Triumph Sports Cars

engine swaps and other performance upgrades, plus "factory" V8s (Stag and TR8)

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gbtr6
Perry Rondou

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09/04/2010 01:17PM

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authors avatar
TR-6 with a T-5?
Posted by: gbtr6
Date: September 04, 2010 01:24PM

Hi All,

New here. I have a '74 TR-6, basically stock. Had it since '77. It has SU carbs, S-4 cam, higher compression, stock tranny. What I'm wondering is, has anyone swapped in a T-5 ? I really like all the V-8 cars, and a friend of mine has a V-8 MGB, but I don't want to have to cut mine up. I want it to look stock, a sleeper. If that's possible, with an aluminum headed 289 or BOP 215, then that's something. I did a frame off on this car about 15 years ago. It's held up well and been very reliable, just would like to have a better highway cruiser. Any thoughts?

Thanks,
Perry


alana
alan atkinson
10567
(232 posts)

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06/19/2008 08:06PM

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68 TR250 LS2

authors avatar
Re: TR-6 with a T-5?
Posted by: alana
Date: September 04, 2010 02:42PM

There's a kit.
Google Geoff Dupont @ dupont machining.
There's also one to put a W58 in there - google HVDA.


dadhadaroverp63500s
Richard Harrold

(15 posts)

Registered:
08/31/2010 11:38AM

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Re: TR-6 with a T-5?
Posted by: dadhadaroverp63500s
Date: September 04, 2010 03:06PM

I've got a much better idea. Go look around some junkyards. Find a BMW with a straight-six engine (and, ideally, a manual gearbox). Much more appropriate engine, much better gearbox. Plus, if it's a recent(ish) one, you could have six forward gears, not just five.

I've got nothing against V8s, and I understand the Triumph engine's shortcomings, but when you've got a straight-six you really ought to keep a straight-six, even if it's not the same straight-six! Lovely though a lot of V8s sound, in a small roadster, there's nothing to beat the snarl and howl of a high-revving straight-six. Pre-VANOS BMW engines will withstand up to about 9000rpm no bother - and I've never, ever heard a V8 to beat a proper BMW straight-six for sheer sound appeal.

Now, I know you're not going to be spending as much money as this, but have a listen to this:
[www.youtube.com]

If that doesn't stir your soul, I don't know what will...



Edited 2 time(s). Last edit at 09/04/2010 03:36PM by dadhadaroverp63500s.


MGBV8
Carl Floyd
Kingsport, TN
(3697 posts)

Registered:
10/23/2007 11:32PM

Main British Car:
79 MGB, Buick 215

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Re: TR-6 with a T-5?
Posted by: MGBV8
Date: September 04, 2010 09:54PM

"but when you've got a straight-six you really ought to keep a straight-six"

I don't think that kind of logic is gonna go over very well, here.


alana
alan atkinson
10567
(232 posts)

Registered:
06/19/2008 08:06PM

Main British Car:
68 TR250 LS2

authors avatar
Re: TR-6 with a T-5?
Posted by: alana
Date: September 04, 2010 10:10PM

For a 6 cyl swap you owe it to yourself to look at this: [s115.photobucket.com]

For a stock car, put in o/d. It adds value. A conversion (imo) doesn't.


Moderator
Curtis Jacobson
Portland Oregon
(4411 posts)

Registered:
10/12/2007 02:16AM

Main British Car:
71 MGBGT, Buick 215

authors avatar
Re: TR-6 with a T-5?
Posted by: Moderator
Date: September 04, 2010 10:44PM

Quote:
"but when you've got a straight-six you really ought to keep a straight-six"
I don't think that kind of logic is gonna go over very well, here.

