Keith True
Well-known member
When you say,the rotor is almost past # one post,are you figuring the rotor turning CW or CCW?I've seen this with people assuming the rotor turns CW,and they timed them perfectly,but wrong.They would be a mile advanced.
Model a kicks backwards
- Thread starter Craziamtoo
- Start date
Craziamtoo
Junior Member
Hole for tmming pin is oval. Dist was rebuilt also carb. Number one piston is all the way up when pin goes into hole. With total retard the rotors trailing edge is near the post.
d.j. moordigian
Well-known member
Have you removed the rotor, loosened the screw in the center(under the rotor),
and with the advance lever up(retarded) moved the cam? At TDC to set the timing?
Normal Distributor rotation is Counter Clock Wise. The rubbing block on the points
will be too the left of the cam lobe. Too deep? Try this..........
..........................http://www.abarnyard.com/workshop/timing.htm................
and with the advance lever up(retarded) moved the cam? At TDC to set the timing?
Normal Distributor rotation is Counter Clock Wise. The rubbing block on the points
will be too the left of the cam lobe. Too deep? Try this..........
..........................http://www.abarnyard.com/workshop/timing.htm................
H. L. Chauvin
Well-known member
Hi Craz,
With your reported oval embossed area around the timing pin, it appears your problem is that you definitely have a B timing cover.
Not at all good for an A distributor.
Furthermore, I have no way to verify this, but I heard years ago from Model A vintage mechanics all A covers are exactly alike as far as locations of timing pins; however, B cover timing varied where some were 15 degrees BTDC, but others were 19 degrees BTDC; hence, were a total nightmare when setting timing.
If you definitely have a B cover, & are "serious" about not having recurring timing problems today & in the future, call Bert's Model A in Denver to order a used A cover, install it & fix it correctly; "or", play around with timing with the B cover for the next 3 months listening to your engine cough; or worse, break your arm the first time you try to hand cranks it.
Hope this helps
Another route while "not" having to replace the timing cover is to go on Ebay &
A. Order a "Model A Distributor Timing Indicator" for $30.00 w/free shipping.
B. Install it, mark your crankshaft with a very short 3 corner file or Dremel tool, & paint it white at "exactly" TDC; &.
C. Forget about your existing timing pin locations.
Often times with new repro engine cams, new repro timing gears, the recess hole in the timing gear may not be exact; however, with this timing indicator device used after setting piston no. 1 at "exactly" at TDC with a caliper dial indicator, you can get your engine running like a Swiss watch.
Any questions, just ask -- somebody will assist.
Hopes this helps.
With your reported oval embossed area around the timing pin, it appears your problem is that you definitely have a B timing cover.
Not at all good for an A distributor.
Furthermore, I have no way to verify this, but I heard years ago from Model A vintage mechanics all A covers are exactly alike as far as locations of timing pins; however, B cover timing varied where some were 15 degrees BTDC, but others were 19 degrees BTDC; hence, were a total nightmare when setting timing.
If you definitely have a B cover, & are "serious" about not having recurring timing problems today & in the future, call Bert's Model A in Denver to order a used A cover, install it & fix it correctly; "or", play around with timing with the B cover for the next 3 months listening to your engine cough; or worse, break your arm the first time you try to hand cranks it.
Hope this helps
Another route while "not" having to replace the timing cover is to go on Ebay &
A. Order a "Model A Distributor Timing Indicator" for $30.00 w/free shipping.
B. Install it, mark your crankshaft with a very short 3 corner file or Dremel tool, & paint it white at "exactly" TDC; &.
C. Forget about your existing timing pin locations.
Often times with new repro engine cams, new repro timing gears, the recess hole in the timing gear may not be exact; however, with this timing indicator device used after setting piston no. 1 at "exactly" at TDC with a caliper dial indicator, you can get your engine running like a Swiss watch.
Any questions, just ask -- somebody will assist.
Hopes this helps.
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Purdy Swoft
Well-known member
If your timing cover has the raised oval where the timing pin goes, you either have a model B timing cover or a service replacement model A timing cover. The model B cover has the threaded hole at the top of the raised oval. The model A service replacement timing cover that was made after model A production, has the threaded hole at the bottom of the raised oval. If you are running the actual B timing cover your timing will be 19 degrees off.
H. L. Chauvin
Well-known member
Hi Craz,
One easy & inexpensive way to locate your engine's TDC is to get a dial indicator with magnet attachment from Amazon.com for under $15.00 & look up how to make such a TDC monitoring device from the following message, located under "Search" :
TDC -- Top Dead Center -- Timing Pin ???
Just did it & works great.
Again hope this helps to get you going.
Hope this also helps.
One easy & inexpensive way to locate your engine's TDC is to get a dial indicator with magnet attachment from Amazon.com for under $15.00 & look up how to make such a TDC monitoring device from the following message, located under "Search" :
TDC -- Top Dead Center -- Timing Pin ???
Just did it & works great.
