Engine starts, but won't restart, starter sheared off

[dalefox]

This is a strange one. My 280 with a 454 starts great when cold and runs great all the time. But once it's been driving for a few hours and is good and hot, there's major trouble when trying to restart the engine. From time to time, when you start the engine, the starter gnashes and makes a horrible sound. My mechanic was under the vehicle and said the actual starter was torquing around and moving way too much. So we replaced it with a new one. On my maiden voyage with that new starter on the engine, I turned off the car after driving for a half an hour and immediately went to restart it. When I turned the key, there was a nasty gnashing sound. Tried again and again and still gnashing but no proper cranking. It turns out that the starter casing had sheared off entirely and the pinion was no longer aligning with the flywheel. So we replaced the starter again. Yesterday, while en route from LA to SF, we turned off the AS at a gas station and it simply wouldn't restart. No gnashing, no sound, no nothing. When you turn the key, absolutely nothing happened. There was good power to both battery systems. We were perplexed and about to call for help. We waited nearly 90 minutes and tried again. Presto, it started up perfectly.

This isn't the kind of reliability I'm looking for. Any idea what could be happening here? I'm about to head to Burning Man and am terrified of getting stranded in the desert!

Thanks, guys (and girls...).

/dalefox

[overlander63]

Many GM engines with the starter you have use a starter shim between the block mount and starter. If this is supposed to be there and isn't, it will cause a really bad grinding sound when you try to start it.
If this is not the problem, you may have a bad starter to battery (main) lead, a bad wire from the ignition switch, a bad ground to the battery or engine, a bad or misadjusted neutral safety switch.
Most people replace them with new starters, but have you replaced the starter solenoid? There is also supposed to be a metal shield over the solenoid, to keep the exhaust from baking it. Is it still there?
Another thing to check is the base ignition timing, if it is too far advanced it will cause the engine to crank slowly, and I have seen overadvanced ignition timing shear the end of the starter off.
I have replaced the OEM-style GM starter with a replacement from a mid 90's Corvette (it is reduction gear, and will spin more freely) with good results. You will need different starter mounting bolts for this, as the replacement starter needs shorter bolts.

[dalefox]

Great suggestions. The starter isn't gnashing anymore. Definitely properly shimmed. My concern is the complete lack of response from turning the key once the engine is hot. The only thing I could think of that could be the answer is if the solenoid is overheating. I did notice that it's mounted on the outside of the battery box...which is near the exhaust. But could that cause intermittent failure to start??

[overlander63]

Originally Posted by dalefox

Great suggestions. The starter isn't gnashing anymore. Definitely properly shimmed. My concern is the complete lack of response from turning the key once the engine is hot. The only thing I could think of that could be the answer is if the solenoid is overheating. I did notice that it's mounted on the outside of the battery box...which is near the exhaust. But could that cause intermittent failure to start??

From the above description, you seem to have two starter solenoids. The main one should be mounted directly on top of the starter, with a minimum of 3 wires going to it. One should be battery +, another one on the same lug should be power feed to the chassis, and the third should be to engage the solenoid.

[richinny]

the longer, high torque starters, should have a metal bracket from the starter to the engine block to keep the starter from shifting. were the teeth on the flywheel examined for damage and wear? a test light will help you track where the power is/isn't going. make sure the engine ground strap is intact and well grounded. if you get no responce from the starter in park, try starting the engine while in neutral.

[mustang]

If your starter works when it is cold but grinds or free spins when it is hot It is you bendix spring. Just that simple. A new bendix comes with a starter/ selenoid combo. If it grinds all the time it is your ring gear on the flywheel with a flat spot. Flywheel needs replaced. IT hardly makes sense to replace the bendix without doing the starter selenoid. Stock is fine. The starter is only operating for a short time.(during startup) Trust me its the starter bendix. Replace it and you will be fine. (before your trip) And check the rear support bracket the starter shouldnt move at all

[dalefox]

Thanks for the suggestion, Mustang, but it's not free spinning when hot. It's just doing nothing. No sound, no vibration, nothing. I'd suspect the solenoid, too (yes, overlander63, there are two--one on the battery case and one on top of the starter. aren't they all built that way?), but the solenoid mounted on top of the starter was replaced along with the starter, as you'd expect. And the solenoid mounted to the battery case isn't anywhere near a heat source. So I don't know why it would only choose to misbehave when the engine gets hot...

[axleman]

Big block Chevrolets are famous for this!

Answer - remote starter solenoid and starter heat shield!

Both can be purchased from Jegs or Summit!

Best Regards,
Henry

[mustang]

I thought it was grinding. I missed replaced and now I got it. I am assuming that the guy that replaced your starter cleaned all connections. The selenoid should have gotten replaced with the starter. You may have gotten a bad starter. second time around (that would be my luck) better luck to you. Dont risk getting stranded in the desert

[Geophilist]

Dalefox,

Listen to Axleman. I have a 280 that does the same thing. Have you tried to push the switch to bring in all three batteries on line to start the thing?

