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I have given the radiator option some thought in the past, and concluded the issue is the shape of the space the radiator has to fit in. There will be little difference between the efficiency of a cross flow and a vertical radiator , for the reasons set out by Robin.
Therefore as the Marlin nose cone is vertical, and has further space above, and below the air aperture, I concluded it makes more sense to have a vertical radiator, allowing maximum core behind the nose aperture whilst having the header and footer above and below where they will be shielded anyway by the top of the nose cone and the front cross member.
This same logic applies to modern cars which no longer have high bonnets, so the designers have made wide but shallow cross flows and allowed the two side tanks to sit behind sheet metal areas.
The Bently manual talks about two types of pressure cap 1.0 bar or 1.2 bar? Dunno what one I have so will have to inspect with a magnifying glass to see if it's marked.
...........
Typical BMW engineering, my cap is nicely marked 1.2 bar +0.15/ -0.1, so that rules that cause out!
I picked up a brand new Pacet 13" Club fan and variable controller off eBay for £60 so I took the day off from work, picked it up from the post office and fitted it.
It's surprising how quick it is to remove all the bonnets, but I still had to remove the old fan and wiring, etc.
I'm not sure which Rad I finally ended up with - memory fails me even at my early age but I had 2 or 3 kicking around, the original BMW 325 fan, an earlier 325 fan Jeremy in Worcester passed my way and I recall asking Marlin about them as well. So whichever I've used is nothing special and also I have a fairly normal fan - nothing fancy.
My engine temp reads about 80 most of the time, above that the fan kicks in and so far it's stayed that way driving 25 miles along the MWay or back roads to work regardless of traffic or lack of. I also haven't got the vents in the bonnet sides yet so will gain a bit there - but it's only been on the road since about October...
I discovered today that my thermostat is knackered and stays firmly shut in the old pan of boiling water.
I feel really stupid that this is one of the few things I didn't change and they are so cheap. (It's also supposed to be one of the first things to check)
GSF and Eurocarparts were shut this afternoon but surprisingly, good old Halfords had one for £9.99.
I'd strongly recommend that everybody who has had their engine laid up dry for any length of time replace it before running the engine again.
I'm still pleased that I changed the rad fan as it should now cope with Global Warming hot summers!
I'm also pleased that I discovered it today and not during the speedo test at the SVA station. Now that would have been embarassing!!
I think it's a 11" Pacet fan.
Still think I may need a bigger one.
Time will tell.
With mine running in the garage, the fan can only just keep pace and doesn't shut off with the engine running.
Stop the engine, and the fan shuts down in about a minute.
I think it's a 11" Pacet fan.
Still think I may need a bigger one.
Time will tell.
With mine running in the garage, the fan can only just keep pace and doesn't shut off with the engine running.
Stop the engine, and the fan shuts down in about a minute.
That's what mine was doing. I'd check your thermostat before doing anything else. I left mine idling on Sunday morning and the fan would run for about 35 secs then stay off for 75secs. Cycle times were pretty consistant so i'm confident it can now cope with a much hotter day.
Using the brackets supplied by Marlin, and using the M10 rad, there is about 4 inches of rad core hidden behind the chassis rail.
So I'm in the process from ditching the Marlin brackets and raising the rad higher.
I can get the rad another 1 1/2 inches higher until it hits the fibreglass.
Doesn't sound a lot but then I can fit a much bigger fan.
With the M50 type engine fitted, you don't have room for a fan between the motor and rad so a blow fan has to be fitted (with gap of another 1 1/2" you could fit the original viscous fan drive and fan) and with the three point Marlin bracket tapering in at the top, you can only squeeze a 10" or so fan behind.
So I figure that a new design for the top mount is needed.
I'll also have to raise the expansion tank as well to suit.
Using the brackets supplied by Marlin, and using the M10 rad, there is about 4 inches of rad core hidden behind the chassis rail.
So I'm in the process from ditching the Marlin brackets and raising the rad higher.
I can get the rad another 1 1/2 inches higher until it hits the fibreglass.
Doesn't sound a lot but then I can fit a much bigger fan.
That's exactly what I did. I was able to support the rad on a couple of brackets that were just horizontal upside down [ sections attached to the underneath of the crossmember. The top rad hose just touches the underside of the fiberglass nosecone and only the tank is obscured by the crossmember - the all important core being fully exposed to the flow of air.
The two strips of metal are not bolted tight, there is layer of chassis sealer between them that absorbs vibration. The bolts were add as a fail safe if the sealer gives way, but they not bolted down.
You end up with enough space to run the oil pipes between:
I had to mount my rad up close to the crossmember otherwise it touches the motor.
