Optima battery suddenly too weak to crank on 48 DeSoto!

[Sniper]

Maybe, there are 10 teeth on the oil pump drive gear, that means 1 tooth is 36 degrees at the distributor, 18 at the crank.

 

There are 6 plug wires on the cap, that's 60 degrees of change at the distributor, 30 at the crank.

 

I don't know how much room the major and minor adjusting plates allow, but you have to be getting close there. 

[MarcDeSoto]

Wow, Sniper really knows his engine geometry!  I'm tired of fooling around.  I think I'm going to put the major adjustment that I made back where it was and pull out the oil pump and the dist. and make sure I do a dead on balls (that's an industry term) accurate static timing.   Dumb question does the no. 1 spark plug fire once on every revolution of the timing mark?  So that if your rotor is pointing to 7:00 at no. 1 spark plug cable when the timing mark is on DC, you are at least in the ball park?  I tried to do a static timing of the dist. using a test light today, but my dist. was too out of adjustment for that to work.  I also noticed that when I had the test light clipped onto the positive side of the coil with the jumper wires, I no longer had spark, but did have the light on.  

[Sam Buchanan]

3 hours ago, Sniper said:

Maybe, there are 10 teeth on the oil pump drive gear, that means 1 tooth is 36 degrees at the distributor, 18 at the crank.

 

There are 6 plug wires on the cap, that's 60 degrees of change at the distributor, 30 at the crank.

 

I don't know how much room the major and minor adjusting plates allow, but you have to be getting close there. 

Are you sure that isn’t reversed since the cam is running at half crank rpm?

[Dave72dt]

 72 degrees crank travel for each pump tooth

 

6 plug wires= 60 deg at dist, 120 at crank

Edited January 6, 2023 by Dave72dt

[RobertKB]

14 hours ago, Kilgore47 said:

Turn the engine to TDC on the #1 cylinder on the compression stroke.  Remove the distributor cap and note where the rotor is pointing.  Move the #1 spark plug wire to that location and then re install all the other spark plug wires in the normal firing order around the cap.  This will get the timing close to the correct spot.  Close enough to start and then it can be fine tuned once you get it started.  The engine will run fine like this.  The engine doesn't care where the wires are located on the distributor - it only cares that it gets spark at the correct time.  Or you could re index the oil pump.  The oil pump may have been installed in a different rotational position than recommended.  

 

You have been given this advice by at least four different people, myself included. Have you actually done this? I doubt there’s any need to pull the oil pump. 

[9 foot box]

   From the book.

Edited January 6, 2023 by 9 foot box

[MarcDeSoto]

44 minutes ago, Dave72dt said:

 72 degrees crank travel for each pump tooth

 

6 plug wires= 60 deg at dist, 120 at crank

If my engine fired on no. 1 cyl. at 25 degs. before TDC, it would seem that moving the oil pump over one tooth would be too far at 60 degs.  I'm going to try to fire it up tomorrow.  

[DonaldSmith]

My mind is melting.   Let's go over these numbers. 

 

The distributor, oil pump and camshaft turn together, at half the speed of the crankshaft.  But for the moment never mind what the crankshaft is doing. 

 

One tooth equals 1/10 of 360 degrees, or 36 degrees, of camshaft, oil pump and rotor rotation.  Not 60 degrees.   

 

Mark says his timing light came on about 20 degrees off.  (Rotor too far clockwise - right?) Ok, throw in some major and minor adjustment, and I can see that accounting for the difference from 36 degrees.   Sounds like the pump is off one tooth.

 

I made a new post "Oil Pump indexing and 7:00" so that, some year, someone may find the elusive oil pump indexing information.   I retyped the gist of it, for legibility: 

 

"Turn pump drive shaft until the slot in the end of the drive shaft lines up with the slot in the end cap screw holes

in the mounting flange. (Fig 14). * Then turn the drive gear one tooth counter-clockwise. 

Loosen the distributor lock screw and raise the distributor just enough to allow the pump to be installed. 

Tighten pump cap screws.  With Distributor still raised, turn rotor as shown in Figure 15* 

until it points to about "seven o'clock", move the rotor back and forth slightly to allow the tongue of the distributor shaft to engage with the slot of the oil pump drive shaft.  Install number one spark plug and distributor cap,

adjust timing as outlined in this section. " 

 

(Fig 14 is looking down on the removed oil pump. Yep, 10 teeth.  Turn the shaft one tooth counterclockwise when looking down on it.   That should make the slot horizontal after installing the pump.   Figure 15 shows the rotor at 7:00, which is the Holy Grail.) 

 

Have fun, everyone. 

[LeRoy]

7 hours ago, MarcDeSoto said:

If my engine fired on no. 1 cyl. at 25 degs. before TDC, it would seem that moving the oil pump over one tooth would be too far at 60 degs.  I'm going to try to fire it up tomorrow.  

Good luck, I'm rooting for ya

[Dave72dt]

 

 

 

9 hours ago, MarcDeSoto said:

If my engine fired on no. 1 cyl. at 25 degs. before TDC, it would seem that moving the oil pump over one tooth would be too far at 60 degs.  I'm going to try to fire it up tomorrow.  

