Snapping sound under load.

[SeaSlugs]

Originally Posted by AzRay

I want to thank everyone for all the great suggestions. Believe me, I'll try them all over the next few days. Someone mentioned blocked water jacket and I think I can check that with the same point and shoot temp gage I'm using to check brake temperature to adjust them. As for watching the engine in the dark. I already thought of that. There's only one problem. This only happens under a load and by the time I stop, squeeze out of the roadster's front seat, (Now I know why they always jumped over the door in the movies) and can look at the engine the snapping is gone. I did suggest to a friend that he rides in the left spare tire fender well while I drove but he wasn't too cool on that idea. However I think I'll let him drive and I'll ride on the fender.

Thanks Again. And I'll keep all informed on how this works out.

Ray

well set the parking brake and put stout wheel chocks in front of the wheels, put the car in 3rd and try to drive it forward slipping the clutch but letting the engine bog, might be able to get it to act up that way - obviously dont do it too long or much for fear of the clutch overheating but if its electrically arcing or exhaust leaking or pinging it should be obvious if your watching it while a friend bogs the engine down.

[H. L. Chauvin]

Mr. Eagle's reply #12 still has tons of merit in that if we had a universal mechanical sound vocabulary that exactly describes the onomatopoeia, many could describe exactly what they hear where this problem could be narrowed as to exactly what needs investigation.

Many of all of us have experienced that Model A engine noises are similar to different musical notes on instruments in that after a few years we become familiar with these many unique different Model A noises such as:

1. "Thump, Thump, Thump", similar to a low note on a bass guitar; or,

2. a much higher note of a "ping, Ping. Ping", similar to striking strings behind the bridge of a mandolin; or,

3. a "Click, Click, Click", similar to similar to hitting (2) hardwood drum sticks together; or,

4. any combination of different sounds with or without a rattling effect, or having a certain rhythm with different intonations.

5. After a few years many Model A owner's ears become familiar with this Model A music.

It is often beneficial to have a neighborhood, experienced Model A mechanic neighbor to listen to what combinations of sounds are eminent in order to "quickly" determine exactly what needs investigation.

Then one has to be careful that some neighbors cannot tell the difference between a Waltz and a Two-step; and worse yet, cannot even dance. LOL

[AzRay]

One last note. About timing. I've always used an ohm meter on hot rods, race cars and family sedans. Regardless of point gap, dwell, worn distributor or whatever. The moment those points open the coil discharges and we have fire. I've checked this a couple of times. Now I'll ask a dumb newbie question. Could the cam gear somehow be off? Is there another easy way to check for TDC?

[H. L. Chauvin]

Remove all (4) plugs & rotate engine CW & CCW while looking in spark plug hole no. 1 with a flashlight, and later describe the location of the piston when the timing pin slips in.

If TDC, check timing of the firing of spark plug no. 1 per reply 11.

If timing is OK, time to look somewhere else.

[AzRay]

H. L. Chauvin - I've thought a lot about recording the sound and posting it here if that's possible. I've had 3 folks listen to the noise in the last week. One is a model A owner since the '60s. No Joy! Today it's off to the locale Antique Club. If I drive at 1/2 throttle and 1/2 advanced there's no noise so I think it will be OK. Someone asked when the noise started. I've only owned the A for a couple of months. When it rolled off the transport it needed brakes so I didn't drive it much. The first time I really drove around the noise was there. That's when I started checking points, timing and buying coils and distributor parts.

[eagle]

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Originally Posted by Mitch//pa

I've learned to sit back on these things, as i hate to jump to conclusions. Just about everytime I / WE never receive all the info needed to come up with a logical response other than an arm chair guess. Usually more info squeaks out as the threads progress. I / WE have learned on post #8 that the engine is quote running very rich. No matter what the end result is, or what the source of the snapping sound is the cause of this condition needs to be corrected.

Amen!!! It's amazing the conclusions we can jump to.

[AzRay]

OK - One last thought before shutting down the computer. I added my favorite 'signature' to my last couple of posts. Having done that I'm thinking maybe I KNOW something that's false. Maybe it's not a spark snap and I should open my mind more to all the other suggestions I've heard here. After all, that's why I'm here in the first place. So -- off to work on the A and check everything and order a carb rebuild kit. Thanks again to all.

[Mitch//pa]

What carb is on it??? Having flow tested jets installed in the Zenith makes a world of difference... renners corner sells them, as the jet sets from all the suppliers are way off ..
i would never rebuild a carb without putting them in...
another common issue on a carb rebuild is Slop at the throttle shaft.. it needs to be tight, the suppliers sell an oversize shaft to correct that...(very easy to do with a drill bit)

I have rebuilt an unknown amount of modern day carbs using the same jets with no issues..
when i first got into model A's i was rebuilding the carbs with the old jets or supplier jets VS getting flow tested ones i couldnt believe the difference...

