MAX BORE OUT TR6 BLOCK ?

[TRTOM2498PI]

On 2/12/2022 at 2:42 PM, TriumphV8 said:

I tried the cheap silver gasket from Rimmer and as it did not fail it stayed some time.

Later I swapped to the custom gasket from Elmeso Reban in Germany.

Price was around 120 Euros, do not know what it takes to bring that to GB......

This gasket is still in the car.

Hi.

How many years have you been running your engine with this gasket ?  I have heard good things about these gaskets.

[Tim D.]

9 hours ago, TRTOM2498PI said:

I am running 25psi, peak(1.7bar), tailing off to 20psi at the limiter, but then again, I have a different engine in mine !

A well built Triumph Stag derived box will absorb a good 230bhp & over 200lbs ft, & will be the way to go with this level of power if you turbo / super charge the original engine.

My stag has a rover v8 with more than 200 ftlbs torque. Seems to be surviving. My original tr6 gearbox lasted <2000 miles including an alpine passes session with the supercharger. Don't know the output, but the next gearbox has the stag upgrade has exceeded that distance easily. 

Tim

[TRTOM2498PI]

13 hours ago, Tim D. said:

My stag has a rover v8 with more than 200 ftlbs torque. Seems to be surviving. My original tr6 gearbox lasted <2000 miles including an alpine passes session with the supercharger. Don't know the output, but the next gearbox has the stag upgrade has exceeded that distance easily. 

Tim

Absolutely. On any seriously tuned engine driven hard, go Stag every time.

You can perform the double bearing layshaft modification on a TR6 gearbox, but still not ultimately as strong as a Stag box, due due size (diameter) of the layshaft, which in turn, has larger bearings to support it. It It is well documented this is the notorious weak spot on these gearboxes.

For most lightly tuned engines, or ones driven occasionally hard, a TR6 box with the double layshaft bearing mod will suffice though.

[BlueTR3A-5EKT]

5 hours ago, TRTOM2498PI said:

Absolutely. On any seriously tuned engine driven hard, go Stag every time.

You can perform the double bearing layshaft modification on a TR6 gearbox, but still not ultimately as strong as a Stag box, due due size (diameter) of the layshaft, which in turn, has larger bearings to support it. It It is well documented this is the notorious weak spot on these gearboxes.

For most lightly tuned engines, or ones driven occasionally hard, a TR6 box with the double layshaft bearing mod will suffice though.

And the Stag diff has a bigger crown wheel and pinion with larger bearings on the pinion.   Looks just like a TR but open it up and you will see the changes.  Sadly only ratio available was 3.7:1  

 

[TRTOM2498PI]

54 minutes ago, BlueTR3A-5EKT said:

And the Stag diff has a bigger crown wheel and pinion with larger bearings on the pinion.   Looks just like a TR but open it up and you will see the changes.  Sadly only ratio available was 3.7:1  

 

A well built TR6 diff will take over 250bhp (flywheel), if you have something like a Quaife ATB inside it.

[BlueTR3A-5EKT]

5 minutes ago, TRTOM2498PI said:

A well built TR6 diff will take over 250bhp (flywheel), if you have something like a Quaife ATB inside it.

THREAD DRIFT.  - SORRY.

 

 

And with the TR diff you have a broad range of ratios available.  Thanks to homologation of the Dolomite Sprint, which uses the same diff case size, making them all factory available ratios.  The only dubious one would be 3.9 that Leyland Special Tuning marketed specifically for the Sprint, although it was definitely available from a Leyland ST dealer at the time.

 When used in conjunction with the close ratio gearbox ratios and a J overdrive working on 4 th only, it gives a delightfully spaced 5 speed gearbox…..or so Abingdon said.

Yes the Quaiffe ATB is a splendid addition that lasts, as against the GKN power-lok plate type units that also need special oil.    Quaiffe told me the police had them fitted in some of their vehicles, and they never had a warranty; and we all know what interstellar mileages they do.

No doubt the racers will have a view on what works best.

Cheers

Peter W

PS I still have a NOS plate set for a Leyland ST limited slip diff somewhere.

[Tim D.]

1 hour ago, BlueTR3A-5EKT said:

And the Stag diff has a bigger crown wheel and pinion with larger bearings on the pinion.   Looks just like a TR but open it up and you will see the changes.  Sadly only ratio available was 3.7:1  

 

You can get the 3.45:1 ratio for a stag. Am running one as we speak. 

