Embarking on a Laycock-overdrive odyssey

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DkFordor

Member
Part 1: Background and general idea

In the on-going restoration of my 1931 Fordor I am currently looking into the possibility of adding a Laycock overdrive. I already bought two overdrives, one Laycock P-type, and the other a Laycock P/J-type. The differences between the two are small - the P-type is slightly older and uses an asbestos friction material in the clutch, the P/J-type is newer and (therefore) uses an asbestos-free friction material. The P-type is able to run a little bit higher pressure internally due to this - but I wouldn't expect a fairly stock fourbanger to be able to bring either even close to the limit of their capability :)

I also have the relevant drive shafts for the two, splined at the OD end and with the cam driving the oil pump of the ODs.

I have searched the forums and the internet for information about the install and the modifications necessary, and found lots of good information.

To my knowledge there are no companies doing conversion kits around here - so the general idea is to do everything by ourselves. I do have the assistance of a skilled machinist and mechanic - my aim is to gather as much relevant information for the task at hand.

If I manage to get it all working I may attempt a write-up of the process and some details for future use.

I apologize in advance that this is already somewhat lengthy - hope you'll bear with me nonetheless :)

Below follows a couple more posts with descriptions and questions - mechanical and electrical issues separately.
 
Part 2: Mechanical approach and questions

I have no extra torque tube and drive shaft to modify for the install - these seem to be difficult to come by here. Therefore we are considering to manufacture the necessary pieces in order to keep the original setup in stock just in case. This would include two drive shaft pieces connecting the Ford transmission to the OD input drive shaft, and the OD output to the pinion gear. I do realize that the splines may be difficult to make, but if I cant find a drive shaft this appears to be the only way forward.

  • Has anyone taken this approach, and what would the pitfalls and challenges be?

For now the working idea is to use flanges suitably welded onto drive shafts, thus connecting the output of the Ford to the drive shaft of the OD, and an additional drive shaft connecting the output flange of the OD to the pinion. This should ensure reasonable balancing and straightness of the total drive shaft pieced together.
The entire setup will be closed into a new torque tube consisting of two sections with the OD in between.

  • Any experience or opinion on this strategy?
  • Would the manufactured drive shafts need balancing nonetheless?

The input side of the OD is designed to be bolted onto the Volvo gearbox it came from, and to share the oil with it. Thus we need to close off the OD, and provide an oil seal around the drive shaft exiting the box. I have also the original spacers between the units - and aluminum casing - and will try to utilize that.

  • Any opinions on the type of oil seal? What is a typical lifetime of such an oil seal?
  • Any experience about the total amount of oil necessary for the OD? (Not the level, but the total quantity)
  • Do they run hot when in use? Ie would it benefit from additional oil capacity?

One of the ODs has provision for a speedo cable attachment, where the Volvo it came from provides a few possible ratios. None match the model A ratio very well.
How have people solved the speedo issue in other OD setups?

  • Can anyone provide schematics or pictures of the mechanical setup they have used - ie what braces, brackets etc are used, what is the placement of the OD on the torque tube, is the unit suspended etc?
 
Part 3: Electrical approach and questions

As far as I have been able to find on the forum the 12 volt solenoid valve should/may/could function on the 6 volt system. If not I will have to look into alternatives - this should be manageable.

The OD must be disengaged whenever the reverse gear is selected - and the first gear is probably too slow for the OD to function properly (and it makes little sense anyway to split 1st gear).

I have seen people talking about using a cut-out switch on the reverse gear to ensure this. In my understanding that would be a 'normally closed' circuit design - where the switch must be activated to avoid the possibility of the OD being engaged.
A friend of mine suggested instead a 'normally open' circuit design - where switches need to be activated in order for the OD to be engaged. The obvious advantage is, that an electrical/switch failure prohibits the OD from engaging - and hence damage to the OD is prevented even in case of a switch malfunction or the like.

  • Has anyone used this setup, or have experience with similar cases?
  • Any thoughts on this?


And finally - just out of curiosity - where did people put their OD toggle switch?
 