Again hope this helps to get you going.
Hope this also helps.
1crosscut
Well-known member
Craziamtoo,
In your post #13 you refer to distributer rebuilt and carb rebuilt. Is this the work you did to your car and after doing so it then would not restart?
Was the car running fine prior to doing "work" on it?
Did you work on it to fix a problem that your were experiencing?
What exactly did you do? With out knowing it is hard for others to give you quality suggestions.
In your post #13 you refer to distributer rebuilt and carb rebuilt. Is this the work you did to your car and after doing so it then would not restart?
Was the car running fine prior to doing "work" on it?
Did you work on it to fix a problem that your were experiencing?
What exactly did you do? With out knowing it is hard for others to give you quality suggestions.
Tony SFl.
Senior Member
I have read and reread his post. Maybe I missed it . Retarding the spark to time the A. Years ago we had a member that restored many many Model a's and insisted the spark doesn't need to be retarded to start the vehicle.. Maybe this fella was never told to retard the spark to time the A. Tony
700rpm
Well-known member
He was lucky.
tbirdtbird
BANNED
wow that is a lotta luck......
Tom Wesenberg
Well-known member
If you have timed your Model A and have a B cover, then as mentioned, your timing will be about 19* advanced. You can take care of this by setting the spark lever half way down, then time your engine the same way. Now, when you have the lever up to start, you should be right near TDC.
d.j. moordigian
Well-known member
Tom Wesenberg
Well-known member
I'm still rethinking this, but I might want a second opinion!
If I set the timing on my Model A with the spark lever half way down, then start the engine with the spark lever full up, won't I be 20* late?
So, it should work the same with a "B" cover, right?
BTW, I'm setting the timing by when the points just start to open for #1, not by the rotor position.
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Purdy Swoft
Well-known member
It is necessary to retard the spark when cranking the engine. Most timing instructions are so difficult and confusing , is why most model A's are not timed correctly. It really makes No difference where the spark lever is when setting the timing. Spark lever setting doesn't change the position of the rotor tip in relation to the number one contact in the distributor cap. Retarding the spark after actually setting the timing is to check if the points are just before opening. If the rotor tip is set correctly, the points will be just about to open. If the points are not just about to open, this would indicate that the points cam was constructed incorrectly or if it was a car with two tooth steering, the column tube would need to be rotated to give full movement of the upper plate for advance and retard. This applies to whether the manual advance is giving full adjustment so that the points are opening correctly, not the actual setting of correct distributor timing. There is a sweet spot that the tip of the rotor needs to point. If the rotor isn't correctly adjusted to point in an exact spot, the timing will be wrong, no matter where the manual adjust lever is, up or down. When the timing pin drops in place, the trailing edge of the rotor must point at the number one contact in the distributor cap body with ALL of the backlash in the counter clockwise direction or the timing won't be correct. Cars with adjustable steering column need to be checked for full advance and retard before setting the timing. The points need to be adjusted (.018 to .022) before setting the timing because the ignition fires when the points open. Too little gap retards timing, too much gap over advances the timing . Testing points and manual advance pertains to timing but not the actual timing adjustment of the tip of the rotor in the distributor.
d.j. moordigian
Well-known member
I'm still rethinking this, but I might want a second opinion!
If I set the timing on my Model A with the spark lever half way down, then start the engine with the spark lever full up, won't I be 20* late?
So, it should work the same with a "B" cover, right?
BTW, I'm setting the timing by when the points just start to open for #1, not by the rotor position.
OK.....Tom and I had 20 minute conversation on the phone over this
problem. We both agree this "should" work. The only thing were not
100% sure of, exactly how much movement(advance/retard) in the
Dist. body and the difference in degrees between the "A" and "B"
front cover. The Dist. I can do here at work, I have a Dist. machine
too check the movement in degrees. I don't have a "B" front cover,
or an engine(on the engine stand) too degree the front cover difference.
J Franklin
Well-known member
Sometimes there can be a lot of backlash in the shaft that needs to be taken into consideration when setting the timing.
Purdy Swoft
Well-known member
Lets say that the distributor timing is exactly correct but the engine is installed in a car with two tooth steering and the steering column tube is rotated incorrectly. The timing would be off because you wouldn't have full advance or retard, because of the position of the steering column. if the movement of the distributor upper plate is restricted , No amount of distributor cam adjustment would correct the timing. Position of the rotor tip is the important thing. The engine will usually run if the points are closed to .010 or open open to .025 , but if the tip of the rotor is off very much, the engine won't run at all. The spark lever and the arm that connects to the spark rod, that advances or retards the upper plate is connecteed to the steering column tube. This adjustment is never mentioned in the timing instructions. What I have seen is, when the timing pin drops in place, with the spark retarded, rotate the dist. cam until the points just start to open and tighten the cam screw. There also is no mention of allowance for backlash and what direction that it should remain. Many unknowing people rotate the distributor cam until the points begin to open and tighten the cam screw. In most cases when the timing is set in this manner , it will end up so far off that the engine will barely run if it runs at all.
