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

After having sit for three or four days, I have a brief engine knock on my 1954 L8 327CI engine. It lasts for about two seconds, and then stops. The engine runs very smoothly after that, and does not appear to burn oil between changes.
Has anyone else experienced this? Is it considered normal operation for this engine? Thanks again.

If it does it hot or cold it may be the exhaust pipe.

If it only does it after sitting then try adding an extra quart of oil to test the oil system.

Not normal. Sounds can telegraph all over the place and can be really difficult to pin down and diagnose, but I can think of a couple of things. If it's more of a click than a deep clunk or knock, perhaps a double-click, it could be a wrist pin and if so I wouldn't be too concerned about it in the short term, as long as it doesn't get worse engines can tolerate this for a long time. If it's a really deep almost guttural knock, I'd suspect the beginning of excessive main bearing clearances. But there are other possibilities as well that don't relate to engine internals.

If your engine has hydraulic lifters it could be just the brief noise they make until the oil fills the lifters. Older lifters get leaky and the oil drains out when they sit. If the engine sits longer there is clicking for a longer time. I have heard that many times on old engines wih hydraulic lifters. No big deal.

Thanks for all those responses. Yes, the car does have hydraulic lifters, so I would tend to suspect some oil drain from the lifters after sitting for a few days.

PS...it only happens when engine cold after sitting for a few days. Once it has run, the knocking sound does not occur on startup when the engine is warm...probably oil has not yet drained from the lifters....thanks again.

Steve, more of a "click" than a "knock", right?

Well, Owen, I would say it is more like a very brief knock than a click, and lasts only for a couple of revolutions.
Thanks again, Warren