I currently have my BJ8 OD in a ?a thousand pieces? !
Prior to stripping, I too built up a similar test rig but 240V variable speed
with 3 ph motor as well. See pix.
This rig was invaluable to help diagnose:
- low pressure that turned out to be a bad accumulator and piston rings;
replacing with modern O ring style and new accumulator spring; used compressed
air to extract the accumulator.
- confirm that front oil leak was GB front seal and not rear main ... phew!
- that brake ring flange was leaking oil; hopefully now fixed with Locktite
518; also leaks at adaptor flanges - new gaskets plus Hylomar.
- bad main clutch bearing; unit was noisy in direct 4th gear but much
quieter in OD; this bearing only works in direct drive and not in OD; it was
shot and interestingly could only be heard on test rig and
not when in car with road and engine noise.
Plan to run the transmission for several hours prior to reinstalling in car to
get up to temp and check the leak enemy.
Thinking ahead, was looking and making one of Michael S?s famous oil pump
release tools; have done a few dry runs using the wire method and wonder why MS
chose the wire tool over holding the spring with some thin wire as others have
done ?
rg
From: Michael Salter
Sent: Wednesday, January 4, 2017 8:47 AM
To: BJ8Healeys
Cc: Healey List
Subject: Re: [Healeys] BN6 Overdrive
Hi Steve,
Best wishes for a Happy and Prosperous New Year.
Yep those symptoms mostly make sense.
"The first time it would engage when cold, but not when hot. The accumulator
walls were severely gouged, probably from too much debris in the oil from not
having been changed frequently enough before I got the car. I found no other
problems. I concluded that the massive leakage prevented the accumulator
piston from moving back far enough against the spring to direct the oil to the
metering pin."
In this case unfortunately you don't mention the pre-repair test pressures but
they would have been quite low, probably 300 odd cold and below 250 hot,
meaning that there was not enough pressure to move the clutch against the
springs. I would imagine that as your drove and the oil heated up the unit
would have started to slip and then dropped out of overdrive altogether.
The second time, the overdrive was slow to engage, felt like it was slipping,
and would make a whirring noise as it tried to do so. I put a gauge on the O/D
and went for a drive. I was reading 350 psi before the O/D switch was flipped,
dropping to 100 psi at it tried to engage and back up to 350 - 365 psi after
engagement. I found a broken accumulator piston ring and a loose ring in the
bottom of the accumulator bore. After correcting that (and a broken thrust
washer behind the planetaries), I read 450 psi before flipping the O/D switch
and 250 psi as it engaged. I neglected to record the recovery pressure. This
was done on a test rig and I did not repeat the test on the road since the O/D
worked perfectly after reinstallation in the car.
In this case the pressure during engagement is a little low but that is, as you
found, probably due to damage in the accumulator. I'm surprised to hear that it
slipped with a 350 -360 engaged pressure but that may have had something to do
with the broken thrust preventing full travel of the clutch member...not sure
about that one.. I have experienced that whirring noise on some units as well
I suspect it is the unidirectional clutch slipping.. I envy your test rig...I
always intended to build one but I never got a round tuit...
M
On Wed, Jan 4, 2017 at 10:46 AM, BJ8Healeys <sbyers at ec.rr.com> wrote:
Mike, what I mentioned to Neil is that both times I have had problems with my
overdrive failing to engage, or engaging sluggishly, the problem was the
accumulator. The first time it would engage when cold, but not when hot. The
accumulator walls were severely gouged, probably from too much debris in the
oil from not having been changed frequently enough before I got the car. I
found no other problems. I concluded that the massive leakage prevented the
accumulator piston from moving back far enough against the spring to direct the
oil to the metering pin.
The second time, the overdrive was slow to engage, felt like it was slipping,
and would make a whirring noise as it tried to do so. I put a gauge on the O/D
and went for a drive. I was reading 350 psi before the O/D switch was flipped,
dropping to 100 psi at it tried to engage and back up to 350 - 365 psi after
engagement. I found a broken accumulator piston ring and a loose ring in the
bottom of the accumulator bore. After correcting that (and a broken thrust
washer behind the planetaries), I read 450 psi before flipping the O/D switch
and 250 psi as it engaged. I neglected to record the recovery pressure. This
was done on a test rig and I did not repeat the test on the road since the O/D
worked perfectly after reinstallation in the car.
Steve Byers
HBJ8L/36666
BJ8 Registry
AHCA Delegate at Large
Havelock, NC
From: Healeys [mailto:healeys-bounces at autox.team.net] On Behalf Of Michael
Salter
Sent: Wednesday, January 04, 2017 9:53 AM
To: Neil McDonald
Cc: Healey List
Subject: Re: [Healeys] BN6 Overdrive
Hi again Neil,
With all due respects to Steve I would not suspect the accumulator because it
is in the hydraulic circuit ahead of the operating valve.
If the accumulator was leaking badly enough to prevent the overdrive from
engaging you would never see 390 p.s.i. if you are testing at the operating
valve plug with the ball and spring in position.
Although the specified pressure for our units is 470 - 490 p.s.i. I have
never seen one achieve 490 p.s.i. and have found units that operated quite
satisfactorily with pressures as low as 300 p.s.i. hot.
Someone suggested running the car on stands and manually lifting the valve
setting lever. That is how I test for correct operation BUT PLEASE be ware of
that driveshaft spinning next to your right hip. Getting yourself tangled up in
that will ruin your day.
Michael S
BN1 #174
On Wed, Jan 4, 2017 at 6:05 AM, Neil McDonald <nmcd10 at gmail.com> wrote:
Yesterday I wrote "I have concluded that the most likely cause of my problems
are low OD fluid levels and/or inadequate opening of the actuating valve. Both
I can readily deal with."
In off line discussions with Steve Byers I have added a third and ominous
possibility, a defective accumulator. The good hydraulic pressure already
confirmed only indicates that the pump is OK because testing was not done while
trying to engage the OD. My understanding is that OD engagement is the
accumulator's function and the pump's role is to pressurise the accumulator for
this task before OD engagement. A definitive test of accumulator condition
seems to be how well it holds pressure after the engine is switched off!
_____________________
Neil McDonald
Email: nmcd10 at gmail.com
_______________________________________________
Support Team.Net http://www.team.net/donate.html
Suggested annual donation $12.75
Archive: http://www.team.net/archive
Forums: http://www.team.net/forums
Healeys at autox.team.net
http://autox.team.net/mailman/listinfo/healeys
Unsubscribe/Manage:
http://autox.team.net/mailman/options/healeys/michaelsalter at gmail.com
--
If you can't fix it with a hammer, you've got an electrical problem.
--------------------------------------------------------------------------------
_______________________________________________
Archive: http://www.team.net/archive
Healeys at autox.team.net
http://autox.team.net/mailman/listinfo/healeys
--------------------------------------------------------------------------------
No virus found in this message.
Checked by AVG - www.avg.com
Version: 2016.0.7996 / Virus Database: 4749/13725 - Release Date: 01/07/17
-------------- next part --------------
An HTML attachment was scrubbed...
URL:
<http://autox.team.net/pipermail/healeys/attachments/20170107/154496c4/attachment.html>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: 20161117_130718.jpg
Type: image/jpeg
Size: 227263 bytes
Desc: not available
URL:
<http://autox.team.net/pipermail/healeys/attachments/20170107/154496c4/attachment.jpg>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: 20161117_130649.jpg
Type: image/jpeg
Size: 242176 bytes
Desc: not available
URL:
<http://autox.team.net/pipermail/healeys/attachments/20170107/154496c4/attachment-0001.jpg>
|
