P6 engine swaps

E

EccentricRichard

New Member
Hi guys

Been having a think. Now, I love P6Bs, but I'm not such a fan of the four-bangers - not so refined nor much more economical. Also not much tuning potential. So, I've been thinking of what to do with a load of four-pot P6s... no offence to four-pot owners intended!

Petrol:

Eight cylinder engines:
Jaguar AJ-V8, 3.2, 3.5, 4.0, 4.2 or 5.0 - all except the 3.2 and 3.5 have been available as supercharged 'R' models.
Ford Modular V8 - 4.6, 5.0, 5.4... as seen in the Mustang, the Explorer and others. Available as a crate engine.
BMW V8s - not the old ones from the E34 5-series, they were troublesome, but the later E39-on models and their contemporaries. 3.5, 4 litre, 4.4, 4.8 IIRC.
Volvo V8 - as seen in XC90, Noble M600, etc. It's a Yamaha engine, narrow-angle (only 60 degrees) - I think it's based on the Ford Taurus SHO's V6.
Daimler 2.5 - it's been done, well some bloke did it in the 60s. Wonderful sound.
Daimler 4.5 - harder to get hold of. Did see a Majestic Major on the A3 the other day, though.
Porsche 928 V8, or the modern one from Cayenne/Panamera? Great engines, anyway.
Audi 4.2, as in R8, RS4, and others. Great engine. Plenty of torque, lots of revs.
Lexus 4.0, 4.3, 5.0 - very smooth, very reliable, not a lot of aural thrills though.
General Motors LS - old-fashioned pushrod engine, but a stonking good one. 640hp supercharged LS9 a mighty thing. Available as a crate engine. Endlessly tunable - 1500hp no bother.
Mercedes-Benz - just about any of them. The 5.5 would be my personal favourite - smooth and torquey. Bonkers AMG 6.2 perhaps a bit too loud for a P6.
Volkswagen W8 - a rare engine, offered but briefly in one generation of Passat. Essentially half a Bugatti Veyron engine, minus the turbos.
Maserati 4.2/4.7 - lovely engine, pity about the cars they've put it in. Ferrari use a similar engine in the F430, the California and now the 458 (and anyone who destroys the hideous 458 is doing the world a favour).

Five and six-cylinders:
BMW's straight-sixes won't fit. The Triumph engine might, but that would probably be akin to heresy!
Volvo do a rather nice straight-six, as does GM in the Daewoo (sorry, Chevy (sorry, Chevrolet)) Epica. Both designed for transverse application - they're quite compact.
Volvo's 5-cylinder is a nice engine - lovely warble to it. The 2.5 is the one to go for - the 2.4 is underpowered and thirsty.
Volkswagen VR6 - sort of a straight-six, sort of a V6. It's basically a very narrow-angle staggered V6 under a single cylinder head. There's a five-cylinder variant, too, but it doesn't sound great, unlike a straight-five.
Alfa Romeo 'Busso' V6 - emphatically not the more modern iron-block engine (which is supplied by Holden). The Busso is a great-sounding engine, and loves to rev.
Ford Taurus SHO V6, built by Yamaha - great engine.
Toyota/Lexus 3.3/3.5 - not the most thrilling, but does like to rev. Lotus use it in the Evora. Sounds OK, too.
Honda 2.0, 2.7, 3.0, 3.2, 3.5... used in the NSX, Legend, Rover 800, etc. A truly great engine - the 2.5 wasn't great, but the others were. Love to rev, sound good, unburstable.
Rover KV6 - creamy smooth, sounds nice, prone to head gasket problems.
Ford Duratec - also used by Jaguar. Nothing special, just a solidly good engine. Found in Mondeos, S-types, XFs, X-types...
Peugeot/Citroen have also made some nice V6s in the past... and the Porsche/Audi V6 is apparently a good 'un.

Four-cylinder engines:
Volkswagen/Audi 1.8 turbo? Honda's 2.0 VTEC (Civic Type R, S2000) is a wonderful engine, a right screamer - no torque, but 200-240bhp at 9000rpm. Toyota and Mazda make some good revvy engines, too, just not as aurally rewarding as the Honda. Alfa Romeo four-pots are always worth a look - the newish MultiAir turbo engines are good, they're very economical, and not short of torque. Volkswagen's TFSI engines are good, too - a bit heavy (iron block), but smooth and economical. No aural thrills whatsoever.

I like three-cylinder engines, but I suspect they'd be too gutless for a P6.

Diesels?
Might just about get a diesel V8 in - they're all fairly good, so take your pick (Mercedes, Audi, Range Rover - BMW never imported its one to the UK, sadly). Alternatively, Volvo make a nice five-cylinder - there's a new, more fuel-efficient 2.0-litre one just coming. The Jaguar/PSA and Volkswagen group V6s are worth a look too - and apparently the new Mercedes-Benz V6s (all-aluminium) are stonking good. Alfa Romeo's 5-cylinder JTD models are worth a look, too - plenty of 156s in scrapyards to plunder! BMW four-cylinder engines are good, especially the most modern all-aluminium lumps. 175bhp and 260 ft lbs from a x20d, or 201bhp and 300 ft lbs from the twin-turbo 123d. I wouldn't touch anyone else's four-cylinder diesels, they're not that nice. Mazda's are OK, but not as nice as the more plentiful (and ready for RWD) BMW ones. Don't suppose there's room for any kind of boxer engine in a P6?

Oh, and I wonder if you could get a W12 from a VW Phaeton, VW Touareg, Audi A8 or Bentley Continental into a P6? Somehow I doubt it... it's basically two VR6s stuck together.
 
To me asking what v8 petrol engine to put in is like selling ice to eskimos... Why would you swap out a rover v8?
 
rockdemon said:
To me asking what v8 petrol engine to put in is like selling ice to eskimos... Why would you swap out a rover v8?
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I'm talking about what to put in a four-banger P6...

As for why you'd swap out a Rover V8? Perhaps the fact that it's an old engine, thirsty and sluggish by today's standards? The Jag quad-cam V8 is a hell of a lot more powerful and a hell of a lot more fuel-efficient.

No disrespect to the Rover V8, though - it was a great engine. I'd probably want to keep my P6 V8's original engine, if I had such a car...
 
EccentricRichard said:
Been having a think. Now, I love P6Bs, but I'm not such a fan of the four-bangers - not so refined nor much more economical. Also not much tuning potential. So, I've been thinking of what to do with a load of four-pot P6s... no offence to four-pot owners intended!
Click to expand...

Unfortantly your entire post will cause some feathers to be rustled, including mine. And refering to the 4 pot as "four-banger" is just dam right inflammatory.

The Four pot is a good engine and for the time it was designed was a dam good engine. My engine after it's rebuild and now with around 10k on it is smooth, quite and very reliable. I get between 28 and 30 mpg (same as my 57 plate Astra 1.8 ) and unlike engines of the same era needs little routine mantance. Remeber the 4 pot was made for the P6!
 
Much as I love my 4 cylinder cars, my biggest concern for them is the long term life of the motor. New parts are getting really hard to find and the best source for pistons and bearings is NOS stuff on Ebay. For that reason alone, I am keeping a wary eye out for potential replacements.
The V8 will have a good parts supply for many years yet and if it seems too sluggish or outdated, there is always EFI and 3.9 or 4.6 and beyond.
The problem with really modern engines is all the electronic crap that comes with them. Many have computer links to the trans, diff, suspension, brakes etc, etc that turns an engine swap into a complete rebuild. I'd much rather find something early to mid '90s with the benefits of injection but without needing all the extra tie-ins.
 
richarduk said:
EccentricRichard said:
Been having a think. Now, I love P6Bs, but I'm not such a fan of the four-bangers - not so refined nor much more economical. Also not much tuning potential. So, I've been thinking of what to do with a load of four-pot P6s... no offence to four-pot owners intended!
Click to expand...

Unfortantly your entire post will cause some feathers to be rustled, including mine. And refering to the 4 pot as "four-banger" is just dam right inflammatory.

The Four pot is a good engine and for the time it was designed was a dam good engine. My engine after it's rebuild and now with around 10k on it is smooth, quite and very reliable. I get between 28 and 30 mpg (same as my 57 plate Astra 1.8 ) and unlike engines of the same era needs little routine mantance. Remeber the 4 pot was made for the P6!
Click to expand...

Sorry, I didn't intend to inflame - it's just that the four-cylinder isn't as nice as the V8s, isn't as economical as it ought to be, and it's getting hard to find parts for it. It's also not enormously durable - if you're talking 300k+ miles, you'll have to do an engine swap at some point.
 
it's likely to be more durable than the engine in your astra if it's petrol! Last vauxhall i had (2002 vectra) had an absolutely appalling engine. They're forever breathing heavily!
 
rockdemon said:
it's likely to be more durable than the engine in your astra if it's petrol! Last vauxhall i had (2002 vectra) had an absolutely appalling engine. They're forever breathing heavily!
Click to expand...

