So, as I expected, my 2nd hand radiator isn’t fit for the job - I won’t bore you with the moot point as to why this is but it’s ‘broken’ rather than proven to be too small.

I’m going to commission a new one. I can order it in the same dimensions as the knackered one or I could utilise some available height and make it 75mm taller.

While bigger is on the face of it preferable, I’m not 100% clear on the interplay between the radiator bleed and expansion bottle. Currently the bleed is significantly lower than the expansion bottle which is as high as it can be. If I increase the height of the rad, the bleed will move vertically toward the bleed-inlet on the expansion bottle.

Are there rules of thumb that I should apply? Should I keep the radiator bleed and therefore the radiator-in-totality lower? If I’m okay to raise the bleed-outlet, is it okay if the small hose to the expansion tank heads down (to the top of the chassis rail) before rising up again to the tank?

‘Tanks’ in advance.

Water is heavy. If you're truly certain that your old radiator was big enough, had it been functioning correctly, then why add more weight in the extreme nose of your car than you really need to?

Having said that, height of the expansion bottle isn't that critical with a pressurized system. I used to run the expansion bottle on my Sylva so low that it's cold level was well below the bleed valve... I used to dismount it from its bracket and hold it up in the air when I bled the system.

What engine? What tune?, what radiator?
What cooling set up: grill, opening, fans etc.

How is it failing?

quote:

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Originally posted by Sam_68
Water is heavy. If you're truly certain that your old radiator was big enough, had it been functioning correctly, then why add more weight in the extreme nose of your car than you really need to?

Having said that, height of the expansion bottle isn't that critical with a pressurized system. I used to run the expansion bottle on my Sylva so low that it's cold level was well below the bleed valve... I used to dismount it from its bracket and hold it up in the air when I bled the system.

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Well in that case, as I said, my solution was simply to make the small diameter hose that links to the expansion tank a bit longer than it needed to be, and take the tank off and hold it up in the air to get enough head when you're bleeding the system.

Once the system is bled, if the cap on your header tank is airtight I can see no reason why you wouldn't be able to have the expansion tank below the level of the bleed and the top of the radiator, even (in fact, I think mine was, from memory).

You'll risk airlocks if there is any localised boiling, perhaps, but if that happens, you've got a problem anyway. Otherwise, the function of the expansion tank is just to allow for expansion - not to act as a swirl pot - so provided there is some volume of gas in it to be compressed, it doesn't matter where it is.

Yes, about as far east as it's possible to get without falling into the North Sea, these days, and my God is it bleak at this time of year - beginning to wish I'd stayed in balmy Gloucestershire!

I thought I’d update on where I got to on this.

I’d normally use Allisport for all things aluminium but they are incredibly busy - and admittedly not the cheapest- quality costs. Anyway, since Andrew @ Allisport had said they were struggling time wise and because the new rad was a slightly nasty surprise (unbudgeted) I had a look around and found Custom Made Rads via eBay. I ended up sending the old rad up to Darren with a list of changes - including thicker core. I’m really pleased with result. Admittedly the welds aren’t quite as pretty as Allisport’s but it was a good chunk cheaper.

Static temps are good - the new fan doing its job nicely. I went 65mm taller than the old one by the way as it made packaging easiest.

Worth a look if you are in the market for a new rad cmrrads@yahoo.com.


NewRad1


NewRad2


NewRad3

My comments so don't be offended.

1. F++++ me that is a huge oil cooler!!! Overcoming oil is not a good thing.

2. For best efficiency oil cooler should be against the radiator, refer to think auto website, I understand having the two far apart is a bad thing.
3. You should have a cowl to draw air through the whole radiator. The cowl would seal up against the frame, although your fan is close to the matrix, it is not a good seal as you'd get with a cowl. Also you are not drawing air through the whole matrix.
4.i do not look those brackets, wouldn't be necessary with a cowl.


Remove. cowl, either find car with same size radiator or make one.

There, I've said it.

Of course if all is well and oil temp is fine, ignore me

[Edited on 11/2/18 by 02GF74]

quote:

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Originally posted by 02GF74
My comments so don't be offended.

1. F++++ me that is a huge oil cooler!!! Overcoming oil is not a good thing.

2. For best efficiency oil cooler should be against the radiator, refer to think auto website, I understand having the two far apart is a bad thing.
3. You should have a cowl to draw air through the whole radiator. The cowl would seal up against the frame, although your fan is close to the matrix, it is not a good seal as you'd get with a cowl. Also you are not drawing air through the whole matrix.
4.i do not look those brackets, wouldn't be necessary with a cowl.


Remove. cowl, either find car with same size radiator or make one.

There, I've said it.

Of course if all is well and oil temp is fine, ignore me

[Edited on 11/2/18 by 02GF74]

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