Overdrive

Author
Discussion

aureliusTVR

Original Poster:

102 posts

99 months

Tuesday 26th September 2023
quotequote all
Firstly, I can see several previous posts relating to retrofitting a gearbox with the J type Laycock overdrive, but the most relevant query I found related to installing it in a 3000S and consequently I'm left unsure whether the resulting advice regarding chassis mods was a result of the 3000S having a different chassis to my standard Taimar?

Soooo apologies for dragging this up again but I'd be grateful if the learned members could clarify:

  • If any chassis mods are required to fit the O/D box to the Taimar? (I am aware the handbrake will need relocating)
  • If I were to source an ex-Scimitar box, will it be a direct match to the TVR unit, or did TVR make mods?
This is aside from the column mounted O/D switch on Scimitars which I assume could be changed to a gear knob switch? (I have seen the correct pattern gear knob/switch available on Moss website)

The 5 speed type 9 conversion is still an option but having owned a 2.8 Capri many many moons ago, I wasn't overly fond of the patience required to engage 1st when cold or ensuring the car was stationary at junctions before engaging it
I went straight from the Capri to my first TVR (3000M) and noticed how much sweeter the Type 5 box behaved but it did need a shorter throw (I don't think the quick shifts were available then) and it desperately needed that extra gear on longer journeys hence my preference for a type 5 with O/D. Plus, I kinda like the old school overdrive which I think suits this era of car. smile

It would be nice to locate an alloy bellhousing to shed a bit of weight so if anyone knows of one that might be available for sale, please let me know. (Long shot I know!)

I often see used O/D boxes for sale but I don't want to end up with an incompatible unit so any advice is welcome




Edited by aureliusTVR on Tuesday 26th September 10:51

plasticpig1972

203 posts

53 months

Tuesday 26th September 2023
quotequote all
I can't help with o/drive info but i have owned a 3000S for 9 years with a T9 5 speed box with no problems. Except when cold not easy to change from 1st to 2nd. I also needed to find a different Gearbox Support because the original one was touching the Belhousing.
It's nice to drive in 5th at 100 kph and only 2200rpm.
Imho much easier to fit T9 than modding Chassis and Handbrake.
Personal choice of course.
Alan

Edited by plasticpig1972 on Tuesday 26th September 19:09

GeneralBanter

973 posts

22 months

Tuesday 26th September 2023
quotequote all
I have a 5 speed in an Essex V6 Tuscan and a Vixen and it’s superb, no issue at all with first gear and never heard of it being a thing.
I did it with external hydraulic slave and original bellhousing, if you’re on a cable clutch it will be a lot simpler. Thought the nearside bulge on the box would interfere with the exhaust but it clears it well. Best upgrade to the V6 I’ve done!

plasticpig1972

203 posts

53 months

Tuesday 26th September 2023
quotequote all
On my 3000S the T9 is with cable Clutch. Very comfortable not too heavy, love it.
When i need to take the motorway it's superb for cruising
Alan

GeneralBanter

973 posts

22 months

Tuesday 26th September 2023
quotequote all
A Scimitar o/d box would be the way to go if you want ‘period’ but you’ve still got electrics/prop do deal with and some parts like the inhibitor switch are obsolete. And by obsolete I mean literally unobtainable!!

plasticpig1972

203 posts

53 months

Tuesday 26th September 2023
quotequote all
I'm not so sure that there was ever a 3000S fitted with an Overdrive. Yes for 3000M or Taimar.
Alan

aureliusTVR

Original Poster:

102 posts

99 months

Wednesday 27th September 2023
quotequote all
GeneralBanter said:
A Scimitar o/d box would be the way to go if you want ‘period’ but you’ve still got electrics/prop do deal with and some parts like the inhibitor switch are obsolete. And by obsolete I mean literally unobtainable!!
Thank you. It's info like this that may steer my decision. I don't want to be left searching for "unobtanium" parts further down the road.

Alan, thanks also, I did refer to the previous article regarding the 3000S gearbox as retrofitted. Whether the contributor actually went ahead with it, I don't know.

So a type 9 maybe the way to go and I'm guessing it's a lighter option anyway.

