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Nick Dean
United Kingdom
444 Posts |
 Posted - 26/10/2009 : 15:57:16
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As the P type is running cold, can anyone advise the number
please of the early Renault Cleo unit which fits in the top hose?
This was a Halfords Part.
N A Dean |
Edited by - Nick Dean on 27/10/2009 08:28:42 |
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George Eagle
United Kingdom
3238 Posts |
Posted - 27/10/2009 : 10:43:49
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Hi Nick
I believe Halfords may no longer make the part but they do stock the equivalent Quinton Hazell thermostat - part number QTH114K.
After much deliberation I fitted one to my supercharged NB and am very pleased with the result. The engine runs at a constant 80 degrees - even on a run out in the quite cold weather last week. I have drilled 4 bypass holes with a total diameter of 1/4 inch. I had previously fitted a thermostat with the diameter of the 4 holes at 1/2 inch but changed as I felt the thermostat was not opening quickly enough.
I spoke to quite a few folk at MGCC Silverstone and all those who use the thermostats were happy with the performance. These included Ray Masters who told me he has used one on his PA for years and does not have any bypass holes, and Walter Kallenberg who uses his K tourer to tour Europe.
This topic has been debated at length on this forum.
Regards George |
Edited by - George Eagle on 27/10/2009 10:45:56 |
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Nick Dean
United Kingdom
444 Posts |
Posted - 27/10/2009 : 17:25:01
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Thanks George, just the info I needed I put one on an NA I had years ago and it worked really well.
Regards Nick
N A Dean |
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Ray Masters
United Kingdom
568 Posts |
Posted - 02/11/2009 : 11:45:42
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| George. Just to put the record straight & clear up any mis understanding, my thermostat does have one small hole in it. At the moment my engine is in pieces so it has given me the opportunity to check the thermostat. In fairness one small hole is probably not enough and after re-reading the 5 pages on thermostats on the forum I think I will drill another one or two!. The one used,by the way, is Halfords HTK 610. Regards, Ray. |
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DADA
Luxembourg
127 Posts |
Posted - 03/11/2009 : 09:26:49
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George,
If you say: The engine runs at a constant 80?....
Please tell us where you measure it; at the top of the radiator or at the outlet of the water manyfold before the thermostat?
Thanks in advance
norbert |
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George Eagle
United Kingdom
3238 Posts |
Posted - 03/11/2009 : 20:41:00
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Norbert
The water temperature guage is the standard one fitted to the radiator header tank. The thermostat is manufactured to open at 83 degrees.
I forgot to mention the oil temperature is of course also higher.
Regards George.
PS Sorry Ray, I misunderstood you! Did your engine show any signs of damage from using the thermostat? |
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Nick Dean
United Kingdom
444 Posts |
Posted - 05/11/2009 : 18:09:06
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I have now fitted the thermostat in the top hose,after drilling 2 8th holes in the outer ring, and the car is running a lot better at a constant 70 degrees.
thanks again for the info,
Nick Dean. |
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Keith Wallace
United Kingdom
367 Posts |
Posted - 06/11/2009 : 08:04:32
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I fitted a pump and thermostat some time ago with good results but have not moved the water temperature sensor to the water manifold, Has any one carried out this modification? is it just a case of drilling and tapping the water manifold and blanking off the old radiator sensor position?
Regards
Keith |
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Ray Masters
United Kingdom
568 Posts |
Posted - 06/11/2009 : 09:04:12
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| Hi George. I have had no problems in respect of the thermostat. Just the opposite in fact; quicker warm-up & engine runs around 70 degrees up hill &down dale. I don't want it any higher, I perfer our engines on the cool side rather than hot. The trouble I had at Silverstone (horrible noise from engine if you remember) turned out to be a loose rear bearing/flywheel on the c/shaft taper. Hence engine stripped for correction!! Ray |
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MaGic_GV
United Kingdom
868 Posts |
Posted - 06/11/2009 : 09:52:56
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I have been following this with interest as I always understood that some sort of by-pass pipe was necessary - am I to understand that the holes in the thermostat are sufficient for this?
Graham |
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Terry Andrews
United Kingdom
546 Posts |
Posted - 06/11/2009 : 12:16:02
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Keith,
With regards to your comment on moving the position of the thermostat sender. This has been tried by John Day (MGCC Chairman) ex Triple-M but with 18/80Æs. He has an adaptor which he has made which has the thermostat fitted within it and a bypass tube back to the fitting in the header tank where the sender was originally fitted. The tube was about ? inch diameter which John found in practice was too big. He then made a series of reducers inserted into the by-pass tube until he felt the thermostat was working properly. He says that he can see the exact temperature that the thermostat opens as the probe is in the exact flow of the water. I think the T is the engine side of the thermostat so he can see what the temperature is coming out of the engine. The temperature rises and then cools as the thermostat opens and then maintains the working temperature. I think he used this dip and rise to determine the size of the by-pass reducer. I am thinking of making one of these adaptors and trying ità. Terry
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Bruce Sutherland
United Kingdom
1564 Posts |
Posted - 06/11/2009 : 13:00:11
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Graham, all,
The technically correct solution with a thermostat is to have a by-pass which is routed back to the water pump inlet (i.e. somewhere in the radiator bottom stub connector pipe/ bottom hose).
