Re: Strange 327 Knock

Posted by PackardV8 On 2011/7/4 18:32:54

If the car accelerates ok but looses power at about 40 mph (a sustained cruising speed of 40 mph) then it is likely that one of the ex. valves has some crud built up directly at the point where the stem is even with the top of valve guide and is allowing the ex valve to hang open ever so slightly. I've experienced this recently of 2 different engines.

Also note that if the oil pump has a FLOATING screen then it is possible that the screen dogs are bent or broken and the float is hitting the crank counterweight. Try draining about 1 qt or more of engine oil to lower float) OR raise rear or front or side of car real high with jack or some steep hill and/or off camber terrain to see if noise goes away.

First check timing chain cover for noise.