Car Starter Motor

[Doc Sprocket]

Will they hit the same RPM with a load? (honest question- I don't know)

 

[anderkart]

Not while cranking an engine but I'm thinking it'd have enough torque to wind out pretty good on a light kart. Heck its got 5" tires, this must be a micro kart.

 

[gokartmozart]

Yeah, it may move a car, and I have known people to move their broken cars off the road by cranking with the car in gear. But, remember there is a 1:12 gear ratio there.

I know just from experience, talking to a hot rodder here, that rotating a mild compression six cylinder engine with a wrench takes quite a bit of effort. Those little starters got some kick.

But, know one has a idea of good starting gear ratio?

 

[devino246]

Yeah, it may move a car, and I have known people to move their broken cars off the road by cranking with the car in gear. But, remember there is a 1:12 gear ratio there.

I know just from experience, talking to a hot rodder here, that rotating a mild compression six cylinder engine with a wrench takes quite a bit of effort. Those little starters got some kick.

But, know one has a idea of good starting gear ratio?

It moved my car in third gear.

Just remember that automotive starters and batteries are only designed to crank for 15-30 seconds. Starters get pretty hot after repeated cranking.

 

[Bluethunder3320]

it can move a car in gear????? is that even possible???? wow. i would go for a 5 or 6 to 1 ratio or somewhere around there...

 

[devino246]

it can move a car in gear????? is that even possible???? wow. i would go for a 5 or 6 to 1 ratio or somewhere around there...

Only on older cars that lack a neutral safety switch. Newer cars have a switch in the transmission that disables the stater when in gear and doubles as a backup light switch.

 

[Bluethunder3320]

Only on older cars that lack a neutral safety switch. Newer cars have a switch in the transmission that disables the stater when in gear and doubles as a backup light switch.

yea, im just suprised that a starter has enough power

 

[devino246]

yea, im just suprised that a starter has enough power

Engines arent easy to turn over.

 

[Doc Sprocket]

Torque, and gearing, baby! Those things can draw a lot of current.

 

[devino246]

Those things can draw a lot of current.

Which is why a battery that can crank for 15 seconds is considered "good".

 

[Doc Sprocket]

Crossing topics with another thread, every now and then the clutch seizes on the Ford 575 tractor, and I have to start it in gear.

And since you're wondering (and I know you are), I cruised an old tractor forum- very common on those machines. Crappy design. Basically, you have to get some speed, then while holding the clutch pedal down, mash the brakes sharpy a few times 'till it breaks free.

Back to the torquey starters thing, not only does your average starter have enough oomph to push a vehicle, it can often do it quick enough to start the engine while doing it.

Years ago, I was driving my 1977 Celica home from my parents place, and the clutch slave blew out in an intersection. I made the 30 minute drive home with no clutch, partially by starting the engine in gear.

 

[devino246]

Crossing topics with another thread, every now and then the clutch seizes on the Ford 575 tractor, and I have to start it in gear.

And since you're wondering (and I know you are), I cruised an old tractor forum- very common on those machines. Crappy design. Basically, you have to get some speed, then while holding the clutch pedal down, mash the brakes sharpy a few times 'till it breaks free.

Back to the torquey starters thing, not only does your average starter have enough oomph to push a vehicle, it can often do it quick enough to start the engine while doing it.

Years ago, I was driving my 1977 Celica home from my parents place, and the clutch slave blew out in an intersection. I made the 30 minute drive home with no clutch, partially by starting the engine in gear.

Sweet! Your starter must have been trashed.

 

[anderkart]

But, know one has a idea of good starting gear ratio?

Bottom of page 2...

 

[gokartmozart]

I can easily mount this starter with a 1:2 (I have some sturdy cam gears) once I fab up my kart. So I will consider it a kinda experiment. With only small 5 inch wheel it should rock.

 

[anderkart]

Cool, I'm still not sure how many rpm that starters gonna turn, so yeah gear it with what you've. I think this is a cool project!

I'd start out with some short rides and feel how hot your starters getting, If yer fingers start sizzling like bacon you'll know its probably time to let-her cool down a bit

 

[Doc Sprocket]

Sweet! Your starter must have been trashed.

Not at all. Over the whole trip home, I think I started in gear twice. A few times I was able to slow down well ahead of a red light long enough for it to turn again. One stop was on a downhill slope to I was able to start rolling forward in neutral and nudge it *gently* into first.

Without a clutch, upshifting is pretty easy. Downshifting is a tad more challenging. But being able to start rolling and nudge it into gear without grinding amazed me. Downshifting into first was a little tricky, too. It's all about matching engine RPM to wheel speed.

 

[gokartmozart]

Once my engine siezed and I cranked on it a few times, and after I rebuilt the engine I thought I had a battery issue. I kept jumping the car, and once I got a new battery I realized the starter was not functioning at 100%. So, I guess a starter can become less efficient, or shot. I mean the starter still cranked but not with the effort it had.

Just sharing my starter knowledge/experience.

 

[Doc Sprocket]

Sorry, we kinda meandered away from the topic. I do think this is a case where it's best to gear it with what you've got, and do some seat-of-the-pants testing, then adjust ratios to suit.

 

[fowler]

just on the over heating thing.
in a davesfarm vidio he says removing the solinoid on a starter makes it better for kart use.
i dont know if this is relivent but it might be the reason it over heats.
also when i bulit and raced electric karts at school one other team put there engine in a modifyed esky and filled it with dry ice to finish the race (not the most practical idea or the cheapest but a surgestion)

 

[devino246]

just on the over heating thing.
in a davesfarm vidio he says removing the solinoid on a starter makes it better for kart use.
i dont know if this is relivent but it might be the reason it over heats.
also when i bulit and raced electric karts at school one other team put there engine in a modifyed esky and filled it with dry ice to finish the race (not the most practical idea or the cheapest but a surgestion)

Dry ice isnt very expensive. A good size chunk is like $8