Packard Forum Index » Post-War (1946-54)

I am trying to track down (or eliminate) the source of a loud ticking or knocking on my '52 250.

I pulled the pan and I note that the sideways play for the rod bearings is about .007, although one is about .010. There does not seem to be any noticable up/down play, but I am not sure I would be able to tell with everything together. Is there any guideline for acceptable side-to-side play?

I would like to also check the bearing clearances. The manual suggests using "plasitgage" to check clearances which should be between .001 and .003. I assume that I should replace the connecting rod nuts when I do this as I don't think they are met to be re-used.

While I have the pan off, are there any other tests I should consider that might be helpful?

New bearing cap nuts not required, the originals are intended for re-use. I think the specification for rod end play is 0.003" to 0.011" but you can check for yourself, it's in the Packard engine specifications.

By individually shorting out the spark plugs one at a time, were you able to isolate the noise to a particular cylinder?

Shorting the plugs had no effect on the sound at all, other than dropping the idle a bit. But the sound remained in terms of volume and intensity as I went down the line individually.