Rover V8 - Crap ?

webmaster

webmaster

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Please excuse the title, but it is a direct quote from Practical Peformance Car magazine this month, there have been a few comments and readers letters recently debating on the pros and cons of the rover v8, so they have gathered together 7 different rover v8 powered cars and rolling road tested them for comparison. This should get you all talking !!

The results are quite interesting, and confirm what I have seen a number of times in other magazines, and that is that Rover v8's never make the power people think they do. (or are told they do by tuners / sellers !)

In the test is a 10.5:1 S1 P6, apparently rover claimed 184 bhp (sounds a lot to me), on 5 star fuel, this one was making 123 bhp, however it had some fault which was probably limiting power, and you can see from the power plot that it might have made about 150 bhp if the fault wasn't there.


Amongst the others is twin plenum SD1, in imaculate condition having had £12k spent on it (the whole car not the engine alone), this one made 171bhp.

The rest included a 5.2 litre with ported heads etc... made 241bhp, and top of the lot was a 4.8litre running ported heads, special cam, and single plenum injection (yes just the one), and that made 261 bhp.

What is interesting, is that during the testing several of the cars have some sort of issue, either weak / rich mixture, power spark etc, and it shows that just getting the thing setup right can make the world of difference.

In next months mag they're going to be testing a bunch of cars with different V8 engines for comparison. Should be an interesting read ! ( I know they recently tested a tuned all-alloy chevy engined car that produced 650+ bhp)
 
Rover 3.5 / nee Buick 215 V8...


....probably the best boat anchor ever made.
.....should have been left in the boat yard where they found it!

:LOL:
 
Post Purchase Dissonance

Now this will never do! you can't have conversations like this one as Buyer remorse or post purchase dissonance will kick in forcing me to part with my beloved Rover for a 2nd time, though after 22 years of ownership of the current "Boat anchor" I think I will weather the storm :mrgreen:

Graeme

Ps it's a tempting thought to put the car on a rolling road and see how it really performs especially after the the many hundreds of thousand KM's my car engine has done with out having a rebore and or new rings. You have planted a seed in my mind that may get some watering. :)
 
Questions like these make you try and rationalize your reasons for ownership and at some point you have have to say that regardless of all the negatives you just like your car, not as a reasoned reponse but something more basic at an emotional or subjective level. Were your decisions to be made at a purely logical point car ownership globally would be quite a different proposition.
The Rover engine is not a power house, for myself I just enjoy cruising around at 30 miles an hour or even slower and that puts a smile on my face and for this purpose the car is ideal, if I want to go faster and still have a smile on my face I drive my 3 litre GTO which effortlessly generates 320 BHP in standard trim with out fuss or drama and rough idling.

Graeme
 
Absolutely, the character of the v8, as I think it is intended in the P6 is more about torque, and smoothness, to give you a refined effortless drive, and that it does very well !

Due to the nature of the magazine, (peformance modifications, engine swaps etc) I guess they are referring to the engines potential for use as an engine swap donor, mainly for performance vehicles, in which case their suggestions are pretty reasonable, you could find many other engines that would easily produce more power, better fuel consumption and would be cheaper to tune. The rover v8 is a pretty old design, and rover didn't exactly go out of their way to develop it over the years.
 
Repower and upgrades

Here in NZ an un-atended Rover V8 engine will invariably end up in a jet boat! 9 times out of 10.
However as a repower in a smaller (older) car they are ideal as the V8 likely weighs less than its iron block 4 cylinder predecessor.

Graeme
 
I may sound cynical but in truth it is a classic case of "Too much ado about nothing".

I have to accept that magazines have to be inventive and create new stories everytime to keep the interest of the readers (and sales...) alive.

However, i am not surpised for example that the net horsepower (DIN) of a worn out engine is substantialy less than the gross (SAE) figure mentioned by the manufacturer for its new engine! (The P6 case)

And why should an engine tuned by Joe's Super Porting using a Magnahouser superbump camshaft that is having fueling issues (again not surprised) no matter how many thousants the desperate owner spend should be a paragon for comparisons? I have learnt (the hard way as usual) that irrelevant porting could actually reduce the engine's bhp.

And anyway, are they trying to prove that an 50's engine design like the Rover / Buick V8 is less efficient than engines designed in the 70's / 80's? Why should i be surprised with this? Also i think that it is common knowledge that the Rover / Buick V8 was better at producing low down torque rather than high rpm horsepower. The successful applications in various Land Rover products over the years speak for themselves...
 
The design of the Rover cylinder heads is the defining factor in limiting the power that these engine can produce. In order to produce lots of power, the heads need to be able to "breathe" properly, and here in lies the problem. However, having said that, the design of the factory heads as they stand does indeed allow the engine to produce lots of very useable torque, without the need for thousands of revs. So given that the majority of Rover V8 engines found themselves powering heavy four wheel drive vehicles, the standard design ws more than adequate.