+1



There are LOTS of great engines to choose from. Some of them ARE inline sixes. However, the best inline six is inevitably going to be taller and longer than a V8 of comparable displacement, and therefore we can logically infer that most V8s will be easier to install and preferable in terms of weight distribution. It's Dale's TR6 that really stirs the pot though. So much performance from a turbocharged four-cylinder!


dadhadaroverp63500s
Richard Harrold

(15 posts)

Registered:
08/31/2010 11:38AM

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Re: TR-6 with a T-5?
Posted by: dadhadaroverp63500s
Date: September 04, 2010 10:52PM

Quote

Posted by: MGBV8
Date: September 04, 2010 09:54PM

"but when you've got a straight-six you really ought to keep a straight-six"

I don't think that kind of logic is gonna go over very well, here.

==

Why not? The inline six is an inherently superior engine, due to its free-revving character and its inherently balanced primary and secondary moments, meaning it's smoother than any V8.



danmas
Dan Masters
Alcoa, Tennessee
(571 posts)

Registered:
10/28/2007 12:11AM

Main British Car:
1974 MGBGT Ford 302

authors avatar
Re: TR-6 with a T-5?
Posted by: danmas
Date: September 04, 2010 10:58PM

Quote:
If that doesn't stir your soul, I don't know what will...

To each his own (and I'm a big fan of inline 6s), but for me, nothing beats the rumble of a honkin' V8.

I attended my first NASCAR race back in '64, and when those guys dropped the hammer when the green flag came out at the end of the pace lap.... WOW! Auditory Nirvana.

If it weren't so late, or if I didn't have neighbors, I'd go out in the garage and fire mine up right now just to listen to it.


dadhadaroverp63500s
Richard Harrold

(15 posts)

Registered:
08/31/2010 11:38AM

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Re: TR-6 with a T-5?
Posted by: dadhadaroverp63500s
Date: September 04, 2010 10:59PM

Re: TR-6 with a T-5?
Posted by: Moderator
Date: September 04, 2010 10:44PM

There are LOTS of great engines to choose from. Some of them ARE inline sixes. However, the best inline six is inevitably going to be taller and longer than a V8 of comparable displacement, and therefore we can logically infer that most V8s will be easier to install and preferable in terms of weight distribution. It's Dale's TR6 that really stirs the pot though. So much performance from a turbocharged four-cylinder!

===

BMW inline sixes tend to be slanted, so the height shouldn't be much of an issue, and the length? If a car's designed for it, fine. Anyway, if an iron-block 302 is lighter than the Triumph straight-six, as I've heard, then surely the weight distribution isn't going to be much of a concern if you used a modern all-alloy six? I'd imagine a modern 330i motor would be lighter than a Ford 302 by some margin, so, even if there's weight further forward than in a 302-equipped TR6, it shouldn't upset the handling balance.

The thing about a V8 in a small Triumph is that, to me, a Brit, brought up on the notion that British sports car = straight six (look at all the various Jaguar sports cars, a lot of Triumphs, everything Donald Healey ever did with Austin, the MGC, plus various ACs and Bristols and even TVRs), the idea of a big V8 in something as small and delicate as the TR6 just wouldn't seem right to me. You need that urgent, snarling, high-revving character, not a big, lazy, torquey lump of a V8. There should no more be a V8 in a TR6 than anything other than a V8 in your archetypal American muscle car (yes I'm looking at you pretentious Mustang V6!).

I so want to get a ride in the TR6 with that BMW M3 engine. That's gotta be epic.


danmas
Dan Masters
Alcoa, Tennessee
(571 posts)

Registered:
10/28/2007 12:11AM

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1974 MGBGT Ford 302

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Re: TR-6 with a T-5?
Posted by: danmas
Date: September 04, 2010 11:30PM

Quote:
...British sports car = straight six...

That sure ignores a lot of British Sports Car history. British Sports cars have been produced in every configuration imaginable - I4 to V12. V8s included. And, if you include British racing sports cars, a V16 and an H16.


