Snapping sound under load.

This morning going to replace points and condenser then take a 5 mile hike to think about all this. :-)
Be back soon.
 
Spray some soapy window cleaner around the head and plugs. I had a popping sound that would change under a load and with the timing...head gasket leak.
 
Have you checked for carbon buildup in the combustion chamber yet?
Carbon buildup plus full or advanced timing plus engine under heavy load equals engine noise, especially just before you stall if you push it that far. Could this be what you're hearing?
 
I'm not giving up!! Just taking a break to take care of some other matters. I did try to see if I have a head gasket leak. First try was masking tape around the head and was indecisive. Right now, can't do more since the carb is on my work bench waiting a rebuild. Will hear more from me once carb is rebuilt, 'B' distributer cam installed and it warms up just a bit. Next week!
Thanks again for all the input.
 
I had a similar problem/sound, drove me crazy. The snapping sound came from the timing gear. The gear finally separated from the hub. It was a fiber type gear. The engine will run normal then, when your far from home...
Time to call a tow truck. :eek:

Mollydog
 
AzRay said:
I'm not giving up!! Just taking a break to take care of some other matters. I did try to see if I have a head gasket leak. First try was masking tape around the head and was indecisive. Right now, can't do more since the carb is on my work bench waiting a rebuild. Will hear more from me once carb is rebuilt, 'B' distributer cam installed and it warms up just a bit. Next week!
Thanks again for all the input.
Click to expand...

Checking for a head gasket leak using masking tape will not indicate the most likely source of a leak, between the water jacket and cylinders.
 
Cornishman said:
Checking for a head gasket leak using masking tape will not indicate the most likely source of a leak, between the water jacket and cylinders.
Click to expand...

If the head gasket leak was between cylinder and water jacket I wouldn't hear it. Also I've checked for bubbles in the radiator. No problem there.
Carb's on the bench - raining big time so it will be a day or two before I take a night time ride in the fender spare tire well.
 
Installed a model B distributor cam - set points - timed it (for about the 5th time), checked compression and it was good. Finally re torqued the head. Couldn't wait for carb rebuild so put it back on. Took it out and all you folks who thought it was a head gasket leak hit the nail on the head. I had actually tightened the head a couple of days ago but my old torque wrench was history and I didn't get close to 55lbs. Bought a new torque wrench, backed off all head nuts a couple of flats and torqued to an honest 55lbs. It worked!! I think it stills needs a new gasket and it will get one whether it does or not. Carb rebuild and it should run great. I was soooo sure it was a spark. A good example of "it is far better NOT TO KNOW one thing that is false than to KNOW 100 things that are true".
Thanks to ALL who pitched in their two cents worth.
Ray
 
Congrats Ray, I've been following this thread with great interest. So glad you've solved it.
Jeff
 
It's a shame that you put in a different distributor cam and torqued the head at the same time as either could have solved the problem. Never mind tho it's running good.
 
Chippy Minton said:
It's a shame that you put in a different distributor cam and torqued the head at the same time as either could have solved the problem. Never mind tho it's running good.
Click to expand...

Quite sure it wasn't the new distributor cam. The old one was fine. I checked points setting on each lobe. No difference. The model B cam simple has a slightly better dwell.
 
I've just experienced this very same issue. Mine was a different culprit. I knew I was running rich and repeatedly tried to close gav. I set it at what I thought was almost closed. Driving at slower speeds, I had no issues but as soon as I passed 30 mph instead of advancing the timing lever I would have to retard the lever. By the time I reached 45/50 mph, the only place I wouldn't here any knocking is at full retard position. So for whatever reason the Gav unexpectedly gave way and I was able to close the gav maybe 2 full turns. That corrected the timing lever issue but then I had to adjust the idle mixture screw on the carb. I've yet to finish my adjustments but that one small issue caused such a big headache.
 
The distributor is an A model. I heard from someone at the local antique club that the B cam is better. In fact when I ordered the B cam Sam at Arizona Model A told me it's the only one he sells. He only uses model B distributor cams in his personal A's.
 
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