So I'm fabricating a bracket using 8mm rod which goes up to the top of the rad and turns 90° across the top and down again.
Welded to 12 x 2.5mm strip to bolt to the sides of the uprights.
Hopefully the 13" fan I've just ordered should fit in the gap.
Okay.
Rad bracket fabricated.
Rad mounted 1 1/2" higher.
13" blow fan mounted.
Now the fan switches on, stays on for about a minute and switches off again.
Brilliant.
The only thing is that the temp gauge goes up to 105°C before the fan cuts in and only drops to 100°C when it shuts off. Could be the sender I suppose but there is a big difference in temp between when the thermostat opens (it's an 88°C stat) to when the fan cuts in. The motor does feel a little hot to the touch but seems to run okay.
I have a Bosch fan switch which screws in the base of the rad, which may need changing to a lower value or maybe I should change this for an adjustable, in-line, hose mounted switch to make the fan kick in sooner.
Having now located my engine, I have very limited space for the radiator/fan (considerably less than the Sporster - and you thought you were hard done by!!). E36 M50 2.5 engines do not like being cooked so I am keen to get the biggest radiator I can, but would like to compare it to what Marlin provide.
Can any one measure the total size of their radiator, and the actual core size, and let me have the details? (H x W x D), and how many cores it has?
I hope to get a local radiator manufacturer to make one up for me - Marlin have struggled to supply any kit parts over the last 5 months - and I can optimise the positions and styles of the Input/Output elbows etc.
Thank in advance for any reponse.
When you say your core size is..... are these the overall dimensions, as I reckon these dimensions are the absolute max size I can fit in the space available, which means the actual core tubes will be , I guess 90-100mm less in one direction allowing 45-50mm for the header and footer tanks?
That was the size of the core including the fins but without the tanks top and bottom. I may have been a bit optimistic on the thickness - it is difficult to get to once it is shoved up in the nosecone - 1.25" possibly more like it.
I raised my rad as far as I could (top hose touches the inside of the nosecone) so that the front crossmember does not obscure the core.
BTW I also have an oil cooler which I hope will help keep the temperature under control although the obvious place to mount this was the front crossmember so it obscures the rad a bit.
The sportster obviously has a much bigger nose cone than the Cabrio your core dimensions are the same as my overall available dims. Looks like I will need to go to a three core minimum, but being mindful of the depth increasing.
Has anyone bought a Marlin rad? - if so what size is it, and how many cores does it have?
Mike
I've got the 2.5l M52 engine - can't remember where the rad came from but I haven't got an expansion tank on it yet...
Anyone with a similar setup got a photo of theirs and where it came from? Vindicator built mine and left that for me to do cos they coudln't find one small enough...
Anyone who has the cross flow rad got any part numbers on there? I'm trying to track down where it comes from. I've had suggestions that it may be from Rover (land rover series 2 has been suggested) or Ford
I figure someone might have made an off the shelf full ali rad if its for a popular model.
I have just spoken to a local radiator manufacurer who is prepared to make me a bespoke raditor to my design - the Cabrio has a smaller nose cone than the Sportster, so I am worried about cooling. he will make any size, any core and add elbow input/outputs, plus fitting for sensor, plus elbow for rad cap etc. No promises on price, but about £150. - similar to Marlin, but bespoke to my exact meeds, and high capacity too. he also advised a good two core can be better than a three core - its all about tube size and fins apparently.
If you interested call Richard at Boston Radiators Rel 01775 722824.
I plan to go to Stoneleigh, so could deliver if you want to go down this route.
Let me know?
Regards
Mike
I'll have a think about it thanks Mike. I'll let you know. It may have to wait though as a bolt in my daily drivers tyres cost me my rad budget today - doh!
Mike I'm going to live with it as is for now, thanks for the offer though
Situation is the temp comes up and keep going up until the fan kicks in when your stopped. The fan stop the temp going further but the rad is not big enough for the temp to come back down again to normal when sat in traffic.
So it will be OK for now, I'll see what it does when the outside temp goes up.
Thought this was interesting, was suggest by someone on the MOC forum to use a Morgan Plus 8 rad (they've got a standard one fitted to theirs)
Saw this while googling, very expensive but its 75mm thick!!!
Big capacity radiator
Keeping the Plus 8's engine running cool when driven hard, particularly on the circuit, is important for reliability and peak power. The competition proven aluminium big capacity radiator has a core depth increased from 42mm to 75mm to ensure more effective cooling. Fitted with the latest high efficiency factory fan and header tank, the Mulberry radiator is a wise investment as you boost the engine's power.
