Racing Engine Starter 1

[ed911]

I am looking for details on the detached type of starters used on some race cars. I'm interested in the connection to the engine and disconnecting once it starts. Anyone know where I can find info? Thanks.

 

[thundair]

Basically it is a starter with a dog bearing or a clutch bearing that allows torque input from a unidirectional way the other rotation will freewheel after the engine starts. These bearings are very costly and I think they are torque rated. The drive input can be a simple spur gear but ratios will come into play as you design, or better yet engineer the requirements.


Cheers

 

[BCjohnny]

Not quite sure what you're referring to by "detached".

Do you mean "disengaged"?

If you could give me more info I could possibly help further.

My past customers have included some well known Race-Car manufacturers (Formula cars, Indy etc).

Most common race type starter motors are based on production units. Very few are bespoke. And they "live" quite well, unless vibration gets to them.

John.

"It's not always a case of learning more, but often of forgetting less"

 

[notnats]

I am probably living in the past, but I always thought that when the starter called "Gentlemen start your engines", they used a big electric drill with a starter handle one way dog clutch fitted to it to turn the old offenhausers over

 

[ed911]

BCJohnny - by "detached" I mean not permenately connected to the engine. I was just looking to find out how, once the engine starts, the starter disconnects so it can be taken away.

Ed

 

[rd400guy]

Since the "clutch" only applies torque in one direction, as soon as the engine turns over, the starter can just be pulled off. As for the actual connection, I'm guessing it's just some sort of spline.

FWIW, I start my B&S lawn mower engine with my power drill ala the racing starters you speak of (very old mower - starts hard). I cut the rope recoil mechanism and a 7/8" 12-point socket fits right on the starter clutch shaft. Spin up the drill, and once the engine's running, I just pull the drill off. However, if for some reason it doesn't fire up, there's a hell of a kick-back, if I leave the starter (drill) on too long.

 

[patprimmer]

Have I missed something here.

To me it seems so obvious that it was difficult to take the question seriously.

The basic principal was used on crank handles used to start 19th century motors.

A simple dog clutch with an undercut on the drive faces to hold it in mesh, and a ramp on the over run side to throw the clutch out of engagement and a spigot in a bore to keep it aligned.

Regards

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[sprintcar]

Indy and F1 cars use a special aircraft starter modified to engage the external shaft on the transaxle. Old indy roadsters had the adapter on the front of the crankshaft snout, so the starter shaft came thru the nose of the car.

I've got one for the sprint car that bolts on the quick change rear end and spins the driveshaft. This is only good for starting in the shop since we normally we push start these cars on the track.

BERT transmission has a line of small on board starters for race applications. The biggest problem (besides weight and the battery) has been the diameter of the flywheel/ring gear which prevented lowering the engine or using rear cam drive pumps. BERT uses the gear reduction high torque starters and small ring gears. They work well.

"If A equals success, then the formula is: A = X + Y + Z, X is work. Y is play. Z is keep your mouth shut."
-- by Albert Einstein

 

[ed911]

Sprintcar - your reply about using an aircraft starter is interesting since I was looking for the info to apply to an aircraft starter application!

Thanks to all the useful posts. The only objectional reply is in the one about not taking this question seriously - it was a serious question to me, not having knowledge of everything in the world!

 

[BCjohnny]

ed911.....

What are you trying to start and how are you trying to start it?

Using an "aircraft starter" is one way, I admit. But they're expensive to buy, expensive to repair, and offer few gains above a correctly chosen geared starter of automotive origin...........

The only exception to this rule would be a diesel engine of say 16 litres or more. But even so commercial vehicles now have 24v geared starters that go 4.5kw and above......

It would take only rudimentary manuf/fabri. skills to attach a geared starter to a purpose built gear reduction unit (consisting of a train of gears housed in a suitably designed frame/enclosure) to achieve the reduction sought. To this the primary starter could be attached so as to be a single manageable unit. You just need to make sure you have an RCD or similar between the starting unit and the engine, and some method of "locking" the two together (in a quick disconnect fashion) so the thing doesn't hurl you into the next county.

A bit more information: engine capacity/cyls/comp.ratio, starter connection point etc wouldn't go amiss.

john.

"It's not always a case of learning more, but often of forgetting less"

 

[Fabrico]

Yes they are made from aircraft motors and are usually run on 24 volts. They have a simple dog engagement with ramped teeth instead of square, so over-running is not a problem. There is usually two alignment pins on the starter that go into a plate by the driven coupling to take counter-torque. Ones I have seen were perfectly round so they had to be planetary reduction. Been trying to find a picture, but no luck.