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Engine choices for a Triumph Roadster
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7777



Joined: 21 Aug 2015
Posts: 24
Location: peripatetic

PostPosted: Mon Aug 24, 2015 3:13 pm    Post subject: Engine choices for a Triumph Roadster Reply with quote

Hello all.

I'm lucky enough (or should that be unlucky?!) to have a 1948 Triumph Roadster, something of a basket-case, which is in need of a full restoration. If you don't know what they are, that's the car that appeared in Bergerac.

The car isn't original. At some point, early in its life by the look of it, the vehicle was adapted for what appears to be racing/rallying/touring. There are modifications to the dashboard and an air intake has been added to the bonnet, amongst various other things.

So, I'm thinking it wouldn't be entirely sacrilegious to consider modern modifications whilst restoring her. Ordinarily, it wouldn't be something which I would even consider - like I say, sacrilege! OTOH, I have a 1946 which is original and all of the parts from at least 2-3 others.

What I'm wondering is, what would you put onto it in terms of engine and gearbox, if you had the opportunity?

I have a Range Rover V8, Ferrari V12, MGC i-6 3litre and 2.3l Rotary engine just sitting around, together with two units which are from Triumphs of the period. The V12 would obviously be stupid, but these engines are just sitting around on pallets together with gearboxes, so.....

Now, obviously enough, some mods will be needed just to mount the things (frankly, anything other than the originals), but my main concern is the fact that it's an A-frame/ladder chassis and I'm guessing that I'll need some (a lot?) of cross-bracing if I think of putting anything with a 3-figure BHP reading.

That's not a problem, the chassis needs work anyway. However, I am concerned that torque-curl will just twist the chassis into little pieces unless careful consideration is given.

So, any thoughts?
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SpiggyTopes



Joined: 17 Jun 2014
Posts: 43
Location: Portugal

PostPosted: Mon Aug 24, 2015 5:23 pm    Post subject: Reply with quote

You could fit a later TR engine ... the last ones produced 100 BHP vs the Standard's 68 ....
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7777



Joined: 21 Aug 2015
Posts: 24
Location: peripatetic

PostPosted: Mon Aug 24, 2015 11:08 pm    Post subject: Reply with quote

I'm guessing you mean the later 2000s from the 1960s? I have some Vanguard/Standard engines along with a TR2000 saloon block, but these would be down at the 68BHP level if I recall. Aren't there issues with the layout that would affect fuel delivery on those? I have a pile of Strombergs which, frankly, would worry me constantly. The original TR fuel delivery parts are full of old glass bits that also leave me looking at them somewhat slightly askance.

I think the design of the bonnet is what will be the sticking point. It seems too narrow to consider anything other than a highly inclined 'V', which to me means either an inline or rotary as the only real choices.

Now, imagine that - a rotary TR Roadster! That would be interesting...
Do away with the dickie seats (not even remotely safe in modern traffic) and put a foam-filled fuel cell instead and it would be very very interesting indeed! Particularly handling-wise, given that the front track is wider than the rear.

What can I say, when it comes to cars and girls I enjoy making bad choices...

I also think that placing the necessary rads will also be an important side issue for putting a modern block into that space.
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SpiggyTopes



Joined: 17 Jun 2014
Posts: 43
Location: Portugal

PostPosted: Tue Aug 25, 2015 9:06 am    Post subject: Reply with quote

No, not the six cylinder one, the four pot wet linered engine was developed to produce 100 bhp or more.

TR block was better, but the casting still the same as the Vanguard one.

You could then bolt up directly to the existing gearbox.
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PAUL BEAUMONT



Joined: 27 Nov 2007
Posts: 1281
Location: Barnsley S. Yorks

PostPosted: Tue Aug 25, 2015 12:42 pm    Post subject: Reply with quote

I always understood that the Triumph Roadster had its engine down-rated because of chassis issues. Is this an Old Wives tale?
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Ashley



Joined: 02 Jan 2008
Posts: 1426
Location: Near Stroud, Glos

PostPosted: Tue Aug 25, 2015 2:20 pm    Post subject: Reply with quote

PAUL BEAUMONT wrote:
I always understood that the Triumph Roadster had its engine down-rated because of chassis issues. Is this an Old Wives tale?


Surely the Triumph Roadster has ceased production by the time the 90bhp TR2 engine appeared in about 1954.

The crank is the same as the later Vanguard but the block and head are different, but it's a lovely engine and would give the Triumph Roadster a boost IMO.
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SpiggyTopes



Joined: 17 Jun 2014
Posts: 43
Location: Portugal

PostPosted: Tue Aug 25, 2015 2:40 pm    Post subject: Reply with quote

The TR block differs from the Vanguard in that the head studs are taken down to the bottom of the block so that the walls of the block are in compression when the head is tightened.

The camshaft is heavier.

The crank is cross drilled to improve oil circulation on both engines.

I'm almost 100% that the external dimensions of the TR block are the same as the Vanguard engine, so would be a direct swap physically.
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7777



Joined: 21 Aug 2015
Posts: 24
Location: peripatetic

PostPosted: Fri Aug 28, 2015 11:30 am    Post subject: Reply with quote

Time for the measuring tape, then!
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SpiggyTopes



Joined: 17 Jun 2014
Posts: 43
Location: Portugal

PostPosted: Fri Aug 28, 2015 12:43 pm    Post subject: Reply with quote

I was married to a Phase 2 Vanguard for several years and know it intimately .... ! I didn't know that the TR head was different but I guess the valve are bigger.

If you go the TR route the parts are more expensive than the Vanguard ones (well, they were?).

So, for example, you might try to fit a Vanguard head to a TR block ..... best to seek advice on this.

The Vanguard is 2,088 cc and the TR 1,998 ... but the liners for the Vanguard used to be a fraction of the cost of TR ones.

The TR has different carb arrangements too.

The engine is easy to work on and very good but heavy.
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stevel98



Joined: 04 Apr 2014
Posts: 74

PostPosted: Thu Oct 08, 2015 4:06 pm    Post subject: Reply with quote

Should be able to accommodate a compact 2000/2500 Triumph 6 in there. Lovely engines, ..smooth, good power and great sound with the right exhaust. Perfect for a roadster like the Triumph..

Swap the Rover V8 for one...
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