71 rocket 350. Sat for about 6 years. The starter can barley turn over the engine. On a fully charged battery I can only get about 6-7 seconds of sustained slow cranking before it dies. I know pretty definitively the problem in NOT the starter, cables or battery. See below about that.
The engine it's self must be the problem. With a 10" wrench on the crank shaft I can turn the engine over by hand but I'm not sure if the force required could be considered excessive. I estimate on compression around 40-50 Fp of torque.
Engine runs perfectly (once I get it started)

What I've done so far:
Even though the engine was not sized, filled cylinders with WD-40 and let sit over night. This improved it slightly for a couple days.

Replaced starter. The old one had a sticking selunoid anyway. NO CHANGE.

New 800/1000 battery. NO CHANGE.

New 850/1000 battery. NO CHANGE.

Checked cables carefully and just to confirm ran jumper cables from battery directly to the starter with existing cables in place. Then to confirm the jumpers had a good connection, disconnected the existing cables and used jumpers only. NO CHANGE.

Added a few shims on starter in case the teeth were bottoming out. NO CHANGE.

 

Do you know that that the timing is not too high.That could make it much harder to turn correctly ,if it is too high in time. Just a hopeful thought. Good luck. If timing is OK , might need to try a high torque mini- starter. Larry

 

It sounds like a bad ground from the engine to the body. Make sure those are clean and the negative battery cable has a good connection. Take all the plugs out and put some Marvel Mystery Oil or a combination of 50% acetone and 50% ATF in the cylinders and let soak overnight. Then try cranking the engine over with the plugs out and see what you get.

 

I agree that the problem could be the timing as well. Another area to check is the ground of the horn relay to the passenger side fender well. Check the ground as well as the positive cable to it.

 

The ground at the horn relay has nothing to do with the starter. Make sure all your connections at both battery terminal ends are clean, shiny, and tight. Make sure your battery cables are not sized too small and are not frayed or corroded. Check the cable connections at the horn relay as stated above to make sure they are clean and tight. Same goes for the connections at the starter lugs . Make sure the negative battery cable connection at the block is clean and tight. Make sure that the mounting surface where the starter mounts is free of paint, clean and tight. Make sure the starter drive gear and the flex plate mating has the proper mesh tolerance with the starter engaged. Should be able to slip a 1/16 drill bit in between the teeth mating surfaces. Ensure your battery is fully charged, should be 12.7-13v

 

When I was 16 I had a job building starters and alternators. Let me just say we did a bad job. I have no idea how that place stayed in business. Once we got an order for 70 alternators. I built a rack of 6 and started to flow bench test them. My super said, "What the hell are you doing? Get those things in the box and get them shipped." No test? No test. A friend of my Fathers owned a local parts store. I asked him where he got his stuff. He told me it was the place I worked. I said, "Not anymore!" Long story long, it might be the "new" starter. Try one of your friends starters for kicks.

 

Gee oldscutlass, but how is it I miss took a bad starter motor in my '70 about a year ago, replaced it with a new one that didn't solve the problem. only to find out that the ground of the horn relay made by its being bolted to the inner fender was loose and caused the problem. I'm not implying that that's the cause of Cstoliker1's problem, just sharing my experience.

 

Because it wasn't the problem, at least not so long as the current laws of physics are still in force.

The horn relay has nothing to do with starter function, grounded or not.

- Eric

 

Cstoliker1, I agree that the starter itself may well be the problem.

- Eric

 

"clean and check, clean and check"
"Ensure your battery is fully charged, should be 12.7-13v"

Electrical connections are important.

OP sounds like he has very little troubleshooting skills. More of a "replace parts and see if that helps" approach.

While mechanical cleaning and tightening are important, ELECTRICAL testing can show if there is a problem, and if so, exactly what part has the problem.

Example: using an OHM and VOLT meter, how would you locate a fault in the ground path from starter to battery? If you [op] or you [any other reader] do not know the answer, then find out. This is the most basic of electricity. Take a class if you have to. Find my story about the 71 Challenger turn signal lamp that would not work, or the Cutlass starter that would not work IN the car but tested fine on the bench. Any actual mechanic / troubleshooter should know what voltage drop is, how to find/evaluate it, where it should be present, and where it should not be present. Voltage, or lack thereof, at crucial points in a circuit. Voltage UNDER LOAD. Current draw.

Semi-random parts replacment until things improve is an alternative that many use, though.

Ground to body, horn relay, or headlights area will not affect the starter circuit. While it is nice to have those connected, and working, none of that affects the STARTING system.

There are only like 6-10 parts in the starter system. Including battery and cables. I was going to say, "this ain't Rocket Surgery" but, actually, it is...

