Early 1850 advice

[sprint95m]

My 1850 has an entirely standard cooling system and copes with traffic jams in 30 degree heat in the summer, never an issue. The standard cooling system is well up to the job as long as its well maintained, i change the coolant every other year.

That is true up to a point in my experience.

I had an early 1850 several years ago. One day i made a return journey of over 110 miles.
After parking and getting out of the car I could a hissing noise....on lifting the bonnet a quick scan
lead me to realise that coolant was escaping from the join of the thermostat housing/inlet manifold.
Wrongly as it turns out, I thought the gasket had failed, when I went to fit a replacement
the actual fault became apparent, one of the thermostat housing bolts had corroded so much
that it was no longer clamping the housing and manifold together.
During the journey the coolant had dropped considerably (I think the radiator was still full but I couldn't
detect coolant in the top hose) but the temperature hadn't changed on the gauge
(there is a warning about this gauge reading scenario in the official workshop manuals).

My opinion is that I was lucky, very lucky, that no damage was done to the engine.
It was this experience that motivated me to look at improving the cooling system.



thanks,
Ian.

[veloce_rosso]

I've taken all your views on board. As regards leaks while out I'm not phased by this because since passing my test in 1982, I've owned over 30 cars (many different makes), including company vehicles, I can't ever remember having any water leaks. That doesn't mean I won't have any but the law of averages seems to be in my favour (touch wood).

As the Dolly will only be used at weekends around our country lanes of Surrey and car shows at Brooklands Museum, waterless coolant doesn't put me off. That said, I haven't decided one way or the other but I have plenty of time to ponder the notion.

[sprint95m]

Sorry James, being a forum moderator, I cannot let this go

The expansion tank on a dolomite is an expansion tank.

The air in it allows for a cushioning effect on the cooling system allowing it to heat up and cool down without putting undue stress on other seals and components.

The definition of an expansion tank is unambiguous,
it is a vessel outside outside of the pressurised loop of the cooling system,
in other words it is always at atmospheric pressure.

(Said expansion tank is connected to the radiator cap's neck on the header
(whether or not said header is within the radiator or is a separate remote vessel).
If the pressure within the cooling rises to a certain (preset) point the cap will
release coolant into the expansion tank. Upon cooling (and the pressure thereby falling)
the action of the cap will permit coolant to be sucked back into the system.)



A header tank is the highest part of the cooling system,
up until the 60s these were normally incorporated into the top of the radiator.
From the 70s separate remote headers have been employed. These incorporate a cap
and two connections, the bottom being a feed back into the cooling system (usually the bottom
hose but always before the water pump) and a top connection for the bleed from the highest point of the engine
(sometimes there are two top connections if the car has two high points, eg Vauxhall Vectra).
Given that gravity is employed, for best efficiency a header tank should be as high as possible.
The remote headers normally have spare capacity to allow for some expansion of the coolant, thereby negating the need
for an additional expansion tank.
Whether it is remote or integral, a header always has the outlet at the bottom.


thanks,
Ian

[matt of the vivas]

The tank on a Dolomite is an expansion tank.... thats what its for and thats what it does - as James points out, its there to absorb expansion and contraction of the coolant to avoid coolant loss. The position of the pressure cap is irrelevant, its still an expansion tank...
Matt.

[James467]

Sorry Ian, having qualifications in automotive engineering, I cannot let this go!

The definition of an expansion tank is unambiguous,
it is a vessel outside outside of the pressurised loop of the cooling system,
in other words it is always at atmospheric pressure.

You are incorrect, an expansion tank or expansion vessel IS part of the cars sealed cooling system, hence why they tend to have one way pressure caps to vent excess pressure, prevent premature boiling, allow the cooling system to run at its optimum temperature and allow expansion of the fluid in the system under pressure.

Dolomites do not have a header tank or remote header, they have a sealed cooling system with an expansion tank/vessel sited on the inner wing which when filled only allow for a very small amount of fluid loss. If you have any doubts the workshop manuals describe the cooling system as follows "The overflow pipe is connected to an expansion chamber which makes topping up unnecessary. The coolant expands when hot, and instead of being forced down the overflow pipe and being lost it flows into the expansion chamber. As the engine cools and the coolant contracts and, because of the temperature differential, flows back into the top of the thermostat housing and into the radiator."

