Top and Bottom Hoses

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Post by Djangoz » Fri Oct 05, 2018 8:03 pm

Quick question - were the top and bottom hoses on the Middlebridge always of the corrugated design?

MB60 going in for some work next Monday (core plugs, suspension, radiator and block flush etc. Etc.). My mechanic seems very hung up on the corrugated hoses being inefficient due to resistance to smooth flow of water. He thinks it won't be helping the tendency to run hot(ish) when idling or in slow traffic after a run. It's not too bad and the fan kicks in at 95 but the indicated temp can still be 105 or so and never seems to come down unless you start rolling again and get some airflow through the engine bay. It would be useful to know if the corrugated design (supplied by GW) is original or a solution to non availability of original (perhaps) non corrugated types.


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Post by mick_gaugh » Fri Oct 05, 2018 11:40 pm

Hi Andrew

Yes all of the Middlebridge's were originally fitted with Gates top and bottom hoses and are corrugated in design, Personally I totally agree with you and think some nice black silicone hoses should potentially improve circulation. If you are considering going this route please count me in, (beer tokens waiting) I can't do it my self at the moment as my car is in use until the new year and I woud need to send the two hose samples 'held in their original contours' to my silicone guy to replicate.

I do hope this helps a little.

Mick



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Post by drcdb15 » Sat Oct 06, 2018 12:35 pm

Sorry to disappoint you, guys, but I'm afraid Andrew's mechanic is way off beam. The fluid flows in any car engine are not even remotely close to laminar flow regions, and the idea of 'smoothing out' the flow is meaningless. A couple of points will I hope dissuade you from going this route.

First, the corrugations are there for a reason - the rad is fixed, the engine block moves - putting rigid hoses between the two is a sure route to fracturing the joint between the radiator top/bottom tanks/body and the stub pipe that the hose is clipped to. Going to silicone is probably OK as a silicone pipe is far less rigid than the traditional rubber with woven fabric reinforcement. Having corrugations in the rubber pipe allows for flexing of the pipe to accomodate the movement between the fixed radiator and the movable engine block.

Second, as I say, you have entirely turbulent flow of the coolant in a car engine - any car engine. And this is a good thing, because it breaks up the boundary layer at the inner surface of the pipes, and allows for even heat distribution and heat transfer along the whole pipeway. With laminar flow you can get pockets of static fluid, and even trapped air where heat transfer is almost non-existent, leading to hot spots. Also the boundary layer in laminar flow is at least an order of magnitude thicker (and hence heat transfer correspondingly lower) than in the equivalent turbulent flow.

If you did want to go to silicone that's fine, but as Mick knows and hints at, we have searched far and wide for a way to get silicone hoses for the MB engine/engine bay set up, so far without success. What that exercise showed up is that typically you will need at least 20-off to get a hose at a price that most members will feel reasonable. A one-off hose is of course possible, and there are plenty of suppliers who make these for race cars and the like, but they will charge you into the low thousands for the tooling and set-up costs. Spread over 50 members that's £20-50 each, but to carry all that cost on just one car is something I think most folks will think OTT.

Besides, sorry to Andrew's mechanic, but that won't make the slightest bit of difference to the engine running temperature (though as Mick says, it does look pretty :lol: ).

If, Andrew, you are concerned about airflow over the radiator, I suggest you look at the spare wheel tray and check that all is as it should be. The front end of the GTE is pretty leaky when it comes to getting air onto the radiator. Radiators are most efficient when the fan is behind, and fitted into a duct so that air is pulled through the fins. When you stick the fan in front and try to push the air through the rad, unless the fan is in sealed ducting to the rad huge amounts of air simply spill around the sides and miss the radiator entirely. This is also true of air being rammed into the front of the car by its forward movement - air spills into the wings, underneath and generally everywhere you don't want it to go. The spare wheel tray forms a major part of the 'ducting', for want of a better description, that actually does something useful as regards funnelling the air onto the radiator and fan. If the tray is missing, or has large holes in it ("to save weight, mister") then this merely contributes more to loss of air going to the fan/rad.

If you're really serious about better cooling, either go for waterless coolant or fit a fan behind the rad to pull the air through. You'll find a range of them at Car Builder Solutions. However, if your car has run perfectly well to date with its present set up, you might like to give some thought to the old adage, if it ain't broke, don't fix it... :wink:

But whatever else you decide, do NOT fit a rigid rubber hose to the radiator.


Chris
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Post by rebel alliance » Sat Oct 06, 2018 12:55 pm

Get a new mechanic 😀 (sorry i could'nt resist)



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Post by drcdb15 » Sat Oct 06, 2018 1:10 pm

rebel alliance wrote:
Sat Oct 06, 2018 12:55 pm
Get a new mechanic 😀 (sorry i could'nt resist)
Actually, Andrew, this was my first thought too. Now this is dangerous and sensitive territory, and I really don't want to cause any offence as of course I know nothing about your situation or the gentleman concerned, but speaking generally we can all get a bee in our bonnet about some idiosyncrasy or other and that's just human nature. But when it's something that can possibly have quite serious and expensive consequences then perhaps it shouldn't be shrugged off.