Like the Borg Warner R10s, these were being converted for torque tube drives. A lot of them came from Volvo cars. They may have been used in early Ford V8 conversions as well. There is not a lot of information out there. I'll have to dig around and see what I can find. Hopefully an owner or operator of one of these will offer up some information.

This is a good link: https://fordbarn.com/forum/showthread.php?t=247462
 
I have a friend into Franklyn cars, and those folks use the Volvo OD's in the Franklyn torque tube with great success. Might look at their forums at the ACCA.
 
Too bad you are so far away, Tom Endy is giving them away.

510643
 

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Rich Little in California has been doing these conversion for sometime, but I think he has stepped back from do these recently. I know David Mossman in Auckland, NZ has been doing these conversion and he may be able to offer you some suggestion and assistance that might help. PM me and I can send you his contact information.
 
Thanks all, for chipping in - much appreciated. I am a little hesitant to call Rich Little from the other side of the world and ask for help, especially if he retired from that kind of work.

Does anyone have information about the attachment of the torque tube on the output side of the OD? The OD-unit is meant for an open drive shaft, and I'd be interested to learn how the connection was made to the casing of the OD :)
 
Bruce, thanks for posting - and good to hear about your long happy history with the unit :)
The pictures of Thelma are indeed helpful - it gives a good idea of how the unit was mounted.


Could you perhaps elaborate on the electric actuation - how do you shift the OD, when is the OD disengaged automatically (if at all), what happens to the OD at gear shifts (2 <-> 3) etc. That would give me a good idea how its wired :)


Thanks!
 
DkFordor said:
Could you perhaps elaborate on the electric actuation - how do you shift the OD, when is the OD disengaged automatically (if at all), what happens to the OD at gear shifts (2 <-> 3) etc. That would give me a good idea how its wired :)


Thanks!
Click to expand...


The OD works in 1st, 2nd or 3rd. It is best to install a reverse lockout switch to prevent damaging the unit. You should never leave the OD engaged when backing up in reverse.


Your 6 or 12V is wired to a solenoid that is an integral part of the overdrive unit. You can change gears "on the fly." - no shift lever or clutching needed. When I was a teenager I had one on my Austin Healey 3000 and I beat it unmercifully. It never failed me. YMMV
 
I too am attempting a Laycock overdrive conversion for our A ,,so far I’ve made a fixture to hold torquetube for measuring and mocking up as I progress,,,no hurry ,,,,it’s not an accurate alignment jig ,got the shaft out of the O/D ,,end plates to attach to be machined and attach to shortened tube ,,,not sure exactly to connect front shaft yet but I have a couple of ideas and will confer with my machinist,,,but have a neat old cable handle which I will connect via cable to a switch and mount to gear stick ,,
 

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Roddyb34, good to hear others are doing this too :) How is the project progressing?


I got my hands on an extra torque tube and drive shaft, so now I can maintain an unperturbed set while attempting/working on the conversion. Will keep you posted on the (presumably) slow progress.


One question: Since the speedo of the A feeds of the front part of the drive shaft it would not register the correct speed when the OD is engaged.

How have others managed to keep a correct speedo reading with an OD installed?
 
Small update:

The physical adaptation of the OD is still pending. Have focused on the electrical side of the installation.
Got my hands on a Volvo OD-relay (12 volt neg ground), that now sits in my test setup and works very nicely - at voltages above ~8.5-9 volt. For voltages below this it cannot toggle the OD any longer.

The relay provides for a cutout switch, or actually a cut-in switch, since the original Volvo design was to allow OD to function only in 4th gear. It also has the nice feature, that i resets to OD off whenever something has disengaged the OD.


If anybody has any detail about putting switches on the model A gearbox or tower I'd be much interested in information on the subject. Particularly if a switch can be employed for both 2nd and 3rd gear at the same time - sort of like switching the right side of the 'H' in the tower :)


For now the plan is to make a separate 12 V circuit for the relay and solenoid.


To be continued at a slow progress :)
 
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