So:
  • Gearbox from a 2.9 Cologne or a 2.8 Cologne with an upgraded 2.9 front bearing
  • Either variant should have a Speedo cable drive (not electronic)
  • Modifications to the input shaft (If anyone can elaborate, I'd be grateful)
  • Possible alternative cross member (Adrian apparently did supply these at one time but not sure now)
  • Quick shift kit (I'm not particularly requiring fast changes but would prefer the reduced gear stick throw)
If anyone can elaborate on the input shaft mods needed and list any other requirements, I'd be grateful





plasticpig1972

203 posts

53 months

Wednesday 27th September 2023
quotequote all
I got the gearbox support from Adrian but i'm not sure he has any more. Not too difficult to get one made.
The speedo cable is mechanical so no problem.
I think mine has heavy duty bearing at front.
When i bought my 3000S it already had the T9.
I will look in the paperwork for info about shortening of input shaft and reduction of diameter.
I'm sure Adrian will know details.
If you find a "short throw" kit sorce please let me know.
Cheers Alan

plasticpig1972

203 posts

53 months

Wednesday 27th September 2023
quotequote all
This is the info on a scrap of paper with my 3000S.
Bellhousing from 2.5 granada casting 72GB7505LA.
LATE TYPE T9.
Shorten Input and written 14mm dia.
John at Somartranstek.
Done a long time ago.
Cheers
Alan

V8Tolerancefit

6,319 posts

257 months

Wednesday 27th September 2023
quotequote all
Silly Idea to use a Type5 Overdrive Box IMHO

Firstly.. they are a fundamentally different gearbox.. Same but different if you like in that they have horrible external linkages and bell cranks. although the guts are broadly similar
Secondly The bellhousing is Different.. IE 1 inch Shorter than your std 4 speed Type 5 Gearbox
Thirdly. Lots of the Overdrive / Gearbox components switches are unobtanium.

You can fit a Heavy Duty 2.8 Type 9 onto an essex but you will need either an ally bell housing or an adaptor set up.
Again with an M derivative car you will be better with an Axial release bearing.
A T5 gearbox with long 1st and Short 5th would be a much better option. Again needs a specific bell housing.

Unless you are crunching the motorway miles then the existing 4 speed has good ratios and is pretty bomb proof.

If you are going to do it then you need a full hit from a scimitar or Tuscan V6.. IE Gearbox and bell housing.

They were fitted to Tuscan V6 and Early 3000M's as an option I think but dropped later in production

I can see the appeal as an OEM concours resto but not as a performance Mod.

N.

plasticpig1972

203 posts

53 months

Wednesday 27th September 2023
quotequote all
Sorry i forgot to say on my 3000S it's a heavy duty 2.8 . So that seems ok then, thanks for confirming Neil.
Cheers
Alan

aureliusTVR

Original Poster:

102 posts

99 months

Wednesday 27th September 2023
quotequote all
V8Tolerancefit said:
Silly Idea to use a Type5 Overdrive Box IMHO

Firstly.. they are a fundamentally different gearbox.. Same but different if you like in that they have horrible external linkages and bell cranks. although the guts are broadly similar
Secondly The bellhousing is Different.. IE 1 inch Shorter than your std 4 speed Type 5 Gearbox
Thirdly. Lots of the Overdrive / Gearbox components switches are unobtanium.

You can fit a Heavy Duty 2.8 Type 9 onto an essex but you will need either an ally bell housing or an adaptor set up.
Again with an M derivative car you will be better with an Axial release bearing.
A T5 gearbox with long 1st and Short 5th would be a much better option. Again needs a specific bell housing.

Unless you are crunching the motorway miles then the existing 4 speed has good ratios and is pretty bomb proof.

If you are going to do it then you need a full hit from a scimitar or Tuscan V6.. IE Gearbox and bell housing.

They were fitted to Tuscan V6 and Early 3000M's as an option I think but dropped later in production

I can see the appeal as an OEM concours resto but not as a performance Mod.

N.
Thanks for the feedback, It's no wonder I can't decide. When I searched previous posts for this subject, you suggested the O/D was a good option! smile

Monday 21st February 2011quotequote all
The old 3 ltr 4 speed was always knows for its bullet proof reliability and very good ratios. At 1 point I even ran a 300hp V8 with a one on the back and an adapter plate.

