VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1933-1936 Chasing engine noise

I hired my granddaughter to do some recordings. Here it is upon startup and around the block.

Sounds like lifters need a proper adjusting

That has been done, redone and done again after several people said the noise was"above" and not "below". We also tried to isolate it by disconnecting each plug in turn, no change. I had a chat with the guy who did the short block and he said camshaft end play can make some strange noises. He also said the "tick" sound may be the fuel pump. Unless I get better results with settings other than .006 and .013 .

It seemed to me that the ticking was intermittent so possibly from a sticking valve. I had a valve stick on my 32 and the noise is very similar.

Is there an "easy" way to check for sticky valves?

Not that I am aware of but perhaps someone else does.

PAT I WOULD REMOVE THE VALVE COVER AND HAND CHECK THE ROCKER ARMS FOR PLAY.

I WOULD THEN GET MY FINGERS AROUND A VALVE PUSHROD TO SEE IF THERE IS UP AND DOWN PLAY THERE, OR POSSIBLE ONE IS BENT..

TO ISOLATE THE SOUND , I WOULD GET A PIECE OF RUBBBER HOSE 3/8" OPEN INSIDE WITH SMALL FUNNEL AND WITH THE ENGINE RUNNING PLACE FUNNEL END TO MY EAR , ONE AT A TIME ON EACH ROCKER ARM, TO LISTEN FOR THE NOISE.

SURE SOUNDS LIKE VALVE TRAIN NOISE. I WOULD ALSO REMOVE SIDE COVER AND WATCH THE VALVE PUSHROD ACTION IN THAT AREA.

FAILING TO DETERMINE THE EXACT CAUSE , YOU MAY HAVE TO ASSUME A WRIST PIN PROBLEM. ITS A PRETTY LOW MILEAGE MOTOR THAT WAS REBUILT BY YOU AND ITS NOT SOMETHING THAT SHOULD HAPPEN , BUT IT MIGHT HAVE ?????

THESE THINGS ARE INFURIATING.


MIKE LYNCH

Thanks Mike. I have drained the engine and will do the "rod check" to make sure that isn't the problem. I had the side cover off in the spring to reseal it. I played with the pushrods while it was off and didn't see anything untoward. That doesn't mean there isn't.

checking the connecting rods for side play and also how tight the wrist pin is.

Think }}} chevy nut is the guy to seek advice on that.

mike lynch

The last thing making that noise is the rods.
I would suspect the valve trsin, sticking valves or push rod hitting the side cover.
The first thning I would do if it were mine is pour sme MMO or ATF through the carb. throat with the engine running.
Also could be in the helper springs and or retainers that are on top of the lifters.I would remove the side cover first and dig from there.
If it was the fuel pump you could feel it when touching the pump.
You could also run the engine with the side cover removed and observe.

If nothing shows up the next thing is a piston.

Don,t fool with the rods.

OK. Oil going back in tomorrow.

Hello Pat,

I had a similiar "upper end " noise that turned out to be a push rod hitting the side cover as it rotated.

The push rod cup was not centered in the stem of the push rod and as it rotated it would bump up against a "wrinkle" that had formed when the factory stamped the side cover.

With the engine idling, I used a long screw driver placed against the side cover and placed my ear against the handle. Once found, I removed the valve cover first to see if there was an obvious bend. That was when I discovered the taping sound was in unison with the rotation of the push rod as the engine was idling. I removed the side cover and found a shiny spot on a "wrinkle" next to the spark plug pocket. ( All of this happened after replacing the gasket on the side cover. ) I also noticed that I could "shift" the side cover from front to rear because of the free play between the size of the screws and the hole diameter in the side cover. After making my clearance adjustment that I describe below, I made sure to hold the side cover toward the front of the engine as I tightened it in place.....noise gone.

I placed a large drift punch along the wrinkle and using it as a dolly, I hammered along the length of the drift punch to try and create a long depression so the push rod would clear.

I did roll the push rod on a piece of glass to be sure it was straight. I also noticed that all of the push rods had varying degrees of rotational off set so you may have more than one rubbing.

I want to run it without the cover in place. That should tell me that is the issue, if it suddenly goes quiet.

I would advise against setting the valve clearance any tighter than the specs you have! At that setting, the valve train should be quiet! If you decrease the clearance the only
thing you will accomplish is burning the valves prematurely!

Pat, It is the same noise I had when I removed my lifter springs. PM sent

OK. It looks like there is nothing hitting the side cover. there are no marks anywhere, not even near the spark plug bosses where it is closest.
And Gene figures it isn't a rod sound. So that leaves piston pins or the piston themselves. I guess i'll try the plug shorting bit again to see if I hear a difference. There is more than valvetrain noise there.







Here are a couple more recordings. The first is cold with the choke on. the other is with the choke off, so a bit slower. Maybe I should take one with the engine thoroughlly warmed up as well.





Could a dipper hitting a trough make the deeper sound?

I can't tell what deeper noise is coming from the lower end, but if you are chasing the loud valve ticking?...

can I make a suggestion?... it sounds like one valve is really ticking more. If I was doing this, I would use a .004 feeler gage slipped into each intake at an idle. Then use a .008 on the exhausts while at idle. (by slipping in, I mean you are taking up some slack for a moment, not readjusting the screw) It is merely a noise elimination test.

I had to do this on a 50s 235 six that had worn rocker shafts and rockers. That test quieted the worst ones that I was hearing, so at least I knew what was wrong, and stopped any guesswork of looking at other random areas.

Just because the valves are set to specs, does not eliminate the same noise if there is abnormal valvetrain wear. On that 235, I ended up using tighter specs on the few that were real noisy. That worked fine until the owner waited till winter to have an engine shop rebuild it, and use NOS rockers/shafts.

OK, thanks Frank. I'll try that.

The lifter springs are there. Could they be weak?Broken?

You could try it without the lifter springs.....ubt if they are permentaly removed you have to install stronger valve springs.
With the engine running at idle speed you should be
able to "feel" the noise by touching the various parts.
If it would be a piston you could used a broom stick or long screw driver, holding it against the top of the cylinder barrel on the left side of the block.

[color:#3366FF]Would a stethoscope work there? I have one of those. It is what we all used to try and locate the source of the racket.

by all means it will work

This might be a dumb question but is it possible to remove the lifter springs and change the valve springs without removing the head? And are the stronger valve springs readily available?

Yes, but you will need a valve spring compressor. The springs you will need are for 1938-1953 216 engine.
I eleminates the lifter spings in my '34 40 years ago. It saves a lot of work when removing the head. Chevrolet finally removed them in 1938.

While I have not listened to the video another possible that I have been caught with is the fuel pump arm being worn at the pivot or a very stiff diaphram and therefore not staying in contact with the camshaft. It is only a wild guess but is at valve speed.
Tony