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			Join Date: Mar 2005 
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			After installing oil fed tensioners on my 82SC, I have noticed a prominent whirring sound from the engine that was not present before the upgrade.  The whirring increases with RPM as expected and is close in sound to a square cut gear harmonic.  To characterize the volume of the whirring, with the stock muffler, you could not distinguish the exhaust note over the whirring.  
		
	
		
	
			
				Before the upgrade, I did have one collapsed tensioner (loose chain) and one tensionser that appeared in better shape. During the upgrade, I only changed the tensioners, not touching the ramps, chains, or cam gears. After the upgrade, I am assuming both chains to be tighter than before. I have posted this question on the 911 tech forum and was advised to post again on this forum. I am wondering if this whirring is something to be concerned about or is the result of proper chain tension. I have read posts of others citing this phenomenon. I have yet to pull the covers and inspect. Partially due to the fact that I am at a loss how to proceed. Assistance is appreciated. Marlin 82 911 SC 
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			For reference please see thread of same title on the 911 tech forums.  Thank you to those who have posted replys on this forum. 
		
	
		
	
			
			
		
		
		
		
		
			Marlin 
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			After reading Waynes comments that preface this board, appologies for the double posting.  
		
	
		
	
			
			
		
		
		
		
		
			I did use the 101 Projects Book as a reference to perform the upgrade, but do not have any direct questions about the material contained within. Just a question about the result. Marlin 
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			Marlin, 
		
	
		
	
			
			
				
					There shouldn't be a change in noise with the new tensioners. I would pull the covers off and see if you can find the problem. Some things to look at are: Is the chain aligned on all the sprockets (duplex chains so dual sprockets at each point). Is the idler sprocket arm moving freely on the rod it mounts on? Is a chain rubbing on something? Sometimes the chains stretch and rub on the chain housings. If you can isolate which side you'll only have to remove that cover. -Andy 
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	72 Carrera RS replica, Spec 911 racer  | 
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