The rotor turns 60 degrees to get to the next plug and the crank turns 120 degrees to accomplish that.  That's all that means.  Each tooth on the oil pump turns the rotor 36 degrees.  If your static timing point does not occur within that particular 36 degree range, you need to move the rotor to a different 36 degree range.  If you had it close 2 days ago by changing the major and minor adjustments and have some adjustability left, leave it there and start it up.  If it did not and it's still too far advanced, you'll need to back the oil pump drive gear up one tooth.

 

 

[MarcDeSoto]

I'm goint to do what Donald said and index the oil pump.  Now I know that it requires two revolutions of the crankshaft for a cylinder to go through four strokes, so just because the timing pointer is on DC, it doesn't mean that the cylinder no. 1 is about to fire.  It could be on the intake stroke.  That's how lots of guys get 180 degs out.  Thanks for all of your help!  

Edited January 6, 2023 by MarcDeSoto

[keithb7]

1 hour ago, MarcDeSoto said:

 just because the timing pointer is on DC, it doesn't mean that the cylinder no. 1 is about to fire.  It could be on the intake stroke.  That's how lots of guys get 180 degs out.  

 

Many of us have tried to explain this in earlier posts in this thread. " #1 TDC on the compression stoke" has been mentioned a few times.  A piston has to travel up and down 2 times, to complete a 4 stroke cycle of the engine. In order to do that the crank has to make 2 full complete revolutions.  Every time the piston travels up or down that is 1 stoke.  

 

A piston goes down. Intake valve opens. It sucks in Air/fuel mixture. Stoke one is now complete. Crank has turned 180 degrees. 

 

Piston travels up. Intake valve closes. Piston compresses air/fuel mixture. Piston continues to travel up until it stops. Where it stops is TDC on compression stroke.  Stroke 2 is now complete.  Crank has travelled 180 again, Spark plug fires just BEFORE piston reaches TDC. Exactly how soon before TDC depends on piston travel speed. Actual firing position is manipulated by mechanical and vacuum advance. We call this timing. Timing is adjusted and you need to get the timing in the ball park before air/fuel mixture will fire and go bang!

 

Violent combustion forces the piston down to the bottom of the cylinder bore. The explosion creates torque on the crank. Stroke #3 is now complete. Crank has turned 180 degrees again.

 

Piston travels back up. Exhaust valve opens. Spent gasses are pushed out the cylinder by way of the exhaust valve. Crank has turned 180 degrees again. Stroke 4 is now complete.  Piston again reaches TDC but not at compression stroke. So spark does not fire here.

 

The 4 strokes of a 4 stroke engine are now all done. The process start over again.

 

A home mechanic rebuilding an engine needs to understand this. One should strive to research, read and understand it.

 

#1 and #6 piston both travel at exactly the same time and motion. They are exactly 180 degrees out.  When #6 is at TDC compression stroke, #1 is at TDC intake stroke.  When #1 TDC is on compression stroke, #6 TDC is on intake stroke. Every single time the crank turns 360 degrees the timing mark on the front pulley passes the TDC mark. You must know how and why ½ if the time it,s not accurate for TDC on #1 compression stroke.

 

What really seems to screw people up is they set a wood dowel down the timing pin hole above cylinder #6. They turn the crank over until #6 is at TDC, and think they've got it. They have a 50/50 chance of being right, on the compression stroke. Why the heck is the darned tootin' timing pin hole above #6? Shouldn't it be above #1 cylinder? People are confused! It is because above #1 piston there is a thermostat and waterneck in the way. You can't place the timing pin hole there. The engineers and mechanics were like, "ya sure. Put it above #6 cylinder instead. #6 and #1 travel the same anyway. We got it"... 100 years later people are still often mistaken.  I am convinced in another 100 years nobody will have an inkling how all this works.

 

The difference between #1 piston and #6 piston movement in the block is nothing, The real difference is the valve timing. Valve timing dictates what cylinder is currently on what stroke. 

 

 

 

Edited January 7, 2023 by keithb7

[Sam Buchanan]

18 minutes ago, keithb7 said:

A piston has to travel up and down 2 times, to complete a 4 stroke cycle of the engine. In order to do that the crank has to make 2 full complete revolutions.

<snip>

A home mechanic rebuilding an engine needs to understand this. One should strive to research, read and understand it.

 

 

Above is quoted for extra emphasis.

Edited January 7, 2023 by Sam Buchanan

[allbizz49]

Suck, squeeze, bang, blow..... That's about as simple as it can be explained.

[MarcDeSoto]

Thanks guys.  I did it just like the manual says.  I didn't need to fool around with the timing hole in no. 6.  Here's what I did.  

 

1. I took out the oil pump and slid the dist. up about an inch.  

 

2. I held my thumb over no. 1 spark plug hole and cranked until my thumb blew off.  Then I moved the DC mark on the pulley to line up with the pointer.  

 

3. I followed the shop manual's directions for indexing the oil pump.  Face the slot toward you and turn the gear until the slot is horizontal to the two mounting holes.  Then turn the gear one tooth to the left.  

