<VV> Maybe the starter.

[Hugo Miller]

I question everything. That is the only way to get at the truth. I know 
there is often a problem with starters acting as though the battery is 
flat when they get hot, despite working perfectly when cold. So does 
everybody else on the internet it seems - I have found no end of 
references to the "well known hot start problem" or "the well known 
starter heat soak problem". What I have yet to find is a definitive 
explanation of the physics behind it. The most plausible suggestion so 
far is higher resistance across the solenoid. But many starters do not 
have solenoids, ad I am not convinced that accounts for the phenomenon..
I do not see anything to commend accepting without question the first 
suggestion anybody puts forward, whatever the topic under disussion. 
This is supposed to be a forum - a place for the exchange of ideas, and 
if you take exception to that, it is your problem not mine.
One thing of which I am quite certan that this phenomenon is nothing to 
do with mechanical friction, whether in the starter or in the engine, 
despite what others on here have suggested. I cannot conceive of 
anything which would make any such friction vanish when everything cools 
down. And the notion that a heavy diesel engine with over a million 
miles on the clock would be so tight at normal running temperature that 
a massive 24 volt starter cannot even turn it over - well that is 
frankly laughable. I am equally certain that an engine at normal running 
temperature will take less effort to crank than a cold engine. I thought 
that was universal knowledge, so obvious that it wouldn't need stating. 
The Wehrmacht found that out to their cost at Stalingrad.
I did once buy an Aston Martin that would sometimes refuse to turn over 
when cold because the main bearings were so tight. But if you could get 
it started from cold, it would start - and run - happily once warmed up. 
Somebody had just rebuilt the engine, and had used the wrong thickness 
main bearing shells.



On 2020-08-08 18:11, Jim Becker via VirtualVairs wrote:
> You asked a question on a subject that you admittedly know nothing
> about "I would like to know why this happens - all I know is it DOES
> happen." Several people replied with reasonable, well thought out
> explanations and proven fixes based on their first hand experience.
> You have chosen to argue with everyone's explanations.  This is in
> spite of your initial claim and subsequent demonstration of no
> knowledge on the subject.
>
> Do you ask questions just so you can find someone to argue with?
>
> Too bad our Delco starters aren't made in England.  Then, rather than
> failing when hot, they would fail at random and you could fix them
> with a hammer.
>
> Jim Becker
>
>
> -----Original Message----- From: Hugo Miller via VirtualVairs
> Sent: Saturday, August 08, 2020 2:53 AM
> To: virtualvairs at corvair.org
> Subject: Re:  Maybe the starter.
>
> Are you saying a hot engine is harder to crank than a cold one? Thats 
> a
> novel concept. Unless it's on the point of seizing of course!
>
>
> On 2020-08-08 05:16, H Smith via VirtualVairs wrote:
>> I am surprised that more of you haven’t experienced the worn 
>> bushings
>> and dragging starter syndrome.  As stated by others the bushings 
>> wear
>> to one side due to the load of cranking against the starter/ring, 
>> gear
>> the same direction all the time.  At this point I realize I am going
>> to run afoul with those that believe a cool engine cranks harder  
>> than
>> a hot one.  In a hot engine the parts have grown to their maximum
>> dimension.  Pistons are bigger, rings have grown in length.
>> Everything in well lubed and oil has closed tolerances .  In the
>> starter the armature moves sideways into the worn area of the
>> bushings.  It starts to turn and runs into the marginally heavier 
>> load
>> of the hot engine.  Due to the worn bushings it is running closer to
>> the field.  It starts drawing a ton of current from what is a 
>> normally
>> well charged battery.  More magnetism than normal which snatches the
>> armature solid sideways against the field coil. It’s not going to 
>> turn
>> till the key is released or the battery goes dead.
>> I request that if anybody wants to challenge this that they pull
>> their starter and look at the drag marks on the field cores and/or
>> armature cores where they have been rubbing together.
>> This is not to say that a bad solenoid ,corroded battery clamp, or
>> other connection can’t exhibit similar side effects   Smitty
>>
>
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