Moderator
Curtis Jacobson
Portland Oregon
(4411 posts)

Registered:
10/12/2007 02:16AM

Main British Car:
71 MGBGT, Buick 215

authors avatar
Re: TR-6 with a T-5?
Posted by: Moderator
Date: September 05, 2010 01:29AM

Quote:
(Carl) I don't think that kind of logic is gonna go over very well, here.
(Richard) Why not?

I don't suppose you noticed the name of this website?

Quote:
...British sports car = straight six...

Elaborating on Dan's comment:
Just how many MG models came with straight sixes? Maybe you don't think MG's are sports cars? There was MGC... but most reviews (contemporary and retrospective) consider that model a technical failure and even it's scattered fans consider the MGC model more of a "touring car" than a sports car.

Austin Healey? There are quite a lot of us who would rather have an Austin Healey 100 than any of the later six-cylinder variants.

Lotus?

No... inline sixes are great for big trucks and okay for Aston Martins (which generally aren't really sports cars so much as sporty luxury cars).

Straight sixes are inappropriate for... LOUSY for real sports cars.

E-type is of course the singular exception that proves the rule.


dadhadaroverp63500s
Richard Harrold

(15 posts)

Registered:
08/31/2010 11:38AM

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Re: TR-6 with a T-5?
Posted by: dadhadaroverp63500s
Date: September 05, 2010 09:12AM

"I don't suppose you noticed the name of this website? "

I did indeed, but what seems to be most discussed is "AMERICAN" V8s being put into British cars.

"Just how many MG models came with straight sixes? Maybe you don't think MG's are sports cars? There was MGC... but most reviews (contemporary and retrospective) consider that model a technical failure and even it's scattered fans consider the MGC model more of a "touring car" than a sports car."

MG is no exception, there are a lot of six-cylinder MGs. The MGC, the K1, K2, K3, the NA, NB, ND and NE. Straight-six powered all. Mind you, over here in the UK, the MGB is reckoned really to be too heavy and crude to be truly sporty, and the C even more so. Bizarrely, the lightest variant of the B was also the one with the biggest engine... it's really only the Spridget is truly sporty (out of the postwar MGs).

"Austin Healey? There are quite a lot of us who would rather have an Austin Healey 100 than any of the later six-cylinder variants."

OK, that's subjective, though I'm not sure why anyone would prefer a less refined, less powerful engine. 2.6 litres for a four-cylinder car engine is just too big. I'd take the 100/6 in preference - in fact, I'd prefer the 3000 over that, since it got an overdrive gearbox.

"Lotus?".

Well, there was the Carlton... but, other than the last Esprits, I'd like you to show me a Lotus with a factory-fitted V8!

"No... inline sixes are great for big trucks and okay for Aston Martins (which generally aren't really sports cars so much as sporty luxury cars)."

Inline sixes great for big trucks? That's where they're least appropriate, where the torquey nature of a V8 would be most useful! Mind you, they were pretty damn good (once the reliability had been sorted) in the old Astons - pity the chassis' of said Astons weren't up to much!

"Straight sixes are inappropriate for... LOUSY for real sports cars. E-type is the singular exception that proves the rule."

Erm, excuse me... TR5? TR250? TR6? GT6? BMW Z1? BMW Z4? BMW E36 & E46 M3? The LEGENDARY BMW M1? Jaguar XK120? XK140? XK150? C-type? D-type? XKSS? The old "Pagoda" Merc SLs? The older 300SL? The old Alfa Romeo 6C? Various legendary MGs? The Maserati 250F? The Maser A6 series? The 3500GT? The Datsun 240Z? 260Z? 280Z? Endless Skylines? Toyota's 2000GT? All the various Supras? The AMC straight-six also powered various successful cars in the Indianapolis 500... and then there were the TVR Cerbera Speed Six, the TVR Tamora, the T350, the Sagaris, the Tuscan...

That's a hell of a lot of great sports cars with "LOUSY" engines. Dear me, some people are so ignorant...


