Results 1 to 6 of 6

Thread: Will a 186 conversion kill a fairey overdrive?

  1. 26th November 2010, 07:04 AM #1
    pfillery
    pfillery is offline Master
    Join Date
    Sep 2010
    Location
    Qld
    Posts
    806
    Total Downloaded
    0

    Will a 186 conversion kill a fairey overdrive?

    I've heard from a few sources (on here as well as other places) that it is bad news to put a fairey overdrive on a vehicle with a 186 conversion as the motor is too powerful and revs too fast for it and will kill the overdrive very quickly.

    Is this true or does it depend on how it is driven? Does the diff ratio and gearing effect it at all?

    Logic says that a 186 engine and a landrover original 6 cylinder engine will be at the exact same revs when the car is travelling at a certain speed, since they are both driving the same gearbox, and after all it is the gearing that determines the speed the car goes at. If an overdrive reduces the revs, wouldn't this be kinder on the engine and the rest of the drivetrain?

    I'd like someone in the know to clarify this for me please. Are there any noteworthy cons to putting an OD on with a 186 and do they outweigh any gains?
    Reply With Quote Reply With Quote
  2. 26th November 2010, 07:21 AM #2
    Jeff's Avatar
    Jeff
    Jeff is offline Wizard
    Join Date
    Sep 2006
    Location
    Northern Beaches
    Posts
    1,426
    Total Downloaded
    0
    I ran one behind a very healthy 202 for years and never had a problem. I only used it as a fifth gear, not as a transfer case, and was mindful of it's strength, but used it for towing, and serious off road with 35" A/Ts and it went great. I think it is how you drive it.

    The only problem was the whine. The amount of noise it reduced due to lowered engine revs, was compensated by gear whine.

    Jeff

    Reply With Quote Reply With Quote
  3. 26th November 2010, 08:12 AM #3
    Lotz-A-Landies's Avatar
    Lotz-A-Landies
    Lotz-A-Landies is offline Super Moderator Gold Subscriber
    Join Date
    Jul 2006
    Location
    East-South-East Girt-By-Sea
    Posts
    17,662
    Total Downloaded
    1.20 MB
    Just remember to have the original constant gear and rear bearing support/cover plate in the vehicle's tool kit carried on board at all times.

    You won't find me on: faceplant; Scipe; Infragam; LumpedIn; ShapCnat or Twitting. I'm just not that interesting.
    Reply With Quote Reply With Quote
  4. 26th November 2010, 09:00 AM #4
    PAT303
    PAT303 is offline OldBushie
    Join Date
    May 2007
    Location
    Safety Bay
    Posts
    8,041
    Total Downloaded
    0
    I had one behind a hot rodded 186 and never had an issue,the noise was the problem. Pat
    Reply With Quote Reply With Quote
  5. 26th November 2010, 09:56 AM #5
    pfillery
    pfillery is offline Master
    Join Date
    Sep 2010
    Location
    Qld
    Posts
    806
    Total Downloaded
    0
    So with lower revs, assuming one uses it as a 5th gear only and not as a constant thing, would it be expected to reduce fuel consumption considerably? The noise doesn't really bother me, I like the rough ride, the lack of all but basic comforts and no radio, however the fuel bill does get tiresome. I'd rather go an overdrive than put her on gas, despite the holden engine (which is out of sight out of mind) she looks really original and I'd rather keep her that way, at least for the most part.
    Reply With Quote Reply With Quote
  6. 26th November 2010, 12:00 PM #6
    bee utey's Avatar
    bee utey
    bee utey is offline AT REST
    Join Date
    Apr 2009
    Location
    Crafers West South Australia
    Posts
    11,732
    Total Downloaded
    0
    Your fuel saving will be a percentage of the revs drop at a given road speed as engine friction is a small part of the overall drag. At 80km/h I would expect a saving of 5 to 10% fuel used for a 30% overdrive. At 100km/h 5 % or less as wind resistance becomes the major component of drag. In a 2wd car I was getting 5% saving for a 15% overdrive (supra gearbox) at 100km/h so engine friction was about 1/3 of the total drag.
    Reply With Quote Reply With Quote
« Disco2 and puma dash button switches question | Auto over heating issues »

Bookmarks

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  

Forum Rules

Search AULRO.com ONLY!
 Search All the Web!