PyjamaSam

Well My car experences this "problem" and I found out yesterday that at least on my car that if you boost the car the Starter turns right over. So that leads me to think that I might have another problem. Maybe with the alternator. More Current = More Starter when it is hot. So based on that I am now assuming that starter is reasionably good and I am starting to look at the electrical system to make sure that is ok.

Just some more info for everybody. Hopefully it might help sombody.

chris.

Larry B.

I have never had a "heat soak" problem on any corvette I have owned but then I do not run headers...

73Ken73

Buy a mini-starter and you will never have any starter problems. I had a heat soak episode only once with my old full size starter. It was about 95 degrees outside and I had driven about 100 miles, a cup of Burger King ice dumped on the starter did the trick.

daily_driver

your saying boost the current and youll get it started ehh??


thats the whole heat soak "myth" as you call it....

resistance changes and thus current does. (V=IR)

as it gets hots the resistance changes....

i cured my heatsoak by installing dynomax ceramicoat headers and thus drastically reduced my engine bay temps and the temps next to the starter...

with the old stock manifolds i went through 4 startes!! with these dynomax ceramicoats i have had this starter for 2 years and never once has it not started..

:)

Cookwithvette

Just wanted to add, while cranking the alternator contributes nothing.

Milest

I would have a look at the battery cables and the wiring to the starter.

Tom454

"More Current = More Starter when it is hot"

More VOLTAGE to over-come the increased resistance due to heat maybe... and therefore the SAME current as would be normal.
If both V and R go up, I will stay relatively constant.

In a typical "hard start" situation, the voltage stays constant (or drops slightly), and the resistance goes up, the current goes down.

I don't think you have a "heat soak" problem though.

Maybe a weak battery and/or alternator (low charging voltage when running) or both.
RE: The myth... in 75 + degrees my 70 LS5 454 gets harder to start as the day goes on, but only when it is very hot outside.

My 66 SB with sidepipes never has this problem. The starter never has a lazy day. So... I put the 66 starter on my 70 and guess what? It does the same thing as the 454 starter.... gradually turns slower & slower as the day progresses.... heat soak.

The wiring in the 454 is in perfect condition.... when the car, engine, and outside temp is below 75, I have no starting problems.
You be the judge.
As mentioned, there is no hard, fast rule... depends on which engine you have and what kind of exhaust system you are running.

One final note.... DC resistance and impedance are not the same thing. When you get into electric motor theory, there are a lot of funky things going on with the windings and magnetic fields... so it's not all pure DC rules that apply.

Check the output voltage of your alternator with an accurate voltmeter... it should be 14.5 when you switch on the headlights to cause the regulator to kick in.

Check the specific gravity of all cells in your battery with a good hydrometer.... they should all be high, and the same.
If one cell is low... it could be shorted internally and this could cause a hard start problem.

Vetterodder

Heat soak is real but many people don't understand what it actually means. As already posted, as the current's path heats, the resistance to flow is increased and requires more power to compensate. That's what you saw when you jumped the car. The purpose of the solenoid is to prevent power going to the starter unless there is enough power to turn in. Without a solenoid, the starter might just hum and burn itself up if there wasn't enough power to turn it. With heat soak, the problem isn't that the solenoid is getting too hot to function, it's the heat of the starter, and also the cables going to it that reduces the amount of current that the starter gets. Often as not, it's a combination of problems that causes that click instead of turning over. A battery may have just enough power to start a cool engine but not enough to compensate for the increased resistance in the starter and/or cables when hot. Also, the power a starter requires will increase with wear and, at some point, it's needs will exceed the power available from the battery. Again, there might be enough battery to crank it when cool but not when hot. Very often, a "heat soak" problem will we be solved by replacing any one of several components. A new and more powerfull battery may overcome the increased resistance of a worn starter, poor electrical connections, or whatever the real problem is. A new starter might reduce draw enough that a marginal battery will now start it just fine. In many cases, guys have solved their problem by replacing a perfectly good starter or battery! The "fix" was made by correcting a bad connection that they didn't know they had (and still don't know) in the process.

Another issue is the battery and how it's normal for their power to gradually dimenish over time. It's always obvious when a battery downright fails but many don't realize that, even if something doesn't outright kill it, they do lose power over time. A 800 amp battery only has 800 amps when it's new. A year later it might have 700 amps and so on. It still takes way less than that to operate the starter so there's no problem until it's power drops to a point below what it takes to operate the starter, or the draw of the starter increases to beyond what the battery can deliver.

Tom454

The definition of a solenoid (as opposed to a relay) is that some mechanical action occurs in a solenoid. By definition, a relay does not have a mechanical function.

Fords have a "relay" to switch the current, and a "Bendix" or "starter drive" to engage the flywheel. These are two separate devices. That's why a Ford has the relay sitting up on the fender well, and only a single heavy gage wire going to the starter.

A relay is a device that uses a low current control circuit to activate a high current circuit... sort of like an amplifier.

Chevys have a solenoid... a relay and a starter drive activator arm combined.
The purpose of the solenoid is to provide a high current switch, and to engage the flywheel (thus... it's a solenoid, not just a relay).

The solenoid has a coil in it that creates an electro-magnet that causes an iron core to shift position... this movement does two things...
One: connects the large battery cable to the starter (relay)
Two: moves an arm & fork that forces the drive gear to mesh with the flywheel.
The solenoid coil draws far less current than the starter field windings and armature windings. This is the "relay" function.

There is no "speed regulation" taking place within the solenoid.
It is a simple switch... connects the high current battery wire to the starter motor.
I run starter motors on my bench regularly for testing purposes.

I never have to run after them. :)




[Modified by Tom454, 8:24 PM 7/28/2002]

daily_driver

arrghhh dammit u beat me too it

:mad :mad

:lol: :lol:

Stephen Irons

I had this problem on my 78 a few years ago. It began to happen intermitently, but always depended on how hot the car had become. On colder days (lets face it, that's a lot over here!) it sometimes never manifested itself. And sometimes, I could actually get over it simply by not putting my foot on the brake when starting, therefore giving it just that little bit more current instead of lighting the brake lights! Friends with a similar problem allso found that pouring cold water in the starter would cure it! (water+ electrics :eek:, but it seemed to work)

I had the starter re-built locally, which included the fiting of a new solonoid, and cost about 10% of what a new starter would have:)). The starter was pretty tired anyway, but it did give me a chance to clean up terminals and connections etc. Since then I have had no problems, even on some very hot days down in France.

I'm guessing it will be a problem of the past now, as last year I went back to the cast manaifolds and single downpipes in place of the headers....

Everything that Vetterodder said seems to align with my experience. Gien th esevere aggravation of getting stuck withe an auto and no starter, I'm glad I "bit the bullet" and got it re-built.

Woodstoc

Check your neutral safety switch.