Here's a common question with a hundred possible answers...

I was checking over my general tune, balancing carb, setting timing, and adjusting valve lash (not in that order!). I noticed a bit of a knocking noise that I had not heard previously. Seems to me coming from the upper block and not the head. I don't think it is the timing gear whacking around as I could feel no vibration in the timing cover.

The noise is not terribly loud and seems to vanish if the car is rev'd up.

Based on the loss of my 67's original 500,000 engine last November, I worry about the oil pump in particular. Are there any ways to check that while the engine is in the car? my hoist setup is in the garage being occupied by my 67 right now).
Are there any other likely sources for a knock?

Well, I did a bit of work on the car today, including installing new plugs, new (updated seal) timing cover, an 1800E radiator with an overflow bottle, an 1800E flex fan, and a new GMB water pump. There was no real change in the knocking noise, but I'm pretty sure that it is not the rocker. The rocker is making a fairly distinct noise of its own.

It sounds deeper... like the tappets or the cam...

I also did a compression test when I was putting in new plugs.

Dry compression:
#1 170 PSI
#2 170 PSI
#3 165 PSI
#4 168 PSI

Very close to stock original and fairly even so I did not do a "wet" test

I need to get install my new points and condenser, set the idle again, and re-set the timing. Perhaps that will help, but I fear something catastrophic down there inside the motor...

When you were changing the timing gear cover, did you try pulling and pushing on the cam? It shouldn't move enough to feel. It's very common for the cam retaining plate to wear down, and when it gets worn enough, you'll hear the cam knock back and forth at low engine speeds.

You can check it by removing the fuel pump -- see if you can lever the cam back and forth by prying on the lobe that drives the pump.

Ack.. I wish I had checked that... I'll try the pump trick and get back on that... when I have some free time...

ghosts

Water pumps can make all kinds of weird noises when they are on the way out. Easy enough to check---take the belt off and see if the noise goes away. Obviously, don't run the engine for very long with the belt off to avoid overheating.

If you have a mechanical fuel pump, how old is it? They can develop a worn actuating lever, which can sometimes be noisy.

I have a newer pierberg fuel pump. It also came with a glass domed AC pump needing a rebuild, and a "new" one with crappy plastic innards that did not work at all.

I did not feel any play in the water pump, but it was suggested by the seller that I replace it. It came with a new pump in the trunk so it's no hardship biggie to replace it. I wanted to swap in a different radiator anyway...

piston slap perhaps. warm it up at a fast idle, once at operating temperature see if it persits at idle.

just a guess. grab a length of tube and see if you can isolate it to any one thing.

My old 74's timing gear went out without a sound, but that could be it as well.
--
64 544 - 66 122 - 70 142 - Blue is broken is beautiful

Hello RepairmanJack:

It sounds awfully similar to the knocking (almost a wood-like "chocking") that showed up in my motor nearly two years ago. I have done a lot of investigation on this one, including removing and reinstalling my timing gear to no avail.

Look at these threads:

http://www.brickboard.com/RWD/index.htm?id=1097042

http://www.brickboard.com/RWD/index.htm?id=1102776

http://www.brickboard.com/RWD/index.htm?id=1122340

A lot of good advice here, but nothing that solved my problem. See if your mileage varies.

Cheers,

Jeff Pucillo

A timing gear starting to go bad will be noisy but pretty much undetectable
when the gear is removed from the engine (except perhaps oil seeping from
between the fiber part and the steel hub).
What happens is that the fiber starts to work loose from the knurled hub and
gets a very slight rotational play. In advanced cases it may even turn on the
hub under heavy load and then settle back into its correct location at idle.
Just about every oldtimer I have had has wiped a timing gear and most of them
looked OK when I removed them. And they all made the knocking noise.
--
George Downs Bartlesville, Heart of the USA!

Hello George:

Good point. I only wish to point out that in my case, at least, I had just changed the timing gear about 10 months prior. My knock came about after I installed a head with new hardened valve seats.

Cheers,

Jeff Pucillo

You might have a loose valve seat insert. They are only a tight interference fit so there's little room for error. Head off I'm afraid unless you come up with another answer but if it is the seat it could be very expensive if it breaks up.