I have a 1941 series 61, it is an unrestored original in excellent shape with 48000 miles. It had a knocking sound in it when i bought the car. I replaced the rod and main bearings. The old ones were OK. I then replaced thetiming chain. It had a lot of loose motion. That stopped most of the noise. I now here a tapping sound. I looked over the valves and lifters, they looked good with no visible wear. i replaced the head gaskets. Thecar runs excellent with grat oil pressure ans compression. I suspect a lifter or the cam idler gear. Please help me with this problem.
Wayne Thompson
A tapping is generally going to be one of the hydraulic lifters. Did you remove and clean them all. you must soak them and make sure you can hear the ball bearing inside., even then one of them can have too much leak-down, there's a tool for checking that but it sometimes pays just to replace them.
While you have the lifter chest off you can check the Idler gear for wear, they don't tend to make a tapping noise as their bronze and play in the distributor shaft would give an indication of wear, don't confuse movement there with the auto advance bob weights though.
Thanks Steve, Are the replacement lifter assemblies tha Terril Machine sale good quality? There is no adjustment on the valves,is there? Will this noise damage anything if I jusy drive it like it is?
Wayne Thompson
No, no adjustment. Iv never had lifters from Terrill Machine and I don't know where their made but I guess their OK,
The last set I bought was new old stock WW2 stuff, getting scarce now.
I suppose it depends on how loud the tap is and whether it is a lifter. I know a lot of people who run their engines with all the tappets singing at them and are not bothered.
A 1941 car with only 48,000 miles has been doing a lot of standing around, the oil solidifies in the tiny chamber in the lifters and sticks the ball bearing if nothing moves for years and years, this is what happened to my 38, over half the balls were stuck solid.
The lifters shouldn't be too worn at 48,000 unless they have been starved of oil. Check if you have a filter interrupting the supply to the lifters that could be blocked starving them of oil.
The last set I got from Terrell were NOS in the Cadillac boxes. They were well packaged, it takes about 15 minutes to unwrap and remove the cosmoline, but worth the effort. Harry