964 cam tower oiling trouble

[911buff]

I have a '91 C2 that is ailing. The cam tower oiling bar supplying oil to the cam lobes and followers is not supplying sufficient oil to #6. I have already had to replace one cam and am now looking at another one only 2K miles later. The shop that did the work said that it was sludge build up in the bar that caused the lack of oil to #6. I can believe it, the engine had 112,000 miles on it. The bar was cleaned when the cam was replaced. but now I am in the same situation in only
2K miles. The "hole" for the intake side is gushing just like #4 and #5. However, the exhaust "holw" is merely oozing, not getting any oil out to the cam lobe. Utilizng a wire, I checked the "hole" for obstructions and found none. But, there is something blocking a good steady flow. My question is, is there any way to "flush" that oiling bar without tearing down the engine? I am drawing a blank and hope someone has the "silver bullet" I need. Any help is greatly appreciated.