DTR - Project Recommission 1972 'Dolomite' Manual

[Carledo]

28 degrees ambient is pretty high for a Brit, but truthfully, the car SHOULD be able to handle it. Much as it sounds like destruction testing, you won't know if it is really overheating until it boils over! Which I presume it hasn't so far? Or even lost any coolant?

The fuel vaporisation is more a product of ambient and an already hot motor than a particular sign of a cooling fault and is due to very hot air collecting under the bonnnet and not being able to escape, it's why we pop the bonnet in traffic, because hot air rises! This can happen to a car with a perfect cooling system. It only needs an extra degree or two to set it off!

I don't think there's a timing error (it would have to be at least back in the -2 to +2 degree range to upset the cooling) and i'm not gonna blame a slight compression increase or big plug gaps either, it's not enough to be a factor.

I hate to say this, but it SOUNDS just like the Sprint I described in Rafe's thread in Dolomite related. That was a blocked rad. Though yours is new and a Sprint one to boot, that is what it sounds like! How much do you trust your rad guy?

Steve

[James467]

Nope, it hasn't boiled over or lost any coolant at all.

I hate to say this, but it SOUNDS just like the Sprint I described in Rafe's thread in Dolomite related. That was a blocked rad. Though yours is new and a Sprint one to boot, that is what it sounds like! How much do you trust your rad guy?

Well, the rad has been sitting around in the workshop for a few years, it was the same guy that did Binnys but you never know, it could have something in it. Maybe a mouse got in there!!!

I have some more that can be reconditioned and I'd need one for YGD so if it turns out to not be the problem then I have one ready to be fitted, Alun where did you get yours done?

[Carledo]

Nope, it hasn't boiled over or lost any coolant at all.

Nothing wrong with the head then!

Steve

[AlastairC]

I would get a modern core in your radiator - worked wonders in my stag. There's lots of things you can do to help reduce the temperature but I would do the radiator first and see how things go from there, thermos switch on your fan is a good idea too, I've debated putting that on the stag as well but re cored radiator seems to be sufficient for NZ summers

[James467]

I would get a modern core in your radiator - worked wonders in my stag.

The rad is a reconditioned Sprint one with a modern core.

It also has a thermostatic switch for the fan, you can see it on the top hose in the pictures, I also have an override switch inside the car.

A massive thanks to Alun, having a rad done at GAT Radiators in Brierley Hill.

[xvivalve]

The rad is a reconditioned Sprint one with a modern core.

That will be your problem; a lot of 'modern core' are less efficient than the original Sprint; does it have a sort of triangular pattern to the fins?

The old bloke at GAT knows what a Sprint requires!!

A massive thanks to Alun, having a rad done at GAT Radiators in Brierley Hill.

Er, not yet you aren't; I'm not dressed yet!

[James467]

28 degrees ambient is pretty high for a Brit

High for a Brit but low for Hungary and Romania! When I drive it over there it's going to be at least 35 ambient.

And Alun, I've seen you in your dressing gown [shudder]

[Galileo]

I hate to say this, but it SOUNDS just like the Sprint I described in Rafe's thread in Dolomite related. That was a blocked rad. Though yours is new and a Sprint one to boot, that is what it sounds like! How much do you trust your rad guy?

Steve

I've got a radiator to test a theory coming from Alun to see what difference it makes as the consensus is that at best I have an 1850 radiator and at worst a partially blocked one. All the symptoms are similar to your's James, temperature whilst making good progress rises to the same position on the gauge too, without the fan on constantly after a fast run it goes even higher when in town and idling at lights. The car also smells hot, not something I can describe as it's just a feeling from years of messing around with cars.

With all these new radiators marketed as 1850/Sprint ones, I wonder if they're full OEM Sprint cooling capacity, or somewhere inbetween? Jeroen's description of with a true Sprint rad you can't get an electric fan tie wrap through sticks in my mind.

[James467]

Comparing my so called Sprint rad to the old 1850 one in the garage, they look similar.

I'm having the same problem as Raf taking a photo!

[James467]

This is the rad that came out of DTR





I also have this which is supposed to be a Sprint rad



and this, which is supposed to be a competition rad



That one is heavy and very dense!

[yorkshire_spam]

I also have this which is supposed to be a Sprint rad

Doesn't look much different to the 1850 one out of DTR in terms of core does it? (or is that my eyesight/the photo?)

[MIG Wielder]

Here is my contribution to the temperature debate.
I run this Waterless coolant in my 1850 daily driver so its not going to run cooler than a 25% antifreeze mix which I accept. And I run a standard mechanical fan.


Here is where the temperature gauge sits today. It was about 75 dg F air temp, so a bit cooler than yesterday, just for reference. Last time I checked the coolant temp; at the outlet elbow, a gnats over 3/4 on the gauge was 92 dec C and 1/2 way was 78 deg C.

Here is an IR shot of the rad hot spot on the top right of the header tank at 82 deg. You can see the bottom hose is somewhat cooler, and the area of the rad; that has lost its gills is running a bit hotter due to less cooling in that area. As you get nearer to the bit of the rad; that is being cooled by the fan the temperature is much cooler.

A 3rd shot indicates the area of the rad right by the fan is being cooled but seems to warm up I think from heat conducted from the uncooled area below the fan being transferred upwards. ( Hot air rises). And the top of the radiator side tanks are hotter than the bottom bits.

So … Is it better to have 2 smaller cooling fans rather than one large one ?
And should they be mounted as high as possible in the radiator core for best cooling ?
Tony.

( Sorry folks; I've been defeated by the technology. I can't post the thermal images. Get back to you ? Note to self; need to be posted as /png. Better late than never I suppose. )

[Galileo]

Even harder to take that picture balancing a smartphone and steel rule...

My 'Sprint' radiator, 21 rows:


Radiator in 1850 project car, 23 rows (could not get rid of sun glare, sorry):


Tricky to tell as the fins are not uniform in distance apart but there might just be more fins in the Sprint one, roughly 20/21 for the 1850 over 50mm and 22 for the Sprint. Less row density in the Sprint one though.

[Carledo]

James' fitted rad appears also to have 21 or possibly 22 rows, the old rad from DTR has 23 or maybe 24, the Sprint labelled one with the sender hole has 30 rows and the so called Compo one has 29. But it doesn't end there, i've used proper compo rads myself and a compo rad is normally 4 rows DEEP (front to back) whereas a stocker is only 3! Hence the weight!
I'm not absolutely convinced that the 4 row rad is worth the eye watering price that used to be charged for them, I think with 4 rows, you run into the law of diminishing returns in terms of the extra row slowing the airflow that bit more and negating its positive effect on cooling area. Also the air is pretty well hot by the time it gets past the first 3 rows! But it's a hunch, I have no science to back it up, just experience!

From this, my guess is that both James and Rafe have the so called "modern core 1850 and Sprint rad" which is nothing of the sort! And by logical extension, it's likely that Binny does too. It's like having a Sprint rad with 20% of the core blocked! It's probably just about adequate until the ambient gets too high, then it's just about useless!

Steve

[Galileo]

Think you're spot on Steve, and you got me thinking about triple rows and core thickness as the final missing figures.

Just nipped outside and in a completely scientific experiment I ate a Fab lolly, took a piece of lolly stick (it was delicious, I do like a Fab!) and used it it to measure the core thickness. Fell all the way through on my 'Sprint' rad and 1850 with no drama, so I can be confident that neither of them are triple row staggered, both measured at 37mm +/- 1mm. Now I could be wrong but I'm sure I've seen that a Sprint rad is triple row (as you say) and 54mm thick?