Snapping sound under load.

[AzRay]

tbirdtbird - Thanks for the spelling lesson. Funny how the mind works (or doesn't work) as we get older.

[AzRay]

I'm working on a theory. Does anyone know what the 'total' lift of the distributor cam should be? I checked mine and it's around 55 thousands. Just wondering if thats OK or if its worn.

[Tom Wesenberg]

Originally Posted by AzRay

I'm working on a theory. Does anyone know what the 'total' lift of the distributor cam should be? I checked mine and it's around 55 thousands. Just wondering if thats OK or if its worn.

I don't know that spec off hand, but for a smooth running engine the most important spec is that the opening of the points be 90 degrees apart, so you have even firing between the cylinders.

Many, if not most, distributor cams have been replaced with the "B" cam, which gives a bit more dwell. Dwell is the time the points are closed so the coil can build up a strong magnetic field. I've measure the new cams and have found them to be within 1/2 degree, which is very accurate.

[Mitch//pa]

If u had an issue with excessive end play (lift) i am sure that the rotor and cap would how signs of excessive rubbing. I think you might be barking up the wrong tree on this theory

[AzRay]

Thanks Tom for the info on the Model A distributor cam. I'm going to order a B cam from Arizona Model A (by the way, great place to order parts). I'm unhappy that when I moved to Prescott two years ago I sold/gave away all my 'old car' tools. Dwell meter, compression gage and a few other items. I would have kept all that stuff if I know I would be wrenching on an 87 year old car today. The theory I spoke of this morning sort of went south after more thought. Still going to replace points, condenser and plugs (again). This will go with new distributor body, rotor, coil and wires. Did a couple of things last night and will test drive this afternoon. I don't want to change a bunch of stuff at once and then not know what fixed the problem.

[pooch]

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Originally Posted by Big hammer

This thread brings back memories of a thread a few years back. That thread was "knock in third gear" after pulling his engine,transmission,checking clutch,and many pages here of helpful tips and trick. He pulled his rearend and found that his pinion nuts where loose, his noise was up front near the flywheel area! So keep at it and you will find the ticking noise!

It reminds me too of a thread on an MGB site a few years back.

5 pages of guesses why an engine would not start.

Even got as far as someone wanting the head removed.

Finally the dude checked the gas tank, it was empty.

Duhh.

[Jacksonlll]

Here is an old, 2010 video of our Amish Tour. Early in the video there is one car with an exhaust manifold leak. It demonstrates the sound of the leak, a tic-tic sound. Someone did have a new gasket and the repair was easy.
https://youtu.be/ZRq_Rb2Ojp0

[SeaSlugs]

Originally Posted by AzRay

Still going to replace points, condenser and plugs (again). This will go with new distributor body, rotor, coil and wires. Did a couple of things last night and will test drive this afternoon. I don't want to change a bunch of stuff at once and then not know what fixed the problem.

ya need to fix your running rich problem first... always fix the known issues before trying to fix the unknowns... alot of times that fixes mystery problems.

[Mitch//pa]

Originally Posted by SeaSlugs

ya need to fix your running rich problem first... always fix the known issues before trying to fix the unknowns... alot of times that fixes mystery problems.

Excellent advice ......it was mentioned in #17 also... after the recent posts it was worth repeating. swapping out parts never helps

[40 Deluxe]

To check for an exhaust leak, go to a shop that has a 'smoke machine'. This will blow smoke into the tailpipe and any leaks will be readily visible. Eliminates a lot of guesswork!

[SeaSlugs]

Originally Posted by Mitch//pa

Excellent advice ......it was mentioned in #17 also... after the recent posts it was worth repeating. swapping out parts never helps

yea ive heard snapping popping before on an A engine. Question: is it too rich of a mixture or too lean of a mixture that can get the manifold glowing cherry red?(aka enough heat to premature ignite fuel mix)

going up a hill the engine is under a heavy load thus means more heat generated...

[Mitch//pa]

Originally Posted by 40 Deluxe

To check for an exhaust leak, go to a shop that has a 'smoke machine'. This will blow smoke into the tailpipe and any leaks will be readily visible. Eliminates a lot of guesswork!

I have one

[tbirdtbird]

" is it too rich of a mixture or too lean of a mixture that can get the manifold glowing cherry red?"

ummmm timing too far advanced, not the mix

[Mitch//pa]

[QUOTE=forever4;1412431]Dammit Mitch, quit using my car as a workbench! QUOTE


But Vince It's not a fine point Model A with a bottle of soda::::

[tbirdtbird]

Yikes that's Charlie Howard's car

what is with the soda, Charlie

i was plate #7

[forever4]

Originally Posted by tbirdtbird

" is it too rich of a mixture or too lean of a mixture that can get the manifold glowing cherry red?"

ummmm timing too far advanced, not the mix

Actually timing too far retarded, not advanced, will heat up the exhaust manifold red hot.

[Dick Steinkamp]

Originally Posted by forever4

Actually timing too far retarded, not advanced, will heat up the exhaust manifold red hot.

Agree.

Also, a lean mixture will result in higher operating temps.

[tbirdtbird]

generally agree on your take on timing, Dick, although the engine will overheat so quickly I am not sure the exhaust has time to get cherry red.

However, I worked on a 1911 Stafford car (last one left) 20 yrs ago that had its magneto ridiculously advanced (2 teeth on the timing chain as it turned out); it had been overhauled wrong which is why I was brought on scene. No one could get it started after the overhaul.

Well, that beast would dislocate your shoulder it would kickback so hard. But if you persisted you could actually get it started....but after 5 min the manifold was as cherry red as could be. There were no timing marks on the motor at all, so I had set up a degree wheel so I could time it by hand the old fashioned way. That was how I determined just how far advanced it was, and how many teeth to retard it. It was at 40° advanced with the lever in the full retard position!

never saw a manifold get so hot

[Dick Steinkamp]

True dat, Dave. If the timing is advanced to the point of preignition (detonation) it will generate a lot of heat. I should have qualified my agreement .

[SeaSlugs]

i did look into a model A recently where the point gap was on the verge to too large. Once it started it ran rough, coughed clacked backfired as it was just enough gap to fire on 2 maybe 3 cyl but not consistently due to slight variances in distributor cam lobes and possible slop. Timing was dead on. Reset point gap to .020 and fired up quick and purred like a kitty.