Volvo Laycock wiring question TEL # CORRECTION

[foxfire42]

I'm going to be installing a Volvo Laycock OD. I've searched both the web and barn but could not find a wiring diagram for the Laycock OD on a Model A. I drew a picture of what I have and would like to know where the connections are made. I've labeled the connection locations with letters. Can someone tell me which locations are wired together. As suggested in one of the posts I read I will be using 12G stranded wire. The slide switch came with G & H strapped together. Also, am I missing anything not illustrated in the drawing I made?

Thanks in advance.

Rich Little's (Volvo Laycock OD) shop number has changed. His current # is 661-809-3451

[MikeK]

Here's a LINK to the entire 35 page service manual for it. I'd lose the slide switch. They are unreliable . Look at the wiring diagram in the manual.

[2manycars]

It needs a reverse lockout switch to prevent the OD from failing if you select reverse with the OD activated.

[Jim in Wisconsin]

I have two Volvo 1800S cars with these overdrives in them. What kind of switch you use isn't so important, but like Bill said - be absolutly sure you can't ever put it reverse with the overdrive engaged. It will ruin it right away. It would be good to have an indicator light in parallel with the solonoid so you can tell when it's engaged. The Volvos only use it in high gear, so there is another switch for that. I don't think you would need or want it in first or second.
Jim S.

[Dick M]

I have the Laycock in my coupe. You will absolutely need the cut out switch for reverse. I drilled and tapped a cut out switch into the trans tower in the shift rail housing at the reverse position. The cut out switch has a button at the bottom of the switch. It is activated (stops all electrical current) when the shift rail is in the reverse position as it makes contact with the button on the cut out switch. I also use a toggle switch below the gear shift stick ball to engage and disengage the od unit. Wiring is from the hot side of the battery to the cut out switch, from cut out switch to the toggle switch, and then from the toggle switch to the solenoid on the od unit. I also have an in line fuse between the battery and the cut out switch. PM me if you have any questions..

[daveymc29]

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I drilled a small hole in the shift tower, so located that when my transmission was placed in reverse the rod holding the shifting fork would push against the disconnect button on a micro switch that I screwed into the hole. All of the incoming power had to travel through that switch to activate the solenoid on the overdrive. From that switch the wire went to the on/off switch that made the shift, so the solenoid was inactive anytime the transmission was in reverse. Works with 6 or 12 volts, if that is questioned.

[Floats]

Hi Gents,
I do not have an overdrive, but used to have one in a MGB.
As a matter of interest.
Say the OD was engaged in top gear or whatever, and the car accidentally rolled back a few feet or yards(up hill traffic light situation) would that damage the OD?

[foxfire42]

Based on the info above I think I have the wiring defined. Let me know if you see an error. Thanks for all the help

[2manycars]

Is your volvo overdrive compatable with 6 volt positive ground? I thhought volvos were 12 volt.

[daveymc29]

The solenoids I have found on the Laycock OD seem to work fine, positive or neg ground and 6 or 12 volt. Just my experience, I have had them on several Austin Healy's and two Model A's. Never had one develop a fault of any sort. Some I drove pretty hard in younger days. I believe they should be fairly bullet proof with 40 HP in front of them. Some of my A/H had 150+ HP and a much younger driver.

[Jason in TX]

I was going to add the lock out switch on the shifter tower also, but others have said that as well.

Dick M and Daveymc29, what lock out switch did you guys use in your trans tower? Have a part number still? I'll be doing another in a 1934 Ford soon and would like to order something.

[Jason in TX]

Oh, I hid my toggle switch under the dash rail to the left of the dash light.

Reach up and turn it off or on.

One real life experience story is that when I slow down to a stop, and forget that my OD switch is still on, the (alternator because I also have A/C) slows down so much that there is a drain on the battery and the OD turns off. I do have the tiny alternator pulley on there, but the car still idles slow enough that the alternator is not charging the battery.

When the light turns green, I accelerate as if my car is in regular first gear, alternator kicks on and the car down shifts into first+OD and kind of lunges. It's not really a problem, other than kind of embarrassing. After a while, I've remembered to turn the switch off when I stop at a stop light so that I'm truely in 1st gear.

[Dick M]

My cut out switch was supplied by Rich Little. The cut out switch came with my OD unit. He is in Bakersfield, CA. He builds the Laycock overdrive conversion kit for the Model A & T. His email is [email protected].

[Boston Bruce]

Originally Posted by foxfire42

Based on the info above I think I have the wiring defined. Let me know if you see an error. Thanks for all the help

Yes I believe this new wiring diagram is correct. I have three Laycock overdrives in my three Model As. They were all purchased from Rich Little. He supplied the reverse lockout switch.

http://thelmasgarage.com/volvo.htm

This story on the web page is quite old now and it's been posted here before I think. I have switched from synthetic oil to regular 40 weight oil.

[kaputiman]

can you give me more info on the kind and model of switch and its location. Did you drill shift tower in top or end of boss for reverse . Can you give me a call at 205-527-3183

[daveymc29]

I used a micro switch from radio shack. (No longer with us.) On the early Healers I had, BN1 and BN2, they used a tractor tranny with the lowest gear blocked off. they left four forwards in the BN2 and it had OD in the tree top gears. They had three lockout switched so you couldn't get into OD in reverse, 1st that didn't exist and 2nd. there was a switch on the dash to put it in OD while in 3rd and 4th. Just run all your power thru a micro switch prior to it reaching the OD and have it activated by the reverse rail movement. You could lock out 1st also if you do the lockouts correctly but I wouldn't bother.

[Synchro909]

I have a friend who has a Laycock O/D in his car. I. Suspect he selected reverse without disengaging it at some time, now it doesn't work properly. How much is involved in fixing that stuff up?

[Big hammer]

Originally Posted by Floats

Hi Gents,
I do not have an overdrive, but used to have one in a MGB.
As a matter of interest.
Say the OD was engaged in top gear or whatever, and the car accidentally rolled back a few feet or yards(up hill traffic light situation) would that damage the OD?

Check out Mitchell's OD six forward gears, and two reverse gears! 26% or36% overdrive!