Moderator
Curtis Jacobson
Portland Oregon
(4411 posts)

Registered:
10/12/2007 02:16AM

Main British Car:
71 MGBGT, Buick 215

authors avatar
Re: TR-6 with a T-5?
Posted by: Moderator
Date: September 06, 2010 01:08AM

Perry,
(1) Welcome to the forum!
(2) I apologize for letting this thread get so far off-topic. Poor form on my part...
(3) I hope you got your question answered satisfactorily?




Richard, "ignorant"? I suppose I just have to respond to that!

I'll start with an easy part.
Quote:
"No... inline sixes are great for big trucks and okay for Aston Martins (which generally aren't really sports cars so much as sporty luxury cars)."

Inline sixes great for big trucks? That's where they're least appropriate, where the torquey nature of a V8 would be most useful!

I suppose you might think that, but in fact straight six turbocharged diesel engines power most of the worlds big trucks. Here in North American, straight sixes propel essentially all current "eighteen wheelers". Worldwide, in applications that call for more than ten liters displacement V8's are almost extinct. One of the big advantages of a straight six is that since the bores are all on one plane, manufacturing and machinery costs are relatively lower. This cost differential increases with displacement. I believe cost constraints and limited tooling capabilities were decisive factors for British car applications. In other words, British car manufacturers would have used more V8's if it had been economically feasible for them to do so.

You reckon that the MGB is heavy and crude, but few cars on your "great sports car" list are lighter than MGB and somehow you saw fit to include the Triumph GT6. Wacky! The MGB features a nice, stiff, unibody chassis whereas Triumph sports cars of the era are all flexible flyers. Body-on-frame construction is another of those ideas that only makes sense on trucks - certainly not sports cars built after 1962. Put a tall, heavy engine too far forward in a skinny/weak little Spitfire frame, slap a roof on it, and it's a GT6. GT6's look neat, but they are truly and profoundly crude. (Great project cars though, because there's so much room for improvement!)

The GT6 isn't the only dog on your list of "great sports cars"... but what really stands out to me is how many non sports cars you included. Luxury sporty cruisers, sedans, very limited production racecars, and even some Indy 500 cars...

I get a kick out of your posts though. In another recent thread you reckoned that the Triumph Stag V8 is a sporty engine compared to the Rover V8. (You claimed that the Rover has inferior throttle response... Maybe you've driven one of the RangeRover-spec versions? I suggest you try one with a lighter flywheel, a higher compression ratio, etc. The little aluminum 3.5L V8's have a nice short stroke and they rev quite freely. Remember, these little jewels were popular with the likes of Bruce McLaren, Jack Brabham, Mickey Thompson, Rodger Ward, Roger Penske, and many others before the aluminum V8 was ever installed in a Rover. Dan Gurney was doing well with one in the Indy 500, until a transmission failure. Jack Brabham won back-to-back Grand Prix world championships with variants of the engine.) Furthermore, you claimed that the Triumph's engine faults are well known and entirely fixable. If these faults had been well comprehended by Triumph, perhaps Triumph should have fixed them instead of canceling the Stag after only seven disappointing years. Triumph finally faced reality, and switched to the vastly superior (and truly more sporty) Rover V8 for their TR8 model. TR8's went on to win a LOT of races. Who ever raced a Stag?

Perhaps you'll get a kick out of this TopGear report:



tr8todd
Todd Kishbach

(355 posts)

Registered:
12/04/2009 07:42AM

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Re: TR-6 with a T-5?
Posted by: tr8todd
Date: September 06, 2010 07:59AM

I just got done yanking a baby 6 out of a euro BMW 320/6. Can't for the life of me understand why someone would want this motor over a V8. This thing is big and heavy, and this is the baby 6 as BMW calls it. The big 6 and some of the more modern overhead cam engines must be even more daunting. The baby six is only good to about 2.9L and 180 HP or so. The slanted aspect of the motor and the side hung intake make getting at the starter almost impossible. And just in case you haven't noticed, BMW parts are a little pricey. Now the Getrag transmissions on the other hand are fantastic. So are the rear diffs for that matter.


dadhadaroverp63500s
Richard Harrold

(15 posts)

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08/31/2010 11:38AM

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Re: TR-6 with a T-5?
Posted by: dadhadaroverp63500s
Date: September 06, 2010 08:13AM

"Who ever raced a Stag?"

