Radiator Water Level & the Overflow

[David Whittle]

My minor always dumps about 1.5 pints of radiator contents out of the overflow within a few miles of running if the rad is topped right up! If I don't top it up the level stays about half an inch over the core all the time.

This has not really been a problem, but in the middle of summer, climbing a long steep hill in 1st for ages the little car would benefit from that missing 1.5 pints as the oil temperature can get very hot! Some Humbers have a sprung loaded ball on the top of the overflow, which seals it from releasing sloshed water, but is realised by any pressure in the system so allows for expansion and problems, which cause any pressure in the system.

I am thinking of capturing the released water in a high mounted washer bottle, then allowing it to feed back via gravity if I can find somewhere high enough to mount it!

Is this common with the OHC cars? Should the overflow be partially blanked off to prevent sloshing lose?

[halbe]

Hello David,

The Aston does the same thing , lose some water when I fill her right up.
After that it stays the same the rest of the season.
Maybe you should drive more in Holland , even in the summer there are no mountains to speak of.
Only Minor speedbumps

Halbe

[chris lambert]

Morning David,
It certainly is a problem common to my two Minors. Trevor W. had an identical problem with his side valve car and has fitted a similar arrangement to that you are proposing. It seems to work perfectly. I tried partially blocking off the overflow on my saloon which simply resulted in a higher pressure relief through the remaining aperture! The overflow pipe in the Semi-sports had a huge lump of solder blocking off the escape route for any liquid and steam, which then resulted in it escaping through the rad cap and calormeter apertures, covering the screen and bonnet with an antifreeze and water mixture - not pleasant. This, despite my best efforts with rubber washers. Apparently the best thing for overheating Minor engines, particularly those used in competition is to fit the M sump, which has twice the capacity of the standard Minor version.
Chris

[Ken Martin]

David, I don't think you need to worry about this. I haven't done so since 1965 when I first noticed it. I just let the water to settle to its natural level. The Calormeter shouldn't be taken too seriously regarding temperature either. I have two and they read differently! The one I use is the original and it reads high. However I have used an M Type sump for 40 years as I didn't like the idea of my valuable engine being lubricated by just four very hot pints of oil. This is a modification that any original owner could have easilly made and surely shouldn't lead to LC&ES 'Modified' classification! I went to Spain and back in my car when I was young and mad enough to do such a thing and the car didn't boil once. One thing that does puzzle me though is that MG Midgets were not fitted with a fan. How come they don't boil on hills - or do they?

[David Whittle]

Thank you Gentlemen; you have confirmed what I suspected! And yes, the real answer is probably to ignore the radiator, and fit the M type sump, as these little engines do seem to be cooled as much by the oil as by the water! I wonder why Morris fitted such a small sump, daft idea!

The M type sump is aluminium I believe, great for cooling, but at risk on a trial if unguarded!

I don't think the Paul Rogers saloon has a fan, and at Madresfield a few years back she boiled while waiting to do a test, whilst mine behind, with the fan was fine. I think Paul values the tenth of a brakehorsepower it consumes!

[Toby]

Very interesting, my sv runs hot, even in winter and boiled on the hill out of cerne abbas this summer, also finds its own water level! I have added an additive that claims to lower rad temperature but it seems to make no difference. Until I realised that rad muffs were to stop freezing I wondered who on earth would need one on a minor!!! By the way, before I refit my rad, has anyone tried cleaning them out with acid? I have access to some strong hydrochloric acid and wondered about using it to flush the rad, off the vehicle.

[Ian Grace]

Paul Rogers hasn't got a fan because the engine in his car is an M Type engine.

One firm in the thirties produced an oversize sump for Minors (and early M Types). It looks like an M sump but is made of sheet steel like the standard Minor sump, and with no fins. It is easy to modify a standard Minor sump to this design - just get the tin snips out and add a couple of boxes - one on each side - if you see what I mean, and such a mod. would be ideal for trials.

[Ken Martin]

Toby: I wouldn't use acid to flush out the rad unless you are prepared to spend hours soldering up leaks. I rather agressively hosed my rad inside and out a few years ago with water. The outside flush produced dozens of vintage wasps and the like. Some muck came out from inside but not much. I was however left with a very difficut job to solder up some tiny holes using a small gas torch. I don't think I could have succeeded had my neighbour not by coincidence just changed his bathroom suite and still had the old bath which I borrowed. By rigging up a hose with a valve at one end of the rad and blocking the other end, I was able to add a small amount of air pressure with a tyre pump and source the punctures by immersion in the old bath. The whole process took hours. In the end I still put in some Rad weld to make sure!

[Toby]

Thanks Ken, I have water flushed several rads before whilst trying to find the one with the best flow rate (this was to cure overheating), they all performed the same!!! In the end the engine got stripped to clear sludge (sv) and thus started 2 years of expense and trouble. I've since had a rad recored and put it on another hot sv only to find it made no difference except that it redistributed my wealth. I have tried changing calormeters and checking water temperature with a thermometer but have since realised that they run very hot! I just thought it might be worth trying to get an as new, cleaned core for my newly reconned engine but think I'll just give it another rinse instead, then try it out.

[Highlander]

My 33 sv Minor has a gallon finless sump (a modification as I can see the welds). When I rebuilt her two years ago I took all the core plugs out and got a bucket full of sludge and rust! I drive flat out all the time and I just keep topping her up (one a month) On a spare minor engine I have I noticed it had a four blade fan! Was this a period modification? Is it off a later model? Another cracking day here in the South East - went to Brighton and back just for the fun of it - just seen the 10 o clock news - deep snow in Durham and further North!! (No water added - 90 miles) Alister.

[prharris25]

Don't know whether it was a mod Alister, but all my SV Minors have had 4 bladed fans. I suspect many SV Minors have acquired later Morris 8 dynamos and their 2 bladed fans.