Tim

[JohnC]

On 2/26/2022 at 3:49 AM, BlueTR3A-5EKT said:

 When used in conjunction with the close ratio gearbox ratios and a J overdrive working on 4 th only, it gives a delightfully spaced 5 speed gearbox…..or so Abingdon said.

Newbie to gearbox stuff, but considering an overhaul. This sounds like a worthwhile change. Is there only one set of close ratios? And do you change the diff ratio to retain the final drive gearing in OD 4th? Or is this really only for racing? I already have a Quaife ATB in the diff BTW.

[BlueTR3A-5EKT]

59 minutes ago, JohnC said:

Newbie to gearbox stuff, but considering an overhaul. This sounds like a worthwhile change. Is there only one set of close ratios? And do you change the diff ratio to retain the final drive gearing in OD 4th? Or is this really only for racing? I already have a Quaife ATB in the diff BTW.

This set gives you an idea.   https://www.moss-europe.co.uk/shop-by-model/triumph/tr5-6/performance-tuning/clutch-gearbox-drivetrain/close-ratio-gear-set-tt2210-gp.html
 

Perhaps a phone call to Peter Cox.   https://petecoxsportscars.co.uk/ To discuss your requirements?  
 

or maybe TR Enterprises or Racetorations.

[TriumphV8]

On 2/24/2022 at 11:52 AM, TRTOM2498PI said:

Hi.

How many years have you been running your engine with this gasket ?  I have heard good things about these gaskets.

Good morning, more than 4 years.

Do not remember because after some time of playing with MegaSquirt this engine is now simply sitting in the compartment and requiring an oil change once a year. My regular job is to add the C-TEK battery fresher and check dipstick level.... It simply runs without complains

[TRier]

On 2/27/2022 at 8:49 AM, JohnC said:

Newbie to gearbox stuff, but considering an overhaul. This sounds like a worthwhile change. Is there only one set of close ratios? And do you change the diff ratio to retain the final drive gearing in OD 4th? Or is this really only for racing? I already have a Quaife ATB in the diff BTW.

Hi John, did you fit the quaife LSD yourself or send them the diff?

[TRTOM2498PI]

2 hours ago, TriumphV8 said:

Good morning, more than 4 years.

Do not remember because after some time of playing with MegaSquirt this engine is now simply sitting in the compartment and requiring an oil change once a year. My regular job is to add the C-TEK battery fresher and check dipstick level.... It simply runs without complains

Thanks.

 

Oh, me & you both.  My car gets treated like a car much newer than something built in 1970's, with reliability. 6000-7000 miles per year is good going as a second car, too ?

 

Cheers.

[JohnC]

On 5/3/2022 at 6:09 PM, TRier said:

Hi John, did you fit the quaife LSD yourself or send them the diff?

I had it fitted by my local classic car specialist. It was not a straightforward swap - the Quaife unit needed some machining to fit (slightly too large a diameter). 

John

[carter]

Hello, anyone paying attention to the current automotive world out there?
It's raining turbochargers !!

Power output is proportional to the volume of air-fuel mixture that you can burn per second.
Increase the displacement by 10% (250 cc) to gain 10% power (15 HP)
Increase inlet pressure by 0.5 Bar (7.5 psi) to gain nearly 30% (45 HP)

Any questions?
 

[Bill944T]

This set gives you an idea. https://www.moss-europe.co.uk/shop-by-model/triumph/tr5-6/performance-tuning/clutch-gearbox-drivetrain/close-ratio-gear-set-tt2210-gp.html

I posted ages ago the different close and wide ratio gear options available at one time.

From that post I've extracted the below for the TT2210 set above with ratios of 2.19, 1,57, 1.23 and 1:1 

All with 3.45 diff so it will take some getting off the line and in reality if you have overdrive, the ratios give you 53, 75, 91/95, 116/119/117 and 143/146 so still only in effect, a five speed box as two of the seven ratios are pretty much duplicated.

1st   2.19 53 mph

2nd  1.57 75 mph A type OD 91 mph

3rd   1.23 95 mph A type OD 116 mph, J type OD 119 mph

4th   1.00 117 mph A type OD 143 mph J type OD 146 mph

Regards

Bill