What's up with it?

jamesmartin · Jan 5, 2016

Vintage-and-Classic said:
We'll have to disagree on that one then. I'd say that on all fronts tech *can* be better but it depends what tech is aiming for. I'd also say that I disagree most strongly with people who blame the old designs for their own lack of competence. Engines with distributor contacts and carburettors produce good power without flat spots, hesitations, misfires or "bogging down"... or unreliability. These are symptoms produced by engines in faulty condition, whatever their design.
Quite simply we are not comparing like with like in this discussion: I am saying that high perfomance carburettors can produce more power than Bosch Motronic. That's not saying that they are better, just that they are engineered to do a different thing. Motronic is not engineered to produce maximum power. High perfomance carburettors do not produce more power than say Weber fuel injection throttle bodies because that is comparing like for like. This last comparison illustrates that modern technology can do better. A 1966 Ford GT40 goes a hell of a lot faster than a Toyota Prius. It's not that the technology was better in 1966 it's just that those two cars are trying to do different things and you wouldn't want to take the GT40 shopping (although I once had a customer who did.....)

its not a matter of blaming old designs they were the lastest thing at one time , but mechanical is beaten by the new tech, a system that can adjust spark and fuel many times a second is allways going to beat one that has a few compromise settings

Vintage-and-Classic · Jan 5, 2016

jamesmartin said:
its not a matter of blaming old designs they were the lastest thing at one time , but mechanical is beaten by the new tech, a system that can adjust spark and fuel many times a second is allways going to beat one that has a few compromise settings

Okay - this is my last post on this one because it's just hijacking the thread but I feel you are missing the point. Of *course* new tech is always going to beat old tech but engineering is all about design objectives. Something designed for maximum power decades ago can still produce more power than something which is designed with other objectives in mind today. Otherwise if modern tech is so good how come a modern 3 cylinder VW can't beat the pants off a 1939 Mercedes Benz GP car. It would be ridiculous to think that it would... because that's not what it's designed to do. You can still say the modern design is "better" if you like but it's not faster. That's an extreme example but I hope it illustrates my point

jamesmartin · Jan 5, 2016

Vintage-and-Classic said:
Okay - this is my last post on this one because it's just hijacking the thread but I feel you are missing the point. Of *course* new tech is always going to beat old tech but engineering is all about design objectives. Something designed for maximum power decades ago can still produce more power than something which is designed with other objectives in mind today. Otherwise if modern tech is so good how come a modern 3 cylinder VW can't beat the pants off a 1939 Mercedes Benz GP car. It would be ridiculous to think that it would... because that's not what it's designed to do. You can still say the modern design is "better" if you like but it's not faster. That's an extreme example but I hope it illustrates my point

thats not really an argument given like for like tech beats a mechanical,though personally theres nothing like steam or vintage engines for appeal

cooltide · Jan 5, 2016

Vintage-and-Classic said:
Otherwise if modern tech is so good how come a 2015 Mercedes gp car can't beat the pants off a 1939 Mercedes Benz GP car

Vintage-and-Classic · Jan 5, 2016

jamesmartin said:
thats not really an argument given like for like tech beats a mechanical

All right... one more post then: That's *exactly* what I'm saying. I really am done now

cooltide · Jan 5, 2016

mordzy said:
It's just sailed through its mot!

Did they emissions test it?

mordzy · Jan 5, 2016

cooltide said:
Did they emissions test it?

Yes all good

Vintage-and-Classic said:
I'd beg to differ: Rover knew what they were doing with the original set up and fitting the aftermarket filters to an otherwise standard engine will only make it go worse, mainly but not only because the standard needles aren't callibrated for that setup It will sound more dramatic with those filters and that may be enough to convince the wishful thinking that it is going better.

I thought about them filters on the way home and figured the original has a lot more thought and design than the after maker k&n style things... So I didn't bother and will look at the condition of the stock filter tomorrow if time allows.

When starting from cold after a week sat idle she fired up right away with a bit of chock on, doesn't misfire or sound rough.

I've googled my evening away looking for someone to set them up with no joy.. I'll keep searching. Seems like a forgotten art.

waldamar · Jan 6, 2016

I can't believe those K&Ns are really that much more free flowing than the originals but anyway, my main point was just to check and see if you've got blocked filters. What colour are the plugs? Also the vacuum leak possibility. If there are any old fashioned garages near you they may still do "Spot On" tuning - where are you based?

mordzy · Jan 6, 2016

I will check all you suggested. In in Bradford West Yorkshire.

cooltide · Jan 6, 2016

www.motoscope.co.uk

norseman · Jan 6, 2016

waldamar said:
I can't believe those K&Ns are really that much more free flowing than the originals but anyway, my main point was just to check and see if you've got blocked filters. What colour are the plugs? Also the vacuum leak possibility. If there are any old fashioned garages near you

Just joined this thread & as a 3.5 (efi) owner myself I've found many of the tech. replies a very interesting read. My own engine runs well at a documented 52k & is serviced every year (1500m) but I'd certainly go for a 3.9 cam if ever a top-end overhaul was needed
For what it's worth I would also look for any vacuum leaks. Simple things like the rubber pipe from inlet manifold to dizzy, they often split where they push onto the metal tubes. Also, if you can find one, the old Colortune plug is good for mixture checking.
Hope you get it sorted

Click to expand...

mordzy · Jan 6, 2016

Ok. I've taken off the air box and checked the filters they look fine.

Here's a pic of the air box

And the carbs

I let the engine warm and also checked the carbs felt 'balanced' by cupping my hands over the air intakes and feeling the suction. Crude but they felt the same as my hands would allow to judge.

Went for a quick blast with no filter and no difference whatsoever. Put it all back together. Checked for vacuum leaks and can't feel anything...

I noticed from counting between gear changes I'm out of first after 5 seconds, maybe slightly longer in 2nd lots of noise to what I guess is redline before I change but Not moving forward very fast if that makes sense. 3 is low power takes ages to build revs. Just seems like there is all drama and no forward motion.

Not sure what's next...

jamesmartin · Jan 6, 2016

check for those restrictors and comp ratio

mordzy · Jan 6, 2016

Sorry James, can you explain what you mean? I take it you mean the restrictor between the manifold and carb block. And the engine number ?

Vintage-and-Classic · Jan 6, 2016

mordzy said:
And the engine number ?

http://www.v8register.net/FilesV8/V8 engine number reference R7 30.11.07.pdf

If your engine hasn't been messed with that might give you a clue as to the compression ratio.

That said, whatever the CR your engine should go better than you describe. The restrictor plates which James describes, however, are the spawn of the devil and should be removed if you have them!!

mordzy · Jan 6, 2016

engine number reads;

CR8 13.1
S24G00181b

jamesmartin · Jan 6, 2016

mordzy said:
Sorry James, can you explain what you mean? I take it you mean the restrictor between the manifold and carb block. And the engine number ?

comp ratio is usually stamped next to eng number ,its possible its a perfectly good example of a low comp defender spec which is not as you might hope for

jamesmartin · Jan 6, 2016

mordzy said:
engine number reads;

CR8 13.1
S24G00181b

tis low comp

Vintage-and-Classic · Jan 6, 2016

mordzy said:
engine number reads;

CR8 13.1
S24G00181b

Probably 8.13 cr then.
Not the quickest ever made but should go just fine and keep up with modern traffic if running properly. Your engine was probably originally on Stromberg carbs. The needles specified for the SU carbs on a post 1985 engine will not be quite correct for that engine.

mordzy · Jan 6, 2016

Hmm. In answer to the keeping up with the traffic it's a no. Based on my assumption on the definition of modern traffic. I've been beeped at and overtook on the slightest gradient by corsas and micras etc while having to drop into 2nd to keep the revs up and prevent it from stalling in 3rd...

Like I said before my only yardstick is the other defender I went in. Assuming his was high compression and had gained 20-25 horses over mine id say it was atleast 100 horses between them.

It also feels weak...

Perhaps it is what it is and my expectations are to high?

What's up with it?

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