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24v Starter on M360?

D

dawilson76

Member
1977 34' Silverton with twin M360's. Money has finally allowed a complete rewire. On the engine side new batteries, coils, solenoids, plugs, plug wires, rebuilt starters. But both engines still extremely drag to start. In fact, a mechanic friend commented that he can't believe they even start with how hard and slow they turn over. Timing and compression checked ok. So hard to start in fact that i've melted the lugs off a couple batteries. Obviously something is very wrong and not safe. She is a project that hasn't been more than a mile from the dock because she needs so much work and is not reliable. Thus the rewire. I was asked a question yesterday that i hadn't even considered before. "Are they 24v starters?" Is this possible? Are 24v starters made for Chrysler 360's? This solution answers all problems with starting. 12v applied to a 24v starter would obviously cause it to turn very slowly.
 
Let's see. What are the clues? Both engines drag. You have melted battery posts. That's 750-1,000 amps at 12 volts. Not good. 24 volts starters? You said the starters were rebuilt. Chrysler may have made 24 volt starters for some military applications over the years but your re-builder, who does this every day, would never try to substitute a 24 volt armature. I don't think it would even fit in the 360 starter motor housing.

My suggestion, considering that you have done extensive rewiring, is the ground circuit. It should work like this, at least for starting purposes. All battery grounds tied together by connecting the engine blocks together with very heavy (3-0) cable. One (or better both engines) connected to the battery bank negative terminal with equally heavy cable. All connections new, bright and tight. Tight is important.

When you try to crank one of the engines, a lot of current is drawn but it isn't a complete circuit until the starter sees a good ground. But since both of your engines drag, you need to look at the ground at the battery bank. It must be continuous - no bolted together negative battery cables, no crazy splices.

A good test would be to bring down a fully charged battery and connect it to the starter (using the starter solenoid) an a really good ground, like a head or intake manifold bolt on just one engine. Give it a crank and if the engine turns over normally, you have a real ground problem.

I'd love to know how this turns out

Bill
 
I'm sure that it's possible, but what causes you to think that these are 24 volt unless they had never been tried and/or have been replaced and not yet tried???
24v motors powered with 12 v only would certainly increase Amp load to the point of heating things up.

I agree with Bill regarding replacing battery cables etc... or at least checking the cable terminals and connecting points! But I disagree with all battery bank negs being tied together. I prefer to see each bank's Negative make it's own independent "system negative common" connection... I.E., Engine Block... to each respective engine. This creates redundancy.
Then join each engine with an additional cable for a combining scenario.

Question:
Are these by chance Bendix drive starter motors? Ya know.... no solenoid arm action pinion lever? The type that are direct drive?
If so, this style motor technology by today's standards is old school.
If your battery banks are up to snuff, all cabling is up to snuff, your Main Battery Selector Switches are good,
why not replace them with a gear reduction starter motor?
These will be listed as HTGR or PMGR and sometimes Mini Starters. Chrysler autos have been using gear reduction starters for many years. No one is using anything but HTGR/PMGR starter motors these days including the Marine industry.

Why... the armature turns up to 3 x's faster, the gear reduction brings the pinion back to the correct rpm (creating more torque), the amp load is usually less, and you end up with faster cranking engines.
 
First..........All connections new, BRIGHT and tight. Tight is important.

Put a wire wheel on a drill and clean em up

load test the batteries once fully charged

Rebuilt starters......hmmmm
 
Thanks everyone for the advise. The wiring is moving along quickly so I should find the cause very soon. I thought 24v starters on a V8 engine sounded very odd and you've confirmed that. The wiring harness will be reconnected today and will be measuring for all new battery cables and grounds. I'm thinking 2 AWG. Copper is expensive these days but in mind worth the cost in this case. Replacing the solenoids again today as well as the ballist resistors. I'll keep posting the updates.
 
Can you tell us more about these starter motors.... or at least about the starter motors that you'll ultimately be using???? :)

I mentioned Bendix drive to you...... are these Bendix drive motors????
Bendix drive type would be absent the solenoid lever action that kicks the pinion gear out.
Non-Bendix style would use a solenoid lever action pinion affair.

Any pictures????

If not, grab one of these and post it.

Here's a generic Bendix drive motor. Very inefficient, draws heavy amp load.
Example image ONLY.
fyVMtP8A

Again... example ONLY.
Here is a solenoid action motor.... stil not the best, but a step up from the Bendix style.
images


This is an example of a Chrysler HTGR/PMGR starter motor... it may even be the correct one... not sure.
None-the-less, these are a high rpm armature/gear reduced starter motor... and they'll kick a$$ over the other styles.
Example only.

http://www.go2marine.com/docs/7/5/7/3/75730F-p.gif

nothing.gif


 
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Rick, I'll be on the boat later this morning and i'll take a picture of a starter to post. It looks very similar, if not exactly the same, as the Bendix type pic. I'll get back to you.
 
This is really an interesting problem because you don't hear about marine engines melting battery posts very often. At least I don't.