OP, did you ensure the strap that runs from starter to block is in place? How else is the power going to get to the block thence the battery (-) cable, thence the battery? It's one of those parts, and it is important.

How about verifying battery voltage *while cranking*?

"Should be able to slip a 1/16 drill bit in between the teeth mating surfaces."
===================
Be aware that you should never pull the starter gear out into contact with the flexplate unless the battery is disconnected. Had a co-woker lose the end of his finger one day doing that. When the gear moves out, whether by solenoid or finger pull, the electrical contact to starter windings is made, and the starter will spin if the battery is connected.


But let's get back to basics. Get the engine to spin properly using the starter motor.

Why would you turn the engine by hand... with compression? smh...
Remove the spark plugs and feel the engine itself, w/o compression.

Remove all the belts and things that are not NECESSARY on the front of the engine. See how the engine feels now. Does it turn freely at least two revs?

If not, take more stuff out of the equation by removing all the rockers so the valves are not active.

If it does turn by hand... then get the starter motor to do the same. Unfailingly.

THEN start adding back in compression, ignition, belts, accessories, etc.

Replaced the starter... did you assume that new = good? Not a valid assumption. Verify before installing.

So, what started all this [pun intended] ??


"71 rocket 350. Sat for about 6 years.
=================
hmmmm... irrelevant, to an extent. I revived a Toronado motor that sat in Michigan for oh 12 years, with mainly a set of points.


The starter can barley turn over the engine. The engine itself must be the problem.
[and yet:] Engine runs perfectly (once I get it started)
=================
That's a heck of a jump right there. I don't get that far when I jump to conclusions. The starting system might have any of various faults. Such as, a dead/ weak battery.


On a fully charged battery I can only get about 6-7 seconds of sustained slow cranking before it dies.
=============
By what means was the battery verified fully charged? I suspect "it was on the charger overnight" - which by no means verifies a fully charged and functional battery capable of providing several hundred amps at 11 volts.


I know pretty definitively the problem in NOT the starter, cables or battery. See below about that.
================
Please, elaborate. You tested every part and each section of the circuit for voltge drop under load, ohms, and voltage at every point in the circuit that should have voltage?

 

Thanks but please read original post before responding. As stated the connections between multiple good power sources and starter are known not to be at fault. They were compleaty bypassed with no change. Power (positive & ground) supplied directly to starter with 2 awg wire.

Timing: Good tip. To see if this could be the issue I disconnected the coil from distributor (no spark) and turned engine over..no change

Starter: Problem predates starter replacement with no change. The likelihood of both starters having the same defect is negligible.

Engine: It runs great with no obvious bearing noises. Oil pressure is good, coolant circulates, alternator and power steering works.

P.O.I. A fully charged lead acid cell's resting voltage with surface charge removed is 2.1V. For a 6 cell pack that's 12.6V. 12.7 at highest. Never 13V

 

Make sure that you have are applying the 12v "start" signal (purple wire) to the right terminal?

If you had it wired wrong at first and got a new starter and wired it the same way......and then tried to "hot wire" it using the same terminals.......

I know it sounds silly but that's what it sounds like to me.

 

"Starter: Problem predates starter replacement with no change. The likelihood of both starters having the same defect is negligible."

If both starters were installed the same way, e.g., lacking the strap which serves to support and GROUND the starter, then, yes two or more perfectly fine starters can exhibit fail to operate symptoms. BTDT. However, that tends to be more of a "will not spin the engine" rather than "spins too slowly" which I believe is what you described.

Have you spun the engine with plugs out, no compression, by hand and then with the starter motor? That's a good baseline.

How about we start with a concise summary of what it is and isn't doing, and what the voltage is at the battery when doing nothing, and whilst using the starter motor to crank the engine.


As for "P.O.I. A fully charged lead acid cell's resting voltage with surface charge removed is 2.1V. For a 6 cell pack that's 12.6V. 12.7 at highest. Never 13V"

That's real handy information there. You must be a scientist of sorts. But, if you think you are going to school "*the*RocketScientist" on electricity, think again. I chose 11V as a good nominal not too accurate figure for a battery WHILST OPERATING THE STARTER- under load.

The above retort is all in good humor, so please do not reply with a pissy response. Let's just get your issue resolved with a brainstorm.

 

Prior to storage the starter operated normally. None of the connections were changed during or after storage (before new starter) It's not wired incorrectly. Besides, the starter solenoid is a logic relay not a transistor.

The starter did not have a ground strap. I believe it gets its only ground from being bolted to the block. When I bypassed the oem wiring the ground was connected directly to the starter's outer housing.

