401 - Oil & water temperature gauges

[p5b401]

Not having had driving/operational experience, I'm not sure if the temp gauges are working correctly. The oil temp hardly moves and the water temp is so slow the thermo fan can cut in an out several times before the gauge registers somewhere near correct.
Pipes to both gauges have had some obvious kinks in them which previous owners/mechanics have 'sort of' straightened.

I'm wondering if there is a practical need for the oil temp gauge or is it just a flow on from its aircraft heritage?

I'm thinking of removing the existing oil temp system and replace the water temp with an electrical style but with the same case and in the same facia style (minus any oil temp scale). Has this sort of thing been done before and does it detract from the vehicles heritage?

[Geoff Dowdle]

Why reinvent the wheel !!
Just remove the gauge with the two capillary tubes and get it serviced at an instrument repairer.
It will be cheaper and easier than the mod you are suggesting & retain its originality & car's value

Geoff

[dave dale]

My advice, for what it is worth, is that the oil temperature gauge is very important. Bristol experts, including those who make a living repairing engines, will tell you that more 2 - litre Bristol engines are wrecked by drivers not waiting for the oil to warm up properly than any other reason as the oilways on this engine are quite narrow. Spencer Lane-Jones wrote an article to this effect in the BOC Bulletin some years ago. It is advised to never put an engine under load till the oil is warm. The 401 / 403 engines notoriously take a long time to warm up in winter partly because the sump is of alloy and is shallow, with a large surface area. I run my 403 with radiator blinds and a windshield on the sump in winter. Even with these aids I sometimes have to travel 20 miles on a cold day before the oil temperature gauge needle lifts off the stop. Use of the lower gears and restrained driving until the oil temperature reaches 50C will protect the engine. Dave Dale.

[Stefan]

If you want to check your oil and water temperature sensors its quite easy. Simply dangle them in a kettle of boiling water and they should both read 100°C. And yes, both are important. Water overheating is the first sign of a leaking head gasket which Bristols are very prone to. Intervene early rather than damage your irreplaceable cylinder head. Secondly, oil temperature is critical as we read below both cold - and hot which should not exceed 100°C. Bristol aerodynes have quite limited airflow under the bonnet in some cases. A spell of high-speed driving on hot day will certainly bring your oil up to its limit, Though I am aware that modern cars may be redlined at 120°C I think it's best to follow Filton's original specification as rebuilds are so costly.

These instruments can readily be repaired by specialist instrument repairers. I I've paid £50 last time? Oh, and when you're finished replace the kettle in the kitchen, having done your best to remove all traces of antifreeze & oil from its interior in the interests of domestic harmony.

[Kevin H]

Originally Posted by dave dale

I run my 403 with radiator blinds and a windshield on the sump in winter. Even with these aids I sometimes have to travel 20 miles on a cold day before the oil temperature gauge needle lifts off the stop. Use of the lower gears and restrained driving until the oil temperature reaches 50C will protect the engine. Dave Dale.

Dave, have you ever considered a sump/crankcase heater?

It doesn't have to be intrusive. You can get heaters nowadays that stick to the outside of the sump, although internal heaters are obviously more effective.

[dave dale]

Originally Posted by Kevin H

Dave, have you ever considered a sump/crankcase heater?

It doesn't have to be intrusive. You can get heaters nowadays that stick to the outside of the sump, although internal heaters are obviously more effective.

Thanks Kevin. I get around the problem on cold days by running the engine at 1300 to 1400 rpm with the car stationary before setting off. With the radiator blinds in place the oil heats up and allows the needle to rise off the stop within about 5 minutes. After setting off the needle rises to 50C shortly afterwards. The sump heater is a good idea but London does not get all that cold these days ( climate change ? ) and, when away from home, there is not often somewhere handy to plug it in. Dave.

[p5b401]

Thanks Dave.
I was thinking on the oil temp being for hot purposes and living in Western Australia when a coldest winters night is +4 celcius, I didn't think of the cold reasons.
My main problem is that the response times seem incredibly slow and I can't find any stats which indicate response time.
I'll do the hot water test and make sure the indicated temp is in the ball park and decide what needs to be done after

[Paul Howell]

Neither water or oil gauges work on my 403. I just took it out the gauge and assembly and am taking it to Howard Instruments - quote of $140 AUD each bulb to fix, refill and calibrate. In Melbourne Australia.

[Paul Howell]

Originally Posted by Paul Howell

Neither water or oil gauges work on my 403. I just took it out the gauge and assembly and am taking it to Howard Instruments - quote of $140 AUD each bulb to fix, refill and calibrate. In Melbourne Australia.

I had the job done - they work well now. Just the rest of the car to go.

[pasini s]

Hello all,

Speaking of radiator blinds, I think that they arer really useful in winter, and here's what my mechanics did build to keep the engine warm:

Bristol 403-1404 custom-made radiator blinds

The long screw lifts or lowers the blinds when you turn the upper black knob. Yes, I've seen the oil needle moving veeeeery slowly upwards now in winter, so I'm trying to keep it easy until it moves from the stop, and this happens only after 15-20 miles, like Dave said. I wouldn't do without all these gauges, they are part of the fascination of the 403 (and other Bristols).

All the best

Stefano

Originally Posted by dave dale

Thanks Kevin. I get around the problem on cold days by running the engine at 1300 to 1400 rpm with the car stationary before setting off. With the radiator blinds in place the oil heats up and allows the needle to rise off the stop within about 5 minutes. After setting off the needle rises to 50C shortly afterwards. The sump heater is a good idea but London does not get all that cold these days ( climate change ? ) and, when away from home, there is not often somewhere handy to plug it in. Dave.

[pasini s]

Hello all,

Speaking of radiator blinds, I think that they arer really useful in winter, and here's what my mechanics did build to keep the engine warm:

Bristol 403-1404 custom-made radiator blinds

The long screw lifts or lowers the blinds when you turn the upper black knob. Yes, I've seen the oil needle moving veeeeery slowly upwards now in winter, so I'm trying to keep it easy until it moves from the stop, and this happens only after 15-20 miles, like Dave said. I wouldn't do without all these gauges, they are part of the fascination of the 403 (and other Bristols).

All the best

Stefano

Originally Posted by dave dale

Thanks Kevin. I get around the problem on cold days by running the engine at 1300 to 1400 rpm with the car stationary before setting off. With the radiator blinds in place the oil heats up and allows the needle to rise off the stop within about 5 minutes. After setting off the needle rises to 50C shortly afterwards. The sump heater is a good idea but London does not get all that cold these days ( climate change ? ) and, when away from home, there is not often somewhere handy to plug it in. Dave.