All,
Appreciate all the feedback. As this was my first time tearing into an
overdrive, I am not familiar with how they work and what is acceptable.
I was following the great articles on the Buckeye website.
http://www.buckeyetriumphs.org/technical/AOD/AOD3/AOD3.htm
Towards the end of the reassembly section, the article discuss the air test
which I thought could save me some trouble of trial and error.
I am happy that the clutch is operating as expected and plan to reassemble and
bench test to check for operating pressure.
Thanks again for the advice.
Greg
Sent from my iPhone
> On Mar 6, 2018, at 5:20 PM, M&M Hado via Fot <fot at autox.team.net> wrote:
>
> I agree. To me using air is not so much to test the ?seals? (O-rings, balls
> & seats, accumulator piston rings, etc.) but to test the mechanical movement
> of the overdrive internals. Greg?s test showed the pistons moving the cone
> clutch very well with only 120 psi so that?s what I would be looking for on
> the air test and nothing more. Plus, this is something you can do on the
> bench before putting it together since oil pressure is not yet available
> before assembly. I think it?s inevitable that you will hear a lot of air
> leakage past the operating valve with this mechanical test and doesn?t prove
> that anything is hydraulically ?tight.? The bottom line is to get the 400
> psig and, if you do, any leakage past these areas is internal and a moot
> point.
>
> Mike
>
> From: Fot [mailto:fot-bounces at autox.team.net] On Behalf Of Charly Mitchel
> via Fot
> Sent: Tuesday, March 6, 2018 1:58 PM
> To: J Wagner
> Cc: fot at autox.team.net
> Subject: Re: [Fot] Type A OD pressure test
>
> Not to me it isn't, it's not really proving anything. Can't tell it it's
> leaking past seals.
> Charly Mitchel
> TR6 #44
> ----- Original Message -----
> From: J Wagner
> To: Charly Mitchel
> Cc: fot at autox.team.net
> Sent: Tuesday, March 06, 2018 11:40 AM
> Subject: Re: [Fot] Type A OD pressure test
>
> Makes sense. Subsequently, is compressed air a viable means of testing seals
> that normally run gear oil?
>
>
>
>
>
> On Mar 6, 2018, at 10:17 AM, Charly Mitchel <charly at mitchelplumbing.com>
> wrote:
>
> I believe the answer is the water molecules are larger than the air
> molecules, which makes them easier to pass through the space. I think
> Gore-Tex work the same way, lets the fabric breathe, but keeps the water out.
> Not sure why I know this :)
> Charly Mitchel
> TR6 #44
> ----- Original Message -----
> From: J Wagner via Fot
> To: fot at autox.team.net
> Sent: Tuesday, March 06, 2018 8:03 AM
> Subject: Re: [Fot] Type A OD pressure test
>
> I?m almost embarrassed to chime in here as I have no expertise on the inner
> workings of a transmission, but perhaps it?s more of a question than an
> answer.
>
> I?ve run a lot of PVC irrigation pipe in my day, particularly in the last few
> years landscaping my house. I?ve noticed that whenever I turn on a new
> system, the air compressed by the incoming water with force it?s way past
> connections of threaded pipe, joined with teflon tape, and take a little
> water with it. Just when I?m thinking that I?ve failed to tighten the pipe
> enough, the leaking stops once all the air escapes.
>
> I suppose it?s a fluid dynamics question. Will compressed air act
> differently on seals than pressurized oil?
>
> Maybe the escape of air is as meaningless as it has been in my sprinklers?
>
> ?Justin
>
> On Mar 6, 2018, at 6:48 AM, M&M Hado via Fot <fot at autox.team.net> wrote:
>
> Greg,
> Just a couple more thoughts to add to the good suggestions already offered. I
> especially liked Jack?s idea of hand-lapping in the aluminum seats with a
> ball welded to a rod.
> I?m guessing that most of the air you?re hearing is leaking around the
> outside of the operating valve since air is much more likely to do so than
> the relatively thick 90 weight oil. Just the fact that only 120 psi of air
> pressure is enough to move the operating pistons tells me that the rest of
> your system is relatively tight. The normal operating pressure after all is
> about 400 psig so you have a lot of ?fat? built into it.
> One thing that might cause the operating pistons to move with a relatively
> small pressure is having weak or incorrect springs pushing the cone clutch
> rearward. Be sure you have the so-called ?long? and ?short? ones in the
> right locations, It?s actually the coil bound length that determines which
> is which. If you put a long one where a short one will be, it may bind
> before reaching full movement, resulting in the cone clutch not reaching the
> brake ring. Don?t ask me how I know this. To check this, I put each spring
> on a threaded rod and run a nut down the rod until the coil binds. Measure
> the length at that point and the long springs will be about 3/8? longer than
> the short ones.
