.

With both lock nuts tightened up, I carefully inserted the pump rod back into the pump cylinder, being mindful of the pump head as it passed any open metal work on the cylinder.

A dab of silicone oil around the pump head makes this go a lot more smoothly.

Reattaching the pump arm is simply a reversal of the removal process; the brass bushing on the pump arm had slipped out a little and had to be hammered back into place before I could get it to fit in the cylinder and sight unit.

I will never understand why they go to the trouble of fitting brass bushings then scrimp on the breech by making it from plastic, still they stand the test of time anyway.

Tapping the roll pin and stud back in with a rubber mallet is always better than using a hammer.

Rubber mallets also vastly reduce the chance of scratching the bluing or paint work.

And do be careful fitting the circlip as it's a bitch to find if it pings off somewhere.

Anyway, that 2 mm adjustment reduced the the 12 ft/lb blow off limit from 7 pumps down to 5 pumps, it is possible to reduce it down to 4 pumps but I didn't want to chance over doing it and having the rod eventually bend.

Now all I had to do was remove my Deben Whisper silencer which I had used for testing over the chronograph.

The Deben adaptor always gets stuck in the sight unit, not scratched it yet though.

And it was all ready to be sent back to it's owner. I am well chuffed to hear he was very pleased with the work I had done for him, it almost made me feel like i actually knew what the hell i was doing (joking!).

TTFN

Best wishes, Wing Commander Sir Nigel Tetlington-Smythe.