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Overdrive issue
- Thread starter bnw
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TimK
Jedi Knight
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Re: Overdrive issu
Have you taken the tunnel off and driven the car then manually pressing the lever on the right side of transmission to see if it activates. If not then I would start with the accumulator which is accessible from the left side behind the solenoid. There are long posts about this if you do a search.
Have you taken the tunnel off and driven the car then manually pressing the lever on the right side of transmission to see if it activates. If not then I would start with the accumulator which is accessible from the left side behind the solenoid. There are long posts about this if you do a search.
5
57_BN4
Guest
Guest
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Re: Overdrive issu
+1 on the pressure gauge thing.
Pretty much anything you need to know about OD pressure is detailed here beginning half way through part 1. https://www.team.net/www/healey/tech/big_hly/od/delborder_od.html
I now have the full 490psi after following the suggestions on modifying the non-return valve and shimming the accumulator spring.
Also (maybe firstly) remove the big brass plug underneath and check the gauze is clear.
+1 on the pressure gauge thing.
Pretty much anything you need to know about OD pressure is detailed here beginning half way through part 1. https://www.team.net/www/healey/tech/big_hly/od/delborder_od.html
I now have the full 490psi after following the suggestions on modifying the non-return valve and shimming the accumulator spring.
Also (maybe firstly) remove the big brass plug underneath and check the gauze is clear.
Healey 100
Jedi Warrior
Offline
Re: Overdrive issu
Tim K asks a good question. When testing the actuation of the lever, the car must be jacked up and running in high gear at 35mph or more. With the car parked, there is much less force needed to move the lever, and a weak solenoid will appear to work fine. But under load, nothing happens.
My experience with my own OD is that 99% of the problems with it are caused by the solenoid, especially when it mysteriously quits after working just fine. A few ohms resistance in the internal contact for the pull in coil is the problem. In that case, the solenoid is just too weak to open that hydraulic valve.
Tim K asks a good question. When testing the actuation of the lever, the car must be jacked up and running in high gear at 35mph or more. With the car parked, there is much less force needed to move the lever, and a weak solenoid will appear to work fine. But under load, nothing happens.
My experience with my own OD is that 99% of the problems with it are caused by the solenoid, especially when it mysteriously quits after working just fine. A few ohms resistance in the internal contact for the pull in coil is the problem. In that case, the solenoid is just too weak to open that hydraulic valve.
Re: Overdrive issu
All good points, thanks. To answer some questions, OD does not exist under any circumstances. Driving down the road, tunnel off, 4th gear, 45 mph, OD switch on, solenoid clicks, lever drops down off its test position, No OD. I am confused, however. All three manuals I/m using (TR6, TR3, AH 3000) all state that energizing the solenoid will put the manual lever in the test ( holes lining up for 3/16 inch rod) position. This Healey works just the opposite. Holes are lined up with OD off, No power to the solenoid. My 57 TR3 is exactly the same. What am I missing here?
All good points, thanks. To answer some questions, OD does not exist under any circumstances. Driving down the road, tunnel off, 4th gear, 45 mph, OD switch on, solenoid clicks, lever drops down off its test position, No OD. I am confused, however. All three manuals I/m using (TR6, TR3, AH 3000) all state that energizing the solenoid will put the manual lever in the test ( holes lining up for 3/16 inch rod) position. This Healey works just the opposite. Holes are lined up with OD off, No power to the solenoid. My 57 TR3 is exactly the same. What am I missing here?
TimK
Jedi Knight
Offline
Re: Overdrive issu
The procedure is to place a 3/16th rod in the holes (holding the manual test lever in the on position. Loosen the nut on the left side lever arm connected to the solenoid. Energize solenoid, tighten nut so that the holes line up when the solenoid is energized. Removing the rod and de-energizing solenoid will cause manual test lever to move rearward and the holes will not lineup. I don't know what yours is doing. I'd start over with the adjustment procedure. The bottom of the left side lever (C in diagram below) must be touching the bottom of the solenoid flange/flare (D below) when the nut is tightened and the solenoid is actuated. Does your manual test lever move forward when you press it (toward front of car) or does it only move backward? There is a spring in the operating valve body (under the plug in the top of the OD)
that returns the lever to rest in the rearward position when the solenoid is de-energized. There should be a noticeable resistance when pushing the manual lever forward and it should return to the rearward position on its own when you let go.
Diagram from Norman Nock's Tech Tips
When did the OD operate correctly and what if anything happened when it stopped working?
The procedure is to place a 3/16th rod in the holes (holding the manual test lever in the on position. Loosen the nut on the left side lever arm connected to the solenoid. Energize solenoid, tighten nut so that the holes line up when the solenoid is energized. Removing the rod and de-energizing solenoid will cause manual test lever to move rearward and the holes will not lineup. I don't know what yours is doing. I'd start over with the adjustment procedure. The bottom of the left side lever (C in diagram below) must be touching the bottom of the solenoid flange/flare (D below) when the nut is tightened and the solenoid is actuated. Does your manual test lever move forward when you press it (toward front of car) or does it only move backward? There is a spring in the operating valve body (under the plug in the top of the OD)
that returns the lever to rest in the rearward position when the solenoid is de-energized. There should be a noticeable resistance when pushing the manual lever forward and it should return to the rearward position on its own when you let go.
Diagram from Norman Nock's Tech Tips
When did the OD operate correctly and what if anything happened when it stopped working?
5
57_BN4
Guest
Guest
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Re: Overdrive issu
Couple more things to check:
If the rubber buffer below the solenoid plunger is missing it can cause no OD engagement as the plunger is too far down for the magnetic field to pull up
If the operating valve cover is removed and the setting lever is operated forward past the setting position, the valve will fall off the internal cam and it won't be possible to rotate the lever back to the rest position without first withdrawing the operating valve with a paperclip or similar.
I don't think either of these things will be the cause of your problem but they confused me a bit last week.
Couple more things to check:
If the rubber buffer below the solenoid plunger is missing it can cause no OD engagement as the plunger is too far down for the magnetic field to pull up
If the operating valve cover is removed and the setting lever is operated forward past the setting position, the valve will fall off the internal cam and it won't be possible to rotate the lever back to the rest position without first withdrawing the operating valve with a paperclip or similar.
I don't think either of these things will be the cause of your problem but they confused me a bit last week.
Re: Overdrive issu
OK, so the lever was grossly out of adjustment. Everything works correctly now. Thanks. BUT, my question to you is that this ran perfectly all last summer. How on Earth does it get out of adjustment when the only wear points seem to be the rod to the operating cam???
OK, so the lever was grossly out of adjustment. Everything works correctly now. Thanks. BUT, my question to you is that this ran perfectly all last summer. How on Earth does it get out of adjustment when the only wear points seem to be the rod to the operating cam???
--bnw: