ok, I have a 3.5 v8 SU carb based manual. Makes loads of noise but is slow and underpowered. I figured that was just how it is.

I bobbed up the road to collect some stuff from an eBay seller and ended up yacking about defenders as he had one in his drive. He's had a few v8 and took be for a quick blast in his. It's the same engine but EFI. It's like a different world. Spun the wheels and flew like a rocket. Says all of his are like that so made me wonder what's up with mine.

Any id easy? It runs ok. Could the tuning be that off? It's just sailed through its mot!

if yours is low compression a high compression will feel better let alone the extra from efi

Most carb V8s are running pretty badly now because it's so long since they left the factory. It needn't be that way though: Mine is an early 110 on Strombergs and it is completely standard in every way. It runs very smoothly with no hesitation and it pulls strongly. Standard V8s keep up with modern traffic and should feel like they are pulling strongly on hills; if they don't then there is something wrong. Firstly - has the engine done 100,000 miles or more without a camshaft change? If so then a new cam, followers, sprockets and chain will be in order and combined with correct settings it should make a nice difference. I'd never suggest a high performance cam in an old engine but going to a standard 3.9 cam in a 3.5 engine will pick up a few BHP without any detriment to anything.
Secondly - how are the compressions? Do the cylinder heads need overhauling?
Thirdly - tune. The original points set up will work just fine but silicone leads don't suit them well. Copper leads with NGK plug covers will work well with points. There aren't many Ballast coils these days for points use which are any good. The only ones I know to are the BERU ZS109 which you can get from Germany via ebay or the NGK U1056 which you can get from Opie Oils. Alternatively *some* of the aftermarket electronic conversions are good.
Do the carbs need overhauling? Spring biased needles don't last longer than 30000 miles after which new jets and needles will be needed. Are they the correct needles? And springs?
Set the dwell angle with a proper dwell meter if you are using points - just setting the breaker gap is not enough. Balance the carbs with a proper balancing tool and set the mixture correctly. (engine should momentarily speed up and then start to die when you lift each carb piston just clear of the bridge with a screwdriver).
For some reason even the motor trade usually make a complete hash of setting up the Rover V8 and you very rarely see a standard engine running anything like it should. A mate in the trade visited me this Christmas and he just couldn't believe how the engine in mine was running because he hadn't realised what they were capable of. Don't forget that the police used V8 Range Rovers to great effect in the 1970s and they were in a lower state of tune than your engine... it can be done!
Best of luck.

I bought the engine from http://www.hobsonindustries.co.uk. It was take from an ex police truck that had done 50k. So I presume it's not low on power due to any of the faults of an older engine...

I'm assuming the carbs need tuning but no idea where to take it ( I'm in West Yorkshire) it's not got points. It's a modern dizzy style and coil. It sounds and runs ok just I struggle to keep up with traffic and have to drop to second...

mordzy said:

I bought the engine from Hobson engineering. It was take from an ex police truck that had done 50k. So I presume it's not low on power due to any of the faults of an older engine...

I'm assuming the carbs need tuning but no idea where to take it ( I'm in West Yorkshire) it's not got points. It's a modern dizzy style and coil. It sounds and runs ok just I struggle to keep up with traffic and have to drop to second...

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Should be fine at that sort of mileage but you might need to make sure that it is designed for it's current set up... ie: has it got the correct compression ratio, does it have any restrictor plates in the manifold? I live in the Malvern Hills and mine pulls up to the highest point (Wyche Cutting) in 4th gear all the way with no problems. Most people's driving isn't that snappy so I see most people off at the lights but I'm not exactly in the hot hatch league! Rover V8s can sound great even when they are producing no power... I drove a 3.9 engined 90 once which sounded lovely but had no go in it whatsoever. Finding a good place to get it sorted is very hard I'm afraid - worth talking to as many local enthusiasts as you can!

Thanks for the advice. I could never do that. I have to drop to second for any slight gradient unless I'm doing 50... Anything round 30 zones requires second...

I had popped it to Simmonites what's close to me but they advised a specialist for the carbs.

Is it worth swapping to EFI... At some point or is finding a specialist as hard

mordzy said:

Thanks for the advice. I could never do that. I have to drop to second for any slight gradient unless I'm doing 50... Anything round 30 zones requires second...

I had popped it to Simmonites what's close to me but they advised a specialist for the carbs.

Is it worth swapping to EFI... At some point or is finding a specialist as hard

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Think you may like to remove the rocker covers turn the engine by hand and see if any of the rockers are actually lifting the valves. Round camshafts are a feature of Rover V8s.

Presumably you mean not lifting as much since it wouldn't run if they didn't lift at all. Not being a mechanic I'm not sure what I'd been looking for if the only half opened or lifted 1mm too short...

Check your engine no. below nearside exhaust header to find out comp ratio

mordzy said:

Presumably you mean not lifting as much since it wouldn't run if they didn't lift at all. Not being a mechanic I'm not sure what I'd been looking for if the only half opened or lifted 1mm too short...

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Worn cam lobes. If you had good lift on some but a lot less on others it would be obvious. If the valves don't open properly the engine cannot breath.

mordzy said:

I bought the engine from http://www.hobsonindustries.co.uk. It was take from an ex police truck that had done 50k. So I presume it's not low on power due to any of the faults of an older engine...

I'm assuming the carbs need tuning but no idea where to take it ( I'm in West Yorkshire) it's not got points. It's a modern dizzy style and coil. It sounds and runs ok just I struggle to keep up with traffic and have to drop to second...

Click to expand...

it will most likely be low compression then, they changed the northern ireland armoured police fleet to 3.9 efi back in the late 90s, which would have been better converting the 3.5 engine to h/c efi

Low comp wouldn't give me the current results...

I guess I need to go over everything. The engine revs fine so I don't think it has an electrical issues. Is my best bet checking lift then getting carbs tuned? Half of me thinks I'm going to struggle to find anyone local who can do that

mordzy said:

Low comp wouldn't give me the current results...

I guess I need to go over everything. The engine revs fine so I don't think it has an electrical issues. Is my best bet checking lift then getting carbs tuned? Half of me thinks I'm going to struggle to find anyone local who can do that

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which are ? runs well but performance isnt special as youd expect a v8 to be,most notice the difference between the 2

It's honestly pants with all sound no power. I can't imagine it ever being usable , I certainly wouldn't tow anything with it. As much as I understand there is a diff between hi lo comp engines this one can't be normal. Just running through out loud as to what seems ok and what my logical next step should be

Valley gasket, vacuum leak worth checking - air filter/s also worth a look. Both often overlooked but cheap and easy to sort. I would also say carbs - that mileage is just about right for things going off a bit. I fitted a cheap electronic distributer from Simon BBC - the old thing has never run so well - your dizzy, if original is no doubt getting a bit tired. Good luck - don't give up..................

mordzy said:

It's honestly pants with all sound no power. I can't imagine it ever being usable , I certainly wouldn't tow anything with it. As much as I understand there is a diff between hi lo comp engines this one can't be normal. Just running through out loud as to what seems ok and what my logical next step should be

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i used to work there , some of those v8s have restrictors in manifold just behind carb in stead of one big hole you have 4 smaller holes, im not saying yours hasnt any issues but the difference is quite noticeable

I'll pop it off and see...

Interesting you mention the air filter... It has the two u bend connectors back to the air box then just a hole in that box.. Looking at pictures I believe the box should have a pipe connected with a filter on the end?

Ah........... wish I could help on that one but I've run an Edelbrock/Weber for years and can't remember the exact layout of the original. Is it an oval airbox? iirc each end ought to have a filter near where the U bend fits. If you have been running with no filtration at all the carbs will need some care [at least]

I've had three 3.5's but they've all been efi auto's so I don't know about carbs.
At the risk of stating the bleeding obvious I would say don't even think about EFI conversions until you get the beast running right, as there is obviously something radically wrong with the engine and/or tuning & efi isn't going to be the magic wand you need.