Diana has an attitude..

[airnutz]

Hello folks!
Well I finally did it.  My 1954 Diana 35 has a new spring, and the old girl has a real nasty temper now!  She is no longer a peaceful easy going girl with a sweetheart charm about her.

The gun is completely different and I'll probably need an arm like an Orangutang to shoot more than 25 pellets at once.   

The rating is somewhere between 850 and 920 fps.

The shooting cycle is very sharp and crisp, and the hardwood backdrop I use at 40 feet is so deeply penetrated that I cannot even see the pellet in the deep hole, using 10.49 grain pellets.

Just the dieseling has me pondering.  This is new.  Is this normal?  Nothing else has been done to the gun.

Greetings.

[rsterne]

Dieseling is never good.... My guess is that the lube present didn't ignite with the old spring but does with the new one.... assuming you didn't over-lube it when you changed the spring.... It will eventually go away (assuming you used the proper spring) and the gun should settle down.... just hope it doesn't damage anything first.... Those velocities are unrealistic longterm on a 35 with 10.5 gr. pellets....

Bob

[airnutz]

Thanks for the info.
I shot the gun some this evening and the smoking has stopped. But I do not like the way the gun handles.  It is just a brute and quite harsh.
I had changed the piston seal a few months back and rechecked it, put put some more grease as was suggested to me, changed out the part that sets the trigger (nomenclature?) as this was really worn out with a deep groove.
When I re-blue the gun, I am putting the old spring back in.  I just don't like it now.  Too loud also.

[thekid]

Too much power.
You could always cut the spring to match the same dimensions of the old spring.
Coil thickness times coils on old spring..... then find the same dimensions on new spring.
At least this way if the old spring breaks you can replace it.

[airnutz]

@thekid, yes I am thinking now in this direction.  The old spring has 38 coils, and the new has 34, but is longer.  I don't know yet how much longer, as I have not measured yet after it was set.  I can check out the wire thickness too.

Would you recommend just cutting back the new one step by step, meaning a little bit each time, or can measuring the thing be more acceptable?

I don't mind if the new one is more powerful than the old,  but not like it is now.  I think it kicks more than a rim-fire .22.

Thanks for the input.

[airnutz]

So I measured the old spring;
38 coils x 3mm thick = 114mm altogether versus:
34 coils x 3,2mm thick = 108,8mm on the new one.

Uhhh, the new one is less.  I guess this follows the info that the export springs for the 35's are the same as for the newer 34, 50 and even the 46 models.  No wonder this spring is unsuitable for on old airgun like the 35.

Shortening the new spring sounds like an adventure I will have to ponder, as it is probably impossible to crimp the ends flat so that the end of the spring is a complete, flush circle.  It seems like I will have to fabricate a piece that would fit on the cut-off end to compensate.  I can do this.  I can fabricate a piece and cast it in a chrome-cobalt-moly alloy, no problem.

Anyone have similar experience with shortening springs?

Oh my, airnutz is doing pioneer work again. 

[PakProtector]

hey-Hey!!!,
Shortening a spring makes it stiffer...that does not sound like something you want to do.
cheers,
Douglas

[RedFeather]

Is this the pre-WWII model 35 you mentioned in your two-barrels thread or another gun?  That slight increase in spring diameter can add a lot of tension, plus the spring is fresh, is of a completely different alloy and hasn't taken a set yet like your original.  One thing I think that people should consider in stuffing new, higher powered springs into vintage guns is the additional amount of pressure they might put on old sear surfaces and other bits of the mechanisms.  Sometimes parts are built to withstand a certain level of use, either through sizing or heat treating.  When you exceed that design parameter, you might accelerate wear or even break something.  I tend to leave the "More Power!" school of thought to Tim Allen's old "Tool Time" re-runs.

[airnutz]

I agree.  I have in the meantime removed the spring, as it was just ridiculous and shooting was not fun and way too loud.

Better I should listen more to what experienced folks say!

I just had to do it though!   

Here are some pics of Diana naked.  Soon to be re-blued.

[lizzie]

Wow- looking  gorgeous there!

[airnutz]

I just can't shoot the thing when the sun shines.

Soon the metal is black-blue.