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Emmanueld
USA
543 Posts |
 Posted - 16 June 2010 : 22:23:18
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Damien, my steering wheel is 15.5" OD, just get a cobra wheel and modify it to look like a 428 wheel. I am going to remove mine an install a Moto-Lita as soon as I get the hub. I will send it to be refinished. This is just a temporary thing, I am not changing the wheel!  Emmanuel |
Edited by - Emmanueld on 18 June 2010 17:40:10 |
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Michael Trotter
United Kingdom
12 Posts |
Posted - 27 July 2010 : 20:20:21
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Damien, it's looking very impressive in the photos - congratulations. Is the paint Guardsman Blue? Do remember not to have your head under the bootlid on a windy day - an AC design error in my view to put the lower pivot of the gas strut too near to the line of the hinge pins. On CF6 I moved the pivot pin down and further back and a longer strut holds the lid against a wind and assists the opening of the lid. What are the 'small black handles' on the dash you were looking for?
Re your cooling/air in the water concerns - I assume your header tank is the original or repro Serck rectangular tank mounted so it slopes down to the front and the front pipe stub is in line with the rad stub. You are right that air bubbles circulating in the water are a BAD THING. Air in the water reduces heat transfer in the radiator, may cause local boiling in the very hot parts near the exhaust valves and at high rpm may encourage cavitation in the pump inlet. I reckon the capacity of the header tank is about 4 pints(Imperial) and the expansion of the CF6 system from cold to hot is normally about 2 pints but has been to 2 1/4 ; let's work on 2 1/4 pints. If your header tank were full when hot with no air in the system then when cold it would have drawn in 2 1/4 pints of air. The inlet and outlet pipes will be uncovered and air will go into the circulating system at the next start. So I think your problem is lack of an expansion tank rather than height of tank or hoses. A single header/expansion tank can work but it needs to be bigger and higher than the rectangular Serck and preferably not part of the circulating system.
Apart from CF1 I think all 428's probably have an expansion tank in addition to the Serck header tank. With this setup the header tank has a plain cap sealing on the top lip of the neck, the pipe from the neck to the expansion tank is pressurised and has hose clips and the expansion tank has the 13psi pressure cap. All 428's I have seen have a black painted expansion tank with a distinctive kidney shape taken from BMC 1300 and 1800's of the 60's. I think this was a design error because the tank has a volume of only 2 pints and the feed pipe which goes in from the side stops 1/4 pint from the bottom so it can only cope with up to 1 3/4 pints of expansion without dumping water on the road and/or drawing air back to the header tank on cooling down. I think it can just about work without topping up but the cold levels would be 1/4 pint of water in the bottom of the expansion tank and 1/2 pint of air in the header tank some of which might get circulated. I found this impossible to judge and could never resist the temptation to top up both tanks. In the discussions about 'overheating' I haven't seen any reference to topping up and wonder how much of this other owners do.
I replaced the original expansion tank with a BMW tank which is translucent plastic, designed for 13psi, has a neck which takes the original AC-Delco cap, is a suitable shape and can just cope with 2 1/4 pints of expansion. I mounted it on the RH inner wing panel above the alternator/front end of the rocker cover and have a cold level line on it so I can check this without removing the cap. The header tank is completely full hot and cold. Since 2004, doing 2 or 3 thousand miles a year I have topped up only at the end of the season when it will need about 1/4 pint to restore cold level which I think reflects coolant loss from pushing damp air out and drawing dry air back in.
On the road indicated temperature, depending on ambient air temerature, is 80 to 90C (88 to 93 true).The electric fan switches on/off at 115/102 indicated (103/99 true at the sensor) in slow traffic and idling. The Otter thermoswitch in the header tank for the fan makes at 90 and I have a manual switch in parallel and a 'fan on' warning light so I can switch the fan on before I reach a traffic jam.This all seems to work OK and I think you should not worry about the number the needle points at if no topping up is needed because, by definition, it has not overheated or lost water.
