Upgrading a Dolomite heater?

[sprint95m]

The heater on my Sprint needs work, so I am wondering if anybody has upgraded the heater?


(A few years ago I did supply dimensions to someone who was looking at this but I don't
know if there was an outcome?)

(Reliant Scimitars apparently used Dolomite heaters and they did upgrade these with a larger matrix
but I haven't been able to figure out which version this is?)


Already the heater feed is from the cylinder head (which improves things somewhat).
So what I am looking at is a bigger volume matrix and bigger bore hose tails.



As always all thoughts are welcome please.

Thanks,
Ian.

[SprintV8]

Scimitar have different heater matrix’s depending on year.
Below is the 75-85

http://www.vehicleheaters.co.uk/Heater% ... liant.html

Sold my Scimitar SE6a to get the Sprint back.

[dollyman]

Hi Ian, when i had a minor 1000 the heater was bad, so upgraded it to an Austin Metro matrix.... Warm as toast after that, even with the single speed blower Bit of a squeeze getting it in though.

Tony.

[cleverusername]

It doesn't need upgrading, the heating system on a Dolomite is more than adequate, at least for the British climate.

[SprintV8]

It doesn't need upgrading, the heating system on a Dolomite is more than adequate, at least for the British climate.

Not for Scottish weather.

[dollyman]

It doesn't need upgrading, the heating system on a Dolomite is more than adequate, at least for the British climate.

Not for Scottish weather.

[James467]

It doesn't need upgrading, the heating system on a Dolomite is more than adequate, at least for the British climate.

Agreed, there's nothing wrong with the heater, my dolly was driven in -15 in Brasov and I was nice and toasty.

[tamtrucks]

i agree,nothing wrong with heater,most of the cause is not changing the coolant often,flushing out and reverse flush and also car not being used often enough to help stop crap building up in rads and pipes

[Carledo]

I'd never considered the Dolomite heater inadequate, till I went on the RBRR in Mahesh's Sprint in 2018.

It worked OK ish in the front, but all 3 of us in the car still needed to be wearing jackets nearly all the time.

But the back seat area was absolutely FREEZING, particularly if you were trying to sleep!

It was not unseasonably cold in October of 2018 and the car and it's heater seemed to be functioning as well as possible, it wasn't overcooling or anything like that. But in 2000+ miles, we never needed to turn the heat DOWN from it's maximum output!

The Dolomega's engine has 5/8" bore engine to heater hose fittings which I have had to step down to match the Sprint's 1/2" bore heater. And the impression I get on limited running so far, is that the air get's hotter, faster than it ever does on a stock Sprint, despite the temp guage never getting above normal.

I may be rationalising, but it makes a kind of sense that this would work, if the engine is pumping water through a larger bore hose which is then constricted into a smaller pipe, this will produce a sort of Venturi effect, speeding up the flow through the matrix and therefore getting hotter water through faster. Then, once it's out the other side, the larger return pipe will let it slow down again when it's already done it's job.

It's a situation that was forced on me by the Vauxhall convo, but it might be worth a try for the sake of a couple of larger bore hosetails and some 5/8" hose! Which you'd have to do anyway, to get the most out of a 5/8" bore matrix!

Steve

PS, I've also, with the benefit of experience gained with the Carledo, made sure to refit or replace EVERY single grommet in the bulkhead, it's quite amazing just how much cold air can find it's way into the car this way!

[James467]

Probably a silted up heater core Steve, I have always back washed the cores of all the cars I have and the heaters are really good.

[Carledo]

Probably a silted up heater core Steve, I have always back washed the cores of all the cars I have and the heaters are really good.

I can't ignore this possibility James, but at that time a) Mash's car was in fairly regular use and b) we'd had the engine out recently to deal with some some oil leaks and fit a new clutch and the coolant was clean and clear, both before and after. We didn't flush the heater as there was no percieved need, so i'm not ruling it out, but I AM dubious!

It wasn't so much that there was NO heat, it just wasn't particularly hot and didn't get to the rear seat area! The latter being unsurprising as the design includes no dedicated rear vents. But I guess I had been expecting it to be warmer in there, with 3 bodies generating heat and all the windows up!

The Dolomega heater, on the other hand, hadn't seen water in at least 8 years, but that works well! For this year's RBRR (if it happens) I will be taking a sleeping bag for the "off duty" crewman to use in the back!

Steve

[sprint95m]

Three decades ago, I went from a T2500S to a Dolomite Sprint and
soon noticed the Sprint had a considerably poorer heater.
After first trying flushing out the heater matrix (and man a lot of sludge did appear)
I went on and fitted another heater from a 1500HL. This was okay for clearing the front screen
and I just put up with it.
In 2007 I acquired an early 1850 which had a dreadful heater.
Flushing it out produced no sludge, so
I reeted about a bit and adjusting the controls improved matters, but
still I wasn't happy with it, so looked at other options....

The TR7 has it's heater input from the cylinder head (just like a 2500S).
From DSR magazines articles I knew that the hottest part of a slant four's cooling system is
at the back of the cylinder head so I bought a TR7 transfer housing,
only to realise, when looking at it. that it won't fit an early 1850.
However, being an early 1850 the transfer housing has blanking plugs, so I bought a new
hose tail and very very carefully fitted it and bingo. a much better heater.
Alas, the saga doesn't end there, the heater performance fell away when it was needed most.

Next, I decided to fit an 88 degree thermostat (which this car should have had) and result,
operating temp now stayed the same all year round and so did heater performance.
Actually had to turn it down quite a lot.


Now the current situation.
Today I have taken the Sprint's heater assembly separate. The matrix is overall 280x130x50mm.
There is plenty of room for a taller matrix and moving to 16mm bore hose should help
and maybe some ducting to the back of the car too...



thanks
Ian

[sprint95m]

Scimitar have different heater matrix’s depending on year.
Below is the 75-85

http://www.vehicleheaters.co.uk/Heater% ... liant.html

Sold my Scimitar SE6a to get the Sprint back.

Thanks for this,
so the Scimitar SE5a had a matrix 10mm taller and 8mm deeper
this being a volume increase of almost 25%.

Oh and a T2000 matrix is 35% bigger but completely the wrong shape.

Ian.

[Carledo]

I should note that the Omega engine's heater output pipe IS right at the rearmost point of the engine, the hottest and therefore, as Ian states, the most sensible place for it! It returns (eventually) to the bottom rad hose.

Steve

[cliftyhanger]

I'd never considered the Dolomite heater inadequate, till I went on the RBRR in Mahesh's Sprint in 2018.

It worked OK ish in the front, but all 3 of us in the car still needed to be wearing jackets nearly all the time.

But the back seat area was absolutely FREEZING, particularly if you were trying to sleep!

It was not unseasonably cold in October of 2018 and the car and it's heater seemed to be functioning as well as possible, it wasn't overcooling or anything like that. But in 2000+ miles, we never needed to turn the heat DOWN from it's maximum output!

On the other hand, same journey in my TR7 powered dolly, we never had teh heater more than just "warm" and we were never chilly. And we are all from down south, so apparently "softies". We did g=have a blanket thing =y for the sleeper compartment, but think that is reasonable.
I reckon it is mostly down to the heater matrix. If sludged up a bit, I think they produce much less heat as they are a bypass design? I remember a rad specialist saying if just a couple of tubes were blocked in a herald matrix it would make a big difference. And sadly flushing is unlikely to clear a blocked tube as the water flow will just go via another tube or bypass. Chemical attack may help, but really a new matrix should do the. Saying that, if a bigger matrix will fit, go for it.