The Triumph Dolomite Club - Discussion Forum

You cannot run a slant without a thermostat and be sure it's the dual valve and not a normal single valve. No or wrong thermostat will run a slant too hot.

Jeroen

I've just fitted a new speedo cable to my od 1850, 3200 revs at 70mph.

The gearing figures for all Triumphs with various tyre sizes are on the excellent Minty Lamb web site.

A dolomite with 3.63 diff and 155 tyres is IIRC 18.5 per 1000 rpm in top.
So 3000 rpm in 55.5 and 4000 is 74 mph...

Max revs of 6000 in top would be 111mph....so a dolomite is very nearly ideally geared for maximum power revs at maximum speed.

Overdrive makes this 21.5 mph per 1000 so 3000 rpm is 64.5 and 4000 is 86 mph. Your instruments would seem to be pretty close...

70 = 3255 rpm.

Jonners

I took the Herald out on Sunday and it ran hot (about 3/4).

Went for a run again today and needle stayed at bang on 1/2 so all OK.

Have you tried yours again?

Hiya Alan,

Having recently run mine its been running a lot better, its always run a little hot according to the temp gauge. I used a £10 IR temp gun, it said the thermostat housing was 77 degrees for normal running, so I think I'm all good!

I always thought the gague should read 1/2, sure your voltage regulator is not over 10/11 volts ?

Good to hear the coolant is not overheating, gagues and electricals are an easier fix.

Guys, the temp gauge has three things which will affect the reading:
The temperature.
The voltage supply.
The temperature sender unit.

The difference between the senders sold by most vendors and nos is significant.
Modern replacements give a higher reading on the gauge and are much more responsive to the temperature, in my experience. NOS on an 1850 with no cooling problems on a hot day and normal running will give a reading a bit under half. Modern senders give a reading on the half, and the gauge varies according to how hard the engine is working often going over the half.
I've bought two senders from Robsport as spares, not been fitted, but they are aware of the problems of some new spares so hopefully they are better than some other suppliers offerings.

Voltage supply - ditch the old stabiliser and fit a modern item, perhaps the club still stock upgraded items? If not, fit a 30 pence chip, search the forum for details.

Interesting question and on a day to day basis when commuting, the answer is as fast as the car in front, and a lot below the theoretical speed limit of 100kph on the motorway. Unless I get out onto back roads everywhere else around Auckland is crawling with unmarked cop cars and unmarked vans with speed cameras, so I generally drive at whatever the maximum is before they give you a ticket. Most of the time it is 9kph above the posted limit but over public holiday weekends and during summer school holidays it is only 4kph over, so that is what I drive at.

Interesting exercise though to calibrate a Dolomite speedometer against a GPS based app. My Sprint with overdrive on standard 175.70 tyre is only doing 95 when speedo indicates 100. The auto Sprint with 185.70 tyres is almost spot on accurate. Almost all run of the mill new cars have a 3-5% safety margin in their speedometer reading, hence why lots of people sanctimoniously drive just below the speed limit. Their speedo tells them they are at the limit.

I firmly believe Dolomites drive better above than at the 100kph speed limit. Even the auto car drives very well at 130kph. However, the suspension bushes and ball joints all need to be in very good order (along with the brakes!).

I suspect the drag co-efficient is higher than we even imagine. My race car will pull a true 175kph before the braking point at the end of the front straight, but as it is doing 170 150m earlier, I doubt it could get above 180, however long the straight. All the extra power seems to do, is get it to that speed a lot quicker than a standard car.

I think the answer for anyone though to drive the car at whatever speed they feel comfortable with and are enjoying their drive. I think we all own Dolomites as we enjoy driving and it should never be just a means of getting for A to B.

Geoff

Voltage supply - ditch the old stabiliser and fit a modern item, perhaps the club still stock upgraded items? If not, fit a 30 pence chip

Absolutely.

There is a nice article here about fitting a 10v regulator into the original case.

http://www.britishv8.org/articles/mgb-v ... ilizer.htm

Nice article that Alan, thanks for that.

Tony

I agree with Geoff about the drag co-efficient, I think I heard somewhere that a Dolly is about .43. The Citroen DS had the leading one in its day at .31 and modern stuff now is heading for .25. The Carledo will not do much over 110 MPH flat out, a speed it can reach in 4th or 5th gear, it's not running out of power, just the wind resistance is too much to overcome easily. It would be interesting to see if anything could be done in the way of splitters and spoilers to improve it, but I suspect not a lot without radically altering the shape of the car, the flat front and steep screen alone is probably responsible for most of the problem, alter those and it wouldn't be a Dolly any more.
In any case, a ton+ is enough to cost you your licence, why would you need more?

Steve

PS anyone like to photoshop a "droop snoot" Dolomite?

My Fourtrak has all of the aerodynamic properties of a garden shed, and when pressed to make progress it tears apart the very fabric of time and space in doing so. There might be a great big 2.9l intercooled turbo diesel under the hood but it struggles to get up to 80 flat out downhill with the choke hanging out. And to those that wonder where all the summer bugs that used to plaster windscreens years ago have gone, simple, clean over the top of the modern car caught in it's smooth slipstream and stuck to my upright flat windscreen!

So quite agree, with all those sticky out bits from the wing mirrors to the door handles, the flat front and upright windscreen you are going to need serious power to break the wind resistance it rolls up in front of it like a bulldozer across the lawn!

Resistance from aerodynamic drag rises as a function of speed squared...
which is why you seem to hit a brick wall at around 120 in our cars...

Jonners

I have not yet hit a brick wall at 120.