 

4. Install oil pump by sliding it under the frame rail and into the hole.  Secure with two bolts using 9/16 open end wrench.  

 

5. Take rotor and turn to 7:00 and slide it into the oil pump slot.  Install minor adjustment screw finger tight.  

 

6.  Attach test light between positive side of coil and distributor points screw.  

 

7.  If light is on, (it was), turn dist. counter clockwise just until light goes off.  Then tighten dist. minor adjustment screw.  

 

8. Then I put a visible spark attachment on no. 1 cylinder to see if it would spark when the DC mark appeared on every other revolution of the crank.  It did.  So tomorrow, I think I'm good to go.   

[Dodgeb4ya]

Yea see....read the god damn shop manual. That's what it's for.

More owners should.

It would help eliminate these endless drawn out threads.

[LeRoy]

21 minutes ago, Dodgeb4ya said:

Yea see....read the god damn shop manual. That's what it's for.

More owners should.

It would help eliminate these endless drawn out threads.

Goodness dodge4bya, I kinda get a kick out of the endless drawn out threads. It's the most entertainment I get theses days besides the high brake cleaner provides.

 

I've read the shop manual lots of times and nothing replaces the school of hard knocks. I think the community of discussing theses old cars is about as much fun as the cars themselves. 

 

If you don't dig the endless threads just skip em. Life is short, be happy.

 

rtfb

Edited January 7, 2023 by LeRoy

[Dodgeb4ya]

I would like to say more but will not.

[keithb7]

34 minutes ago, Dodgeb4ya said:

Yea see....read the god damn shop manual. That's what it's for.

More owners should.

It would help eliminate these endless drawn out threads.

 

This is why I always push automotive system fundamentals. A person cannot troubleshoot and find a problem if they don't understand how the very fundamental things function.

 

If you don't understand exactly what 4 stroke means and valves and what they do and why, how can you troubleshoot for no start? Then add the ignition system. Things get more complex then. Another variable added. How does it work? Why, and what is it supposed to do? Make a spark is not the right answer, showing not enough understanding. 

 

Next add the fuel system. 7 circuits of a carb. WTH does that mean? Fuel pump? Choke? Fuel pressure?  More confusion added.  WTH does all this do? Knowing we need all systems to work to start the car is not enough. When you understand the basics you can easily eliminate some variables and get the engine started. A shop manual eliminates all the fundmental info. They expect you are not a first year apprentice when you read the shop manual. Reading it will help you maybe get things going, but likely not if you don't understand the basics. If you do get the engine going with some info in the manual, you won't be able to explain why.

 

I heard a saying one time....If you can't explain it simply to others who have no knowledge, you do not know the subject well enough yourself.

 

Get some books. Read them. Today I will highly recommend the book "Automotive Fundamentals" by Frazee & Bedell. Published from 1949 to 1958. If you want to work on your own old Mapar, a book like this is a priority to own before socket sets and screwdrivers.  https://www.amazon.com/Automotive-Fundamentals-Frazee-Bedell/dp/B0013ZH02W

 

PS: I suppose owing the book is not enough. You have to read it.

Edited January 7, 2023 by keithb7

[LeRoy]

14 minutes ago, Dodgeb4ya said:

I would like to say more but will not.

Maybe a few hours in the garage alone with Motown blasting on the radio and a 6er of cold ones would help? It always makes me happier.

 

Or maybe a strong laxative....

 

?

[Sam Buchanan]

I'm reminded of the four phases of learning.

 

1) Unconscious incompetence; I don't know what I don't know....

2) Conscious incompetence; I know what I don't know...

3) Conscious competence; I know what I'm doing but I really have to think about it...

4) Unconscious competence; I know what I'm doing so well I barely have to think about it....

 

Some phycologists add another phase:

 

5) Complacency; This is where you get the timing light too close to the fan...... 

[Sniper]

2 hours ago, keithb7 said:

PS: I suppose owing the book is not enough. You have to read i

 

The corollary is that you have to understand it as well.

[MarcDeSoto]

I tried to start the engine today.  I put gas in the float chamber and cranked.  No start.  I checked for spark at no. 1 cyl.  No spark.  I pulled the coil cable out of the dist. and checked for spark.  Coil is putting out plenty of spark, but no spark going to spark plugs.  I'll have to do some dist. troubleshooting.  Points bad or condenser?  It sparked last night.  I checked to see if the cables were on tight.  The coil cable that goes into the dist. cap feels a bit loose.  It doesn't snap in like the others.  Any ideas?  

[Sniper]

On 1/5/2023 at 11:32 PM, Dave72dt said:

 72 degrees crank travel for each pump tooth

 

6 plug wires= 60 deg at dist, 120 at crank

 

My thinker hurts, lol

 

[Dodgeb4ya]

5 hours ago, LeRoy said:

Maybe a few hours in the garage alone with Motown blasting on the radio and a 6er of cold ones would help? It always makes me happier.

 

Or maybe a strong laxative....

 

?

I'm on my 9th rum and coke...

I think it's wurking....