How does a Rover 3.5lit compare to the Triumph 3.0lit?

[Guest]

Ok so being a bit of a purist myself I am completely convinced that the Triumph 3lit is the engine to have ......but humour me please.

Objectivley, can anyone tell me how these compare in a Stag?

:dude:

[Westfaling]

imported post

My opinion - Rover has more low end torque as you might expect and slightly more power (in standard 3.5l form but why not go for a 4.6 litre!!). Triumph motor revs better and sounds better. Reliability tick has to go to the Rover but resale value always goes to originality.
Some Rover conversions seems to need a bonnet bulge - no idea why but the deepest pit in Hell is reserved for people who do this! That may raise some comments.
Regards
Nick

[Ian B]

imported post

Rover didn't make a V8 but Buick did

you can expect about the same power output from the two engines in standard form,but the Buick V8 can be tuned to a much higher level and has the advantage of bolt on EFI, many will tell you that the BV8 will give you more reliability but if that were true then why are the vast majority of stags still using there original TV8 more than 33 years after production ended, the BV8 will never sound as good, if power is the main advantageand desire then i wouldbuy a TVR.

the BV8 is a fantastic engine in the right place (just like a Weber or Holey)

ian

[stustag]

imported post

Ian B wrote:

Rover didn't make a V8 but Buick did

you can expect about the same power output from the two engines in standard form,but the Buick V8 can be tuned to a much higher level and has the advantage of bolt on EFI, many will tell you that the BV8 will give you more reliability but if that were true then why are the vast majority of stags still using there original TV8 more than 33 years after production ended, the BV8 will never sound as good, if power is the main advantageand desire then i wouldbuy a TVR.

the BV8 is a fantastic engine in the right place (just like a Weber or Holey)

ian

Hi Ian

Not wishing to be picky Buick designed the 3.5L V8 that Rover & Land Rover used but the engine was 'made' as in manufactured (machined) and assembled at Solihull at Landrover then sold to Rover,TVR,MG & Morgan amongst others.

It is a great engine all alloy so lighter (mod suspension) and as stated very tunable with little effort and still reliable if done correctly.

The best conversion I have ever seen is Monstags ex monarch stag lovely!

Does notsound as good asa TV8 and not as smooth revving.

Stuart

[neil.henderson]

imported post

I have a Rover 3.5 with Strombergs in my Stag & I love it - no bonnet bulge. Even better since I removed the 3 speed auto and remplaced it with a 5 speed Toyota Supra manual gearbox.

The Triumph engine does make a good noise I do admit. My next job is to do the EFI conversion - then I shoudl have more power + more economy.

Neil Henderson

[Guest]

imported post

Thanks for the replies so far guys - I did know the Rover unit was a Buick design.

I wasn't aware that it would sound differnt to the Triumph unit though. Does it sound really different?...if it does I guess its due to a change in the headers as I thought that exhausts determine noise?

From what's been said there isn't a big difference between performance with a standard 3.5RV8?

I should say that the reason I am asking isn't because I want more power, but that I am fairly interested in a Stag that has a Rover lump which doesn't need any visually spoiling bonet bulges and, other than that, it is ticking a lot of boxes.

[martin thaddeus]

imported post

Hello There

I have fitted driven both and have no reason to be biased in favour of either.

The Rover was originally fitted in order to give greater reliability as we all know.
And of course there will always be those who want more power, and the Rover is much easier to tweek as there is more stuff and more specialist tuners out there.

In normal form, both engines give something like the same power, but the Triumph is more Whizzy.

So today you pays your money and takes your choice, if you want big power easily go for hot Rover or a new 4.6 range rover. But you will then want a stronger diff and possibly upgraded brakes.

The original stag lump is no slouch and it sounds lovely, but by comparison with modern engines the Volumetric efficiency ( as in horsepower to capacity ratio) is not great.

[Stagdad]

imported post

piscean57 wrote:

I wasn't aware that it would sound differnt to the Triumph unit though. Does it sound really different?...if it does I guess its due to a change in the headers as I thought that exhausts determine noise?

Isn't it firing order and the dual plane crank?

Cheers Steve

[jpyke]

imported post

Stagdad wrote:

piscean57 wrote:

I wasn't aware that it would sound differnt to the Triumph unit though. Does it sound really different?...if it does I guess its due to a change in the headers as I thought that exhausts determine noise?

Isn't it firing order and the dual plane crank?

Cheers Steve

It's down to the firing order I think. Both use a cross-plane crankshaft as you get good 2nd order balance without needing balancer shafts. The other feature of a cross-plane crankshaft is uneven firing which is what results in the V8 burble. There aren't many v8s that use a flat-plane crankshaft- the only examples I can think of are the AJP V8s as used in TVR Cerberas. They're don't sound like conventional V8.

I wonder if its also to do with the exhaustport configurations, Rover are evenly spaced along the head but TV8 are paired so perhaps adds to the burble sound.

[flying farmer]

imported post

Most of the stag burble comes fom the clever design of the standard system, whereby the twoexhaustpipes are of similar length from the down pipe, but the balance pipe between the exhausts is much closer to the exhaust manifold on the offside.