As an example, the 3.5 litre Range Rover sold in Australia during the late 1980s, with the vehicle fully laden, a fully braked trailer of FOUR tonnes could be pulled up to 110kph (70mph). Loads of useable torque. Try doing that with a Suburu WRX, even with more than twice the HP!

Running various cars on a rolling road and using a dyno to measure rear wheel horsepower is one way to make a comparison between different makes and models. Extrapolating from that figure in an attempt to determine the power delivered by the engine at the flywheel is always just a guess, as there are many variables involved. The power figures provided by manufacturers, such as Rover in quoting 184 BHP for the Rover V8 as fitted into the early 10.5 : 1 CR P6B engines is a case in point. That figure is for the bare engine so the maximum figure is achieved. No ancillaries are connected, ie...no alternator, power steering pump nor engine fan. The bare engine only on a test stand.

My Rover has been on a dyno and the rear wheel power measured. With the 3.5 running an original 10.5 : 1 CR, 93 HP was delivered. When my 4.6 was fitted, after 2500 miles of running in, it too was run on the same dyno. In both cases, the gear for the run was second, and no other changes had been made. The engine delivered 150 HP at the wheels.

To make a comparison between my Rover and others, I did some research for a range of vehicles that had been tested on the same type of dyno, thus only the vehicles themselves would be the defining factors.

A P6B running a four barrel carburettor on a dual plane manifold delivered a minimum of 96 HP and after a change of camshaft plus fitment of tubular manifolds and a large free flowing exhaust system power rose to 128 HP.

In Australia, the 6 cylinder Holden Commodore uses a Buick 3.8 litre V6. The quoted engine power is 196 HP. The dyno results that I have seen for a variety of cars showed rear wheel power figures of between 121 HP and 132 HP.

The Ford XR6 is powered by a 4.0 litre straight 6 running a 10.3 : 1 CR which delivers 256 BHP at the flywheel. On the dyno, the power delivered is 147 HP. The car has a 6 speed automatic transmission, plus all the ancillaries contribute in sapping power from getting through to the ground.

So in reality, the Rover V8 does not do too badly after all... 8)

Ron.
 
The V8 P6s 'waft' the car along, without fuss, as they have the torque. As has been noted, this was the point of the engine being used rather than total power.

My only gripe with the V8 is that whilst the sound inside the car is lovely, the best 'spine-tingling' sound by far is gained from standing behind the car, particularly when accelerating. Not that practical for the driver! :D
 
Phil Robson said:
My only gripe with the V8 is that whilst the sound inside the car is lovely, the best 'spine-tingling' sound by far is gained from standing behind the car, particularly when accelerating. Not that practical for the driver! :D
Click to expand...

That's what long tunnels and open windows are for....

I do think we need to rember that power is calculated has changed over the years. The 184 bhp for the P6B was probably calculated to a different standard from those used in modern tests - there are old fashioned God-fearing imperial horses and those nasty modern atheistic metric horses. Older engines do lose power as they wear which is another factor to consider.

Brake horsepower is also taken at the flywheel not at the wheels so modern tests on rolling roads aren't really comparing apples to apples. The TP SD1 was rated at 210bhp IIRC, so 171 at the rear wheels is about what you might expect after allowing for accessories and power train losses.

But I think the idea of the 3.5 and its ancestors and descendents as a "performance" engine is stretching things in the 21st century. It was intended as a refined way of delivering adequate power and was thoroughly well suited to the sort of car bought by the sort of people who had traditionally bought Buicks and Rovers. What it does do is deliver a good chunk of torque at fairly low revs but it was never designed to be a horsepower monster - smoothness and refinement with adequate power were the name of the game.

Yes it can be tuned to deliver more but it is still basically a 1950s design for a smooth running and low stressed engine. If you want big HP numbers and lots of revs then really a modern injected overhead cam V8 is probably a better starting point. The Rover V8s success over the years has been due to it's wide availabilty, relatively light weight and overall simplicity, which can deliver performance that is usually more than adequate rather than startling (and can be startling if the vehicle it's in is light enough).
 