For those still reading this I add a few general points. Discussion of 'overheating' has focussed on water, engine bay and car interior temperatures. On the water temperature issue I think the larger expansion tank is a good start plus: 1. Cure all water leaks - even a small one will lose significant water with hot 13psi water behind it over time.2. Pressure cap valve lift at 13psi is vital to maintain system pressure and is worth checking regularly. At 13psi water boils at about 117C and this is important to maintain a safety margin over water temperature. 3. Fit a big fan. I have a 16" Kenlowe; it pulls 21 amps but shifts 2320 CFM in free air and about 1900 CFM installed - still only about the same as 15mph. The matrix of my radiator is 19.5" wide x 17.25" high x 2.75" deep. Is this a typical size? 4. I think you must have a thermostat to get a fast warmup and reduce engine wear which is dramatically higher at low temperature. I reckon opening at 74C and fully open at 86C is about right in the UK. 5. For most of us who see highest temperatures at idle/low speed an aluminium Edelbrock water pump is worth considering. They claim higher, but unquantified, flow rate at low rpm and I was prepared to believe this having seen the crude 'paddle wheel' impeller in the original Ford pump which also weighs a ton. 6. With a header tank always full there is a case to eliminate it.I think the Cobra Mk1V has a header/expansion tank with a system filler in the pipework at the highest point. I kept my header as it's a convenient place for the Otter fan switch and I thought the internal baffle directing the water flow under the filler neck would capture any air bubbles (inevitable when you have drained the system).
So far as engine bay temperature is concerned I didn't like the fierce heat which hits you when you open the bonnet after a fast run and in years of motoring the 428 is the only car in which I have experienced fuel vapourisation. I think you should have a minimum of fuel pipework in the engine bay and insulate it where you can. I fitted 2 extraction fans to draw air out and through the side vents which seem otherwise to be more decorative than functional.These shift 1200 CFM of air total and lowered the engine bay temperature by about 6C on test with no noticeable effect on water temperature. However this modest reduction takes some of the sting out of the heat and I think has avoided fuel vapourisation which has only happened at idle/low speed. Incidentally I don't understand the aerodynamic theories we have heard and the talk of bonnet louvres. Whilst I would expect louvres to lower engine bay temperature I doubt they would have significant effect on water temperature except perhaps at very high speeds. I wouldn't want to change the lovely lines of the car but if you were to add bonnet louvres I would have thought 1/3 to 1/2 way back from the front end would be a low pressure area to put them whereas the rear end of the bonnet just ahead of the screen is a high pressure area - isn't that why modern cars have their interior heating/ventilating air intakes there? And is there evidence that an Aceca with louvres runs cooler than an Ace without but otherwise the same ahead of the screen?
So far as excessive heat in the interior is concerned I think the solution is don't drive a fastback, do drive a convertible with the soft top down, don't drive in California, don't have an auto, do have good footwell fresh air from the fans at the front end with the ducting going above the front wheels outside the engine bay and, if all else fails, follow Emmanuel's advice on heat insulation to isolate you from that 7 litre space heater!
I hope Damien that you (and others) may find some of this helpful and that it may elicit other/differing views and experiences. The 428 is a super car and I hope you get as much enjoyment and fun out yours as I have from mine.
Michael
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cliffordl
United Kingdom
122 Posts |
Posted - 28 July 2010 : 10:25:43
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All sounds like good advice to me. CF25 runs a large aluminium rad and edelbrock water pump but original expansion tank. In the current hot weather even with roof down my feet get heated so I guess one day I'll get around to an Emmanuel style heat proofing exercise still it's nice in the winter. The water temp was getting over 100 degrees so on the advice of Thunder Road I added 'water wetter' which has dropped things by a good 10 degrees or more.
BTW Thunder Road did a great job for me on sorting out some rather dodgy old electrics and fitting Hawk Cars new shocks along with a complete suspension refurb/re-bushing. Getting to the point where the car is almost reliable..
Oil temp still goes well over 100 degrees so a cooler is next on my list of improvements.
Happy motoring
Cliff. |
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Emmanueld
USA
543 Posts |
Posted - 28 July 2010 : 21:42:32
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Michael,
I agree with what you wrote with one exception. The configuration of the header tank and recovery bottle. The pressure cap has to go on the header tank at the highest point to let the air escape and the recovery bottle down below must have a non pressured cap. Otherwise, you will have trapped air in your system and loose too much coolant. My car still has its original radiator which has been cleaned and runs cool below the 90 degrees mark. The electric fan has been replaced by a much larger one. I drove it in 110 degrees heat a week ago and although it ran hotter than usual, it was steady at about 100 degrees in traffic and back to 90 on the highway. Remember, the engine is a 454 cubic inch which generates more heat than a 428. The car has a 5 speed box and the gear ratio is a bit long despite the 3.08 conversion. I think the perfect compromise will be 3.31 with that gearbox. We were able to install the gearbox without any major modification to the car so all is well. It was basically an easy swap. The heat inside the car is now tolerable but I need to take it for an afternoon drive to know for sure.
I am planning on adding some openings on the hood to let the hot air escape, Probably like on the Ferrari Daytona or the Maserati Ghibli. A hood scoop like on the 427 Cobra would work well for cold air intake, but we have to see if it will work with the car design.