I am in the process of doing what Axleman suggests as part of a new exhaust system install.

Steve

[overlander64]

Greetings Dalefox!

My 8.2 Liter Cadillac V8 in my Eldorado tow vehicle experienced the same difficulties. The final solution on mine included the heat shield for the starter along with a seasonal adjustment to the Exhaust Heat Riser Valve that would typically freeze in the partially closed position signficantly increasing the temperature underhood and along the firewall partially cooking the starter motor causing slow or no cranking. In addition (two years ago), a heavy duty motorhome starter was installed along with a new flywheel as there were several "deadspots" on the original flywheel.

I held my breath at every fuel stop this summer, but the starter performed flawlessly throughout my 3,500 mile tour of the Western US towing my Argosy.

Kevin

[dalefox]

Thanks, Kevin, Axleman and all. So I think my conclusions are as follows:

1. The sheared off starters were/are due to high compression in the cylinder that the starter couldn't overcome. As a result, it torqued and sheared off the housing. The solution is to retard the timing a bit so there's less compression to overcome before TDC.

2. Get a remote solenoid setup and reinforce the heat shielding around the starter. What an amazingly pitiful design flaw!!!

Anything else I missed?

Ps, just a quick shot my baby mid resto. New sink and throne in place!

[Silverhobby]

I tow part time with a 1979 GMC equipped with a 454. The heat shield is the main culpret in the starting problem. A friend also had a problem with a 350 Chevy V-8 in a class C motorhome. Best of luck, and have fun at Burning Man.

[HowieE]

If you are still having problems when the engine is hot but starts normally when cold. Remove the ground wire or wires on the engine batteries and check the main battery terminal on the starter for tightness. This terminal frequently loosens over time because of the expansion and contraction of the copper stud. Be careful and don't over tighten the nut because the stud is only held in the solenoid by cast plastic and will spin free if over tightened.

This loose condition becomes an open circuit to the high current draw of the starter. Ever thing will GOOD with a voltmeter at the stud but it will not pass current and start the engine.

Not sure why this showed up on the replacement starters so soon but it is very common on GM truck starters. This is a completely separate problem from the mechanical failures you had

[mustang]

One thing I might add retarding timeing wont change compression it will change when cylinder fires. Stay with in spec. How High is the compression? Your still running pump gas right?

[dalefox]

Mustang, you're right. Hadn't thought about that. I was imagining valve timing, which would have an issue, but I'm sure that's set right. Hmm. So why is the starter shearing off twice in a row?

Here's a question: the starter we have mounts with only two bolts into the block. But it seems like the block has room for an extra bolt hole.

Does your starter connect with two or three bolts to the block??

[mustang]

I Know it was mentioned earlier in the thread but sometimes shims play a roll, less shims would put the gears deeper together when starter is accuated. I have seen starters both ways 2 up front and 1 on a bracket at the rear for toque issues. or it may be that 1 of the old starters ground down the gears to the point that you need a new ring gear (flywheel). If the engine cranks hard timeing could be to far advanced but if it was set before it should be fine. I deal with High compression Raceing engines, and then only time I have burned up starters is when I bumped my compression over 15:1 I had to go with a gear reduction starter. The starter should not move once mounted, it becomes part of the block and will only move with the block, unless something is wrong. Really look at it. If you need to remove a shim try it, the only thing that will happen is the gears wont mesh right and you will get a grind. There is a possibility that threw all these starter swaps you got 1 with a weak bendix spring, or your battery is weak causing ampres drop.

[Mexray]

Had an old suburan with a 454 and had the same problem...

Solved it with a cheapo 12 fan for a boat that you could attach some flexible ducting to...aimed the outflow right at the starter...it ran all the time the engine was running...I used a three way switch so I could turn on the fan without the ignition to cool the starter after shutdown, etc...

Heat shield sounds like a winner also...

I saw I guy in Mexico take a funnel with a hose attached that was aimed at the starter...he carried a jug of agua, and poured some down the funnel when the thing was hot...seems there's always a 'cure' down there below the border....

[mustang]

I just cant beleve these units came out of the factory like that, or needing that. It sound hokey. This problem didnt develpoe over night. If Airstream put a 454 in a motor home or chevy put it in there suburban. Why all the rigging to make it work? They spent countless engineering hours and time testing these rigs. Baffles the heck out of me. I would fall over if I took my SuperDuty back to Ford if it overheated and they put a fan on the starter. I would say tell that to the jury with a straight face.

[Geophilist]

Dalefox,

My starter is a two bolt setup. As we have the same model and year, they may be alike.

Steve