whistle in MK25/S650
Posted 07 December 2010 - 03:22 AM
Anyone have any idea? Intermediate pressure problem? Internal damage?
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Posted 07 December 2010 - 03:25 AM
I've had it with Mk25's-it is caused by the spring in the first stage resonating. The best way to deal with it is to add plastic shims on both sides of the first stage main spring. I think SP do these as a part, but techs will often add them to one or other side, rather than both.
Posted 29 January 2012 - 10:50 AM
Posted 07 February 2012 - 08:46 AM
The MK25 has adjustable interstage pressure anyway via the pre-load screw at the top end....
the only problem with adding shims is that it raises your intermediate pressure thats ok if your spring is at the low end of the acceptable range but if it is already near the high end then a shim will likely put it over the top,just as often it is caused by harmonic resonance over the end of the piston tube and this is much more difficult to get rid of the scuba pro kits come with several different hp seats and generally a mk 25 will have a + seat i have switched to a t seat in alot of these whistlers and it has solved the problem,you may have to adjust the shimming after switching seats to get the intermediate pressure back into spec but your tech should be able to figure that out no prob.