It may well be the mechanic merely made his remark as a 'something you might like to think about' comment, and if so that's fine. But if he's really insistent on this, and adopts a belligerent "well if you won't take my advice don't come crying to me when it all goes wrong" attitude, then it's time to walk away. Since you already have a chunk of work committed I imagine it will be very difficult and personally uncomfortable to just cancel the job entirely, so best approach might be to say "really appreciate your advice and expertise, but for now I think I'll just stick with the standard parts, thanks".... *then* you find a new mechanic!


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Post by rebel alliance » Sat Oct 06, 2018 1:26 pm

Oh dear that was meant as a joke bud...long running forum response not to be taken the wrong way 😊



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Post by mick_gaugh » Sat Oct 06, 2018 5:59 pm

Hi Chris

Wow, I had not given this subject anywhere near enough thought and just took it as a given that converting to the 'flexible' silicone would give a better / speedier flow rate. But hey, that's the great thing bout forums. incidentally my silicone guy has done me a few specials including the MB induction pipes from scratch for under a £100.


The Middlebridge Scimitar should not suffer with any overheating issues unless there is a specific fault. Dan's Pre=Production MB spent much time at Dagenham being chamber tested by Ford before they would allow Middlebridge to purchase and fit their then flagship engines / running gear to the cars.

Once again Many thanks

Mick



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Post by AJL Electronics » Sat Oct 06, 2018 6:28 pm

drcdb15 wrote:
Sat Oct 06, 2018 12:35 pm
If you're really serious about better cooling, either go for waterless coolant or fit a fan behind the rad to pull the air
Waterless coolant, although I think it a really good thing will not improve cooling nor will it mask an overheating problem. The finest coolant is plain water, nothing else has the same thermal transfer efficiency. However, we all know the problems of plain water, even when anti-freeze is added so have to accept some compromises to the transfer efficiency. In a good and well maintained system, it doesn't matter at all, but in a marginal one the running temperature may increase a surprising amount with waterless coolant in the system.


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Post by drcdb15 » Sat Oct 06, 2018 6:55 pm

AJL Electronics wrote:
Sat Oct 06, 2018 6:28 pm

Waterless coolant, although I think it a really good thing will not improve cooling nor will it mask an overheating problem. The finest coolant is plain water, nothing else has the same thermal transfer efficiency. However, we all know the problems of plain water, even when anti-freeze is added so have to accept some compromises to the transfer efficiency. In a good and well maintained system, it doesn't matter at all, but in a marginal one the running temperature may increase a surprising amount with waterless coolant in the system.
This from the man who sells the stuff ! :lol: Just kidding, Andy. What I actually said was waterless will give "better cooling", not lower temperatures. All of what you say is true, in an ideal world, but of course an engine is not laboratory conditions. When I talk about "better" cooling, what I mean is keeping the engine at a more even temperature, without hot spots and extreme localised temperature gradients. Whether the "overall" temperature of coolant is 95 or 100 or even 110 degrees is really irrelevant when the combustion chamber is seeing up to 800 degrees. What is important in the overall perfomance (including the reliability and longevity) of the engine is to avoid sudden changes. It is extreme localised expansion/contraction that leads to cracks and metal distortion that in turn leads to leaks and catastrophic failures, and as I understand it this is precisely what waterless coolant provides, in particular in the cylinder heads region, by eliminating hot spots and cavitation caused by localised (water) boiling.

The other point I'd mention to Andrew is not to get too hung up about what temperature figure you are seeing on your gauges - how do you know how accurate they are, have they been calibrated? And where are they measuring the temperature that they are showing - in the cylinder head, or some arbitrary point somewhere around the engine? What really matters is, is the reading the same from day to day, is it the same under repeated similar running conditions? Remember your primary coolant isn't water or Evans anyway, it's the engine oil, and I expect you have no idea at all what tempreature that is at - neither would I. So there is really no need to worry about the "temperature" of the water - it will vary across the engine and the radiator and all the hoses anyway, and with the pressure in the system. As long as the oil pressure is good and the water temperature is consistent, then that says all is well.

Obviously if there's some underlying issue like sludge blocking a passageway (and let's face it, we've all been *there* :lol: ) then this needs to be sorted before worrying about more esoteric concerns.


Chris
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Post by mick_gaugh » Sat Oct 06, 2018 7:29 pm

I have owned 5 Middlebridge's and not one registered the same temperature on the guage when compared to readings taken from various points cooling system wise. My regular MB reads 8 degrees high on the guage. This did use to bother me but over the years I guess I have got to know her better. The point being that my other ones all registered hotter at the guage than the factual figure. As was mentioned much earlier maybe there is no real issue at all.

