71 351 Cleveland starting/cranking issue

[FirstMach1]

I'm an average mechanic and have accomplished more in the last week than I thought possible. I hate electronics. But now I'm at a dead end and need your help.

1. Had no spark
2. Tested battery and coil. passed
3. Diagnosed a bad magnetic pickup in a relatively new distributor and replaced it. whew that was a job
4. Got spark again!!
5. Found TDC and roughly aligned timing
6. After a few attempts at starting I'm getting some carb backfire. Not the problem here but confirms fire in the hole.
7. Battery seems to run down quickly. ie.. cranks normally for a few seconds then acts like the battery is dead and doesn't crank at all. "The problem"
I continuously keep the battery charged up before trying to crank. I get one good crank for a few seconds if I'm lucky.
8. Battery checks out ok at auto shop and fully charged. Cables get hot when it does crank.
9. Pull starter and have it tested. It's one year old and passes test easily
10. Clean all contacts. Nothing looks awry.
11. Suspect starter relay. I jump the relay and at first it cranks normally and then slows down to no crank as before.
12. I'm out of ideas and need some help here please.

Thanks,
Eric

 

[Zach]

In terms of starting maybe too much timing maybe can cause extra stress? All you need is spark air/fuel and compression. Verify the rotor is hitting the right contact when you are at TDC of the compression stroke of cylander 1, out your thumb over the spark plug hole and feel for the blow, wait till it’s at the top. The rotor should be at spark plug ones connnection. You can put the spark plug in the boot and ground it and physically see the spark to make sure. Also make sure the carb is getting fuel, use some type of fluid if need be. Should at least fire.

It does sound like an electrical issue somewhere but even then it should still start. Have you tested the right voltage is being sent to the coil, distributor etc, not too much not too little.

 

[FirstMach1]

Thanks for the reply.

I have fuel (rebuilt the carb)
I’ll re check the voltage. I’ll search here for that.
I know timing isn’t right yet but without more than 2 seconds of crank I can’t experiment much. Dizzy is pointing to #1 at TDC. I’ve tried to get about 10 btdc roughly.
But again it just won’t crank long enough to give it a chance.

 

[Hemikiller]

First thing to check is that you actually have an engine to chassis ground path. Very common for this to be missing on our cars. Factory chassis ground point was the lower screw for the voltage regulator (#9)

If yours is present, or an alternative is present, and the cables and connections appear to be in good, clean condition, then a cranking voltage drop test is needed. If it's not present, add a temporary ground from battery (-) to the radiator support or fender apron and try again.

 

[boilermaster]

FirstMach1,
How well did the engine crank when you had no fire ?.
If in doubt, simply disconnect the distributor and take the timing out of the equation.
With no fire the engine doesn't know or care what the timing is.
If the engine still does not crank well the issue is with cranking.
Once that is sorted you can go back to timing the engine.
Boilermaster

 

[FirstMach1]

Thanks guys! It’s definitely a crank issue. It started just fine with good crank a few months ago. Then lost spark. Now this.
I do have a good ground cable. Cleaned all connections even though they looked ok.

I definitely need to check the voltage drop. Ok stupid question but I’m not sure so….
Which setting do I use on the multimeter when checking the drop?
DC v I assume

 

[Don C]

Thanks guys! It’s definitely a crank issue. It started just fine with good crank a few months ago. Then lost spark. Now this.
I do have a good ground cable. Cleaned all connections even though they looked ok.

I definitely need to check the voltage drop. Ok stupid question but I’m not sure so….
Which setting do I use on the multimeter when checking the drop?
DC v I assume

Yes, dc voltage, probably 20v on your digital meter.

Here is a tutorial on using multimeters for car diagnostics.
https://www.msn.com/en-us/money/oth...&cvid=d5beb2c8def14ffaa20d13785512ae41&ei=196

 

[basstrix]

When you jumped the solenoid and it cranked normal and then slowed way down, you isolated the issue to the battery, cables, starter, solenoid, and cable connections. You said the cables get hot when it does crank. That's an indication of excessive amperage through that cable....there's may be a short circuit somewhere or the cable is too small or compromised.

 

[will e]

Did you pull the distributor to fix it? If you did, then as mentioned above, you need to double check you are at TDC of the compression stroke. These will run 180 degrees off but will backfire (ask me how I know).