> Also, the seating of the balls on the aluminum seats in the casing is indeed
> important but it?s also important to have a good seat between the ball and
> tip of the operating valve. I had a D-type OD that was eating my lunch with
> low operating pressure during engagement and the tip of the valve was nicked
> resulting in a bad seal. Changing the valve solved the problem. The oil
> flow is very small in the system so a leak of even the smallest area will
> drop the pressure quite a bit.
> Lastly, you mentioned the ?relief valve? and I?m not sure which valve you are
> referring to since the pressure relief occurs when the accumulator piston
> moves enough to uncover the relief holes back to the sump. Since you only
> had 120 psi, the accumulator piston would not have moved nearly enough to
> ?relieve.? I?m guessing you were referring to the operating valve.
> Mike Hado
> From: Fot [mailto:fot-bounces at autox.team.net] On Behalf Of barry rosenberg
> via Fot
> Sent: Tuesday, March 6, 2018 5:31 AM
> To: Jack Wheeler; Greg Blake via Fot
> Subject: Re: [Fot] Type A OD pressure test
> I used to put the ball in a tap in down with a blunt punch. As the case is
> aluminum and the ball hard steel, it made a very nice seat for itself. This
> can be done without pulling the OD apart. Just pull the plug, spring and
> little plunger.
> Barry
> On Monday, March 5, 2018 5:26 PM, Jack Wheeler via Fot <fot at
> autox.team.net> wrote:
> Hi Greg. Here is a tip for you. When I used to rebuild A-Type overdrives, I
> would "lap in" the surface that the ball sits on. I had a spare ball of the
> correct size, and I welded a small rod to it (about 3/16" diam.). Then I put
> a bit of valve grinding compound on the ball, inserted it down into the hole,
> then turned it back and forth, thus lapping the surface that the ball sits
> on. This is a tip that Hardy Prentice gave me years ago, when we were both
> racing, and obviously the purpose was to minimize any leakage past the ball.
> This may be to late in your case, as you would have to do this while the unit
> is apart, so that you can carefully clean all of the grinding compoound out
> of the housing after the lapping. Maybe this will help you next time. Good
> luck.
> Jack Wheeler
> On Monday, March 5, 2018, 12:12:29 AM EST, Greg Blake via Fot <fot at
> autox.team.net> wrote:
> All knowing FOT
> Attached is a video of my Type A OD unit ready to bolt up to the
> transmission. I decided to do a pressure test with 120psi of compressed air
> plumbed into the operating vale port.
> The engagement seems to work well when I move the operating lever. But I am
> concerned about the amount of air that can be heard leaking. I believe it is
> going past the relief valve. Is this abnormal amount of leaking?
> I noticed upon tear down that the nonreturn valve had a 1/4" ball instead of
> the 5/16" this unit should have had. The test you see in the video is with a
> new 5/16" ball. I am sure on a previous rebuild someone mistakenly used the
> later style 1/4".
>
>
> Just wanted opinions before I buttoned this up to the transmission for some
> bench testing.
>
> Thanks.
>
> Greg
>
> Sent from my iPhone_______________________________________________
> fot at autox.team.net
>
> http://www.fot-racing.com
>
> Donate: http://www.team.net/donate.html
> Archive: http://www.team.net/archive
> Forums: http://www.team.net/forums
> Unsubscribe/Manage: http://autox.team.net/mailman/options/fot/jwheeler1947 at
> yahoo.com
>
>
>
> _______________________________________________
> fot at autox.team.net
>
> http://www.fot-racing.com
>
> Donate: http://www.team.net/donate.html
> Archive: http://www.team.net/archive
> Forums: http://www.team.net/forums
> Unsubscribe/Manage: http://autox.team.net/mailman/options/fot/britcars at
> bellsouth.net
>
>
>
>
>
> _______________________________________________
> fot at autox.team.net
>
> http://www.fot-racing.com
>
> Donate: http://www.team.net/donate.html
> Archive: http://www.team.net/archive
> Forums: http://www.team.net/forums
> Unsubscribe/Manage: http://autox.team.net/mailman/options/fot/4msonset at
> gmail.com
>
>
> _______________________________________________
> fot at autox.team.net
>
> http://www.fot-racing.com
>
> Donate: http://www.team.net/donate.html
> Archive: http://www.team.net/archive
> Forums: http://www.team.net/forums
> Unsubscribe/Manage: http://autox.team.net/mailman/options/fot/charly at
> mitchelplumbing.com
>
>
> _______________________________________________
> fot at autox.team.net
>
> http://www.fot-racing.com
>
> Donate: http://www.team.net/donate.html
> Archive: http://www.team.net/archive
> Forums: http://www.team.net/forums
> Unsubscribe/Manage: http://autox.team.net/mailman/options/fot/gblake58tr3 at
> icloud.com
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL:
<http://autox.team.net/pipermail/fot/attachments/20180306/587b929f/attachment.html>
|