Incidentally another MB querk, turn all your lights 'n' heater on and the gauges can rise by up 10 degrees. :shock: :shock:

I do as a matter of course have all my cars thoroughly flushed out run di water with AF.

Hope this helps

Mick



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Post by RonH » Sat Oct 06, 2018 8:25 pm

GTC 404 has run with Evans waterless fluid for approximately 6/7 years as well as a full set of silicone hoses and stainless pipes plus a Radtec uprated aluminium radiator etc. In the 3 years of my ownership I’ve checked regularly the fluid level and never needed to add a spoonful. As Andy mentioned Evans fluid does appear to run hotter (at least by my gauge) but also as Chris says as long as it remains consistent nothing to worry about.
Accordingly, I’ve never been too concerned by constantly looking at the gauge (and that’s a lie :oops: ) dab nab it it’s a Scimitar :lol:
RonH



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Post by AJL Electronics » Sat Oct 06, 2018 8:46 pm

Quite, the beauty of waterless is the consistent temperature and lack of microboiling effects. Far more important than absolute temperature at one point. Running a few degrees hotter is no bad thing, the heater works better and the engine is more efficient. It's just a shame that so many owners are mesmerised by the gauge. ;-)


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Post by Djangoz » Tue Oct 09, 2018 12:27 pm

Thanks one and all for your comprehensive replies! Chris your point about turbulent flow being preferable to laminar is well taken. I may have done my chap a disservice by using the words "very hung up" on the corrugated hoses. It was really more of a comment made among many while he was giving the car a good inspection and listening to my description of my slight concern over the cooling efficiency. Some context may be of value here.

I took ownership of the car back in May which coincided with the start of very hot weather down here in Cornwall. Temperatures were in the upper 20s for quite some time (and indeed throughout the summer). I noticed that the temperature gauge tended to sit at around 95 on a run (a little over half scale deflection) but would rise to 105 or so if idling in traffic - greater than 2/3 deflection on the gauge. As I mentioned the car has; at some unknown time, been fitted with a single speed Pacet fan (diameter unknown at present) and a capillary type thermostat instead of the original Otter switch arrangement. This functions correctly and dutifully kicks in once the temperature exceeds 95 (95 set on thermostat). My only concern is that this never seems to drop the temperature as one might reasonably expect. However once you start travelling again at some speed it will drop back to an indicated 95. Looking back through receipts over the past eight years, previous owners have fitted a recored radiator, most hoses have been replaced and a new temperature sender fitted (this last item in 2015 from QRG). Perhaps this has been a long term concern?

Now I am mindful of the fact that one cannot necessarily take the gauge reading as gospel. Of interest here is that according to the MESS gallery information MB60 is one of only two Middlebridges fitted with a particular set of VDO gauges from the factory. So perhaps the QRG "standard" sender may not be quite right for the VDO gauges? If only the indicated temperature would drop somewhat while the fan is running I would probably be happy to accept that this is just an instrument problem.

The engine is coming out anyway in order to replace core plugs - there is a leak from one or both of the two at the rear between engine and autobox. So we're going to flush out the waterways and separately inspect and flush the radiator. I did wonder whether there was any possibility of the water pump impeller slipping or thermostat being partially stuck. We will see. At any rate I'm sure he will be happy to accept that the main hoses were corrugated from the outset. After all - we do know that many MBs run perfectly satisfactorily with these hoses with no cooling issues.

If all else fails and we become confident that this is simply an indication fault, I have experimented with a variable resistor (5W wirewound 25 or 50 ohm) inserted in the sender circuit which allows me to adjust the reading around the middle of the gauge's range. I know the scale is not linear but as long as a small adjustment around the middle of the range works it will stop me obsessively looking at it while driving! Once happy with it I can substitute a fixed resistor of whatever value turns out to be appropriate.

I take on board the concerns about mechanics who "dabble" but this guy is the proprietor of a long established local garage and very respected in the area and looks after all my cars. He lives and breathes cars including classics - it's his hobby as well! He is always busy and I was willing to wait 6 weeks before he could accomodate MB60 and be sure that he could concentrate fully on working on her himself.

Anyway the die is cast - she went in yesterday so will update with results in due course!


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Post by Coupe Racing » Tue Oct 09, 2018 12:39 pm

If you have leaking core plugs then the boiling point of the coolant will surely be altered!


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Post by Djangoz » Tue Oct 09, 2018 1:09 pm

Coupe Racing wrote:
Tue Oct 09, 2018 12:39 pm
If you have leaking core plugs then the boiling point of the coolant will surely be altered!
True - I assume the boiling point would be lowered although the actual temperature would be the same. However we are not talking about rapid coolant loss. I think it is a weep more than anything. I can collect 15-20ml in a drip tray over a week or so - so not drastic - but not a "safe" feeling as it could worsen at any time with unpleasant results! The system is still pressurised despite the slow leak.


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