  • It seems to me that having an original 4 speed plus overdrive is a pretty good thing for a TVR. **
  • The type 9 is a weaker box with not particularly good ratios in standard form and a notchy shift. **
5th gear is also known to shear of the end of the shaft

I can understand upgrading a 3ltr to a T5 box but not a type 9 ??

N.
  • *************
Can I ask is the T5 easier option straightforward? are they and the associated bellhousings readily available?





aureliusTVR

Original Poster:

102 posts

99 months

Wednesday 27th September 2023
quotequote all
plasticpig1972 said:
This is the info on a scrap of paper with my 3000S.
Bellhousing from 2.5 granada casting 72GB7505LA.
LATE TYPE T9.
Shorten Input and written 14mm dia.
John at Somartranstek.
Done a long time ago.
Cheers
Alan
Thank you Alan, much appreciated . I just found the following useful link which confirms your info

https://wiki.scimitarweb.co.uk/images/0/07/Type9.p...

Edited by aureliusTVR on Wednesday 27th September 16:55

plasticpig1972

203 posts

53 months

Wednesday 27th September 2023
quotequote all
No problem anything to help.
If you decide to fit one of these horrible T9 Boxes like on my 3000S i can take a photo of the Gearbox Mount. So you can make one.
Alan

aureliusTVR

Original Poster:

102 posts

99 months

Wednesday 27th September 2023
quotequote all
plasticpig1972 said:
No problem anything to help.
If you decide to fit one of these horrible T9 Boxes like on my 3000S i can take a photo of the Gearbox Mount. So you can make one.
Alan
Now I'm really confused ...."horrible" ?
Yesterday you said you loved the T9 !
I need another cuppa smile

aureliusTVR

Original Poster:

102 posts

99 months

Wednesday 27th September 2023
quotequote all
So in summary:

The O/D option looks unwise given the availability of spares
The T5 looks equally unlikely after I just checked the prices on ebay !!
Given Neil's advice that the 4 speed is bombproof, I might just get the car on the road with the existing box and see if I can live it first, if not the type 9 maybe the sensible choice.

Thanks all for your feedback.




plasticpig1972

203 posts

53 months

Wednesday 27th September 2023
quotequote all
I'm joking i find the T9 on ma 3000S fantastic.
With the V6 it has the torque to pull in 5th and what a super sound. Go for it as Adrian Venn once said the best thing you can do.
Alan
Give Adrian Venn a phone lots of info. He and Duncan Rubens fixed me up with a Hardtop too

Edited by plasticpig1972 on Wednesday 27th September 17:29

GeneralBanter

973 posts

22 months

Wednesday 27th September 2023
quotequote all
aureliusTVR said:
So in summary:

The O/D option looks unwise given the availability of spares
The T5 looks equally unlikely after I just checked the prices on ebay !!
Given Neil's advice that the 4 speed is bombproof, I might just get the car on the road with the existing box and see if I can live it first, if not the type 9 maybe the sensible choice.

Thanks all for your feedback.
You would be able to fit a heavy duty very strong Type 9 easily, and the small extra over cost to an overdrive Type 5 makes it a no brainer IMO.

aureliusTVR

Original Poster:

102 posts

99 months

Wednesday 27th September 2023
quotequote all
plasticpig1972 said:
I'm joking i find the T9 on ma 3000S fantastic.
With the V6 it has the torque to pull in 5th and what a super sound. Go for it as Adrian Venn once said the best thing you can do.
Alan
Yes I read Adrian's remarks. I'll continue to trawl ebay and if the correct box appears for a good price, I'll put a bid in. I'm assuming if I used an adapter plate, it will push the gearshift back a touch?
Can the T9 bellhousing just be drilled to mate up ?

aureliusTVR

Original Poster:

102 posts

99 months

Wednesday 27th September 2023
quotequote all
GeneralBanter said:
You would be able to fit a heavy duty very strong Type 9 easily, and the small extra over cost to an overdrive Type 5 makes it a no brainer IMO.
That seems to be the consensus smile Thank you .