I read that Jaguar engines of the same period never made the power figures claimed

It 's all back in the days when advertising wasn't strictly regulated
 
I don't think I'll ever own a blisteringly fast car as there's nowhere to use one regularly & safely & my distaste for modern machinery precludes owning something that can be classed as really fast unless modified. Also I find that I never keep a high speed for long as I just seem to naturally take pressure off the throttle once I've passed the situation I built the speed up for. Maybe I'll have a blast for a mile or three but then just go back to cruising. Passengers in one of the V8 cars, be it P5 or 6 do comment on the way they can pick their heels up though as they do seem fast especially when you take off after just serenely burbling around (I've had more than one lady comment on how nice the engine sounds in the past.. :wink: ). Being aware of the speed is probably a factor in it as most people are used to being insulated from the sensation whilst in their blandmobiles though cruising around town is still a very smooth & satisfying experience in the old Rovers. The V8 has a mystique among most people though & you're always asked if a P6 is a V8 rather than a 2000 (people just assume a P5 has one & in most cases they're right). Only a few speed-freaks may be disappointed in the relatively low performance I think. The general all-roundedness of the engine will keep the legend alive.
As well as that awesome burble.
 
The power figures quoted by "Webmaster" in his original post are not rear wheel power figures, but engine flywheel figures determined by estimate after the rear wheel power figures are measured on the dyno.

The 171 horsepower as example delivered by the twin plennum SD1 is an estimate of the engine power, not the rear wheel power delivered.

Ron.
 
I always thought that the 10.5 CR engine produced 176BHP and that was on 5 star fuel.

The bloke I bought Sparky from reckoned he had it showing 178BHP at the rear wheels - I might try that :shock: could be fun.

I remember in my dim and distant past hearing that Ford took the weight of a Capri and then the 0-60 time to work out the BHP of the 3L Essex engine and found it to be 136BHP. But after they weighed it, they removed a lot of weight to cheat the figures a little - not sure how true that was, just a rumour from long ago.
 
The figures quoted were flywheel calculated figures, they use losses measured during "run down" to calculate transmission losses etc, it's supposed to be very accurate these days, more important though is repeatability, as long as all vehicles are tested on the same gear the results will be comparible. Will be interesting to see next months results for other v8's

Would also be interesting (to us anyway) to see 2000 / 2200 SC / TC tested in the same way.

I also remember seeing several brand new cars tested in this way on Top Gear recently, with surprising results, one even making more power than quoted.

I've been to several "rolling road shoot-out days" where all the "boy racers" tip up in their supposedly tuned cars and get the power measured, all on the same rollers under the same conditions, it's always hillarious when most of them produce much less power than they think they do, and then somebody always turns up in a "shed" that beats them all.... :D

Back in the old days, the yanks used to quote power outputs "gross", measured on an engine dyno, but usually using optimised exhausts / inlets etc to get the best figures, these usually bore no resemblance to the figures produced by the engine once installed in a car running standard exhausts, air filters etc.. It wasn't until the mid-late 70's that they adopted the sae measurement system based on "as installed" hardware. Not sure if Rover were doing the same sort of tricks with their figures early on.
 
Not the first time PPC have taken a dig at the Rover V8, if Will Holman is still editing it it certainly won't change. He's always been a good editor but just seems to have a personal grievence against that poor engine.
 
If you compare fuel consumption, the 4.6 litre powering my 3 speed automatic P6B has delivered a best of 29mpg (9.8 litres/100km) for highway running. In Australia, the Hyundai Genesis is powered by an award winning 4.6 litre quad cam V8 running through a 6 speed ZF automatic transmission. Hyundai are proud of the vehicles fuel economy which is 30mpg (9.4 litres/100km) for highway running.

Twin SU carburettors powering a Rover V8, not bad at all... 8)

Ron.
 
webmaster said:
The figures quoted were flywheel calculated figures
Click to expand...

Jag did this for the E-Type, 265bhp for the 3.8 XK was at best wishful. Was really around the 180 mark (at best). I always thought the standard rover v8 was around the 125bhp mark but had lots of torque. Which is what they saw with their standard P6B.
 
I copy from James Taylor's book "Rover P6 1963 - 1977".

Three Thousant Five, 10.5:1 CR, 184 bhp SAE @ 5200 rpm; 144 bhp DIN @ 5000 rpm.
These are both factory quoted figures and as it has been explained before by others the difference stems from the different way of measurement, in the first case without anchilaries, in the second with everything attached.
So i don't think that Rover was trying to cheat anyone. As Richard stated before the standard P6B would turn out about 150 bhp without the fault it had, which seems to be a match with the factory DIN figure.

I insist that if someone tries to make comparisons, he should do them right, otherwise, we should be suspicious about his motives...
 
Probably the most important aspect to consider when discussing the power output of the Rover V8, regardless of capacity, is not so much peak power, but rather average power.

Average power is calculated by determining the area beneath the power curve, be it rear wheel or flywheel. A broad largely flat power curve is far more desirable, and in this regard the Rover V8 delivers.
Looking at the dyno printout for my 3.5 litre engine (rear wheel power curve in second gear), between 90kph (56mph) and 135kph (84mph) the power delivered only varied by 5hp.

The design of the engine itself may now be considered obsolete, but that does not mean that the performance that it can and does deliver is somehow lacking.

Ron.
 
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