VansAirForceForums  
Home > VansAirForceForums

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

- Today's Posts | Insert Pics

  #1  
Old 05-16-2018, 07:17 AM
lr172 lr172 is offline
 
Join Date: Oct 2013
Location: Schaumburg, IL
Posts: 3,120
Default Determining Prop Gov Drive Ratio on 540

I have a narrow deck 540-C4B5 that I am rebuilding. I have decided to have the accy cover modified and will be installing the later revision camshaft with the integral gear (too much pitting to grind). This leaves the question of whether I will have the lower, narrow deck gear ratio or the higher wide deck ratio for the prop gov.

The Cam gear drives an idler gear and the prop gov drive ratio should be based upon these two gears, but I can't figure out if the cam gear changed or the idler gear changed or possibly both between the narrow deck and wide deck versons. Does anyone know if one or both of these gears have a different configuration between the narrow deck and wide deck engines?

Thanks,

Larry
__________________
N64LR
RV-6A / IO-320, Flying as of 8/2015
RV-10 in progress
Reply With Quote
  #2  
Old 05-16-2018, 07:27 AM
Auburntsts's Avatar
Auburntsts Auburntsts is offline
 
Join Date: Jan 2005
Location: Dumfries, VA
Posts: 2,590
Default

I'd contact an engine builder like Allen Barrett at BPE to get the answer.
__________________
Todd Stovall
PP ASEL-IA
RV-10 N728TT - Flying!
WAR EAGLE!
Reply With Quote
  #3  
Old 05-16-2018, 07:56 AM
lr172 lr172 is offline
 
Join Date: Oct 2013
Location: Schaumburg, IL
Posts: 3,120
Default

Ok, Lycoming tells me that the cam gears are the same. Same # of teeth and same pitch. Therefore, something else in the arrangement accounts for the different ratios between wide and narrow deck. I should be able to assume that I will have the same drive ratio after the cam change.

This makes sense as lots of folks have had to go to the new cam and the service instructions do not reference a change in drive ratio.

I am trying to find SI 1439 that lists the details of the cam swap. However, I can't find it on the net. Does anyone have a copy of it?

Larry
__________________
N64LR
RV-6A / IO-320, Flying as of 8/2015
RV-10 in progress

Last edited by lr172 : 05-16-2018 at 07:59 AM.
Reply With Quote
  #4  
Old 05-16-2018, 09:20 AM
HFS HFS is offline
 
Join Date: Aug 2009
Location: Lemoore, CA
Posts: 230
Default Lycoming SI 1439

I have a hard copy, but dated at December 13, 1991. Don't know if there are later revisions.

David Howe
Reply With Quote
  #5  
Old 05-16-2018, 01:06 PM
lr172 lr172 is offline
 
Join Date: Oct 2013
Location: Schaumburg, IL
Posts: 3,120
Default

Quote:
Originally Posted by HFS View Post
I have a hard copy, but dated at December 13, 1991. Don't know if there are later revisions.

David Howe
Thanks David. I ended calling Lycoming and they emailed me one.

Larry
__________________
N64LR
RV-6A / IO-320, Flying as of 8/2015
RV-10 in progress
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 05:38 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.