camshaft (Long)

J Franklin said:
Mouse nests clogging the exhaust? Or a backfire dislodging baffling in the muffler? That can mess up how an engine will run. I know that doesn't jibe with all the symptoms but if all else fails.....
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Don't think so but wish it was as that would sure to be easier to check than the timing cover plunger spring,

Thanks, John
 
aermotor said:
I would like to find the problem with the original set up. I did run a Mallory with a centrifical advance for a while but got tired of fooling with the springs to get what I felt was a decent curve.

Thanks, John
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I'm not saying to fit one, but if a previous owner has fitted one it may not be obvious.
 
aermotor said:
ursus was on the spot with several symptoms, so timing cover next - nice to have Tom's advice to go along. I may have been demoted to Newbie. What size is that slippery little roll pin that was a booger to get out with the engine in the car and is it hardware store quality?

Thanks, John
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I can't think of any roll pin. Where is it located?

The only pins I can think of is the two dowel pins for the cam gear.
 
aermotor said:
i have never had an a engine totally apart. My question is - can a model a "jump" timing if the camshaft thrust plunger is not doing it's job because of a weak spring or some other reason? Reason i ask is because after complete trouble shooting the timing and entire ignition system the engine runs fine at idle and a little above. However when the advance lever is pulled down the engine will "bog" down and eventually quit. The distributor plate lever is touching both sides of the housing at full advance and full retard. Note, again, that this is happening with the advance lever being pulled down from full retard. I did pull the distributor shaft housing and shaft gear and could see no problems. The steering box is 7 tooth so no adjustment is available there but the dist. Plate arm adjustment is okay as stated above. Timed with newrex tool and once again the entire ignition system was trouble "shooted" and no problems noted. The carb was taken apart and rebuilt 2 times so carb. Problems should not exist as the condition is all related to the spark advance - so i think. I have no way to know if it is going more retarded or advanced when it bogs down. I know how to determine with a timing light but i don't believe they even existed in the model a days and this problem should be fixable without one. The problem started with an erratic miss which could not be pin pointed to any one cylinder and occasional back fire when rapidly letting up on the gas pedal at higher rpm's when it was running. So i fixed it till it's really broke. O, yes the point gap is .017 and rotor to housing contacts all the same @ .025.

John

john
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check valves condition,compression and leakdown,tappet clearance,stop throwing parts at it.
 
Post 28 & 29. Check Bratton's oil pump distributor drive gear sleeve. Mine would not come out with out removing that top shaft about 1" or so long.

Thanks, John
 
rocket1 said:
check valves condition,compression and leakdown,tappet clearance,stop throwing parts at it.
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Go through the entire thread starting with the first one and tell me what was wrong with my trouble shooting and where I was throwing parts at it. Valves have less than 500 miles since installation by a reputable shop, it has no tappets and the valve stems were ground for proper clearance. I still say it is an ignition problem and compression and leak down should be non-issues. I may be wrong but I am going for the walking cam shaft theory because of a possible broken or weak plunger spring as others have suggested. No way to trouble shoot that without pulling the front cover that I know of. If you know of a way let me know as I have just jacked the car and do not relish going the rest of the way. Changing parts was a double check. I did find a distributor bad that a friend loaned me that he had timed and under his back seat for emergency road repair. He is glad we found it now rather than when or if needed. There was another thread on this titled "Fixed till broke"

John
 
aermotor said:
go through the entire thread starting with the first one and tell me what was wrong with my trouble shooting and where i was throwing parts at it. Valves have less than 500 miles since installation by a reputable shop, it has no tappets and the valve stems were ground for proper clearance. I still say it is an ignition problem and compression and leak down should be non-issues. I may be wrong but i am going for the walking cam shaft theory because of a possible broken or weak plunger spring as others have suggested. No way to trouble shoot that without pulling the front cover that i know of. If you know of a way let me know as i have just jacked the car and do not relish going the rest of the way. Changing parts was a double check. I did find a distributor bad that a friend loaned me that he had timed and under his back seat for emergency road repair. He is glad we found it now rather than when or if needed. There was another thread on this titled "fixed till broke"

john
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john did not mean to upset you you changed the dist> and coil to no avail,yes it has tappets we call them lifters today.i would want to know the compression and if the cylinders will hold in a leak down test,nothing to take apart and all to gain.i think you said problem gradually worse not all of a sudden,possibly rebuilder left out the plunger spring? Best of luck hang in there you will find the problem.
 
rocket1 said:
john did not mean to upset you you changed the dist> and coil to no avail,yes it has tappets we call them lifters today.i would want to know the compression and if the cylinders will hold in a leak down test,nothing to take apart and all to gain.i think you said problem gradually worse not all of a sudden,possibly rebuilder left out the plunger spring? Best of luck hang in there you will find the problem.
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Not upset at all, My understanding is that the engine does have tappets but they are not adjustable and the valve clearance is obtained by grinding the valve stems - 500 miles ago so the clearance should not have changed since that time. This is not a rebuilt engine, it was out to change the clutch and the valves were done than, I figured what the heck do the valves the machine shop was almost next door. It was more like a skip than miss. I did pull all the plugs, cleaned, replaced and ran the engine for about a minute. The skip was still there and all the plugs had about the same amount of soot. The engine ran fine at idle and slightly above but would "choke " down when the advance lever was brought down a little bit, moving it further down it would quit. I will do a compression test better than thumb over the spark plug hole method. Once again sorry if my response to your post sounded that I was upset with what you said.

John
 
This all is giving me a head ache so I want return that. Ponder how my 8 cycle hit and miss engines work. Maybe start an O.T. thread with your chosen name.

Thanks, John
 
You have an Aermotor water pump !? Thats a rare monster. There is one in this area. Never have been able spend enough time to figure out how the thing works.
 
John,

You have stated several times that you think this is an ignition issue. The only thing that I can think of that would give you the response with your advance lever is that the engine is too advanced or becomes too advanced. Check the plunger in the front. It is not too hard to do. But before that try a timing light. You can just put a mark with a bit of paint on the front pulley at 12:00 at TDC. You don't even need a pointer or you can just jury rig something up. Nothing like data to help understand what is wrong. It will be easy to see if the timing is 25 degrees advanced or 50 degrees. You don't need exact numbers for this first test. Or if you want to be more exact, put another mark 25 degrees advanced of the 12:00 position (12:50). With a 25 degree advance (close to ideal) the mark for TDC at 12:00 will be at 11:10. To be on the safe side you can take the fan belt off for the test.
 
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Regarding a hit and miss engine. The intake valve is opened by the suction in the cylinder against a weak spring. When the flyball governor senses that the engine is running too fast, it will open the exhaust valve and turn off the magneto. The engine coasts with air being sucked in and pushed out with the open exhaust valve. The intake valve will not open because there is not enough suction. When the flyball governor senses that the engine has slowed down it will allow the exhaust valve to close and a fuel/air charge will be sucked into the engine and ignited by the now working magneto. The magneto is not like a modern one but operates by moving a magnet in a linear motion.

Fascinating engines. It seems like they run forever.
 
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