The part that gets me is that both engines drag. I'll admit that the OEM Bendix-type starters aren't very efficient but they spin my 360s pretty fast. And there are thousands of those starters in use on marine engines right now.

Bad starter rebuilds? That could be common to both engines, since the poster says that both were rebuilt. Incorrect armature rewind? Armature windings that are coming in contact with the field windings? That would draw a hell of a lot of current as the starters destroyed themselves. But any experienced re-builder would have noticed that, I hope.

I keep re-reading the original post. There's one phrase..."both engines still extremely drag to start," that sounds like this isn't a new problem. Have the engines ever turned over normally or close to normally since the poster has owned the boat? In other words, are the engines themselves dragging, causing this huge current draw? Since we don't know, I'd offer that as a possibility although, I am running out of ideas.

Like Rick, I'm going to be back here until we find out what's really happening.

Bill
 
Bill, I understand... it is odd that both do the same. You said that there are thousands of Bendix motors still in use. That may be true.
However, don't you think that it would be money better spent on HTGR replacement units today...., rather than to over-haul Bendix motors?

Bendix drive technology is from the 1940's, back when we did not have solenoid technology, nor internal starter motor reduction options.

Just for fun, my money says that cleaning up the battery cables... both Pos and Neg, and tossing those Bendix units and replace with the HT units, will correct the problem.
images
 
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Whats that tranny fluid looking like....send you down a non-electrical road,whats it do with the plugs out?
We gotta get to the bottom of this:)
Im supposed to working on mine:(
 
Ok, I've taken a couple pics of the port side starter. I'm almost sure they're the Bendix drive starter type. Bill, to answer your question, yes, they have always had extreme drag to start. As mentioned in my original post i've replaced most parts that I would associate with starting the engines. The rebuilder of the starters I would consider reputable as they specialize in marine starters/alternators. The one thing I haven't replaced is the grounding wires. I have sanded and cleaned them but not replaced. I ordered 30' of 2 AWG battery cable this afternoon to replace every inch of pos/ground wire as well as new battery selectors. I'll keep updating on how it goes. Tranny fluid is clean. She runs like a charm after I get the engines to start. But, after she's been run, and hot, no chance of the starter turning either engine until she cools down. I have not run either engine with the plugs out. Compression tested normal and new plugs.
IMG-20120313-00677.jpgIMG-20120313-00682.jpg
 
Yes, I'll guarantee you that no matter which brand.... Prestolite, Arco, Delco..... those are bendix drive starter motors.
Most any motor that is minus a solenoid lever action pinion kick out, will be a bendix drive.



I'll be kind and not mention what I'd do with them. :D



Re-Cabling is not a bad idea.

Just an FYI. The Perko 90 degree sweep battery selector switches have very light contacts and light springs in them.
They don't seem to handle heavy current very well.
I toss them in the recycle bin...., and use Blue Seas or Cole Hersee.
 
One of the most un-appreciated and misunderstood battery switches, is this old black, out dated looking, ugly, Cole Hersse switch.
By design, I have two of these on my own boat. They replaced nearly new Perko Switches.
Full Sweep..... huge contacts... heavy spring... removalable rear panel.

april-cole-twin01g.jpg
images
 
Run a black jumper wire from the solenoid ground to one of those mounting bolts
and/or
Ground the battery at the starter mounting bolts with a star washer

important
one of those bolts I believe is longer and makes its way into to the cast iron block ....get that one

why is the pos stud not copper with a brass or ss not and a star washer? looks a tad rusty were the cable lug sits
 
I have the same starters. The Bendix drive locks in and stays in until the motor starts--a fact I found out the hard way (after embarrassing myself by chewing out my rebuilder! He, ah, explained it to me--and how!)

I suspect you have bad starters, worn bushings in the starters (that creates massive drag on the gears), and/ or bad connections.

First thing I'd do is jump the starters directly with a GOOD battery and heavy jumper cables. If it spins over nice, great--bad connections. If not, rebuild the starters. (I have a great starter rebuilder if you need it. They take parts by mail and are reasonably priced and good )

Jeff

PS: No way are they 24 volt starters!
 
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I'm currently waiting on the new cables and lugs. It will probably be mid next week before I get them and wired into the boat. If, after replacing all of it, I still have drag then I will try to jumper the starter. Easy enough procedure to determine if the starters are bad. I would do it now but all of the old "stuff" has been stripped out including batteries and battery box to make room to work on the wiring harness and house wiring. All I can do now is HOPE that when she's reassembled, the starters spin. If they don't, then the starters are the problem. Jeff, at that time I'll get the address from you for the rebuild or replace the starters with geared down versions.
Rick, the battery switches I'm installing are Blue Seas w/alt disconnect model. Has anyone had trouble finding tinned battery cable sold by the foot? I've looked all over the internet but the only seller I found was Defender. That's who i ordered them from. Every other site only had set lengths or preassembled lengths with lugs mounted.
 