This is because the offside manifold exits toward the rear, and the nearside towards the front. To get the extra length back in the offside pipe it had to go the long way round the diff before returning to the nearside tail pipes

This has the effect that when the pulses of exhaust gas reach the tailpipes they have been modified by the pressure pulses from the opposite cylinder bank through the balance pipe and this gives the burble

On my stag, and the TR, which both have rear exiting 4:2:1 exhaust manifolds with equal length exhausts, there is no real burble, more of a howl, due to the stag engine being a short stroke revvy engine. It still does not sound anything like a rover

The stag powered estate has stag tubular manifolds but equal length exhausts, so it has the mismatched length to the balance pipe, but not the compensatory extra length round the diff. As a result it has far more burble than the other two but not as much as a proper stag system, and it also has a resonant period at about 2000 and 4000 rpm when it gets much noisier. It is as loud in the estate as in the Stag with top down at these revs, but only when accelerating fortunately

Complicated business this exhaust design:?

Neil

[mickjo]

imported post

Ok purist b/s appart, buick designed it but rover bought the design and interlectual rights for the engine, basically what purist whinge about is that the buick is a load of sh*t because its from the 30s or something, the same argument is for Frank Whittle and the jet engine, the original jet would destroy itself due tolack of money/testing under-developement, (hang onisnt that the TV8), the Rv8 is the most widely developed engine to give all the reliability you need. As for the burble, I never had it asthe TV8 engine destroyed itself within 5 miles of me driving it, RV8 for me now on. oh happy days.

[Dave M]

imported post

flying farmer wrote:

Most of the stag burble comes fom the clever design of the standard system, whereby the twoexhaustpipes are of similar length from the down pipe, but the balance pipe between the exhausts is much closer to the exhaust manifold on the offside.

This is because the offside manifold exits toward the rear, and the nearside towards the front. To get the extra length back in the offside pipe it had to go the long way round the diff before returning to the nearside tail pipes

This has the effect that when the pulses of exhaust gas reach the tailpipes they have been modified by the pressure pulses from the opposite cylinder bank through the balance pipe and this gives the burble

On my stag, and the TR, which both have rear exiting 4:2:1 exhaust manifolds with equal length exhausts, there is no real burble, more of a howl, due to the stag engine being a short stroke revvy engine. It still does not sound anything like a rover

The stag powered estate has stag tubular manifolds but equal length exhausts, so it has the mismatched length to the balance pipe, but not the compensatory extra length round the diff. As a result it has far more burble than the other two but not as much as a proper stag system, and it also has a resonant period at about 2000 and 4000 rpm when it gets much noisier. It is as loud in the estate as in the Stag with top down at these revs, but only when accelerating fortunately

Complicated business this exhaust design:?

Neil

Just modded mine as per pic and it does sound different now that exhausts are equal length, it seems much louder but still has the burble. Not sure if I like the increasedloudness of it but will live with it for a while and can always put it back to original if I want to. Need a tunnel or suitable road to have a blastdown to help me decide.

Dave

[martin]

imported post

piscean57 wrote:

Ok so being a bit of a purist myself I am completely convinced that the Triumph 3lit is the engine to have ......but humour me please.

Objectivley, can anyone tell me how these compare in a Stag?

:dude:

It's quite straightforward, the RV8 is a single cam pushrod engine, with a fairly low rev limit in standard form, the TV8 is a twin overhead cam unit with a rev limit of 6.500 rpm.
If you really want a monstrous Rover engine, why not buy the car that it was fitted in ? Like it or not, Stags with non original engines are - and always will be - less desirable, and worth less than the original. Martin.

[jpyke]

imported post

In original form the TV8 and stock 3.5 RV8 compare reasonably well in terms of power output. Someone has rightly pointed out that the RV8 can be tuned more than the TV8 but I would hazard a guess that it is more to do with the availability of uprated parts than the merits of the raw engine design? (Although the TV8 is perhaps a more advanced design being OHC). Admittedly you can really go up in capacity with an RV8 but even the standard 3.5 can be tuned to produce quite a lot of power compared with a stock unit.

With the RV8 there are loads of options (such as mallory distributors, cams by crane, crower, piper, etc., various manifolds, different heads, different lifters, different con rods, pistons etc. and many many more performance parts and of course companies such as JE Engineering and Wildcat that specialise in that particular engine. I think the unit's US origin has given it a real leg up here as many of the performance parts have been produced by 3rd party companies to fit the scores of Buick V8s over there. (When Buick originally dropped the original ally V8 they continued making thinwall cast iron equivalents which had heads with the same ports as the RV8 hence the demand for parts across the pond).

Tony Hart has proved that the TV8 can (reliably?) produce 280bhp; who can say what it would be like if there were a plethora of off the shelf performance components available akin to those for the RV8...

What we need is the TV8 equivalent of an Edelbrock 360 inlet manifold and perhaps some piper cams. I don't think 200bhp would be particularly hard to reach then

[V Mad]

imported post

I think that if you want the RV8 then go for it, but if you are looking for significantly more power than the TV8 the you will be disappointed unless the RV8 is a tuned up one. By that I mean at least a Vitesse spec 3.5 engine, or a decent 3.9 I had one with a Vitesse engine which was fast but all top end; if I bought another RV8 stagit would have to haveat least a 3.9 for the extra low end grunt.

As far asthe sound goes,you can get an awesome V8 sound; one of our Surrey member's has a bespoke system that sounds like a TVR if you like that sort of thing (and I do). Also make sure the RV8 conversion has been done professionally, or it will lower the value, and some things may not work too well.

But I really like the TV8 as well, it is a very sweet engine, and as we have seen from the RR tests at Fontwell,can produce a healthy BHP if properly set up.