VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1929-1932 Help adjust valves

My 29 is back from rebuilding. I am trying to set the clearance to book specs. .006" intake and .008 exhaust (hot). I noticed that the clearance varies with the crank position. I measured the clearance every 45 degrees on #1 cylinder starting at TDC power stroke. There seems to be an area of about 135 degrees where the clearance seems to be even,and then the tappet seems to go into a deeper area on the cam and the clearance is much more. I am thinking I should set the adjustment at the level area. Is this normal for a camshaft?
See attached graph.
Thanks
https://www.snapfish.com/photo-gift...FVlsnry-HF6qBeg/AUS/27938492962/SNAPFISH

or

Sorry if the photo does not appear. Photobucket wants me to upgrade.

You can initially set the valves with the car not running and the intake and exhaust valves on each cylinder closed. Then, readjust with the car running at idle and the engine warm.

If I understand your description correctly, then the answer is "Yes". Set your clearances when the tappet has gone up as high as it goes and it momentarily stays there a few degrees rotation.

As Skip said, do this intending for it to be a "rough" measurement. Then once the car is running and has warmed up, you and do a second adjustment to get it within the specs.

Bill B

The valve clearance is set to be sure that there is enough gap between the rocker arm and valve stem so a given valve is closed for the duration intended. It also, assuming the cam is properly ground, gives the amount of lift so the valve is open for the duration intended.

The initial setting (cold) should be loose. I just did the initial setting on my 54 and the recommendation was to set them cold .005 more than the hot setting then adjust when hot to specs. As posted above the valves need to be closed when set and the easiest way I know is to check the distributor rotor and do them in order when firing.

This has been helpful, setting the clearance when each cylinder is set to fire seems like a good spot. I allowed an extra .002". I'll see how that looks when the engine is hot.
Thanks

I have never found a significant difference between cold and hot valve settings. However I always set them loose for the first few hundred miles.

Hot is when all parts are the same temperture and cold is when all parts are of the same temp. It is in between when the parts are of different temps. is when the clearence becomes the greatest.

Me too, in these days,I worked to set the valves.
Me too I noticed that the clearance varies with the crank position.
Or better: "There seems to be an area of about 135 degrees where the clearance seems to be even,and then the tappet seems to go into a deeper area on the cam and the clearance is much more".
Anyhow, the clearance should be measured with the engine warm (the pieces are dilated).
I say one last thing: the book "Instructions for operation and care" indicates .006" and .008", but the book "Chevrolet repair manual" indicates .008" for intake and exhaust. I set both to .008" (engine warm).
I'm sorry for my "bad Ehglish".
Saluti dall'Italia

I mark the damper at TDC on #1 and every 60 deg. Then just keep turning to the mark.

What?

I do not know:"damper", "TDC", #1, "60 deg".
I'm sorry.
Saluti dall'Italia

Here the post from when i initially did mine the first time, and will do this again this time:1929 Engine Timing/ Tune-Up [Plan of Action]

set to Top Dead Center Compression Cylinder No 1
set the valves per the manual, then turn handle 180 to set 6 @ Top Dead Center, then set the other Valves.
Pretty easy, just follow the Manual.

"Damper" is the torsional vibration damper (which is also the pulley to drive the fan belt) located on the front end of the crankshaft.

"TDC" means "Top Dead Center", when the piston is at the very top of the cylinder.

"#1" means the Number One cylinder, the one closest to the front of the engine.

"60 deg" means 60 degrees of crankshaft rotation, or 1/6 of a full rotation.

Be patient with us -- we sometimes forget that not everyone is speaking English in their shop. Good luck with the project.

All the Best,

Chip

The consensus seems to be that the timing should be 18 deg. BTDC. Since the flywheel mark is 12 deg. how do you determine where 18 deg. is? What is the difference in degrees between the fully retarded and fully advanced settings? I am wondering if I set it at 12 degrees when the distributor is retarded what will the degrees be when I set it to advanced?

You might want to do a search on Chevy Chatter because there have been many, many discussions here in the past about setting the 18 degrees on the flywheel.

18 degrees on the flywheel is when the 12 degree mark is even with the top edge of the timing hole. In other words, 18 degrees is when the 12 degree mark is just starting to disappear out of the top of the timing hole on the bell housing. Keep in mind though that for the 18 degree timing your AC C-86 or C-87 spark plugs have to be set at a .040" gap.

If you set the timing at 12 degrees then the distributor will not be retarded because you have to advance the distributor to set the timing at the 12 degree mark.

Here's a very good explanation ---
http://1931chevrolet.com/specs7c.htm

and a sample of the graphics



The full story is located HERE.

Bill

Harmonic balancer in the front!

Nice write up Bill. Thanks