Lots of people. Go to Le Mans Classic if you don't believe me. Dozens and dozens of Stags being driven hard.

"You reckon that the MGB is heavy and crude, but few cars on your "great sports car" list are lighter than MGB and somehow you saw fit to include the Triumph GT6. Wacky! The MGB features a nice, stiff, unibody chassis whereas Triumph sports cars of the era are all flexible flyers. Body-on-frame construction is another of those ideas that only makes sense on trucks - certainly not sports cars built after 1962. Put a tall, heavy engine too far forward in a skinny/weak little Spitfire frame, slap a roof on it, and it's a GT6. GT6's look neat, but they are truly and profoundly crude. (Great project cars though, because there's so much room for improvement!)

The GT6 isn't the only dog on your list of "great sports cars"... but what really stands out to me is how many non sports cars you included. Luxury sporty cruisers, sedans, very limited production racecars, and even some Indy 500 cars..."

Thing about the MGB is you've still got a Hotchkiss rear end - ie two longitudinal leaf springs suspending a big live axle. The Triumph's rear end is much more sophisticated, and the whole car is lighter. Yes, it lacks rigidity, but it makes up for it in other ways.

As for the stuff I put in my list, I don't see any cruisers or sedans... and the whole definition of a "sports car" is that it's a car you can use in motorsport. Hence the various Triumphs, Jags, BMWs, Nissans, etc.



dadhadaroverp63500s
Richard Harrold

(15 posts)

Registered:
08/31/2010 11:38AM

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Re: TR-6 with a T-5?
Posted by: dadhadaroverp63500s
Date: September 06, 2010 08:19AM

"I just got done yanking a baby 6 out of a euro BMW 320/6. Can't for the life of me understand why someone would want this motor over a V8. This thing is big and heavy, and this is the baby 6 as BMW calls it. The big 6 and some of the more modern overhead cam engines must be even more daunting. The baby six is only good to about 2.9L and 180 HP or so. The slanted aspect of the motor and the side hung intake make getting at the starter almost impossible. And just in case you haven't noticed, BMW parts are a little pricey. Now the Getrag transmissions on the other hand are fantastic. So are the rear diffs for that matter."

It'd be helpful if you could give us its E-number, or its model year. BMW have continually redesigned their sixes - the current magnesium 3-litre is actually pretty damn light. Certainly much lighter than any big iron-block V8. I think another thing is BMW chose a single architecture for their sixes, and the bigger the capacity, the thinner the cylinder walls (anybody knows different, feel free to correct me). I've worked on a few BMW sixes of various generations and I've never found them difficult to work on. Plus, over here at least, BMW parts are pretty cheap as long as you don't buy them from/through a main dealer. Also, they're dead reliable, rev to kingdom come (8500-9000rpm is pretty feasible with a few changes here and there), they sound unbelievably good, they're incredibly smooth and they're also pretty economical (my E39 520i 2.2 Touring, all 1650kg or so of it, does 33MPG combined, 41 on a long motorway run - them's big European gallons, mind).


gbtr6
Perry Rondou

(2 posts)

Registered:
09/04/2010 01:17PM

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authors avatar
Re: TR-6 with a T-5?
Posted by: gbtr6
Date: September 06, 2010 07:16PM

WOW. I don't mind the discussion. I'm also on a Vintage Mustang Forum for my 67 Coupe. They can really get into it also.

I would love to do a V-8, probably a 289 with 351 aluminum heads to lop off some weight, but don't have the time or money. I don't even have the money for a T-5 conversion.

