Thread: Knock Knock
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Old 11th September 2008, 23:58
G-CPTN G-CPTN is offline  
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Join Date: Sep 2008
Location: Tynedale
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Why should a piston start to hit a valve?
I suppose if it started to stick after the engine had been running.
(The indication seems to be that on startup there is no misfire or knock)

Had a mysterious misfire on a Detroit Diesel V engine.
All static checks OK. On stripdown it transpired that a fuel leak from a injector pipe (within the engine casing) had diluted the lubricating oil and subsequently caused wear of a roller-follower that operated the injector. Thus the injector-timing was wrong as the injector was late (due to the increased clearance caused by the flat on the roller-follower) causing the engine to misfire. In addition, the engine sump oil level continued to rise . . .
Checking the injector clearance statically gave the correct value as the roller-follower rotated onto the high point.

I'm not suggesting that the Routemaster has the same fault BTW.

Is it in fact an AEC engine, or is it a Leyland engine?
Or is it perhaps an Iveco or Cummins engine?

Quote:
Originally Posted by billyboy View Post
needs the head off to check the piston is not hitting the valve. Check the fuel injection system first though

Quote:
Originally Posted by billyboy View Post
needs the head off to check the piston is not hitting the valve. Check the fuel injection system first though
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