Loud clicking from my '52

Posted by Jim Kavanagh On 2018/10/23 19:16:07

I recently replaced the hydralic units in my lifters for my 52 Convertible. The units I used are new manufactured units. I used to have a quiet tick after the car got up to full operating temperature.

After I finished, I had no noise for a few weeks, but it ran a little hot, so i did not drive a whole lot. The heat issue was addressed and I drove it for a couple hour long drives. The car was very quiet and ran great.

About a week ago, after a long drive, I noticed a very loud ticking noise, which sounded like a lifter to me. Once the car cooled down, there was no noise.
When I start the car, there is no noticable noise, but after about 10 - 15 minutes, again the (very) loud ticking. Seems to go away under acceleration and higher RPMs. Comes back as soon as the RPMs decrease.

I have pulled the belt with no change, so i can rule out the generator and water pump. I switched out the fuel pump with no change. Pulling individual plug wires does no affect the frequency or pitch. I pulled the valve covers and can see each valve moving, but I do not know if they are moving enough. I can see that all the keepers are in place and all the springs look good.Compression test is good across all eight cylinders, so I am assuming no bent valves. At the time I did the lifters, the valve guides seemed good.

Sounds very high up in the engine to me, like it should be valve train, but with new hydralics, I don't see how it can be.
I don't think I can attach a sound file (just tried - can't). If it is not valve train, then I think maybe wrist pin, only because it does not sound low enough to be a rod bearing.
Any ideas on how to narrow this down?