A header tank just needs to be sited in the engine bay so that it is higher than the highest point of the radiator to provide the 'head of fluid'. Gravity is only employed when filling, once the system is full and bled it is under pressure and circulated by the pump. They do exactly the same job as an expansion tank as well as providing a convenient location to fill the cooling system and (in my opinion) a better supply of fluid in the event of a leak or fluid level drop. Late TR7s have a remote header setup, if you look at them the tank is higher than the rad but about the same height as the stat housing which has no filler. The only time that you need them higher than the highest point of the engine is when the system is filled. To fill and bleed the system you just remove the header and suspend it up high on the bonnet to allow excess air to circulate and escape, which is what I did on Aluns and we never had any issues with air bubbles on that! Modern cars with much more complex cooling systems and engine bays that are more tightly packaged will have additional feeds, you will find that even they have specific ways that the cooling systems must be filled and bled correctly but in essence the system still functions in the same way.

Header tanks can be vented into catch tanks situated outside of the cooling system loop (I had one of these on my racing MG midget to prevent coolant spilling all over the track when the thing got hot), these are sometimes known as expansion tanks (which they are as they do allow fluid to be sucked back into the cooling system in some cases) which may explain your confusion.

[veloce_rosso]

I used to buy the mag Triumph World and this person (I'll try and lay my hands on it over the weekend) had adapted his 1850 almost beyond recognition: He replaced the slant 4 with a modern Japanese engine; upgraded the suspension etc etc etc.

That doesn't make sense as I like all cars to be as original as possible, regardless of the foibles. Still it got him into the mag. If it was bog standard I doubt the mag would be bothered, which is a pity.

[Carledo]

I don't think this is quite fair to Triumph World (may it Rustle In Paperbin) I had a subscription to it for a long time and they always seemed to strike a balance between stockers and modifieds.

My cars haven't been in TW and never will now, but are similarly updated with more modern Vauxhall engines etc . I like classics for their distinctive looks and feel on the road, i'm a big fan of RWD too. But I use my cars every day, just as they were designed to be used, and I like to keep up with modern cars in both the Go and Stop departments. So I build cars to my own tastes and requirements, not being able to obtain or afford such things "off the shelf"

If you like your cars as they came from the factory, warts and all, that's fine with me, i'll even help you attain this level with advice and parts if I can. But please don't disparage those of us who think otherwise. This is a friendly forum where all points of view are recognised and the aim is to keep our cars on the road, however you choose to achieve this.

Steve

[veloce_rosso]

I don't think this is quite fair to Triumph World (may it Rustle In Paperbin) I had a subscription to it for a long time and they always seemed to strike a balance between stockers and modifieds.

My cars haven't been in TW and never will now, but are similarly updated with more modern Vauxhall engines etc . I like classics for their distinctive looks and feel on the road, i'm a big fan of RWD too. But I use my cars every day, just as they were designed to be used, and I like to keep up with modern cars in both the Go and Stop departments. So I build cars to my own tastes and requirements, not being able to obtain or afford such things "off the shelf"

If you like your cars as they came from the factory, warts and all, that's fine with me, i'll even help you attain this level with advice and parts if I can. But please don't disparage those of us who think otherwise. This is a friendly forum where all points of view are recognised and the aim is to keep our cars on the road, however you choose to achieve this.

Steve

Hi Steve.

I wasn't being disparaging, and if I came across that way then I apologize to you and anyone who thought I was. By the same token, public forums are in existence for people to give their personal preferences and views. IMHO a Dolly should be kept as stock as possible. If I wanted a Mazda or Honda engine fitted to a Dolly I'd go and buy the said vehicles. However, if anyone wants to lance the warts that's also fine by me.