Vauxhalls have generally had poor engines (the Carlton/Senator's straight-six being the exception). The 1.7 diesel is a terrible engine - why they're still using it I cannot think.
 
I've got two observations on the thrust of this suggestion.

First I do think there are quite a few things you can do with the four pot.

Second I'd rule out most of the engines you suggest on the grounds of width. Modern V engines invariably have twin cam heads and that usually takes them outside the confines of the Rover engine bay. Remember it's a narrow car and the engine bay is further restricted by the front spring humps at just the sort of level where the heads want to be. I also don't see the point of replacing the four with another four. To get anywhere near the torque characteristics of the Rover engine - which is at the heart of the cars' character - you'd have to go for a diesel anyway. That really takes me back to just the five and compact six Volvo's and the narrow angle VR6 and VR5. You could add the older 5 cyl 2.5ltr VW/Audi as well, in both petrol and diesel. I don't know the Daewoo Epica engine but sounds worth a look. I'd love to think the VW W8 would fit....

So back to the rover 4. I don't see a huge problem with pistons and bearing shells. The shells are reasonably easy to get re-manufactured. Pistons are usually easy to get machined up - both imply greater cost than at present though ... Now to power and reliability. The SC head is just a disaster, but luckily Rover gave us the TC head. If you have a 2200 then bore / stroke / valve sizes are in really quite good proportion. Plus it is an 8 valve so torque characteristics are going still to be suited to the car. Big problem with the TC is that the carbs are just too big! As a number of people on here are discovering, this makes them quite difficult to set up to work at low revs. Rover knew this too and EFi was due for launch on the four for the 1970 model year. Yes 1970! This was the Lucas hot wire system as later fitted to the SD1, Maestro/Montego and Rover 216. (I can send you a copy of the workshop manual thanks to KiwiRover if you don't believe). I'd guess you ought to be able to get another 10bhp on the top end whilst improving the driveability of the bottom end and especially fuel economy. On a 2200 that gives a worthwhile engine, especially bearing in mind how light the P6 is by comparison with a modern car. I really wouldn't want to go further than this without thinking carefully about how to strengthen the block. Rover worked hard to make it light, the penalty was those huge windows in the sides. I might be inclined to fit a stiffening tray in place of the bottom main bearing caps if it was to be worked on seriously.

Chris
 
I think it all depends on what you're trying to acheive, most of the engines listed I would class as "dream" engines, destined to give the car more power etc. In which case I'd just use the biggest all alloy LS V8 I could afford, should fit easily being marginally smaller than rv8 and lighter too, and opens you up to pretty much unlimited power.

On the other hand if you just want to replace the rover 4 cylinder with something more modern at roughly the same performance levels I would consider (and currently have one waiting to go in my car) the Rover/Austin/whatever you want to call it T16 2ltr engine as used in 800/200/400/600 throughout the 90's. These have simple, reliable efi system that you can get running on 3 wires, the non-turbo versions produce 140bhp (180 and 200 with turbo) and I've seen abused ones manage 170k miles without complaint. There is also a fairly easy rwd gearbox option. The only thing they really suffer from is Rover's classic 'o' ring head gasket oil leak, which I think makes it perfect for a P6 !, although this can be sorted fairly easilly, or just ignored.

And the best bit, they say "ROVER" on the rocker covers. :LOL:

Of course if you were REALLY brave you could use a 1.8 k series from a 75, would certainly make the P6 much lighter.

Oh, and the Honda 2.7 v6 won't fit, it's too wide being a 90 degree v6 with overhead cams it would basically touch both inner wings, I know I offered one up !
 
I'd agree with the comment about T series and K series... On K series you just put the strengthened bits off the last freelander to use the engine on first and supposedly the problem wont occur again...
 
I'd go as far to say that the K series and an unwillingness to fix it when the problems first surfaced to customers were the biggest nail in the coffin of Rover... Especially when they are fixable by fitting uprated gaskets...
 
Seems to be uprated gaskets , new bolts and and uprated oil rail for the bolts to screw into.
I was amazed to see how narrow the edges of the block and liners are for the gasket to seal against .Gone are the days of flat top blocks
 
Interesting thread as I choose to drive a 4 cylinder daily over a V8, as it's fun to drive and is economic enough.
Have you driven a 4 cylinder car Richard? :)
 
If you are set on a 4 cylinder, why not go for the Toyota 4A-GZE? It has lots of scope for fun stored in it.
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Lovely little engines, my partner had a '92 Trueno with a 20 valve quad throttle (non supercharged) one and it went really well but I wouldn't put one in a P6 as they really don't have any torque. However I would love to stick one in a Triumph Dolomite... :mrgreen:
 
GrimV8 said:
Interesting thread as I choose to drive a 4 cylinder daily over a V8, as it's fun to drive and is economic enough.
Have you driven a 4 cylinder car Richard? :)
Click to expand...

