VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1933-1936 34 Standard 181 6 cylinder knock sound

Hi all,
Hoping someone can point me in the right direction. Inherited a 34 Standard from my father-in-law recently and the motor has a knock that sounds as though it is in time with the valve train but have been unable to locate any signs of it being there.
A little history on the engine he rebuilt the engine about 2 years ago and it was completely quiet and ran well, the knock started as a lite tap about a year ago and has since increased to a knock sound. The sound as best I can tell has been isolated to the area of the last 2 cylinders around the cylinder wall lifter area with the pushrod access cover removed.

I have pulled the oil pan and adjusted the connecting rods per the manual but no change. I did notice the springs the assist the lifters had been removed, I'm not sure if they had been removed previously or by him.
Any thoughts are greatly appreciated?
Thank you,
Rick

The first thing I would do is lubricate the valve guides with either Marvel Mystery oil or ATF. You can squirt the guides through the coils of the valve springs and by poring through the carburetor throat with engine running at fast idle`. This would "fix" if a valve is sticking.
The helper springs on the lifters can be removrd but then it is necessary to use stronger valve springs.

Is noise worse when engine is hot or cold?

Disconnect one spark plug wire at a time....does noise change?

Can you feel it on the push rod cover....push rod contacting the cover? push rod bent?

Thank you for the reply.
I did try the ATF through the carb at just above an idle no change, pulled the plug wires one at a time and could not isolate the cylinder with this method.

We ran it without the valve cover and access plate using a screw driver to keep pressure on lifters and no change.

Noise is there cold or hot and does not change. Have the pan pulled right now looking for any signs of marking or rubbing and can't see anything like that going on.

Completely baffled on this one.
I'm not sure which valve springs he used in the rebuild, I did read in another post about the heavy springs being used when eliminating the assist springs.
Appreciate your reply!

A 1934 Standard did not have springs in the lifters only the master .

Parts book says spring, valve tappet, 1934 All.
1934 Engineering says it has tappet springs.

The block is drilled and tapped for what I assume are for the spring perches?

I'm going to try the Marvel Mystery Oil directly in the guides and see if that helps.

Appreciate all the suggestions!

I removed my lifter springs when I did my valve job. Developed the same knock. Put the lifter springs back on and no more knock. 1935 Standard 207. Gene is right on. Thoroughly check your push rods. Also be sure your lifter adjusting nuts are secure. I had two that the threads in the lifter and the nut had to be rethreaded. One had to be replaced. I know a great company for replacement push rods if you need. Be sure not to mix up your push rods. Put them back in with the same rocker. This is what I experienced. I hope you make your problem a memory with a happy ending.

Removing the springs will not cause a knock...that was some other problem that got fixed by luck when springs were reinstalled.
My '34 was as quiet as a mouse with the springs removed.

When all else fails take a broom handle about 4 feet long. Place the end at various locations on the engine and your ear on the other end. This will at least pin point the location of the noise.
From your description and great trials I doubt if it is a bearing or piston, rather something hitting against another object.

I bought my valve springs on ebay. I don't think they were the later year heavy springs. My friend tells us his F__D's interior light doesn't work in third gear. Some say pull the tranny. Some say kick the tail pipe???

Yes you are right, I guess my memory is failing.
I will call that a WOOPS !

Is it a heavy knock or light knock? Upper engine or lower? Wrist pin on cylinder?

It's what can be described as a light knock.

Using the broom handle method I have isolated it to the 5th cylinder down around the lifter bores and cylinder wall.

Dropped the pan again and double checked the rod clearances all were good, while I was in there checked to make sure the bolts on the wrist pins were tight and no evident twist or looseness of the wrist pins. The MMO directly on the guides and in the fuel has not changed the sound.

The intensity of the knock has not increased or decreased with everything I have tried, went as far as dropping the belt off no change. Removed the fuel pump no change.
Getting ready to pull the head to see if possibly something went through the intake.
I do appreciate everyone's input, will find it eventually and keep everyone posted.
Thank again

You may have a loose main.

On my previous post I meant to say "rocker nuts" not lifter on the adjusting nuts. My bet is still on the lifter springs not being there.

If it is a main bearing it will pound for a few seconds when you first start the engine, go away when the thick, cold oil gets to them, and come back as the oil heats up and thins

There may be something caught on top of a piston and hitting the head when the piston comes to the top.

Just wanted to update everyone and appreciate all the suggestions in trouble shooting.
Finally had an opportunity to investigate the issue further. Pulled the head and found light scoring of the #6 cylinder wall. Not bad and a ball hone should be sufficient to clean up the bore.
Removed the piston and rod and found the piston skirt had collapsed allowing the piston to rock in the bore creating the knock sound. Haven't determined the cause yet but possibilities are running it to rich or the piston was to tight in the bore when installed.

Ordering pistons, rings and some other parts and hope to have it back on the road in the very near future.
Again thank you, this forum is an excellent resource.

If the scoring in the bore was caused by the edges of the broken piston I would suspect the grooves would be too deep for ball hone to remove, but then from here I cant see them.
Tony

Glad to hear you found the problem. Sad to hear it isn't an easier fix!

Did it have iron or aluminum pistons in it?
What are you going to use for replacements?
Are the cylinders bored oversized?

It has the aluminum pistons from what I believe are made by Rebuilders Choice and is currently .020 oversize.
The cylinder bore doesn't appear to have much damage but will see how it cleans up. My hope is it was caught soon enough. If it does clean up I will order a replacement piston and rings from them. If not it looks like I will be going at least .030 oversize.

Thanks Wisbri, just glad to have finally found it. Had several people listen to it and all including myself were convinced it was valve train related.

Again want to thank everyone for their input. Replaced the piston with the collapsed skirt. Took the car out this morning for its maiden voyage and it's running perfectly.

Best regards,
Rick

Glas to hear your problem has been solved