Radiator

[davidwheeler]

Old Boot's radiator was last rebuilt after the crash some 20 years ago, with a honeycomb matrix which at first worked well but gradually has become more clogged until it has become impossible.  Vintage Radiator Co said "nearer £2000 than £1000" ( and, by past experience, meant nearer 4000 than 3000).   Now, I have an original radiator which consists of some 49 vertical 5mm tubes in a finny matrix with a faux honeycomb on the front, something that VRC can not do so I consulted Mr Google thinking to fit a modern core.  I came up with Cumbria Radiators Ltd who are some 20 miles away from me and who fitted a modern vertical tube core matrix with room at the front for a faux matrix for the grand sum of £624 all in.   It looks OK as it is but I am on the track of a honeycomb film to go on top (more later perhaps).
There is now only one problem.
With 2/3 of the core blanked off so far I still cannot get the engine temperature above 140 F.      A problem I am delighted to have!

[davidwheeler]

I have finally managed to get the water temperature up a bit by blocking off 3/4 of the radiator.    Out of town that got me to 160F but in a long traffic jam in Carlisle it got up to 195F so I turned the engine off while waiting.
It needs a thermostat.  I remember vaguely something about fitting stats to the upper tubes but two would be needed and of small (motorcycle) size otherwise cooling of the head would be asymmetrical.    I wonder about fitting one in the tube at the bottom from the block to the water pump?   Anyone tried this?

[JohnMillham]

I used to use 2 thermostats from a Malaguti (?spelling) scooter, but my car prefers to run cool, so I no longer use them. Would you like to try them?

[Sebastien]

David,
I wrote the article that was in the LWR Newsletter 3/2020 on thermostats.
That article is available on the LWR website, under the member login, using the search function for the archives - very useful!
So that you are spared the search for your password, etc. I have appended the article.
I recommend using the SYM thermostats, which have a much bigger passage section than the Malagutti.
I would not use a thermostat at the entrance to the water pump - this would close the water passage to the pump, and the pump would start cavitating!
Hope this helps.

[davidwheeler]

Sebastian.  I knew I had seen it somewhere.  Thankyou for that.  Not cheap at £27 each and not deliverable from Netherlands because the order is too small,  I have emailed them to see if there is a solution.  There is a dealer not too far away in Scotland which is currently still in the UK so I shall try there.    Do you have the dimensions to hand?

[Sebastien]

David,
Here are the dimensions, in mm.
I would check with scooter workshops in England - those SYM scooters are pretty much everywhere, and someone must maintain them, and have spare parts on hand.

[davidwheeler]

The thopught occurs to me, since it is not atm, possible to get the thermostats from Europe because of Brexit, that putting a stat in the outflow pipe pf the pump between pump and block should not cause problems with cavitation and would avoid pressurising the water in the block as well.

[Sebastien]

Have you tried: https://www.symuk.co.uk/parts-spares ??

[JohnMillham]

The thopught occurs to me, since it is not atm, possible to get the thermostats from Europe because of Brexit, that putting a stat in the outflow pipe pf the pump between pump and block should not cause problems with cavitation and would avoid pressurising the water in the block as well.

I think that would cause the engine to overheat. You don't want to slow down the cooled water from entering the engine, you want to slow down the hot water from entering the radiator. If the thermostat is down the bottom of the radiator, it would never open, as the water is already cooled. That's my theory, anyway!

[davidwheeler]

Well thought John!

[davidwheeler]

I used to use 2 thermostats from a Malaguti (?spelling) scooter, but my car prefers to run cool, so I no longer use them. Would you like to try them?

John kindly sent me these and I fitted them by placing them in the outlet pipes of the side panels/water manifolds having first drilled four small bypass (3mm) holes in the skirts.   They are retained by the rubber hoses which fit tightly around the skirt.
I took her out on a cold day with only 2/3 of the radiator blocked off and struggled to get the temperature above 140F, only managing 160F in a long traffic jam!   I shall have to solder up some of the holes.   I am amazed at how much more efficient is a modern core as compared with the honeycomb even when it was new.

[15519]

I have been down this road, but the issue I have is that my aluminium cylinder head is shedding dust into the cooling water, and this is blocking the fancy narrow tubes in the modern core. And yes we have flushed it out numerous times, and tried different combinations of coolant, water wetters etc. I am now trying to locate a core with bigger tubes, otherwise there is a man who can make me up a core using 1/4 inch copper tubes, but that will not come cheap. Or else just get the proper cast iron head welded up and put back on the car.

[davidwheeler]

I have installed magnesium sacrificial anodes in my blocks.   They do get eroded too.   I wonder if this would ease your problems with the head shedding dust (?from corrosion).  An internet search yielded some half Kg blocks suitable for installing on barges for not a huge sum of money (and much cheaper gram for gram than smaller ones) which I - very cautiously - handsawed into smaller pieces and held in place at the front of the block with long 6mm bolts and nuts.   There is a post in the technical information thread with the address of my suppliers and also pictures under the Cylinder block corrosion thread.