You Bendix Starter Motor lovers are going to hate me for this:

I beg you.... do not have a Bendix drive starter motor rebuilt!
They were inefficient when new.... and are inefficient now. :mad:
The cost to over-haul one would be spending Good money after Bad, IMO.

At least look into the cost of the HTGR/PMGR motors..... or second best, the Delco style solenoid arm action motors.
If you need a loan, let me know. :)
 
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Rick, old buddy, I am forced to disagree: I have two of these old starters and never had a problem with either. After 20 plus years of use the teeth were a bit worn, so I had one rebuilt. The other is still going strong.

Jeff
 
I'm back to read the next chapter of "The Dragging Engines."

I have to agree with Jeff. My old OEM starters spin the engines just fine. While doing a cooling system rehab this winter, I had both starters rebuilt because with the heat exchangers and plumbing out, they were easy to get to. The rebuilder - a third generation shop - replaced the bushings in both starters. When I asked him about that he said, "You asked us to rebuild those starters and rebuilding for us always includes pressing in new bushings. They will not operate properly with worn bushings."

Guess I'll have to stop back for the next chapter...

Bill
 
As I suggested, the industry has long since moved away from these and has gone to the smaller and higher armature RPM with a final gear reduction to the pinion gear. We see more torque to the flywheel ring gear and typically faster cranking RPM, and they normally require less voltage to do it.

The Bendix style work just fine if the voltage is up where it should be, and if the cables are also keep in good condition. Since the Bendix pinion arrangement relies on a steeply cut spiral spline affair, and lots of initial armature inertia (aka torque to to kick the pinion gear out), during a low or lower voltage scenario, they will sometimes not do this.
In such a scenario, we're left with a starter motor that spins..... but may not kick the drive gear out.

You guys that are having good luck with these are no doubt keeping your battery banks and cables healthy.


BTW, I don't necessarily think that there's anything difficult about over-hauling a Bendix starter motor...., they're actually quite simple in design.
I've over-hauled quite a few of them in their days..... I've even pulled the Bendix units apart, cleaned them up, greased them, and they work just as intended.

Guys...... I have no dog in any fight here...... just say'n!


.
 
To update all who have helped on the progress. The new battery cables came in yesterday. 45' of 2 AWG. The lugs are being delivered today so I should have her ready for a test by early next week. Crossing my fingers to see what happens. When removing the old cables, I found some to be marine and some automotive, ie not tinned, with some corrosion creeping into the jackets including the grounding cables. I'll update as soon as I have an outcome.
 
dawilson76 said:
To update all who have helped on the progress. The new battery cables came in yesterday. 45' of 2 AWG. The lugs are being delivered today so I should have her ready for a test by early next week. Crossing my fingers to see what happens. When removing the old cables, I found some to be marine and some automotive, ie not tinned, with some corrosion creeping into the jackets including the grounding cables. I'll update as soon as I have an outcome.
Click to expand...

Now you are on your way to recovery! Or at least a healthy baseline to test further!:cool:
 
This really has my attention. I'll check back very day or two to see what the problem really was. Always learn from posts like this.

Bill
 
I hate to toss a snake in the pudding, but even IF bad connections WERE your problem, the starters might be fried from all that low voltage cranking. I hope not, but...

Jeff
 
Did you consider the advance on the timing? If ti too far advanced it may run fine the starters will drag and be almost impossible to stare when hot!
Bob
 
Thanks for the warning Jeff. I hope not as well but knowing that at least I won't be totally frustrated if all doesn't go well. The cable assembly is coming along faster than anticipated so I'm purchasing the 2 new start batteries this morning to wire in this afternoon. Should be ready to test tomorrow or Monday.
Bob the timing was checked when i was initally trying to figure out the problem. My thoughts too. If the timing were too advanced then spark would be on upstroke of piston making it very hard to start. But that wasn't the problem.
David
 
dawilson76 said:
My thoughts too. If the timing were too advanced then spark would be on upstroke of piston making it very hard to start. But that wasn't the problem.
Click to expand...
Dave, spark always occurs on the upstroke. It's the degree of spark lead to crankshaft angle that can cause what some refer to as "bucking".... and that can cause a starter motor to fight hard.
So yes, using a BASE that is conservative will certainly help.

However, note that any change or reduction to BASE (for a mechanically advaning ignition system), is also the same identical change or reduction to your progressive and total advance.
If the starter motors are fighting too much BASE lead, then you may need to open up the advance limit, and reduce BASE.
 
I've got good and bad news. Good news, success!!!!, the starters spin like they never have before. The bad news, I don't know which component changed out fixed the problem. Almost everything but the starters was replaced. Batteries, cables, connections, solenoids, coils, all grounds, battery switches, etc. I'm overwhelmed by all the help and advice provided and thank everyone who contributed for the input. I wish I could point to a particular solution for the problems I was having in case anyone in the future experiences the same symptoms but i'm impatient sometimes and went to an entire system upgrade instead of troubleshooting one by one. Result, no real data to contribute but a fantastic running boat for now. Thanks again.
David
 
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