Optima battery suddenly too weak to crank on 48 DeSoto!

[MarcDeSoto]

I finally charged up my Optima 6 battery using my old Schauer battery charger.  I kept trying to let the NoCo charger take over, but it would only charge for five minutes and shut off.  So I kept charging with the Schauer and the amperage kept going down as the voltage on battery kept going up.  Finally, my battery reads 6.5 volts on my new Centech battery load tester that I bought at HF today for just $15!  Then I hooked up the jumper wires to the coil and cranked the engine over to test for spark.  I have spark, so I didn't fry my coil, points and condenser!  My friend says to buy some starter spray to induce starting, so I'll try that tomorrow.  

[Marcel Backs]

stay away from starting fluid at all costs unless you want your cylinder bores to look like 33rpm record grooves. It is best to be patient and figure out why it will not run.. If you have spark a fuel delivery problem is present and I would start with fuel pump and carb for issues. Again ether in not your engine's friend since it washes the bores of any oil which is not good for even a microsecond! M

[MarcDeSoto]

Marcel, thanks for that advice.  Tomorrow, I think I'm going to just remove the carburetor air horn and just fill the float chamber with gas.  If everything is good, it should start then!  

[allbizz49]

I'm not a big fan of starting fluid myself but I wonder if that's true or just another theoretical possibility being told from one person to another. I figure if everything is s how it should be, a motor should fire without it. I have shot starting fluid in a few motors over the years without issues. I'd like to see some real world testing on that. Either way, good luck Marc on getting it fired up. I'm sure it will light off for you 

Edited January 2, 2023 by allbizz49

[RobertKB]

I still suspect timing. 

[keithb7]

I too am not an advocate of starting fluid. Ether. The engine was not designed to need it. It may help startup tired, old engines. Engines that have other things wrong with them. 
 

Troubleshooting and fixing your engine is very important. It’s not diffIcult. A fuel delivery test can easily be proven, although this is not required to start the engine. The engine will and can fire when you add a little fuel to the intake. Without a carb even installed you can get it to fire. If everything else is right. 
 

3 simple things are needed to fire up your engine. Compression, fuel, and spark at the right time. 

 

Get all the spark plugs out and get a compression gauge. What is the measured compression of each cylinder at cranking speed? This will help verify valve timing and valve seat seal-ability . 
 

You say you see spark. When? Where is the piston position when the spark fires? What are the positions of the valves when the spark fires? 
 

For now I’d ignore the fuel delivery concern. You don’t need it if you are able to get fuel into the intake yourself. I’m betting on a valve timing or spark timing issue.  Can you record compression and report back with data?  
 

Both valve timing and ignition timing has got to be right. 
 

Do not throw a bandaid at the problem. Find it and solve it. Starting fluid is a bandaid. 
 

At this stage, this pic shows the only fuel delivery system you really need. 100% reliable delivery of fuel to fire up a dormant engine. Any doubts about fuel delivery are completely eliminated. Enabling you to focus on and find the real problem why your engine is not starting. 
 

Edited January 2, 2023 by keithb7

[MarcDeSoto]

I guess I can check spark timing by turning the fan by hand and seeing if the spark on No. 1 occurs right at TDC.  I can do a compression test too.  

[DJK]

In 2015 I removed a battery from a brand new Titan that failed Nissan pre delivery test, charged it over night at 2 amps, re-tested, passed, been in my  2010 Altima no issues.

[kencombs]

I've always static timed engines.  Set the nbr one up on compression, align the timing mark on the crank pulley.   The loosen the distributor, rotate until the points are closed.  Turn on the ignition and attach a test light to the primary wire post on the distributor and ground wire.  The light will not be lit.  Now slowly rotate the distributor until the light comes on indicating the points are open and the current path to ground is now through the light bulb.  That is the point where the spark occurs.  Tighten the clamp bolt.

 

Done correctly, that removes any doubt.

[Sam Buchanan]

If everything is set up correctly the engine will want to run.....no prompting needed. 

[allbizz49]

1 hour ago, Sam Buchanan said:

If everything is set up correctly the engine will want to run.....no prompting needed. 

100% 

[desoto1939]

I attended a battery seminar several years ago at the AACA Annual meeting and Conference. Here isa bullet point taken from the seminar on batteries on AGM Batteries.

 

Rich Hartung

 

[MarcDeSoto]

I felt my Optima battery all through the charging process, and it never even got warm.  

[MarcDeSoto]

I guess I would need to make a test light with a 6 volt bulb, right?  Or does HF sell one that would work?  

[Los_Control]

My 12 volt test light does work on 6 volts, the bulb is not as bright as should be but you can tell when it is on.

[keithb7]

A spare 6v tail or head light bulb and two wires with an alligator clip on each end will do it. Or a digital multimeter set to continuity beep will also do it. You don’t need to buy a test light if you have any of these options mentioned. 

