Flathead 8BA Engine Knock - Noise Troubleshoot Help

I'm at my wits end trying to find the cause of metalic knock in my 8ba. (Actually a 1BA)

Its not a deep sounding bearing knock. Its more lighter sounding but not like lifters.
Its somewhere in between. I tried to track it down with a metal rod to my ear and its loudest torward the front. I feel its the loudest at the timing gear housing. If I put my finger on the timing case housing I can actually feel the knock.
I pulled the pan and ran the engine with the pan off. Also checked for any slop in the rods brgs.

I also changed the distributor. I pulled the timing case cover and from the front the gears seem OK.

Obviously I can't see the back of the camshaft gear where it bolts to the cam. I realize sound can travel so I'm not ruling out anything.

I just bought this recently. It was professionally rebuilt.
It was bore .030. new hyperuretic pistons, ground & polished crank, new brgs, new ISKY Max-1 cam with new adjustable lifters.
I installed Fenton heads after checking clearances. Valves are all ajusted.

PLEASE any suggestions

 

Just went throught the same issue. I took a video with sound and posted it. It turned out to be wrist pin slap. Here is the tread
http://www.jalopyjournal.com/forum/showthread.php?t=311740

 

Just FYI, it says your video is unavailable. I'd like to hear it as I've got a noise in mine that sounds like what you described

 

I attempted to listen to the video but its no longer available. Do you still have the video file. I love to hear it and compare the sound

 

Sometimes metal timing gears can be noisy

 

I had a similar noise in a 300 ci Ford 6 that I rebuilt. Turned out to be that one of the teeth on the cam timing gear had been damaged on the edge and everytime that tooth meshed with the crank gear it made a clicking sound. Like to drove me crazy trying to find the noise! Smoothed and deburred the tooth with a file and the noise was gone.

Bob

 

Question, Half speed knock or crank speed knock,
Crab dist, or beehive?

traderjack

 

Not that I want it to be, but in one of my motors I developed a knock. thought it was bearings, pulled the motor and put a new one in. just pulled the motor down the other day, I had broked a piston skirt. Not to add to your troubles, but just something else to tick off the list of things to look at.

if it had been built by a shop you could take it back to them to diagnose.

 

I'm with flatoz - take it back to the engine shop and get them to diagnos it. Diagnosing a sound is too hard to correctly diagnose without actually hearing it.

 

If my ears serve me correctly, I feel its a crank speed knock.

Its has the later 8ba type dizzy

 

Pulled pan & inspected all cylinders & piston skirts appear OK.

Shop that built the engine is half way across the country from me. I bought it threw a third party many states away.

How might I narrow down whether its a wrist pin?

 

tear it down before it gets worst

 

Pull the plug wires one at a time. Narrow it down. If it quits knocking with a wire off, you've found which cylinder it is.
Coming from the front, it could be a chipped gear, as stated above. Also stated above, it's tough to diagnose a sound without being able to actually hear it.
Could be a chunk of crap fell in and sitting on a piston. I'd pull the heads and check that before doing anything else. Shipping it halfway across the country, who knows?

 

Do a compression check to see if your valves are seating. Perhaps a valve seat came loose and is banging around.

 

Pull the plug wire individually and noise did not change at all.
Noise is constant on both acceleration and deceleration.

When using a steel rod held up to my ear to try to localized the area, it is the most severe when the rod is on the aluminum timing case cover. (maybe because of the thinness of the cover compared to other block or head areas) If I put my finger on the timing cover I can slightly FEEL the knock.

 

Pull the timing cover dude and let us know what u find !

Rat

 

Take the belt off and see if knock is gone. Might be a waterpump. May sound improbable, but I had one that made a tapping/knocking sound.

 

Take it back to the professional rebuilder.

 

Belt disconnected -no change

 

Just a thought --- Where as I'm fairly certain I'm hearing the knock/tapping much more pronounced from the timing case cover, is it possible that the nose of the cam is tapping against the timing case?

When I pulled the cover off, the gears appear OK.

 

Had a friend that had an itermittent knock in his flattie. Happened to be the flywheel was cracked from miss installing the flatomatic adapter. Also have heard noises like this from loose standard flywheels also.

Good luck ...

 

Crank speed knock eliminate anything in the cam section, although could be valve interference , both of them , with head. Kind of like a tappet click

Perhaps broken ring, or, perhaps, rod interference with something,

Piston slap? Should go away when engine warms up.

Other possiblity, exhaust knock, something in front exhaust passage, should be louder on one side then the other

Not louder on acceleration or deceleration, not in bearings!

check for loose key on crank snout!



Good luck

traderjack

 

One other thing, check for excessive endplay in crank, Pry on flywheel to see if flywheel move back and forth in the engine.

And , after all is said and done, drive it until it blows up, and then rebuild it, take it all apart and inspect everything now


traderjack

traderjadck

 

Thanks for the suggestions--- Checked the end play and it hardly moves.

Tell me, on the later flathead with upright dizzy, does the cam nose end ride against the center of the timing gear housing?

 

You might want to check this out!

http://www.hotrod.com/techarticles/engine/hdrp_0511_ford_flathead_engine/index.html


traderjack

 

This is one of those cases of starting at the basics and working your way up. sound to me like you going to have to start pulling it down.

if you turn it by hand without the water pump belt on, can you decern the knock then? if so is it at a certain point or multiple etc? can you feel any unfriendly feeling as in metal on metal that you shouldn't be able to feel?

I would take the timing cover off if you seriously think its there, then do the above by hand and watch/listen and if nothing seems astray well your going to have to move on to other things.

my next move would be to pull the intake and do the same, as in turn the motor by hand and watch and listen, not a broken valve spring, or lose valve guide etc, either lose in the valve guide bore, or valve bore in the valve guide, or the horse shoe clip not in correctly?

if nothing seems astray then it would be heads off for a closer inspection of the valves. I wouldn't discount even a valve hitting the head? if nothing there, well its sump off and check from there.

which ever way you look at it, you got to tear the motor down bit by bit, that is the only way you will find it.

Cam gears not lose?

needle in a haystack stuff.

 

Pulled the intake; rotated throughout all cylinder cycles and all valve train normal.

Pulled the pan off; bearings good; piston skirts good; all rod side clearances within specs.

Heads were just installed and clearances for piston and valves were checked prior to installation.


Pulled the timing cover; Gears appear OK; Cam bolt lock plate in place.

Thrust surface at front center of case cover has shiny spot on one side. Maybe normal--Maybe not. I'm not sure if cam nose end is supposed to ride against this or not.

Do NOT Hear or Feel anything when turning engine by hand, only when running and at all times.

 

Are your cam gear and your crank gear a matched set for the 8BA? There is a difference in gears for old "crab" distributors and later side angled distributors. One is angled for forward cam thrust and the other for rear cam thrust.

 

Gears are correct for 8ba. Although I don't remember which engine is supposed to have forward thrust & which has rearward thrust.

I assume the 8ba has forward but I'm not certain.

 

Correct. The timing cover takes the thrust on 8BA. Earlier front mounted distributor has timing gears that put cam thrust against block. I've been following your thread closely as I'm currently building a flathead ('42 Merc 99A) and I'd like to know what's causing the noise.

Bob