I like the 6 as it is, but as is the case with all guys, wish it had a bit more. Or a lot more as is the case with a V-8. A standard overdrive may be a possibility, I had a TR-4 with it and that was nice.

Thanks,
Perry


Moderator
Curtis Jacobson
Portland Oregon
(4411 posts)

Registered:
10/12/2007 02:16AM

Main British Car:
71 MGBGT, Buick 215

authors avatar
Re: TR-6 with a T-5?
Posted by: Moderator
Date: September 07, 2010 01:08AM

Richard wrote:
Quote:
Thing about the MGB is you've still got a Hotchkiss rear end - ie two longitudinal leaf springs suspending a big live axle. The Triumph's rear end is much more sophisticated, and the whole car is lighter. Yes, it lacks rigidity, but it makes up for it in other ways.

Richard, it's so wonderfully ironic that you'd go for this comparison. Yes, the MGB's live-axle has relatively high unsprung weight and can be faulted for providing a harsh ride by modern standards, but live-axle suspensions are HUGELY superior to swing-axle suspensions (as used on Herald/Spitfire/GT6) in terms of camber change. In a nutshell, tires should stay basically perpendicular to the road as the body sways side-to-side in turns. The more camber change that occurs, the more the tire's contact patch is compromised - a problem that gets worse if you fit wider tires. Result: you lose grip on turns. Hotchkiss (and also deDion) suspensions are quite good in minimizing/eliminating camber change - but very few car models in history have been as horrible as the Spitfire/GT6 in this respect. As I recall, about 21 degrees of camber change in roll on the early ones (through ~1970) and about 7 degrees (still way too much) after that.

That's not all that's screwy about the Triumph swing axle rear suspensions. Example 1: since Triumph installed their transverse leaf springs clamped tightly to the top of the differential (through 1970), the suspension's roll center was quite high. By contrast, with a Hotchkiss suspension roll center is basically at the height of the axle centerline, but it can be relocated lower by installation of a Panhard rod or Watts linkage. Example 2: the early Spitfires/GT6's famously suffered jacking issues. Particularly when making a quick change of direction, one tire could tuck under, the suspension would violently lift the car, and sometimes this caused rollover accidents. (Ever heard of "Unsafe at Any Speed"?) Example 3: Consider what happens as the transverse leaf spring sags over time. The static camber setting changes rather dramatically. (Go to a British car show, walk along a row of Spitfires or GT6's, and observe that the rear tires lean inward at the top and that the amount of lean varies dramatically because so many people apparently don't know how to properly make compensating adjustments.) There are of course modifications to improve Triumph's cocked-up rear suspension, but it's probably a better idea to just throw it out and start fresh with something less "sophisticated".


dadhadaroverp63500s
Richard Harrold

(15 posts)

Registered:
08/31/2010 11:38AM

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Re: TR-6 with a T-5?
Posted by: dadhadaroverp63500s
Date: September 07, 2010 01:27AM

First of all, how the hell do I do the quote thing? I don't seem to be able to find how... once I've found out, then I'll reply properly! =)


Bill Young
Bill Young
Kansas City, MO
(1337 posts)

Registered:
10/23/2007 09:23AM

Main British Car:
'73 MG Midget V6 , '59 MGA I6 2.8 GM, 4.0 Jeep

authors avatar
Re: TR-6 with a T-5?
Posted by: Bill Young
Date: September 07, 2010 09:08AM

Perry, as far as I know the T5 hasn't been swapped into a TR with the original engine. There is a kit for installing a 5 speed transmission and I've heard it really works well behind the TR six cylinder. Check out [www.blindmoosefab.com] for information.
As far as any engine swaps go, then there are plenty to check out using a variety of power plants, but almost all will require some alteration to your car which from your original post it appears you'd like to keep pretty much intact. In that case then the HVDA 5 speed kit would be ideal.
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