Haven't driven a four-pot P6, just ridden in one, noticed it was slow and a bit unrefined next to a V8. Also, for me, sound is a big part of what makes a car, and, for that, the V8 is much nicer than the four-cylinder...

Incidentally, one exception to the four cylinders sound dull rule is Honda's Civic Type R/S2000 engine - I encountered a chap recently with an S2000 he'd supercharged with a centrifugal supercharger. 320bhp at 9,000rpm, but also something like 260 ft lbs of torque at 3000-ish rpm - not all that low, but low enough to give it real usability. Also, 320bhp and 260ft lbs from a two-litre four, that's unbelievable... and it howled like a wounded beast. If you've ever been lucky enough to hear a V8 Ferrari (up to the 360) at full chat, you'll know what I mean.
 
EccentricRichard said:
GrimV8 said:
Interesting thread as I choose to drive a 4 cylinder daily over a V8, as it's fun to drive and is economic enough.
Have you driven a 4 cylinder car Richard? :)
Click to expand...

Haven't driven a four-pot P6, just ridden in one, noticed it was slow and a bit unrefined next to a V8. Also, for me, sound is a big part of what makes a car, and, for that, the V8 is much nicer than the four-cylinder...

Incidentally, one exception to the four cylinders sound dull rule is Honda's Civic Type R/S2000 engine - I encountered a chap recently with an S2000 he'd supercharged with a centrifugal supercharger. 320bhp at 9,000rpm, but also something like 260 ft lbs of torque at 3000-ish rpm - not all that low, but low enough to give it real usability. Also, 320bhp and 260ft lbs from a two-litre four, that's unbelievable... and it howled like a wounded beast. If you've ever been lucky enough to hear a V8 Ferrari (up to the 360) at full chat, you'll know what I mean.
Click to expand...

Interesting :) I'd like to hear your view after actually driving them to be honest.
The V8 appeals to me because it is far from refined. Rovers left that behind with the 3 Litre IMO That V8 engine configuration with the uneven firing arrangement is awesome. The brute force of each plug firing is even apparent at walking pace as it romps through any gear you pick 8) Don't get me wrong, it's my favourite engine of all time. I even have a 360BHP one in my Capri :oops: but the 4 cylinder is smooth and charming bearing in mind its lack of 1 1/2 litres :)
Compare the figures on a 2200TC to a 3500 and you might be shocked how close behind that ol' 4 banger is :wink:

All the later engines you mention are great in their own environment and feats of modern engineering, but I feel no place for them in my P6 unless you wish to create a bit of a monster like my Capri rather than a daily driver :)
 
It'd be really interesting to know if anybody has tried to retrofit the latest fuel saving technologies to older cars. I'm thinking regenerative braking, stop/start, hybrids even. Any thoughts?
 
I have been doing yanks for the past 25 or so years. I have restored 11 (yes, eleven) 1957-63 Imperials, drove various other makes and models, Caprices, Oldsmobiles, Pontiacs, Mercurys, Lincolns, etc. I also had 14 (yes, fourteen) MKII Granadas.
I have been on many forums and in many clubs. On each one, there was the ongoing discussion, what alternative engine can be installed in which car and especially in the field I was active, this was pretty common practice. It is even worse in other cicles, e.g. there are now very few DKW Mungas left, which still run with their original 2-stroke engine.

I completely disapprove of it. I have yet to fit a non-original engine to a motorcar which is not used in racing. A car comes as a whole package, including the engine, which gives every car it's typical heartbeat and character. If I don't like it, I don't buy it.

In a typical 'what's next?' mood, I fulfilled my childhood dream and bought my first Rover P6. Despite the car was far from pristine, I was hooked instantly. I have never before driven a car which befits me better, style, driving habit, and all the rest. The only thing I didn't like, was the fact, that I had to shift myself. I now have my second one, which is a much more unmolested car and it's automatic. It is exactly what I expected it to be and again, I am astonished how good the car really is. Swap the engine for something different? Not even in my dreams!

Fitting an old car with a modern engine feels like fondling silicone -erm- you know what I mean.
 
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