 

[rcadd1ct]

180 out if time will burn up a starter. Trust me.

 

[FirstMach1]

Thank you for that! I’ve avoided electrical knowledge for decades other than the basics. I’m ready now. Ha

 

[FirstMach1]

Definitely getting some large voltage drop numbers from the battery to the starter along with both cables getting hot. Should I assume that it’s the starter relay if all the connections are good?

 

[Don C]

The cables will get warm during a prolonged cranking, but shouldn't get hot. It sounds like a bad starter to me, could be either electrical or mechanical, preventing the starter from spinning, or even something wrong with the engine, like hydrostatic lock. You might try pulling all the spark plugs and see if it will crank.
Remove the battery cable and starter cable, connect your multimeter to the battery and starter terminals, with the meter set to read ohms. engage the solenoid by running a jumper from the battery positive terminal to the "S" terminal on the side of the solenoid. The meter should show a very low ohms reading, like below 5 ohms, for good solenoid contacts.

 

[rcadd1ct]

Definitely getting some large voltage drop numbers from the battery to the starter along with both cables getting hot. Should I assume that it’s the starter relay if all the connections are good?

Try disconnecting the coil wire and try spinning it over. If it spins easier timing is off.

 

[Hemikiller]

Heat is generated by resistance. Resistance causes voltage drops. It's more likely that your cable is bad than the starter. The starter relay simply connects the battery (+) to the starter cable.

 

[will e]

I am messing with my engine too and have moved initial timing from 15 degrees advanced to some value close to or after TDC. The engine will idle with any of these settings, I didn't say it would run good but it will idle. The initial range of timing an engine will idle in is rather impressive.

You need to verify you are not 180 degrees off on your timing. The distributor only rotates once for every two times the crank does.

Here's what I'd do:
Pull all of the spark plugs. This will make it easier to rotate the engine by hand and will help with the timing steps further down.
Remove distributor cap. Rotate the engine to TDC with the rotor pointing to where #1 on the cap is.
Hand rotate the engine (it will be pretty easy now that the spark plugs are out).
Using either a compression tester or your finger as you approach TDC on the crank the first time (spark plug now pointing away from TDC) you should not get compression or feel the push against your finger. If you don't it is probably the exhaust stroke. Rotate the engine again and verify it is opposite of what you found before. Which ever rotation is the compression stroke set the crank to TDC. Now check that the distributor is pointing close to #1 plug if it is pointing to where it was before then your timing was not 180 degrees off. If it isn't, and is pointing in the opposite direction, simply move the wires on the cap

Optional after verifying timing is not 180 degrees off:
You can get the initial timing pretty close without the engine 'running'. Replace just #1 spark plug (or better, ground it so that you can see the spark). While cranking with no spark plugs in the engine it will spin pretty quick. You can adjust the initial timing this way. You just want to get it somewhere between 7 and 16 degrees doing this, you can make the final adjustment when the engine is running.

 

[c3garagesc]

Not sure if you found the problem, but I had a customer's in with a no start problem. He said the engine turned over very slowly and would not start. Long story short, he had the wrong starter in it. His car is manual transmission and he had the starter for an automatic installed. When I removed the starter, you could see where the flywheel interferred with the back of the starter. I put in the correct starter and the engine cranks very nicely now.
If the flywheel is binding on the starter, that could possibly cause the high draw on the electrical portion.
Just a thought.

 

[FirstMach1]

I’m back on this today. I did in fact have the dizzy 180 off. Changed that a couple weeks ago. Put in a new ignition solenoid switch. That did not solve the slow crank though.
I just took out all the plugs and it cranks freely.
I’m gonna recheck TDC timing and putting things together one plug at a time and check things as I go.

 

[FirstMach1]

Definitely seems to be a compression resistance. 4 plugs back in and struggling to crank. Underpowered starter maybe? Same starter when it was normal. Not enough voltage to starter?
More questions but at least we’re ruling out some things.

 

[FirstMach1]

It’s running again! All the stars aligned and we’re back in business. Now I can get down to the fun and easy stuff again like timing and fluid changes.
Thanks for all the input as it was invaluable and I learned so much during this mechanical adventure.