Russ Furchner
Member
I'm curious if anybody else has run into this before. 1970 T/A, original 340 6 pack, 80k miles. When I got the car, there were lots of noises, issues I've been working to resolve. Rocker arms and shafts rebuilt, new lifters, pushrods, fuel pump, water pump, clutch, starter, exhaust. Compression is good and even, no smoke ever. I've endoscoped the cylinders, pulled the pan and inspected the bottom end, it all looks really good. I did find a retainer from an old lifter in the galley, and witness marks on the bottom of a rocker, so I know it had at least one valvetrain problem in the past. I also found a rivet from the intake heat shield in the galley, it's a miracle that neither of those found their way into the rotating assembly.
The Engine runs great, performs well, but there is still this rattle on deceleration and at about 1600 rpm not under load. Not above or below, very narrow band, maybe 200 rpm +/-. I've been all over the engine with a stethoscope a few times, which was initially inconclusive since the noise was consistent across the back of the intake, so I've been living with it. It was suggested that it might be the intermediate shaft/distributor drive, which got me thinking that there may have been some damage to it, or the cam gear when the lifter came apart, so I got the stethoscope out again and as before, definitely located in the back of the engine, but when I put the probe on the base of the distributor, clear and loud right there.
My conclusion is that either the gears are damaged or just worn, and that shaft is bouncing off the bottom of the distributor, or the distributor shaft is not long enough to take up that slack. Curious if anybody else has had this problem, or can offer a suggestion/solution.
The Engine runs great, performs well, but there is still this rattle on deceleration and at about 1600 rpm not under load. Not above or below, very narrow band, maybe 200 rpm +/-. I've been all over the engine with a stethoscope a few times, which was initially inconclusive since the noise was consistent across the back of the intake, so I've been living with it. It was suggested that it might be the intermediate shaft/distributor drive, which got me thinking that there may have been some damage to it, or the cam gear when the lifter came apart, so I got the stethoscope out again and as before, definitely located in the back of the engine, but when I put the probe on the base of the distributor, clear and loud right there.
My conclusion is that either the gears are damaged or just worn, and that shaft is bouncing off the bottom of the distributor, or the distributor shaft is not long enough to take up that slack. Curious if anybody else has had this problem, or can offer a suggestion/solution.
