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[vod80]

Hello everybody - I have finally got my 109 completed and roadworthy.

I've been driving it a bit and I'm really surprised by how slow it is.
It's very comfortable at 30mph, it will do 50mph but everything's a bit harsh and the engine has only just been rebuilt, it's too soon!

Are my numbers correct? To get 50mph, I need +/- 3000rpm?

[autorover1]

According to my old LR Dealers handbook the 109" is geared at 16.5 mph / 1000 revs on 7.50 x 16 tyres , so 50mph at 3000 is about correct . Once run in, I found  my old S2 & S3's would run comfortably  all day at that sort of speed . Michelin 7.50 x 16 XS tyres were slightly larger dia. giving 17.2 MPH /1000 revs.

[Craig T]

My 109" is the same, it will do 55mph and has achieved 60mph but I wouldn't take it much past that and wouldn't want to do 60mph for too long as it is revving the engine pretty high.

Only solution is to fit an aftermarket overdrive, higher ratio differentials from an early Range Rover / Discovery or get the transfer box modified for a high ratio Ashcroft gearset.

Diffs are probably the cheapest but will affect all gears including low ratio.
An overdrive is good, only works when selected but does involve cutting the transmission tunnel to fit it. Not cheap, second hand overdrives can be heavily worn on the input splines.
The Ashcroft gears affect all the high ratio gears leaving low ratio alone but does involve removing the transfer box, machining it then reassembling it all again, not a five minute job.

Craig.

[GRMac]

Just out of interest when working the speeds out are you working off the speedo or GPS? My 109 will sit happily at 'indicated' 50 in 4th without the overdrive engaged but to go 'true' 50 feels uncomfortable.

[Craig T]

I was talking indicated speed on the gauge.

I have tried it with the satnav as well though and it does overread a bit so indicated 60mph is probably more like 55mph.
Indicated 60mph though does feel a bit harsh on the old girl...

Craig.

[vod80]

Thanks for your thoughts.

I saw a discussion about TOMs in another subject so I did check mine.
I have an 860TP(k)M speedo fitted. By my calculations, it should be 864 so pretty close.
The indicated speed is very close to the real (GPS) speed.

Well. 50mph it is then!

More respect from me to those people who drive Land Rovers long distances!

[Exile]

Personally, I wouldn't try to test the maximum speed on an engine that "has only just been rebuilt".

Run it in properly and with patience. It will then serve you well for many years.

Then get an overdrive?

[jkhackney]

Great-looking 109 by the way!

The best addition, besides an overdrive, is to remove the rear-view mirror, if that's legal where you are.

It's not required on my S1, as it wasn't original equipment. Not seeing what's brewing behind me makes the slow speed much easier to tolerate!

[island dormy]

  Hi

  55mph is a nice speed in the dormobile anything over that starts to get hard on the ears, its revving at 3250rpm at that speed, 70 mph is 4000rpm and that also its top speed (with a long enough runway.)

   I agree with Jeremy remove the rear view mirror (that's the first rule of Italian driving) "what's behind you is no longer in front of you", of course that might not apply when your driving a 65 HP Land rover instead of a 500 HP V-12 Ferrari.  But you will still be at the front of the parade and that's always a nice feeling.

   Victor

[Genem]

For comparison I drove the 1000 miles round trip down to Cheddar for the Rally at GPS indicated speeds of around 50-55 which did not involve "flooring it". I measured the fuel consumption between fills and achieved up to 22 mpg. On the way home I did increase the speed and even pushed it to accelerate up Shap Fell in the Lake District, topping out at 60 mph. (This is on an engine rebuilt a couple of years ago.) The "higher speed" section dropped the fuel consumption to 19mpg...  Overall I'd say its happiest in the 50-55 range.

[vod80]

Personally, I wouldn't try to test the maximum speed on an engine that "has only just been rebuilt".

Run it in properly and with patience. It will then serve you well for many years.

All sorts of cans of worms but I do take care with engines. It is important to be sure to warm the engine up first and to then be sure not to baby the engine, nor to labour it. But making rated power is not detrimental - in the correct doses

I had a Blackburn Cirrus major rebuilt to zero time (probably the most expensive thing I’ve ever done…) and the rebuilders were very clear about that. That engine’s still flying and reported to be the best engine that people have been behind 😀

Cheers, Tony

[S3upra]

Just my opinion - have a swb with a v8, 750 tyres and an ashcroft transfer box,will do over 90 easily(only did it once) however it's happy at 55, smooth,not too much other mechanical noise. Always wanted a v8 and i love it. But the 2 1/4 is a fabulous engine(though as thirsty as mine) i think series Land Rovers are just happy at 50-55mph,it's a good speed, allows you to enjoy the scenery.

[Mr Ed]

One reason for the high consumption of these vehicles above 50 mph is due to the fight against the wind...
Keep it slow and enjoy the ride.

[vod80]

The speed itself isn’t really a problem - 80kph is our speed limit in most places. 3000rpm in a diesel doesn’t seem natural. All my previous Series Land Rovers were petrol…