Which model overdrive unit is appropriate for a series V

[Acollin]

Hello all

i have a series v alpine and am curious as to which model laycock overdrive unit would bolt up , trouble free, to my stock 4 speed synchro transmission. I have a leaker - front seal— so it should come out anyway and thought I would consider options for OD when I disassemble my car. The car really needs another gear.

I have sent and email to the “overdrive “ guy that many recommend and have not yet heard back and have seen “P” and “D” units for sale. For now, I just need to know which OD unit was used in 1966 seriesV.

thanks

be well
Andrew

 

[RootesRacer]

Andrew,

Only the D type OD is used on series alpines, later rootes vehicles used the J type but this transmission is too long to integrate into the series alpine chassis without major mods (and likley using the non rootes flange type OD unit).

Rootes had a special "D" type that uses a splined output shaft like the std transmission, that part (the anulous) is also the most damaged part since the shaft can twist with a clutch dump.
Nearly all other MFGRs of cars used a flange type output on the OD making these far more common than the rootes variety. (You can use these OD units if you modify your drive shaft for a sliding joint and a flange from the donor vehicle)


Based on your question, you may be unaware that the overdrive unit is one item, the more important item is the overdrive transmission, which is different from the std transmission and uses a special trans mainshaft and OD adapter.

You should seriously NOT consider just buying parts, most are junk, instead buy a complete and tested unit, trust me here as the owner of 2 junk OD transmissions and 2 equally junk OD units.

 

[Mike O'D]

Andrew - Alpines used a D type overdrive. Please note, the transmission main shaft is different for using an overdrive. These can be more difficult to find than the overdrive itself.

 

[Mike O'D]

Almost at exactly the same time RootesRacer!

 

[Acollin]

Thanks all
I believe I have been saved from a costly and troublesome end. I recently did an overdrive swap on my MGB GT and it was simply out with my failing transmission and in with the functioning overdrive unit. — quick and easy/ more of nuts and bolts work than anything thoughtful. I was thinking that it would be a similar swap in my Alpine.
More thinking and planning to do- I guess. I am tired of leaving a gear oil puddle wherever I go. I won’t attempt any fix as my weather is turning near perfect. For now its drive and top up the gearbox!!!

thanks again all

 

[Bill Tippy]

I hope you don't mind me tagging along with a related question.
How do you know if your Alpine has overdrive?
A fifth gear?

 

[hartmandm]

Here's a write-up of what I did to swap in an overdrive gearbox, so you get an idea of what is entailed.
http://mhartman.net/files/sunbeam/OD gearbox installation.pdf

Mike

 

[RootesRacer]

Here's a write-up of what I did to swap in an overdrive gearbox, so you get an idea of what is entailed.
http://mhartman.net/files/sunbeam/OD gearbox installation.pdf

Mike

Nice writeup.

 

[hartmandm]

I hope you don't mind me tagging along with a related question.
How do you know if your Alpine has overdrive?
A fifth gear?

The standard gearbox has a long tail on its rear. The overdrive gearbox has a second section on the rear, which is the overdrive part.

Standard gearbox:


Overdrive gearbox:


Another tell tale of having an overdrive is having two 'stalks' on the steering column. One stalk is the turn signal, the second stalk is for engaging / disengaging the overdrive.

Mike

 

[Mike Broome]

I fitted the later "J" type overdrive to my S5 as I wanted the stronger unit to deal with around 140bhp. I had my gearbox overhauled by John Roseby and fitted with the later fine spline output shaft to match the new overdrive. I purchased a fully reconditioned overdrive unit from a company who up-rated the internal clutch and pump to give faster changes. I also needed to fit a shortened prop shaft. The "J" type requires a small modification to the gearbox mounting as it is different to the "D" type, but easily done. Otherwise it is a straightforward change, and has worked well with no issues.

Mike

 

[alpine_64]

I fitted the later "J" type overdrive to my S5 as I wanted the stronger unit to deal with around 140bhp. I had my gearbox overhauled by John Roseby and fitted with the later fine spline output shaft to match the new overdrive. I purchased a fully reconditioned overdrive unit from a company who up-rated the internal clutch and pump to give faster changes. I also needed to fit a shortened prop shaft. The "J" type requires a small modification to the gearbox mounting as it is different to the "D" type, but easily done. Otherwise it is a straightforward change, and has worked well with no issues.

Mike

Mike great to see you back on the forum.
Do you still have the alpine?

 

[Silver Creek Sunbeam]

I hope you don't mind me tagging along with a related question.
How do you know if your Alpine has overdrive?
A fifth gear?