H. L. Chauvin
Well-known member
Humble Opinion On Timing & FWIW:
1. Even though timing has been hashed out so many times in so many ways on all Model A Forums, Nu-Rex, under their "Technical Information Section" explains in detail that standard, stock original Model A's should "always" be timed as detailed by them, & "always" with the spark levers set at least "two (2) clicks down", as opposed to "all the way up", such that afterwards, when starting with the spark lever "all the way up", the engine will always start "ATDC" in lieu of TDC.
2. There is a real, proven, definite "reason" given for this detailed Nu-Rex timing recommendation which is of "utmost" importance for increasing the life of the Model A engine Babbitt; but, it is almost never discussed on Model A Forums, except for "in-shop" discussion among extremely knowledgeable engine rebuilders who provide re-Babbitt services. Re-Babbitt people will acknowledge that advanced Model A timing with the spark lever set "all the way down" is the major cause of slowly beating up one's Babbitt -- nobody wants to "hear" this. E.g., senior ears hung out of the Model A side window to find the so-called Model A timing "Sweet Spot" is mentioned often; however, how well does it work with some seniors we know who cannot even hear their wives asking them to take out the garbage.
3. The reason for Nu-Rex's recommendation is that is that "maximum" advanced timing on a Model A, (verified with a timing light), should never be increased more than 28-29 degrees.
4. In going to the Nu-Rex site, one can read some interesting Model A timing reports.
5. And, kicking back at start, don't rule out & forget the distributor "Body", as noted below by Nu-Rex:
"An "A" owner in Southern California recently reported he was experiencing a kickback problem on start. His car is a '30 with a Hi-Compression Miller Overhead Valve Assembly and capable of speeds of 70 MPH and greater.
Recently he experienced "kickback" at start. He retarded the spark setting to a measured (timing light) value of 15°/20° ATDC (Full Retard) and it still occurred sporadically.
Conversation with him and measurements led to the diagnosis and conclusion-the fault was due to "cross-firing" within the distributor body.
Cross-firing occurs when the spark travels to an adjacent distributor contact and thus to a wrong spark plug. It is caused by a carbon conductive track, open crack, or other defect within the distributor body. It only gets worse with time.
It was suggested that a different body be installed.
Follow-up confirmed that the body was intermittently "cross-firing." The new body corrected the mal-performance - normal timing was reset and proper operation was attained.
Summary
Kickback at start can thus occur by -
1. Even though timing has been hashed out so many times in so many ways on all Model A Forums, Nu-Rex, under their "Technical Information Section" explains in detail that standard, stock original Model A's should "always" be timed as detailed by them, & "always" with the spark levers set at least "two (2) clicks down", as opposed to "all the way up", such that afterwards, when starting with the spark lever "all the way up", the engine will always start "ATDC" in lieu of TDC.
2. There is a real, proven, definite "reason" given for this detailed Nu-Rex timing recommendation which is of "utmost" importance for increasing the life of the Model A engine Babbitt; but, it is almost never discussed on Model A Forums, except for "in-shop" discussion among extremely knowledgeable engine rebuilders who provide re-Babbitt services. Re-Babbitt people will acknowledge that advanced Model A timing with the spark lever set "all the way down" is the major cause of slowly beating up one's Babbitt -- nobody wants to "hear" this. E.g., senior ears hung out of the Model A side window to find the so-called Model A timing "Sweet Spot" is mentioned often; however, how well does it work with some seniors we know who cannot even hear their wives asking them to take out the garbage.
3. The reason for Nu-Rex's recommendation is that is that "maximum" advanced timing on a Model A, (verified with a timing light), should never be increased more than 28-29 degrees.
4. In going to the Nu-Rex site, one can read some interesting Model A timing reports.
5. And, kicking back at start, don't rule out & forget the distributor "Body", as noted below by Nu-Rex:
"An "A" owner in Southern California recently reported he was experiencing a kickback problem on start. His car is a '30 with a Hi-Compression Miller Overhead Valve Assembly and capable of speeds of 70 MPH and greater.
Recently he experienced "kickback" at start. He retarded the spark setting to a measured (timing light) value of 15°/20° ATDC (Full Retard) and it still occurred sporadically.
Conversation with him and measurements led to the diagnosis and conclusion-the fault was due to "cross-firing" within the distributor body.
Cross-firing occurs when the spark travels to an adjacent distributor contact and thus to a wrong spark plug. It is caused by a carbon conductive track, open crack, or other defect within the distributor body. It only gets worse with time.
It was suggested that a different body be installed.
Follow-up confirmed that the body was intermittently "cross-firing." The new body corrected the mal-performance - normal timing was reset and proper operation was attained.
Summary
Kickback at start can thus occur by -
- spark rod control inadvertently left near a full advance setting
- timing mis-set to advance greater than approximately 28° BTDC
- cross-firing within a defective distributor body/cap."
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