VansAirForceForums  
Home > VansAirForceForums

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

- Today's Posts | Insert Pics

  #1  
Old 11-12-2016, 02:52 PM
lowandslo lowandslo is offline
 
Join Date: Jun 2012
Location: So. Cal & AZ
Posts: 39
Default Vans tach dies

Only about 160 hours on it. Works great until it goes to zero. Works great next flight. Change the gauge or sender first? Anyone else already been through this? Thanks for any input.
__________________
flying RV4
building RV7
Reply With Quote
  #2  
Old 11-12-2016, 04:18 PM
jdiehl jdiehl is offline
 
Join Date: Jan 2011
Location: Williamsport, Pa
Posts: 146
Default Tach failure

During phase 1 I had a few of the vans gauges intermittently go off line. In the end, I took a closer look at the terminal crimps, grounding points, and tightness of the connections on the back side of the vans instruments. For the past 250 hrs, I haven't had any issues. Wiggle the wires and see if the tach gauge comes back on line.
As a side note, while flying, an audible whine would intermittently be heard. The frequency of the whine would change with rpm. I had a lot of concern as to where this noise was coming from. Answer: I removed the short tach cable and it was dry (no lube) on the inside. I added lithium grease and all is well.

Jim Diehl 7A
Reply With Quote
  #3  
Old 11-12-2016, 04:20 PM
Larry DeCamp's Avatar
Larry DeCamp Larry DeCamp is offline
 
Join Date: Apr 2010
Location: Clinton, Indiana
Posts: 524
Default Free replacement

I have a Vans tach and sender I no longer use. Its yours if want it. Total hours 28 on both units. I now have 2 Pmag and EIC for RPM.
Larry
765-505-1160
__________________
Larry DeCamp
RV-3B flying
RV-4 fastback project in the shop
Clinton, IN
Reply With Quote
  #4  
Old 11-13-2016, 01:22 PM
lowandslo lowandslo is offline
 
Join Date: Jun 2012
Location: So. Cal & AZ
Posts: 39
Default Thanks

Jim and Larry - thanks for the suggestions and offer of parts. It's been going on for a while with longer and longer durations of it dropping to zero so i checked the connectons. Everything seemed tight. The sender is mounted directly to the tach drive with no cable. I found it loose and tightened it. Still was intermittant so ordered both the gauge and sender from vans. Just trying to decide which to change first. Does Van recommend the cable to get the sender away from engine heat? Charlie
__________________
flying RV4
building RV7
Reply With Quote
  #5  
Old 08-14-2017, 12:14 PM
pa38112 pa38112 is offline
 
Join Date: Mar 2008
Location: Clarksboro, NJ
Posts: 443
Default

What was the outcome of this? My Vans Tach has started reading low and bouncing a little. The gauge is $48 and the sender is $88. I was thinking of starting with the gauge, but don't want to waste my time if the sender is a known failure point... 735 hrs on both.
__________________
http://aprs.fi/N153MC
2004 RV6A Flying
Reply With Quote
  #6  
Old 08-15-2017, 04:59 AM
mantry mantry is offline
 
Join Date: May 2014
Location: Bountiful, UT
Posts: 98
Default

This worked out to be the best suggestion for me:

http://www.vansairforce.com/communit...d.php?t=127086

I installed the 20K resistors and had it where the values would jump around and to the point where the tach though it was seeing a MAG completely drop out and display a MAG FAILURE. I switched to the 47K resistors and it has ben ROCK SOLID.

This is the: http://www.fdatasystems.com/t-30-tachometer/ Tach
__________________
Donation for 2017 complete! Thanks VAF and DR!
Reply With Quote
  #7  
Old 08-15-2017, 10:15 AM
dougknight dougknight is offline
 
Join Date: Jan 2006
Posts: 104
Default

Sending unit for me, twice. The shaft inside is to long (even if the unit seems loose). Feel the backside of the unit, if there is a bulge on it, the too long of shaft pushes the internal wheel out of alignment with its magnetic pick-up.

I have the proper length of shaft on record at the hanger if you want it I can get it for you. You can order replacement shafts from Van's and they will be various lengths, you have to get it right or it just happens again. Ask me how I know.

500 hrs since I figured it out with no problems.

hope this helps
doug

p.s. if it has reached the point of being intermittent it has stretched the housing and the whole unit needs replaced not just the shaft.
Reply With Quote
  #8  
Old 08-15-2017, 12:37 PM
pa38112 pa38112 is offline
 
Join Date: Mar 2008
Location: Clarksboro, NJ
Posts: 443
Default

Thanks! I ready your earlier posts on the subject and decided to check that before ordering any parts. I am away from the plane for a week, but will post my findings...
__________________
http://aprs.fi/N153MC
2004 RV6A Flying
Reply With Quote
  #9  
Old 08-15-2017, 01:25 PM
Canadian_JOY Canadian_JOY is offline
 
Join Date: Aug 2007
Location: Ontario, Canada
Posts: 1,402
Default

My solution was to purchase a 12" tach drive cable and use it to remotely mount the tach sender on the firewall. Went through two of the senders before realizing they really hated life when directly mounted to the engine. I've got about 250 hours now with the sender remotely mounted on the firewall and its working like a charm.
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 07:25 PM.


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.