These carbs need to be very precise as simple as they are. When set up and rebuilt properly they run great and look proper. Many have gone to other style carbs because they could not master the proper techniques to rebuilding the zenith.

Just my experiences

http://www.modela.org/
A good site for reference.

[H. L. Chauvin]

Every large mechanic shop has at least one miracle mechanic guy.

After everything on a problem vehicle has been changed from bumper to bumper, and everybody gave up, they go to ask this one guy.

He starts the engine, moves the throttle, listens, moves a few other things, listens, and this engine is speaking a very unique foreign language that nobody else in the shop understands.

Then he tells them what to check; but they all disagree because they checked this item 10 times with delicate instruments following the "Cook Book" method.

But he checks it in a different way and the problem is resolved.

That is why most people cannot cook fluffy rice ..... they follow a recipe of (2) cups of water to (1) cup of rice that has been written on every rice package a million times and they wind up with a sticky, wet mush.

Like the miracle mechanic guy, sometimes it is time to cautiously observe what is actually happening, switch gears, and time to begin experimenting, and altering this written rice recipe.

[George Miller]

Originally Posted by AzRay

OK - One last thought before shutting down the computer. I added my favorite 'signature' to my last couple of posts. Having done that I'm thinking maybe I KNOW something that's false. Maybe it's not a spark snap and I should open my mind more to all the other suggestions I've heard here. After all, that's why I'm here in the first place. So -- off to work on the A and check everything and order a carb rebuild kit. Thanks again to all.

It has the signs of a loose center main, but the sound is wrong.

[rocket1]

could it possibly be a spark jumping from the plug to the rod that goes to the distibutor?

[Tacoma Bob]

Don't laugh......I had a similar experience and it too drove me crazy. Did all the stuff posted so far. It wound being a radiator support rod. It had slipped out of the bracket and was pinging against the top rad tank. Took a month to figure it out.

[Towd56]

I just had a very similar noise appear. Turns out, the firewall was cracked behind the bracket which holds radiator support rod. Sounded exactly like "the snap" of electricity going to ground. Drove me crazy until I found it by accident. For what it's worth........

[AzRay]

Today I drove the A to our Antique Car Club here in Prescott. We have that model A 'miracle mechanic guy' that H. L. Chauvin mentioned. We took the A out and headed to the closest hill. (Thumb Butte) My A did what I knew it would do and started the snapping noise as soon at it warmed up and put under a load. At TDC no noise. Half advanced, noise is noticeable. Full advance very loud. And like I knew it would. Once back at the club not a sound! :-( Once back we tried putting under a load by hold the brake and slowly engaging the clutch. Not a sound. Our 'miracle mechanic guy' was stumped. Agreed it sounded like a 'spark snap' but couldn't see any reason. I'm going to rebuild the Zenith carb, try looking at everything some "Ford Barn" members have suggested and keep reading this thread to see if maybe someone has another idea.
Thanks to all! Once again I'll keep you all in the loop.
Ray

[Tom Wesenberg]

If you have a leaking exhaust gasket, try squirting some oil into the carb, and the smoke should show through the leak. A leaking exhaust can make some strange sounds.

[Greg Jones]

I had a bad plug that behaved that way, would run current down the side and "snap" on the block. I finally found it running in the dark-no questions then, you can sure see it. Bad plug. Just my experience. Maybe a defective porcelain or something, i.e. crack.

[H. L. Chauvin]

Hi Ray,

1. It is quite clear that you "repeatedly" reported that the sound "only" occurs when your spark handle is moved "downwards" when climbing a hill.

2. The spark rod is moved closer to the steering shaft when spark lever is pulled downwards ....... with engine vibrations, could you have a spark rod slapping on the steering column or something else when pulled downwards on an incline?

3. If not, moving the spark lever downwards, & thus advancing the top distributor plate "appears" to be causing something to make the noise.

4. If I were in your shoes, I would not hesitate to try Reply No. 24 in no less than 5 minutes; and next, Reply No. 11 with plugs already out in an additional 3 minutes, to actually "see" what is happening with timing ..... all in no more than 8 minutes.

5. In my humble opinion ....... making mechanical corrections for any type of "unseen" used car problem ......... rather actually "seeing" the actual problems ....... makes about as much sense as a Doctor-In-Training trying to perform a colonoscopy on a patient who claims to experience a mild tooth ache ...... seems so much easier to just open his mouth.

Please let us know and do not give up.

[Greg Jones]

In any event, please let this forum know your solution once you find it. By definition, without anyone on this forum actually BEING there, these are guesses (with lots of other stuff thrown in, of course).

[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!

[Chuck Sea/Tac]

Originally Posted by H. L. Chauvin

That is why most people cannot cook fluffy rice ..... they follow a recipe of (2) cups of water to (1) cup of rice that has been written on every rice package a million times and they wind up with a sticky, wet mush.

Boy, isn't that the truth!!! Sharpening a knife or in my case, a slicer blade, is another example. It's not just following a formula, but using some brain power, and common sense.