Long story short...I bought an "original" 78k mile GN last fall. Have put a couple of thousand easy miles on it (all stock). I the last few months, it has developed a slight knock only audible for a few seconds during 3/4 throttle acceleration. Sounds almost like a lose rocker arm for just a second or two. No noise present at idle or full throttle. Doesnt sound like bottom end (at least not like spun rod bearings I've had before) Has more of the frequency of valve train. so, I thought I would go ahead and change timing chain, fix header weld, and pull, clean and paint the intake manifold and change valve springs with the heads still on the car. Well, as I started dissassembling, I doscover the motor is painted gray, which I am told is not stock, I'm now thinking this may be a Jasper or other rebuilt motor. so, who know what's really on the inside.The rockers all seem to have similar travel and the cam lobes do not, visually, show any sign of wiping. The current valve springs have red stripes on the inner springs. I've kinda resigned myself to clean up and button everything up and see how it does. With the rockers looking good, no sign of bent pushrod, and good looking cam lobes.....should I change lifters while I'm in there....Any lifter problems I've had before, were audible at idle. Hate to pay $100 for another set of lifters when these may be ok. any way to bench test lifters?
The engine runs about 10 lbs oil pressure at hot idle and 25 - 30 on acceleration. The engine does seem to rattle for a second or two at start up until oil pressure builds. Cold compression check showed cylinders ranged from 125 to 140.
Really don't have the time or funds to to a full rebuild right now, so I guess I'll chase as many gremlins as I can with motor still in car.
Any suggetions would be appreciated.....I'm one year away from 50 and crawling around and under these things isn't as fun as it used to be.:frown:
The engine runs about 10 lbs oil pressure at hot idle and 25 - 30 on acceleration. The engine does seem to rattle for a second or two at start up until oil pressure builds. Cold compression check showed cylinders ranged from 125 to 140.
Really don't have the time or funds to to a full rebuild right now, so I guess I'll chase as many gremlins as I can with motor still in car.
Any suggetions would be appreciated.....I'm one year away from 50 and crawling around and under these things isn't as fun as it used to be.:frown:
