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Volvo J Type Overdrive & Spitfire

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Taco Richard Dalrymple
Hope Mills, NC, USA   USA
I'm a new member so please forgive me if I ask a question folks are tired of answering. The forum's search was no help. I know what's required to convert a Spitfire single rail four speed to the dedicated Spitfire j overdrive.

What is required to convert a volvo 200 series j overdrive to a spitfire with the appropriate mounts and driveshaft on hand?

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spitfire50 Avatar
spitfire50 Paul Mugford
Rochester, N.H., USA   USA
Richard,
I think you will need to tap the holes for the mount. Volvo doesn't use the OD case for mounting, but goes directly to the gearbox case. If you are lucky the rear flange will be the same as the Triumph, so an appropriate length drive shaft is all you will need. If the flange doesn't match, the Volvo driveshaft would use a larger U-joint. Then the yoke for that larger U-joint would have to be grafted onto the Triumph shaft. Since the Volvo shaft has a center bearing it isn't usable.
AFAIK the OD unit itself will work with the Triumph OD adapter and mainshaft. There might be some issue with the speedometer angle drive. Volvo used a VDO angle drive to match their instrument. The thread may not suit the Smith's angle drive. E-mail John at http://www.quantumechanics.com/ for better and more definitive information. He may be able to sell any parts necessary to make the Volvo unit work in a Triumph.
All the best,
Paul

spitlist Avatar
spitlist Joe Curry
Sahuarita, Sahuarita, AZ, USA   USA
Assuming that the Volvo OD unit is the same as what was used on the Spitfire single-rail gearboxes, you will need the following parts to complete the tranformation:

The OD unit including the solenoid and wiring
An Adapter that replaces the standard tail housing and mates with the OD unit
A long main shaft that is designed for the Single rail OD combinations
The lockout hardware that prevents the OD from being energized in any gear but 3rd and 4th
A gearshift lever with the in/out switch on the shifter knob (or suitable substitute)

I think I have covered everything but I am sure that I will be notified if I missed something.



Edited 1 time(s). Last edit at 2018-05-13 07:07 PM by spitlist.

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2manyspits Avatar
2manyspits Thomas Schlundt
south bend, IN, USA   USA
Why go through all that trouble just buy an overdrive complete and sell your trans

grumpicus Steve Jackson
Leicester, Leicestershire, UK   GBR
In reply to # 1532845 by spitlist Assuming that the Volvo OD unit is the same as what was used on the Spitfire single-rail gearboxes, you will need the following parts to complete the tranformation:

The OD unit including the solenoid and wiring
An Adapter that replaces the standard tail housing and mates with the OD unit
A long main shaft that is designed for the Single rail OD combinations
The lockout hardware that prevents the OD from being energized in any gear but 3rd and 4th
A gearshift lever with the in/out switch on the shifter knob (or suitable substitute)

I think I have covered everything but I am sure that I will be notified if I missed something.

Joe - only minor stuff missing from your list!

The Volvo unit may well have different internal components controlling the hydraulic pressures for overdrive speed of engagement and running pressure, but as it's on a single rail box, it should be OK. Excessive pressures can be a problem with the J type on the three rail boxes, due to the smaller mainshaft tip.

The nylon speedo gear pair within the overdrive will probably be different in the Volvo, depending on axle ratio and the turns per mile of the Volvo speedo head. An external right-angle speedo drive (120694) will be needed for the Spit speedo drive, I don't know what's fitted on the Volvo.

The drive flange on the rear of the overdrive may be different, depending on whether the Volvo uses the same size flange on the front of the propshaft/driveshaft. My guess is that it will be larger, possibly like the TR6 flange?

The other bits for the mainshaft will be the driving cam (and its retaining clip) for the overdrive pump, and the spring clip (159503) for the rear of the overdrive mainshaft.

TinDrum Herald Ma
cologne, NRW, Germany   DEU
The rear housing for the J-Type overdrive on the single rail gearbox is different from any other j-Type i know of.
It has aditional mounting bosses on the top for mounting the gearstick housing.

Herald

grumpicus Steve Jackson
Leicester, Leicestershire, UK   GBR
In reply to # 1532932 by TinDrum The rear housing for the J-Type overdrive on the single rail gearbox is different from any other j-Type i know of.
It has aditional mounting bosses on the top for mounting the gearstick housing.

Herald

Ah, yes, I'd forgotten about that! To fit the single rail gearlever & linkage would need one of those, or some creative metal fabrication to make a support for the gearchange turret. If I remember correctly, most of the J type rear castings have a couple of bosses under the tail of the casting, which could possibly be used as attachment points for any such creative metalwork!

