[Healeys] Overdrive Question

Fri Oct 28 08:52:44 MDT 2016

If the oil in your transmission is boiling you have bigger problems than an oil leak, but not for long...

The vent is there to allow the oil (and air) to expand as it warms up without pressurizing the housing and to draw air back in as it cools. You may have a problem if the orifice is blocked or if it is too small, but for normal use I can't imagine that being the case. I suppose the breather may be located in the wrong place and allowing pressure to build in some inaccessible places.

I've seen extended breathers on four wheel drive vehicles, but that is too keep from pulling water into the housing during fording operations. In my Healey I always plan to use a bridge or ferry for water crossings.

Bill Lawrence

BN1#554

________________________________
From: Healeys <healeys-bounces at autox.team.net> on behalf of Chris Dimmock <austin.healey at gmail.com>
Sent: Friday, October 28, 2016 11:09:22 AM
To: John Harper
Cc: healeys
Subject: Re: [Healeys] Overdrive Question

Hi all
I'm with Mike Salter
There is also a similar "top hat" breather on the top of your diff banjo. It screws in.
Hands up if you've taken either off and cleaned the crud out of these in the past 50 - 60 years; or hands on your head if you're still having issues with leaking diff/ gearbox oil seals?
Of course there will be no oil by blow mist or  "telltale" marks if the breather top hat is blocked and sealed with crud, or you aren't driving long distances enough to get oil really hot. Or if it's parked.
Anyway - mostly - the engine oil blow by is hiding it! :-)
The cleaning of breathers - engine - diff - gearbox - was probably a standard procedure on a hoist in a BMC service back when the cars were new.
Most people who drive their cars a bit harder or raced them have also probably already replaced their "top hat" breather with a clear tube. Gearbox and Diff. Especially diff. To increase the ability to breathe (bigger air escape area than the top hat lid arrangement), and to also route the clear plastic tube vertically to breathe cleaner air.
Hope this isn't too non tech
Keep you roof down, your revs up, and your sense of humor
Chris
P.S. I still can't find Mike Salter's 1st motion shafts. My spare Healey Head. But I found my glasses tonight. So I'm back in the game Mike! ;-)

Sent from my iPhone

On 28 Oct. 2016, at 7:56 pm, John Harper <ah100register at gmail.com<mailto:ah100register at gmail.com>> wrote:

Mike - Just to add to this I have never seen oil 'blowing' out of this vent because if it did it would show. I don't believe the claim that gearbox oil would boil.

Best regards

On 27 October 2016 at 22:32, Michael Salter <michaelsalter at gmail.com<mailto:michaelsalter at gmail.com>> wrote:
Somebody suggested that the reason that BN1 gearboxes leak is that they are not "vented".
I have been thinking about this as I was sure that they are vented..
Well they are and here is how...
[Inline image 1]
The above is the gearbox vent. It is located on the top of the overdrive unit, in this case a 32% and, as the gearbox and overdrive units share a common oil reservoir this vent serves them both.
All Healey overdrives have this vent (or breather) on a BJ8 its part number is 17H5825
Just sayin'.
Michael S
BN1 #174

On Wed, Oct 26, 2016 at 10:34 AM, Tim Davis BN7 <tld6008 at mchsi.com<mailto:tld6008 at mchsi.com>> wrote:
no.... Neither of the two types will not seal that joint.....jeeez <undefined>

________________________________
From: "Bob Spidell" <bspidell at comcast.net<mailto:bspidell at comcast.net>>
To: "John Spaur" <jmsdarch at sbcglobal.net<mailto:jmsdarch at sbcglobal.net>>
Cc: "healeys" <healeys at autox.team.net<mailto:healeys at autox.team.net>>
Sent: Wednesday, October 26, 2016 8:40:33 AM
Subject: Re: [Healeys] Overdrive Question

Soooooooo ... both types of Hylomar WILL seal the joint?

________________________________
From: "John Spaur" <jmsdarch at sbcglobal.net<mailto:jmsdarch at sbcglobal.net>>
To: "WILLIAM B LAWRENCE" <YNOTINK at msn.com<mailto:YNOTINK at msn.com>>, "healeys" <healeys at autox.team.net<mailto:healeys at autox.team.net>>
Sent: Tuesday, October 25, 2016 8:27:53 PM
Subject: Re: [Healeys] Overdrive Question

In my experiences neither of the two types Hylomar will not seal that joint.

John Spaur
San Jose

From: Healeys [mailto:healeys-bounces at autox.team.net<mailto:healeys-bounces at autox.team.net>] On Behalf Of WILLIAM B LAWRENCE
Sent: Sunday, October 23, 2016 8:26 PM
To: healeys at autox.team.net<mailto:healeys at autox.team.net>
Subject: [Healeys] Overdrive Question

…disassembly of the OD because it is seeping oil at the clutch ring. There are no gaskets, but I would like to smear some Hylomar on the joint faces to stop the leak.

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If you can't fix it with a hammer, you've got an electrical problem.

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Best wishes

John Harper

AHC UK 100 Register Secretary
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