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Overdrive problems

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I'm very much interested in learning more about installing the fuses. Is this done via a fusebox? If so, what does the wiring look like? I'm a learner by doing and appreciate all information, diagrams, photographs etc. Before I get any safety warnings, I would like to point out that I let everything to be checked over by a professional. However, I want to undertake the initial work myself in order to be able to understand how things work.
regards ---Higgins
 
In line with this overdrive topic, maybe someone can assist me with an issue. After rebuilding the engine, tranny and overdrive, my mechanic (who has years of experience) is finding that the overdrive is having pressure problems. We did replace the piston or pump, as it was scored, but he cannot get the overdrive unit to function, and he mentions something about a pressure problem. Any ideas what we should look into? (I did see a pressure gauge hooked into the side of the o/d unit).

Thanks
 
Wow - Hard to answer.
Any place that lets pressure leak down when it shouldn't is suspect. There are a few possibilities that can be checked from the outside. No guarantees.

The pump non return check ball seating & spring.
The accumulator piston bore liner seal OR the piston's rings.
The control valve ball not seating when the OD is not operated. This ball must seal against the top of the valve when the OD is operated AND it must seal against the aluminum housing when the OD is not operated.


Internal problems could be many possibilities. A couple are:
You didn't say if it had low pressure or zero pressure.
If zero pressure the pump plunger could be stuck in the spring compressed position.
OR
The pump operating cam could be installed backward.

If the pressure is just low, the main operating piston seals could be leaking.

You & your mechanic have my sympathy. I hope he is experienced with the Laycock Type A OD. It is a really complex can of worms. This is a very brief list of possibilities. I assume he is testing by running the engine & gear box with the drive shaft disconnected.
D
 
If it was split then the pump pushrod roller may not have gotten back on the cam lobe. This is an easy enough mistake to make and would cause low/no pressure.
Dave's list is a good start. To check pressure it has to get spun up to a certian RPM range. How is he checking pressure? As Dave points out he might be doing it in situ or alternativly the guys that work these alot have bench testers driven by bench motor test beds. Have you considered dropping the unit off at a known Healey shop that does these often. Might be less expensive to get a flat rate rebuild than racking up mechanic hours while the mechanic learns these things.

Normanville Laylocks are neato but when they do not work can be frustrating which is another reason why I did a Smitty er... Delaney conversion.
 
Dave Russell,
Regarding your in-line fuse between the OD relay and the OD Solenoid. On my BJ8 I have two white/green wires crimped together into a female spade connector that fits on the OD relay. One of the white/green wires goes to the OD throttle switch and the other goes to the OD Solenoid. The question is: do you place the in-line fuse so it just interrupts the one white/green wire between the relay and solenoid or before the spade connector so it would also interrupt the w/g wire to the throttle switch? Or does it even matter?
Thanks.
 
Thanks for all of the advice. I visited the shop today, and my understanding is that we have only 200psi instead of the 450 we need. He has checked the OD unit now twice, so it has been gone over pretty well. The Selonoid is functioning, and we are testing it in the car. We have replaced the piston and sleeve o-rings as well, the old sleeve was worn though! It is so frustrating, the engine is rebuilt, as the tranny and this is all that is keeping me from getting the car back. My mechanic has been in business quite some time and is well respected with his shop and British car work, it really has him digging on this one.
 
Hi Shorn,
I would think you’d want to add the fuse to the white wire. On the overdrive relay, there is a double white wire. One goes to the overdrive switch on the dash, the other goes to the fuse box. It would be this last wire that I would fuse.
 
HI RV, if your indicated changes do not bring the pressure up to 490 psi I suggest you test the spring that fits in the accumulator piston bore,it may just be tired. It can be shimmed just like the oil pressure relief valve with washers to raise the pressure to the desired level.---Fwiw---Keoke
 
[ QUOTE ]
Hi Shorn,
I would think you’d want to add the fuse to the white wire. On the overdrive relay, there is a double white wire. One goes to the overdrive switch on the dash, the other goes to the fuse box. It would be this last wire that I would fuse.

[/ QUOTE ]

Well Greg, I do not see any need to add an additional fuse at all.Just pick up the white wire at the fuse box and move it to the otherside of the fuse.---Fwiw---Keoke
 
For this case Dave, it doesn't make much difference.A steady state say 2 amp load added won't even be noticed by the other circuits.The momentary 19 amp transient will also be gone before they know it occured. Similarly, the variable "T" Time is so short that the energy content in the transient will not cause any heating of the fuse---Keoke
 
Dang! short, green, handsome and smart!!! /ubbthreads/images/graemlins/jester.gif
 
DAR100, Keoke---ROFL- /ubbthreads/images/graemlins/thumbsup.gif
 
Well Dave, me and this alleged trouble have been living comfortably in my cars for the last 15 years or so.The themal leakage provided by the wiring circuits attached to the fuse reduce the energy content that the transient can transmit to the fuse.--Keoke
 
Keoke,
Have you looked at the condition of the insulation on the wires on the back of the o/d switch or the soleniod lately ? There is never any " trouble " until the accumulated effects of excess heat over time has completely damaged something. Fuses and inline fuse holders are very cheap insurance against this kind of damage.
/ubbthreads/images/graemlins/square.gif
 
Yep ED,completely rebuilt that wire harness and put it inside a flexible conduit long time ago.However, I do have the advantage of a fuse without adding an inline one. On my other car, I just too a look.I have a different fuse box on it and use a dedicated 5 amp fuse for the overdrive circuit its been there for years no problem.--Keoke
 
It seems to me that if you just move the wire(s) over to the other side of the fuse holder (you could do that for either or both the overdrive relay and fuel pump)you would have lots of things on just one fuse. If it doesn't overload the fuse, then perhaps the fuse might be higher amp than necessary to handle the items originally on that fuse. If that is the best way,one might ask why they just didn't set it up that way at the factory. Of course, one can always ask why they didn't install a fuse block with additional fuses so that all electrical items could be properly fused. Just cheap< I guess. Although I don't like the look of additional in-line fuse holders, that seems to be the better way to go. Besides if you blow a fuse, it narrows down the places to look for problems.
 
Yes Shorn, you could do that .However, the problem with the fuel pump might be the higher duty cycle where the energy inputs mightoverlap and be cumulative.You must have a solid basis for doing things like this or you can get into trouble. AS for plain speculation I wonder why all the cars have not burned up years ago. /ubbthreads/images/graemlins/grin.gif---Keoke
 
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