Flathead 8BA Engine Knock - Noise Troubleshoot Help

I'll be pulling the timing case cover again today to get a complete look at the gears. I hope I'm not being too stubbon, but I still feel the knock is coming from the timing case area.

 

Might be you but a similar discussion on the Fordbarn with similar problem:

http://www.fordbarn.com/earlyv8/forum03/messages3/5241525.html

 

Yea That's me. Tryin to cover all my options, but found HAMB to

be more helpful and thorough

 

I'm trying to distinguish & comfirm whether the knock is timed closer to a crank assy noise or valve train noise. I used a timing light and although not exact, I tried to gauge the intervals between light flashes against the intervals between knocks.

The light and the knocks have the same repetative spacing. If the timing light only flashes once every two rotations of the crank, this tells me the noise could be coming from somewhere in valve train as each valve opens once for every two revolutions of the crank.

Does this make sense to anyone else?

 

Is anything not flat in there? Shiny spot should be round and symmetrical, not one-sided. Could be burr or nick in one of gears causing odd thrust when running - pull gears, check for flatness - polish gear teeth (many are noisy anyway & lots of folks start off with polished teeth).

Stab in the dark...

 

Had this happen with a freshly rebuilt flathead also. It turned out to be the crank was hitting the oil pan. While the vehicle was on a hoist we took a 3 ft long 2 x 4 and wedged it between the front cross member (in this case a Mustang 11 front end) and the front of the oil pan while the motor was running making the noise. When it was wedged in there we ever so gently moved the pan back enough that the noise stopped. It was enough to move the pan away from the crank. Now with the motor shut off, We loosened off the pan bolts and with tension on the board pushing the pan back a few thousands we retorqued the pan bolts. Started up the motor and the noise was gone. Problem solved!

 

Have you had any luck with this one? hope you have.

 

look in carb see if screws are all in butterfly these little brass screws can make a lot of noise when they fall out and get on top of a piston this happens when you put new screws in the butterflys and dont pean them spidercoupe

 

Dab a little paint on the shiny side of the timing cover and crank it, does it only strike when running? Could maybe a little metal taken off the shiney spot, redab paint try again?

 

Does it have a Miss in the Engine when the Noise appears!
since you say it had the Noise when you had the Timing light on it
on the Second Revolution!
Just wanted to know

 

Engine runs smooth; no skips, no misses.

 

I'm having an experience flathead "ear" come over and give a listen.

An experienced flatmotor mechanic can most likely pin point the type of noise or at least rule out what it isn't.

 

I think we have a concensus

I've been leaning toward the timing case cover area. The covers inside cam thrust surface does not have an even symetrical wear surface. It IS shiny only on about 1/3 of the circular surface.

I had an experienced flathead "EAR" give a listen which a stethoscope and it pretty much "PIN POINTED" the loudess area of sound dead center on the timing case, right on the nose of the cam.

We think the thrust surface on the timing case is worn and causing the extra play for the cam to slightly walk back & forth tapping on the case.
This also goes along with the interval of tapping being consistant with valve train timing verses crank timing.

"Never really thought that that timing case cover could wear."

Plan is to scrounge up another timing case cover and see if it eliminates the noise.

 

Well....????

 

Still looking for an aluminum timing case cover. Feel more confident that it's not a dangerous issue, so I've taken it out on a few cruises.

 

I had the same noise in my 59a just rebuilt, used badger pistons and a pair of old alum. heads.I checked valve clearance but did not check piston to head clearance very close.Anyways my noise sounded like it was coming from the timing cover also.I pulled the driver side head off and you could see were the dome of the piston was contacting the head.I compared the stock piston to the badger pistons and you could see the dome was different on the badger piston.Installed a pair of head shims and it fixed the knock.Don't know if this could be your problem,but it isnt that hard to pull a head to check.
good luck,Randy

 

Did you ever find the cause? I had the same noise and I found some shrapnel imbedded in the aluminum timing gear and a chuck missing from the crank gear. Didn't see it the first time I pulled the cover, but it got worse. It was floating around the timing area and caused my dist gear problems. Read here http://www.jalopyjournal.com/forum/showthread.php?t=387652

 

Did you put the timing light on EACH plug to see if the knock is 'tied' to one particular cylinder?

 

Yea I checked with the light on each cylinder but it does match any one cylinder.

 

My next effort will be to pull the cam timing gear and inspected the back of it

 

Have similar problem as ACE High. Knocking sound appears after engine warms up after driving about 5-10 miles. Sounds like valve rep rate and disappears if engine is shut off for a few (3-5) minutes but returns after engine is run for a while. Have Schneider cam and aluminum timing gear. Removing spark to cylinder(s) has no effect. Any ideas?