[MarcDeSoto]

Keith, I tried to do a compression test today, so I pulled out my old 40 years old Milton compression tester.  I screwed it into no. 1 and cranked.  The needle would not hold.  It would go up, then collapse, and on and on.  I looked at the Schrader air release button and it looked collapsed.  So I guess I need a new compression tester.  

[allbizz49]

I wouldn't sweat a compression test. I'd check and double check my plug wiring order, make sure you're firing when you're supposed to, fill the carb bowl and crank her over. I bet she'll light off for you. Good luck, crossing my fingers for you to get it fired up 

[keithb7]

My reasoning for the compression test was the gather intel on the valves. Sealing properly? Once confirmed i planned to guide you through ignition timing. 
 

Getting down to basics and building up from there. 

[MarcDeSoto]

I got my new water pump from Moparpro.  He sent it Priority which was nice.  I'll install it tomorrow so I have a cooling system in place when I start it.  I checked and double checked my firing order.  Looks good.  I put visible spark connector on no. one so I can see it spark.  It seems to fire right on TDC when I crank, but I haven't static timed it yet.  With wp installed, I can put the fan and belt on, then connect my jumper wires to the coil, and check the timing.  Can I use the spark gadget instead of the test light to check timing?  

[LeRoy]

Hey Marc

When I was going through initial start up after rebuild I ran into a similar problem. My wires ended up being off 1 position as someone else mentioned earlier in the thread. I went through the same though process you're going through - compression, spark, fuel, head scratch - repeat. When I finally got the wires in the right spot the timing wasn't very critical for the first start. If you're within 10/15deg either way it will start, or at very least cough and sputter for you.

I agree that a big squirt of gas down the throat or filling the bowl and pumping a fair amount will get you the initial start where fuel is concerned.

To Keith's point if you have a valve hanging open it won't be happy about it but all other things correct it will start on 5 without too much challenge. If you have multiple jugs not holding pressure it probably won't go. You can put your finger over the plug hole and spin it over for a shade tree compression test (press it in there hard) It will blow your finger out of it's got enough compression. If you can hold the pressure with your finger chances are it's too low.

 

So all those words and I got nothing new for you. My process would look something like this.

 

Be sure battery is full and starter is spinng engine quickly.

 

Stick your finger in each plug hole and spin it over, if they all blow your finger off assume valves and rings are good enough to start.

 

Ensure you have a nice bright spark - good coil and condenser, points clean and operating ok, plug wires not frayed, clean cap and rotor. Spin it over several revolutions while watching the spark to be sure it's not intermittent.

 

Double check that your TDC timing mark on the front pulley is near the pointer. Ensure piston #1 is at TDC, rotor is pointed at the #1 plug post, wires are on correctly and correct firing order, plug gaps are close. (#6 will be in same position as 1, if you can't get that plug out weld a nut to it (get it good and hot when you weld it on then spray it with a little water to cool it down quickly for some thermal shock) and back it out).

 

Dump a tablespoon or 2 of gas down the yap and try again. 

 

Cuss (maybe ingest another adult beverage)

 

One additional thought. Please keep in mind I got no idea what I'm doing so everything in my post is pretty questionable advice.

Edited January 3, 2023 by LeRoy

[Dave72dt]

On 1/2/2023 at 10:47 AM, kencombs said:

I've always static timed engines.  Set the nbr one up on compression, align the timing mark on the crank pulley.   The loosen the distributor, rotate until the points are closed.  Turn on the ignition and attach a test light to the primary wire post on the distributor and ground wire.  The light will not be lit.  Now slowly rotate the distributor until the light comes on indicating the points are open and the current path to ground is now through the light bulb.  That is the point where the spark occurs.  Tighten the clamp bolt.

 

Done correctly, that removes any doubt.

With a clockwise firing order, your initial turn of the distributor should also be clockwise until points are closed, then turned counter clockwise until  your light comes on.  That puts the point opening on the front side of the distributor cam where you want it.

[MarcDeSoto]

Keith, Here are my compression results.  I bought a new Compression tester kit at HF today.  It works well.  

 

No. 1  - 80;  No. 2 - 80;  No. 3 - 80;  No. 4 - 100;  No. 5 - 92;  No. 6 - 102

 

Could the lower readings on Nos. 1 - 3 be due to the tappet gaps being adjusted too wide, or too tight?  

[Sniper]

2 minutes ago, MarcDeSoto said:

Could the lower readings on Nos. 1 - 3 be due to the tappet gaps being adjusted too wide, or too tight?

 

that is a possibility, of course your rings aren't seated yet either.  I would not be too worried about the numbers you have. 

[Los_Control]

I'm a firm believer you need over 60 psi to get a engine to run .... 80 is low but you are in the ball park. After running the #'s will increase.

I think it is a good idea to write them down, then in a few weeks run test again to compare. ... Then for future reference you have data to compare with if needed.