The times I have turne over the engine without plugs was to remove the WD40 from the cylinders wich would invalidate it as a test. I will go out and try it today.
However, as I said after the WD-40 treatment the starter performance did show a marked improvement for a short time. But it is a running, working engine. Wouldn't any resistance in the cylinders due to gum or rust be cleared or at least improve since it's been running and driven?

 

"The starter did not have a ground strap. I believe it gets its only ground from being bolted to the block. When I bypassed the oem wiring the ground was connected directly to the starter's outer housing."

Well, not having a strap might prevent the starter from working. That was the entire point of the story I referred to. Before that experience I too believed, and experienced on many occasions, that the starter could ground thru the nose piece and two large mounting bolts. Not that day.

When bypassing vehicle wiring, gnd was connected exactly where on the starter, by what means? A booster cable clamped to the nose piece is no better than the vehicle gnd cable to block to nose piece.

Also, I have not heard yet the actual bettery voltage whilst the starter motor is in use.
A dead battery will behave as you descibe: "On a fully charged battery I can only get about 6-7 seconds of sustained slow cranking before it dies. "

See, we DO read your story. It is a bit disjointed though. Can you trim it down to the bare facts of symptoms and under what conditons they occur?

 

This is best case scenario. About as fast and as long as I can get it to turn over. Most of the time it's considerably less. To the point I can't start it. Engine cold, battery freshly charged yesterday, spark disabled and about 92 degrees out.
Brand new 850/1000 battery. It holds up better then the others I've tried it with.
Other power sources I've tried it with.
Brand new 800/950 battery
1year old 800/950 battery pulled from my working truck.
Newer 650/800 from working car.

 

That's not right, under the circumstances you've described.

There's something creating a drag.

I wonder about the mechanical connection between the starter drive and the block / flexplate - is there something not quite aligned or otherwise tight?

This whole problem is very mysterious.

- Eric

 

That starter sounds awful. Reread the end of post #5.

 

That is pretty funny. I mean, I feel for you suffering this issue, but man, that is so WRONG. Great video, it helps to understand what you are saying.

I keep coming back to a battery that is not up to snuff- it should not drop to 10V in 10s no matter WHAT you do to it

New battery- New is not the same as good.
Can you do a DC ammeter reading while that is taking place? Either your amps is correct and the battery is a dud, new or not... well, it could be cables and connections... or the amp draw is absurdly high for some reason such as bad starter, corroded inside the jacket cables, poor ground circuit, etc. If the battery is really good, and yet dying that fast, then that energry has got to be heating the problem area nicely.


get the batt tested with a loading tester at the local store.

The only other thing that comes to mind is a tight engne. Anything been "fixed" on the engine lately? Trans been out and tork converter not seated in the trans right?

I would be taking off all parasitic loads and get the engine down to just the crank, pistons [no spark plugs], and the valvetrain. Well, and the trans/ TC. See what that feels like, by hand, then via battery and starter.

Was that video done with no spark plugs?

 

UNLESS there's a helluva load on it.

I agree that an ammeter reading would be very helpful here - I've got a SnapOn battery testing station that does that - if you could rustle one of those types of units up, maybe from a buddy, it would really help.


I should have asked this - if it does the same thing without compression, then you know that SOMETHING is very wrong, located somewhere between the starter windings and the somewhere inside the engine.

- Eric

 

exactly why I like to turn an engine by hand. After you have assembled a few you know what each stage feels like. The crank alone is a sweet smooth spin, so nice.

PS the store can also ck the starter, and see what kind of current draw it is exhibiting. I know you can't wait to extract it AGAIN.

Hey, before you remove the starter, do a loaded voltage drop [VD] test across the starter and path back to battery. I would start with the bk lead on the battery negative post and the red lead on the starter's case- not the nose, not the end cap, but the case to which the coils actually mount and ground. If that is not oh 0-0.5V or so, whilst the starter is in use, then move the test leads closer together one component at a time until they are across the portion of the circuit that has all the VD.


It sounds to me like a spun bearing, nearly siezed motor.

Here is my 403 starting after 5-6 months sitting [well I did fill the carb first]

http://vid19.photobucket.com/albums/...psnqnqmat1.mp4

 

Just put a Power Master 9610 in it. Spins like a top now. Incredibly fast with no slowing.

 

So the problem was two different bad stock-type starters?

- Eric

 

No, that never happens...

 

The jury is still out. The OEM starters are direct drive. The 9610 has a 4.4:1 gear reduction (kW and hp ratings are same as stock). The 45 yo engine may have resistance that the 9610 is easily overcoming.
However, the speed the new starter is achieving even with the reduction does point to the last two starters having the same defect as more likely.