The fact remains that even a stock Dolly, regardless of engine size, is more than capable to keep up with modern traffic. I live in Surrey and most of the 'A' roads either have speed cameras or average speed limits between point A and B, usually set at 50 MPH. And I only live 4 miles from the Surrey section of the M25, and if you can get out of 2nd gear that's a good journey.

I'd always look at the prospect sympathetic upgrades, such as modern brakes or tricks to keep the engine ticking more sweetly than in the 1970s.

Being out of the Dolly loop for so many years I'm trying to rekindle the knowledge I once had.

Best wishes, Richard.

[Carledo]

I wasn't being disparaging, and if I came across that way then I apologize to you and anyone who thought I was. By the same token, public forums are in existence for people to give their personal preferences and views. IMHO a Dolly should be kept as stock as possible. If I wanted a Mazda or Honda engine fitted to a Dolly I'd go and buy the said vehicles. However, if anyone wants to lance the warts that's also fine by me.

The fact remains that even a stock Dolly, regardless of engine size, is more than capable to keep up with modern traffic. I live in Surrey and most of the 'A' roads either have speed cameras or average speed limits between point A and B, usually set at 50 MPH. And I only live 4 miles from the Surrey section of the M25, and if you can get out of 2nd gear that's a good journey.

I'd always look at the prospect sympathetic upgrades, such as modern brakes or tricks to keep the engine ticking more sweetly than in the 1970s.

Being out of the Dolly loop for so many years I'm trying to rekindle the knowledge I once had.

Best wishes, Richard.

No worries mate, maybe i'm just a tad too touchy! But if the Jap engined 1850 you mentioned is either of the 2 I have in mind, (Black Nissan CA18DET turbo powered car or one with a Mazda MX5 lump) their owners are on this forum!

You have my sympathy on location, I live in Shropshire which has lots of empty (ish) A and B roads, less people per square mile than anywhere else in the UK south of Scotland and less fixed speed cameras than any other county! Houses are cheaper too! At least I get a chance to stretch my car's legs almost every day (or did till this pesky lockdown, which I AM observing)

I wish you well with your search, no matter what, it's another Dolomite preserved by an enthusistic owner and that can only be a good thing!

All the best, Steve

[matt of the vivas]

Has Triumph World stopped now then?

[Carledo]

Has Triumph World stopped now then?

Sorry mate but yes! The publishers announced it would be dropped quite recently though there may be a possibly twice yearly book/mag to replace it in part.

Steve

[matt of the vivas]

Damn. I used to buy it regularly, not been into WH Smith for about 4 months now so i didnt know it had gone.... real shame.

[Carledo]

Damn. I used to buy it regularly, not been into WH Smith for about 4 months now so i didnt know it had gone.... real shame.

You and a lot of others mate! Probably part of the reason for it's demise! I had a subscription because the nearest source otherwise was a 30 mile round trip. But gave even that up about a year ago, purely on cost grounds. (I also gave up my TSSC membership as it offered the least of my 3 club memberships)

But I have virtually a complete set including issue one!

Steve

[veloce_rosso]

Has Triumph World stopped now then?

Sorry mate but yes! The publishers announced it would be dropped quite recently though there may be a possibly twice yearly book/mag to replace it in part.

Steve

That's a shame. I've collected quite a few over the years. Along with Auto Italia mag I've got a fair archive.

[cleverusername]

The cooling system isn't a great design and sadly it seems to be an area that trips up British car makers over and over again. My father has an MGF, another car whose cooling system you have to watch like a hawk. Along other cars with the larger K-series lumps. The Stag and the Imp are two others that come to mind.

Having fought to keep the system on my Sprint engine sealed, I don't have much confidence in the slant cooling system design. You have the transfer pipe, which leaks if not seated correctly or the O-rings are tired. The inlet manifold coolant inlet to the head seems like a bad design, especially when you look at the bolt pattern around it. No-way to apply clamping forces to the bottom if it isn't seated properly. I could only fix that by having it skimmed.

The slightest air leak seems to lead to coolant in the expansion bottle and the thermostat housing running dry. If you're really unlucky the sender runs dry and you don't know you have a problem.

I think I am going to go the route of fitting a header tank. I just don't have very much faith in the design.