VansAirForceForums  
Home > VansAirForceForums

- POSTING RULES
- Donate yearly (please).
- Advertise in here!

- Today's Posts | Insert Pics


Go Back   VAF Forums > RV Firewall Forward Section > Traditional Aircraft Engines
Register FAQ Members List Calendar Search Today's Posts Mark Forums Read

Reply
 
Thread Tools Search this Thread Display Modes
  #1  
Old 11-07-2012, 08:56 AM
William William is offline
 
Join Date: Nov 2006
Location: Tampa, Florida (KVDF)
Posts: 491
Default How many tooth flywheel do I need for my Lycoming O-320-B2A?

I have a Lycoming O-320-B2A with the stock starter and I'm in need of the flywheel/pulley assembly. I'm not in my hanger to count the number of teeth on the starter, but I need to know how many teeth are on the starter to go with a 149 tooth flywheel, and 122 tooth flywheel respectively. SO when I get to the hanger I can count the teeth on my starter so I know which flywheel assembly to buy. Thanks in advance for your help.

Bill

Last edited by William : 11-07-2012 at 06:03 PM.
Reply With Quote
  #2  
Old 11-07-2012, 07:04 PM
John Ciolino John Ciolino is offline
 
Join Date: Jan 2006
Posts: 51
Default

Quote:
Originally Posted by William View Post
I have a Lycoming O-320-B2A with the stock starter and I'm in need of the flywheel/pulley assembly. I'm not in my hanger to count the number of teeth on the starter, but I need to know how many teeth are on the starter to go with a 149 tooth flywheel, and 122 tooth flywheel respectively. SO when I get to the hanger I can count the teeth on my starter so I know which flywheel assembly to buy. Thanks in advance for your help.

Bill
Bill,

The starter should have the "pitch" indicated on the data plate. A 10/12 pitch fits the 122 tooth flywheel, a 12/14 pitch fits the 149 tooth wheel.

John Ciolino
RV-8
N894Y
Reply With Quote
  #3  
Old 11-08-2012, 06:11 AM
William William is offline
 
Join Date: Nov 2006
Location: Tampa, Florida (KVDF)
Posts: 491
Default

Hi John thanks for the information, that is exactly what I needed to know.

Bill


Quote:
Originally Posted by John Ciolino View Post
Bill,

The starter should have the "pitch" indicated on the data plate. A 10/12 pitch fits the 122 tooth flywheel, a 12/14 pitch fits the 149 tooth wheel.

John Ciolino
RV-8
N894Y
Reply With Quote
  #4  
Old 11-08-2012, 06:46 PM
grub0927 grub0927 is offline
 
Join Date: Aug 2012
Location: Newberg, OR
Posts: 18
Default Tooth pattern

The 149 tooth (12/14) ring gear has a "U" shape to it and the 122 tooth (10/12) is more of a "V" shape. That's a simple way to figure it out.
Reply With Quote
  #5  
Old 11-08-2012, 06:54 PM
William William is offline
 
Join Date: Nov 2006
Location: Tampa, Florida (KVDF)
Posts: 491
Default

Thanks Grub0927 for the additional information.


Quote:
Originally Posted by grub0927 View Post
The 149 tooth (12/14) ring gear has a "U" shape to it and the 122 tooth (10/12) is more of a "V" shape. That's a simple way to figure it out.
Reply With Quote
  #6  
Old 11-09-2012, 07:44 AM
William William is offline
 
Join Date: Nov 2006
Location: Tampa, Florida (KVDF)
Posts: 491
Default

I checked the starter today and no pitch was indicated on the data plate. The starter has 9 teeth and they have a v appearance to me. I did get the following numbers off of the starter; does this help? I checked my lycoming parts manual and that was no help

Delco Remy 12V

model 1109657
serial 7385


thanks
Bill
Reply With Quote
  #7  
Old 11-09-2012, 09:29 AM
William William is offline
 
Join Date: Nov 2006
Location: Tampa, Florida (KVDF)
Posts: 491
Default

Ok I've narrowed it down a little. I know now I need a 122 tooth 10/12 pitch ring gear, but what pulley do I need? I have a Denso 12v alternator with the following part#18504-6220. The outside diameter of the pulley is 2 14/32" and the inside diameter of the pulley is 1 14/32" with a groove approximately 3/8". What diameter pulley do i need on the flywheel, the 1.91:1 or the 3.25:1?

thanks,
William

Last edited by William : 11-13-2012 at 07:44 PM.
Reply With Quote
  #8  
Old 11-13-2012, 12:36 PM
grub0927 grub0927 is offline
 
Join Date: Aug 2012
Location: Newberg, OR
Posts: 18
Default Pulley size

William,
The lower ratio drive (1.91:1) has the smaller pulley used with a generator and the higher ratio drive (3.25:1) is used with an alternator. It gets wonky because the older narrow deck engines had the V (122tooth) ring gear and had generators so they had the smaller pulley diameter and then newer wide deck engines had 149 teeth and alternators. (I'm sure there is some overlap so don't jump on me whoever you are that knows of an exception).
If you're going to stay with your current starter then find a 76628 ring gear support (ECI makes them as AEL76628) (large pulley) and have a Superior SL60882 122 tooth ring gear put on it. Lycoming Service Instruction 1141 tells you how.
Hope this helps. Grub
Reply With Quote
  #9  
Old 11-13-2012, 07:43 PM
William William is offline
 
Join Date: Nov 2006
Location: Tampa, Florida (KVDF)
Posts: 491
Default

Hi Grub,

Many thanks for your help. This has helped me greatly.

cheers,
William
Reply With Quote
  #10  
Old 11-13-2012, 10:13 PM
gasman gasman is offline
 
Join Date: Mar 2007
Location: Sonoma County
Posts: 3,821
Default

You might be better off with the smaller pulley on the flywheel if you are running an automotive alternator. Due to the fact that they have a much smaller pulley than aircraft alternators and you will be over speeding the alternator.

Look at the pulley that drives the alternator on your car. Your car motor lives under 2000 rpm most of it's life.
__________________
VAF #897 Warren Moretti
2019 =VAF= Dues PAID
Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -6. The time now is 05:17 AM.


The VAFForums come to you courtesy Delta Romeo, LLC. By viewing and participating in them you agree to build your plane using standardized methods and practices and to fly it safely and in accordance with the laws governing the country you are located in.