Group 2400-L Starter installation instructions.


Our ‘ultimate’ evolution of starter systems is the 2400-L  series. It was flight tested on the SPA/Panther early in 2015, and has since become the benchmark for simple, ultra-light, efficient and powerful starters for Corvairs. We have produced several hundred, and they are now our standard starter we recommend to every builder.


The great majority of flying Corvair powered planes utilize one of the Nippon Denso based starters we sold between 2002 and 2015. These are good systems, and they use the same basic starter design as most of the high performance aftermarket starters for Lycomings.  To justify a new generation of starters, the New 2400-L series would have to be significantly lighter, simpler to install, and be even more efficient. After a lot of R&D and testing, we met all these goals. The new starter is 3 pounds lighter, it has a very simple set up that takes only minutes, and surprisingly, it cranks the Corvair faster, while using less amps, and having a much lower voltage drop.  It meets these goals at a modest price increase over earlier systems.


We sell the system as a complete kit which includes all the items in the 2400 starter group. This is explained in detail in the conversion manual. The included items are the Starter itself, the mounting brackets, the Gold top cover, and the ring gear.  The direct link to see the kit for sale is here:




Above, The 2400-L system atop my own personal Corvair engine. The starter is powerful enough to crank any Corvair (Dan Weseman has one on his high compression 3.3 Liter Corvair: SPA / Weseman 3.3 Liter Corvair now running) on a very light weight battery.  The view shows how compact the unit is, the starter motor itself is smaller than a 12 ounce soda can. The starter above sports black powder coating that we put on some 2400-L starters for aesthetic reasons. The 2400-L kits are specifically made to mate with Weseman Group 3000 5th bearings.




Top view of a Corvair built in our shop, showing 2400-L starter arrangement. The black part is the starter motor, the silver part is the integral solenoid. The Top Cover, brackets, main starter plate, and the starter nose are all made on high end CNC machines here in the US, and for this reason they are very accurate and easy to set up.




Rear view of 2400- L starter on the dipstick side (Cylinders 1-3-5) of the engine. Because this starter has a very stiff 3/8″ think billet main plate, it does not need a tail bracket like our previous designs.  The mounting bracket on this side has a 7/16″ bolt fixed in it. This is the pivot bolt for the adjustment. On installation this bolt is snugged up just enough to still allow the starter to pivots for adjustment. After it is set, the nut is tightened to 45 foot pounds.




Above, the non-dipstick side (Cylinders 2-4-6) of the engine. This mounting bracket has a 3/8″-24 stud fixed in it. The main plate, seen in natural aluminum here, is actually sloted where the stud goes through it. This provides the adjustment for the mesh between the ring gear and the starter. Once the adjustment is set, the NAS locknut is torqued to 25 foot pounds and the unit will hold this adjustment for good.


Instillation sequence:

1) The ring gear is mounted on the Gold prop hub using the hardware that comes with the Gold hub. Most people paint the ring gear before installing it, other wise it will rust. Powder coating is not recommended, as it tends to fill in the valleys between the teeth and affect the mesh.

2) The gold top cover is mounted on the case with the twelve 5/16″ fasteners, each with a lock washer under the head. These need a light coat of anti-seize  (like ARP lube)  on the threads. The heads of the two fasteners which go under the starter must be the “button head” style provided, for clearance. The four starter bracket mounting bolts clamp the top cover, making the total fastener count sixteen, matching the number of holes in the top cover. The top cover gasket should have a thin film of Permatex ultra grey RTV sealer applied to each side. Before putting the sealer on, match the bolt pattern on the cover and gasket to the case, it is not symmetrical.

2) Each mounting bracket is held down by two 5/16″ bolts with lock washers under the heads. These bolts should have a light coating of anti-seize (like ARP lube) on the threads where they go into the case. They are torqued to 15 foot pounds. Bolt down the dip stick side, but leave the other side off for now.

3) The starter is mounted on the 7/16″ pivot bolt, and the nut is just snugged up to take out the slack, but still allow the starter to pivot. Using a pair of pliers gripping the starter gear teeth, pull the teeth forward to their extended position. Sick a small screwdriver behind the clutch ( the round part behind the teeth) to keep the clutch/gear teeth  extended forward.

4) Install  the non-dipstick side bracket on the main plate by putting the 3/8″ stud through the slotted hole in the plate. put the nut on lightly.

5) Pivot the starter down to meet the ring gear, and when it is close, install the two 5/16″ mounting bolts in  the non-dipstick side bracket.

6) Put a 1/16″ drill bit or welding rod in the valley between the two ring gear teeth where the lowest starter gear tooth meshes. snug up both the 7/16″ pivot bolt nut and the nut on the 3/8″ stud. Push the starter down hard enough to pinch the 1/16″ drill between the ring gear teeth and the starter gear tooth, so it cant be pulled out with bare fingers. Tighten up the nuts fully, pull the small screwdriver from behind the starter clutch. Rotating the ring gear slightly should cause the 1/16″ drill to come out, and the starter gear will automatically retract. The starter is now set.

7) The small 1/4 spade terminal on the solenoid is connected to the starter switch; the outboard stud is where the 12V battery cable connects.

8) You can judge a good gear mesh by the sound. It will sound just like your car cranking if it is right. If it is too loose it will make excessive metallic grinding sounds, it it is too tight, the starter gear will hit the back of the ring gear instead of engaging it. If you want to test it, make sure you do so with the spark plugs in to provide a full cranking load. Without them, even a very loose mesh will sound good. BE VERY CAREFULL WHEN THE STARER IS HOOKED UP – EVEN IF YOU DON’T HAVE AN IGNITION OR CARB INSTALLED.  A cranking starter, even if the engine doesn’t start, will turn a prop 350 rpm, this is plenty of power to inflict a fatal blow. Even if you have no prop on, be careful, having your hand or shirt sleeve near the gear, could draw your fingers into the meshing gears. Anytime you have a battery near the system, use your brain, pay attention.






Rear quarter view of the 2400-L starter system. It is an efficient, elegantly simple system.




About William Wynne
I have been continuously building, testing and flying Corvair engines since 1989. Information, parts and components that we developed and tested are now flying on several hundred Corvair powered aircraft. I earned a Bachelor of Science in Professional Aeronautics and an A&P license from Embry-Riddle Aeronautical University, and have a proven 20 year track record of effectively teaching homebuilders how to create and fly their own Corvair powered planes. Much of this is chronicled at and in more than 50 magazine articles.

5 Responses to Group 2400-L Starter installation instructions.

  1. Jeff Moores says:

    Hi William,

    for those who have a flying engine and would like to convert to the new starter, can the starter with brackets be purchased without the ring gear and top cover?


  2. henka says:

    Hello, In automotive, there is the design rule for starter solenoid that B connector shall be above and M connector (to motor side of starter) in the lower position. But I cannot say if that rule can apply your aircraft application – probably if you have a battery switch.

    • Friend,

      I can understand the idea, but I have not heard of such a standard being applied to aircraft. As you point out, unlike cars, the master solenoid in a plane can disconnect the main positive cable to the starter. -ww.

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

%d bloggers like this: