How to improve MPG on old V8

wish mine did 14mpg, then i'd be happy (er)! I get 10 out of mine in 'normal' use and 13 on a run. The roof rack will add a lot of drag, removing it should add about 10% ish to mpg.

Richard

Hiya,

Okay take off the roof rack - should up it to about 15 m.p.g I would get the carbs balanced, there is too much fuel going through that is why you are getting a back fire.

I would put on BF GOODRICH tyres I know they are not cheap but they will help.

If you fit a K&N Air filter I reckon you could then hit 16 m.p.g.

All of this will help and I also reckon that HiCiclones work well. Add at least another 1 m.p.g So you could then be hitting 17 m.p.g I woudl also slick 50 the engine it probably won't help the m.p.g much but it will make everything a little smoother. I take it that the tappets are adjusted correctly.

Yours

Andy

P.S. If you want to go the whole hog get yourself a Stainless Steel exhaust.

I'd personally advise against using Slick 50. If you do a search you'll see that there is quite a lot of evidence to support the fact that it reduces friction but it also clogs up the smaller oilways and can cause oil starvation to the parts that are fed by these oilways. Just do regular oil and filter changes with a decent quality oil.

The other thing that is common with the V8 is that beyond about 80000 miles the lobes on the camshaft become quite worn and reduce power and economy.

Regards

Phil Gardiner

I'm definitely coming to suspect this with mine, apart from loss of power are there any obvious symptoms or checks. Economy remains the same almost regardless of driving style, only dropping for short journeys.

AJH0

The ONLY method guaranteed to improve mpg is amputation of right foot!

Don't use Slick 50 - I have used it in the gear box and it's fine but I wouldn't put it near the engine.

My 110 V8 CSW ex police will do 18mpg on a run - sometimes it has done

I have a 3/4 roofrack - a riot screen AND 4 big spots on a light bar so plenty of drag. I have noticed that as long as you stick to 65mph it is fine - at 90mph it is dropping like a stone.

Engine is standard as is the exhaust. SU carbs - Colway mud terrains. It does run like a dream and scares people because it is so quick.

My new 300tdi is not much better on fuel and is not as quick either.

Why have you left the riot screen on? Do you anticipate using it? ;)

It is great in amongst the trees - or certain housing estates.....

Less than a month old.

Why should a worn cam affect emissions?

AJH

I have to bet that the police garage bods will have tweaked the nuts off it thats not a bad figure at all. When I had the Rangie ( efi 3.5) the best figures were on long runs Timperley - Stranraer at just under 24 mpg cruising at around 70 on clear roads ( left 5am ) daily driving to work was horrendous at

I took it in for a tune up a few years ago and to have the carbs balanced. Bloke did it to the book - the engine pinked like hell - I turned the mixture screws about 1/2 a turn each - now runs like a dream.

I had a similar thing on my old sII 2.25 petrol. I set the timing with a strobe light, got it perfectly on the right mark, ran like a dog. Then I just grabbed the distributor and turned it until it ran sweetly, which left the timing "way off" but working better. LAnd Rovers eh...

Whereabouts are the mixture screws?

Stuart

|| It is great in amongst the trees - or certain housing estates..... ||

Is it to keep the chavs out, or the passengers in?

Mixture screws are in the sides just under the body of the carb on the SU if I remember correctly.

See

Thanks, but I've got the other type of carb (Stromberg?)

Ta, Stuart

You adjust the needle position relative to the piston - the adjuster is accessible after you remove the damper/plug from the top of the piston housing.

A 'special' tool may be required to stop you rotating the piston at the same time and damaging the diaphragm. The typical sort of thing usually used can be viewed here:

adjuster is down at the bottom of the damper bit

Its either a long allen key (the special part of the tool is a collar that holds it central). or alternatively there is a lump almost like a grain of rice down at the bottom of the damper hole and the tool turns that (a straight screwdriver with a cut in the centre works too)

Oooooooookay. So assuming I can find a suitable bit of metal to do the turning, how do I know I've done the right thing? Presumably whilst the engine is running, turn it one way until it starts to cough then back off a little - but two at the same time? Never had a V8 before, only

TIA, Stuart