If you are trying to identify it aesthetically from the top, it's not a '5th gear' on the shifter.
You will have a stalk switch on the column, opposite the blinker, that is the trigger for the OD.

 

[RootesRacer]

If you are trying to identify it aesthetically from the top, it's not a '5th gear' on the shifter.
You will have a stalk switch on the column, opposite the blinker, that is the trigger for the OD.

What he said...
Additionally, OD is available in the 3rd and 4th gear positions (due to a switch on that gate) that makes a rootes OD trans technically 6 speeds although 3rd+OD ratio is very near the same as 4th NON-OD.

You can tell if there is supposed to be an OD in the car by the vin#. You tell if it actually has an OD trans my inspecting the transmission in the car. The difference is so profound that you can do it with a mirror viewing the trans from the ground.

 

[Tom H]

Thanks all
I believe I have been saved from a costly and troublesome end. I recently did an overdrive swap on my MGB GT and it was simply out with my failing transmission and in with the functioning overdrive unit. — quick and easy/ more of nuts and bolts work than anything thoughtful. I was thinking that it would be a similar swap in my Alpine.
More thinking and planning to do- I guess. I am tired of leaving a gear oil puddle wherever I go. I won’t attempt any fix as my weather is turning near perfect. For now its drive and top up the gearbox!!!

thanks again all

Andrew, I'm not sure you understand the OD situation, but maybe you do. To be clear, understand that it's pretty straightforward to replace your existing tranny with one that is an OD tranny, that is, one that has an OD unit already as part of it. Seems that's what you have done with your MGB GT. That's what most of us have done to get an OD into our Alpines. What is difficult is finding just an OD unit and trying to add it to your existing tranny. Hope that helps.

Tom

 

[Mike Broome]

Hi Michael,
My Alpine now has a new owner. After 29 years of ownership it was time for someone else to enjoy. Great memories and with the right modifications they do go very well. I now have an historic Formula 3 racing car to keep me busy.

 

[Acollin]

I am fairly certain I get what is being said and I understand well my limitations and know when to ask for more information. This discussion has been very helpful.

my main take-aways:
1) swapping out a standard trans for an overdrive trans is pretty straight forward.
2) it is possible but not advisable to buy “bits” and adapt a standard trans making it an overdrive trans. It could take for ever to assemble necessary bits and be beyond my ability as a hobbyist mechanic.

for me, the best solution seems to wait for a series V overdrive transmission to come my way.

thanks all

 

[alpine_64]

I am fairly certain I get what is being said and I understand well my limitations and know when to ask for more information. This discussion has been very helpful.

my main take-aways:
1) swapping out a standard trans for an overdrive trans is pretty straight forward.
2) it is possible but not advisable to buy “bits” and adapt a standard trans making it an overdrive trans. It could take for ever to assemble necessary bits and be beyond my ability as a hobbyist mechanic.

for me, the best solution seems to wait for a series V overdrive transmission to come my way.

thanks all

1. Correct
2. The mainshaft is the real hard part to get.
3. Jeff Haworth offers fully rebuilt full OD kit.. Rebuilt OD trans, Relay, column switch, speedo tail shaft ... Many members here have used his services

 

[RootesRacer]

1. Correct
2. The mainshaft is the real hard part to get.
3. Jeff Haworth offers fully rebuilt full OD kit.. Rebuilt OD trans, Relay, column switch, speedo tail shaft ... Many members here have used his services

Thats Jeff Howarth but close enough to get the point across.

 

[Acollin]

I emailed Jeff an inquiry , but have not heard back— yet.

can someone tell me approximately ( ball park, of course ) what his kits cost?
They sound complete.
Is shipping cost outrageous?
Thanks

 

[Jay Laifman]

Here is another difference not listed here.

The S1-IV OD switch clicked on and clicked off, and there was a light on the dash if it was clicked on. The SV had a self cancelling switch. The stalk was always in the middle you could push it up and down, but it would spring back to the middle. The OD unit has switches on the box that allows the OD to turn on if you are in 3rd or 4th, and otherwise turns off the OD. With the S1-IV OD, if you leave the switch in the "on" position, the OD always comes on when you go in 3 or 4. But with the SV box, once you drop out of 3rd, the OD goes off and never comes back on unless you spring up the OD stalk again.

At least when I did the installation, the relay necessary for the SV version was close to impossible to get - though I found one. Some one had devised a way to wire up two non-stock relays to duplicate that. You should be able to find the instructions on this site somewhere.

The ODs also had a shorter drive shaft. You can get yours shortened. I was lucky enough to find an NOS one.