Reason: because it is not good engineering practice to dilute warming-up/hot water by admitting cold water from the radiator, thus slowing the rate of warm-up.
A neat by-pass installation for a P Type is illustrated by John Wells PAs trial car:
This also shows a logical positioning of the coolant temperature gauge sensing phial in the rear ælegÆ of the water outlet manifold û i.e. on the æhotÆ side of the top hose-mounted thermostat.
The K Type by-pass pipe size was ?ö OD.
An archive search for Bob ClareÆs initial posting titled ôThermostatsö dated 23/01/2005 has much other discussion on this subject.
Bruce. (PB0564) |
Edited by - Bruce Sutherland on 06/11/2009 19:37:08 |
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Terry Andrews
United Kingdom
546 Posts |
Posted - 07/11/2009 : 09:38:21
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Bruce,
I think, John Day method does emit hot water to the TOP of the tank (using the original header tank connection) so this should get over your issue of: ôit is not good engineering practice to dilute warming-up/hot water by admitting cold water from the radiator, thus slowing the rate of warm-up.ö
Regardsà. Terry
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PaulusPotter
Netherlands
202 Posts |
Posted - 07/11/2009 : 20:06:50
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Hello Bruce,
I guess in the Wells PA by-pass lay-out there will be some by-pass holes in the thermostat housing to enable warm water to increase the temperature of the thermostat itself. Thus, if I understand well, the by-pass as seen in the photograph provides an extra by-pass which will never close. This could be a problem during very hot summer days and driving in low gears.
Please correct me if I do not understand it properly!
Paul |
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Bruce Sutherland
United Kingdom
1564 Posts |
Posted - 07/11/2009 : 22:53:05
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Hi Paul,
From my days when I was responsible for cooling system design and development (amongst a number of other engineering features over the years), a few vehicles had thermostats which included a 'plate/disc' which moved as thermostat opened; this plate/disc progressively closed the inlet to the by-pass. Some modern vehicles use a more sophisticated electrically controlled thermostat.
However the majority of mass-produced cars tend to use a 'simple' thermostat which just opens to the radiator, leaving the by-pass open.
Provided the cross-section area of the by-pass is not too large, the coolant flow pressure drop through the radiator is generally much less than that through the by-pass, hence most of the flow goes through the radiator, particularly when the thermostat is fully open û as in high ambient temperatures at low speeds/traffic jam situations.
Radiator heat dissipation/rejection, as with heat exchangers generally, is a function of the temperature difference between the hot fluid (in this case coolant/water) and the æcoldÆ fluid (in-coming air), so as the coolant temperature in our unpressurised (unpressurised cooling system) cars approaches boiling point c.100C the heat dissipation/rejection increases.
In the extreme, you are correct that some loss of radiator coolant flow down an open by-pass will have a small adverse effect on cooling performance. However I suggest that such a loss would be more than compensated for when a water pump and electric fan are fitted (recommended).
Cleanliness of the entire cooling system is important û there should be no æsludgeÆ in any part of the cooling system, such as I found when stripping my radiator, block, and cylinder head where a previous owner had been running on plain water. The amount of brown corrosion deposits was very considerable û e.g. the water galleries in the cylinder block in particular were several inches deep behind the jacket side plates; similar can be found in the radiator and cylinder head û nothing came out when opening the drain taps on the block and radiator!
To keep the coolant passageways clean (after removing all evidence of the corrosion æsludgeÆ), it is essential to have plenty of anti-corrosion additives in the coolant; I prefer to use a 50/50 water/good quality ethylene glycol anti-freeze solution, though others claim success with æsummerÆ coolant/water wetting solution (or some such thing).
æAnti-freezeÆ is really a misnomer, as for the majority of time freeze protection is not required but corrosion protection is required 100% of time.
Note that in a weak anti-freeze solution the anti-corrosion additives get æused upÆ which leads to corrosion and eventual sludge formation û I know, I seen it happen in 100,000mile endurance test car!
The effect of corrosion/sludge, apart from impeding coolant flow, is to reduce the water-side heat transfer extraction from the hot metal in the engine and the heat rejection to the metal tubes/passages inside the radiator exacerbating cooling problems.
The essential thing is that when checking the coolant there should a clear, clean, usually coloured fluid with no rusty brown evidence.
ThereÆs lots more I could add, but I guess IÆll save that to bore you with later.
This topic should be in the Technical forum.
Bruce. (PB0564) |
Edited by - Bruce Sutherland on 07/11/2009 22:58:48 |
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PaulusPotter
Netherlands
202 Posts |
Posted - 08/11/2009 : 14:20:27
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Hello Bruce,
Thanks for your explanation. With repspect to the coolant I can confirm you are right the anti corrosion is actually very important. And many times people do not know the anti corrosion substance is consumed in the cooling system after some time. Allthough the anti freeze is still OK. Since I am in chemical engineering I am familiar with fouling of heat exchangers (equal to cilinder block heat transfer). The cleanliness of the surface for the heat transfer is very important and might be the cause for overheating of many cars. Diluting coolant with plain water brings in an extra amount of oxygen which I would only advise against, this at the end can be very costly diluting. This for sure is the cause for many of our cars having the fouled water channels. Next to fouling this will speed up the loss of metal at the water channel walls by factors of 100 and more.
Regards,
Paul |
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