Try to narrow down the location of the loudest "tok tok" using a stethoscope or a length of rod touching the engine in various places. You may at least be able to narrow it down to the upper side (valve train) or the bottom end (bearings).
Never had this happen in a Chevrolet six, but have had a knock in a small block V8 turn out to be a broken spring in the fuel pump allowing the lever to fall away from the cam lobe between strokes.
Thanks for the comments, but now I'm really getting scared. The engine is completely overhauled and a month ago it sounded like this.
There is not so much rattling and since then the car has not been driven. I'll have to go there probably more accurate troubleshooting. I have to drive Wednesday to a workshop because of the rear window about 3 miles one way. Can I risk that?
Try dropping the fan belt off and run for a "very" short time.
The "tok tok" sound in the second video doesn't sound as serious and sounds louder on the left side and may just be belt noise judging from the frequency.
Still seems to make more noise than it should, but doesn't sound nearly as serious as that deep "tok tok" heard in the first video. Sounds more like a deep "squeek" now.
What you want and expect from the car will determine the clearance you will want to set the valves at.
Factory specification was .006-.008 inches for intake and .013-.015 exhaust. Except for heavy duty truck use where .010 intake and .020 exhaust was recommended.
If you want quiet, go toward the lower spec, but I myself don't like to go below .008 and .015, which will "clack" a little more but leaves a better margin of safety against burning valves. Because I have a truck, I set to .010 and .017 and just put up with the noise. It is a truck after all! :-)
I have had similar sounds with the 1940 216 in my 38. I used to get a rattle in the motor, going down the road. Several of the valves would have excess clearance after a short drive. I used a piece of 3/8" tubing to listen to each valve tappet. What I found was that a number of pushrods had excessive wear on the top end. The rocker ball had actually descended into the pushrod socket as the socket metal got thinner and yielded. After I installed new pushrods, most of the annoying noises disappeared.
I don't think that you have a serious knock there. It is not deep or hard in sound. By the way your engine bay looks amazing!
My 1951 1 Ton is now on the road! My 38 Master 4 Door is also now on the road .
I sent you a PM but I'll try contacting you here as well as this is important.
On viewing your blog... I noticed you have the "little metal hats" on the exhaust valves. They NEED to be on the INTAKE valves. I don't know if this is the source of some of your valve noise, but it could be.
The caps were meant to prevent excess oil from getting on the intake valve stems and being drawn into the combustion chamber. If you have the newer style valves with two grooves at the end of the stem, and an O-ring has been installed in one of them, you don't need the caps at all.
The metal hats were first used on the 1941 intake valves. From 1942-1947 on both intake and exhaust. They were often removed be cause they breated more valve noise.....refered to as rattle caps.
My 1942-46 overhaul manual only shows the hats on the intakes, and that's the only place I found them on my truck... so I didn't know they were ever on exhausts as well.
A question for you then Gene... When they were removed, did that necessitate using the newer 2 groove valves with O-ring seals? Or was there much noticeable difference if you just threw the hats away with no other change?
Would Andre be able to back off his tappet adjusting screws enough to remove the hats from his exhausts without removing the rocker assembly? (I'm thinking he can.)
Surprise, surprise, Before I went to the workshop, I checked the belt tension. The alternator was loose. The nut on the clamping screw has turned through because of defective thread. New nut with new screw and from the noise was almost nothing more to hear
Actually I wanted to write here much more about my experiences / setbacks and feelings of happiness during the restoration of my 40 Chevy, but repairing was always somehow more important - sorry What started with a transmission repair and an engine overhaul ended in a complete restoration, including a new interior. I never regretted it and had a lot of fun doing it. Above all I would like to thank this forum for the mental support, many tips and also spare parts. Very special thanks go, among many others, especially to
Mike Buller, 41specialdeluxe, Mike Deeter, Curt K. (cskennedy10?)
In July 2022, the Chevy had its first ride since 2015. It passed the technical inspection without any faults and the engine now runs like a sewing machine, thanks to a capable mechanic. Here are a few pictures.
That is so nice of you to post all the photos so we can see and appreciate all your hard work especially living in wonderful far away Germany.The best of luck to you and continue to enjoy your manty years of restoring your car.
I've always had a hard time deciding which I like the look of better, 1940's or 41's. You are definitely swaying me toward 1940! Beautiful! Got any pictures of the dash and instrument panel?
Great looking 1940 sedan. You have truely done an excellent job.
dtm
the toolman 60th Anniversary Meet Chairperson Dave VCCA # L 28873 VCCA #83 Tool Technical Advisor for 1914-1966 VCCA #83 1940 Chevrolet Technical Advisor
Mike Buller, 41specialdeluxe, Mike Deeter, Curt K. (cskennedy10?)