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trzavie Avatar
trzavie Al S.
Vast, Midwest, USA   USA
I have both the OD 3 rail and Volvo M41 gearboxes on my test bench. The early 25% ratio OD's all had nearly identical specs as far as operating pressure, just add or remove shims to the operating valve to adjust pressures. 99% of the early Volvo OD's I rebuilt had operating pressures within the Spitfire specs without doing anything. Later 27% Volvo OD's and turbo Volvo OD's had higher pressure specs. I've personally never had a problem fitting a later 27% higher pressure spec OD to a 3 rail or single rail gearbox. With the 3 rail as Steve says the smaller mainshaft tip can be an issue. Depending on driving patterns you have to pull the gearbox and replace the needle bearing on a regular basis, but if you are vigilant not a big deal. All the 3 rail 27% conversions went to GT6 owners who had spare mainshafts and the ability to keep up maintaining the gearbox. Pulling the gearbox on an annual basis was a matter of fact kind of thing for them.
As Herald mentioned the rear case on the single rail is unique. I've never had an issue obtaining the AAU1387 rear case so easy peasy, just swap out the rear case. You'd have to remove the rear case to pop in the correct speedo gear anyway. The shift tower is different on the OD and non-OD single rail and obtaining those can be a problem, much easier to convert a 3 rail IMHO.

In summary, if the parts are free or cheap, go for it, however I like this quote from Thomas the best:

In reply to # 1532874 by 2manyspits Why go through all that trouble just buy an overdrive complete and sell your trans



1974 Triumph Spitfire 1500

Taco Richard Dalrymple
Hope Mills, NC, USA   USA
All of you, thanks for all the experienced and pertinent information. What Internet information I gathered prior to posting hinted any such conversion would perhaps require an effort better satisfied with a bonafide Spitfire swap for swap.
That is easy enough for me to do (Spitfire for Spitfire swap) considering I own two Spiifires, 78 & 79, one with, and one without an operational overdrive (J type). The 78, my second SF purchase, is low miles and in extraordinary condition mechanically and aesthetically but it's lacking the overdrive and has a clutch that has begun to slip. Perhaps the slip is due to the leaking valve cover or the degreaser I used to clean up after resealing the valve cover soon after purchasing it. Don't know.

The 79, was an impulse purchases years prior to the 78 deliberate buy, isn't so pleasing to the eye but is rust free, shifts, runs, and does pretty much what a Spitfire should do that sat outside on someone's car porch for over 3 decades, begs for more attention and more parts. It does sport a sound overdrive mated to a single rail that other than a moody 1st gear syncro, is by all other measures, mechanically sound.

Anywho, my plan was to swap the 79 od into the 78, drop new clutches in both, and sell the 79. Then I kicked around the idea of ("what if"winking smiley) I could use an affordable Volvo od in the 78? Then I could sell the 79 for a more handsome price to bankroll niceties for the 78. After listening to all of your sage advice sounds like Plan A is the better option.
Again, thanks all.

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Mister Mitch Mitch Roe
Phoenix, AZ, USA   USA
It is sacrilege to sell a spitfire...ever...ever

Mitch

just do NOT do it...

spitfire50 Avatar
spitfire50 Paul Mugford
Rochester, N.H., USA   USA
In reply to # 1533452 by Mister Mitch It is sacrilege to sell a spitfire...ever...ever

Mitch

just do NOT do it...

Mitch,
And how did you acquire your car? For every buyer there is a seller. Keeping one and letting someone else also enjoy the Spitfire experience isn't wrong.
All the best,
Paul

TheZster Avatar
TheZster Steven Z
SAINT LOUIS, MO, USA   USA
1978 Triumph 1500 "BLK-BRY"
In reply to # 1533668 by spitfire50
In reply to # 1533452 by Mister Mitch It is sacrilege to sell a spitfire...ever...ever

Mitch

just do NOT do it...

Mitch,
And how did you acquire your car? For every buyer there is a seller. Keeping one and letting someone else also enjoy the Spitfire experience isn't wrong.
All the best,
Paul
+1 thumbs up

Share the wealth!!!!

Z

GeorgeOhr Nonya Business
Yes, confused, USA   USA
In reply to # 1533033 by Taco Perhaps the slip is due to the leaking valve cover or the degreaser I used to clean up after resealing the valve cover soon after purchasing it. Don't know.


I doubt that unless you tried to degrease inside the bell housing and even then it would be difficult to make one slip from doing that.

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