Emmanuel |
Edited by - Emmanueld on 28 July 2010 22:01:29 |
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J Jones
USA
39 Posts |
Posted - 28 July 2010 : 22:34:09
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Just to clarify my understanding of the purpose of the overflow tank: the header tank must not allow air to be drawn in when the coolant is contacting (cooling). the vacuum in the header tank draws coolant from the overflow, thereby keeping the header tank topped up, right?
So far, I've replaced the original radiator with a larger aluminum one. The Transmission cooler has been repurposed as an engine oil cooler. The C6 auto box has been replaced with a Tremec T5. The Intake manifold has been replaced with the nearly identical Police Interceptor Aluminum intake. The heads have been replaced by Aluminum Edelbrock heads. Edelbrock (aluminum) water pump in place of the original cast iron lump. New ceramic coated stainless steel headers and exhaust. Insulation, a la Emmanuel.
We shall see what effect all this has on performance and heat issues. As my car is a fastback, and it lives in Southern California, Air Conditioning is still an option. I certainly have no need of a heater, so I expect that will be going as well. |
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ACOCArch
United Kingdom
24 Posts |
Posted - 28 July 2010 : 23:32:01
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Hi Guys,
Sounds like you are all having great fun with your 428s in a lovely climate. No need for a heater - wow!
I am no expert on this model, but my sketchy recollection from the late 1960s is that AC fitted a footwell cold air vent (inward bound!) to the Autocar road test Fastback during the test - at Autocar's request! A fine example of AC's bespoke service!
The test car was CF7. If you can locate the present owner the chances are the vent is still fitted.
Enjoy! |
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J Jones
USA
39 Posts |
Posted - 29 July 2010 : 07:03:45
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Hello ACOArch - Yep!... "cold air" vents in the footwells. My car has them, though the ductwork runs through the engine compartment, where the "cold air" gets nice and toasty before it actually gets to the footwells. That, too, will be changed by re-routing the ducts through the wheel arches (where they were subsequently placed in later models).
Emmanuel will be doing bonnet modifications to facilitate the flow of air through the engine compartment ( therefore eliminating back pressure, hopefully improving air flow through the radiator and reducing hot air flowing into the passenger compartment). Also we hope to fashion a subtile way to bring denser, cold air to the Carb. Making the decorative side vents actually function will be a part of the endeavor to pull air out of the engine compartment.
An odd thing about CFX29 (my car) - all the dated engine parts and transmission were from 1967, just late enough to have been 1968 model year parts. Yet my car 'left the factory' in 1969 and was shipped to Montreal, Canada (subsequently shipped to the USA as a 1970 Ford). Was it fabricated in England earlier, then held up by the Strikes in Italy? Or were the engine and transmission ordered in 1967, then held in stock? Might it have been for another purpose (an AC 428 big block?). The block is a "Police Interceptor" reinforced block with a scratched letter "C" - the same block used on Shelby GT 500 and "Cobra Jet" mustangs. The heads are not "cobra Jet", though the original Intake manifold could be.
We ARE having fun. It's a real benefit that parts (original and reproduction) are available a fairly plentiful. The original "Cobra" guys are still alive and still working. Excellent! |
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Emmanueld
USA
543 Posts |
Posted - 29 July 2010 : 19:43:03
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quote:
Originally posted by J Jones
Hello ACOArch - Yep!... "cold air" vents in the footwells. My car has them, though the ductwork runs through the engine compartment, where the "cold air" gets nice and toasty before it actually gets to the footwells. That, too, will be changed by re-routing the ducts through the wheel arches (where they were subsequently placed in later models).
Emmanuel will be doing bonnet modifications to facilitate the flow of air through the engine compartment ( therefore eliminating back pressure, hopefully improving air flow through the radiator and reducing hot air flowing into the passenger compartment). Also we hope to fashion a subtile way to bring denser, cold air to the Carb. Making the decorative side vents actually function will be a part of the endeavor to pull air out of the engine compartment.
An odd thing about CFX29 (my car) - all the dated engine parts and transmission were from 1967, just late enough to have been 1968 model year parts. Yet my car 'left the factory' in 1969 and was shipped to Montreal, Canada (subsequently shipped to the USA as a 1970 Ford). Was it fabricated in England earlier, then held up by the Strikes in Italy? Or were the engine and transmission ordered in 1967, then held in stock? Might it have been for another purpose (an AC 428 big block?). The block is a "Police Interceptor" reinforced block with a scratched letter "C" - the same block used on Shelby GT 500 and "Cobra Jet" mustangs. The heads are not "cobra Jet", though the original Intake manifold could be.
We ARE having fun. It's a real benefit that parts (original and reproduction) are available a fairly plentiful. The original "Cobra" guys are still alive and still working. Excellent!
Jeffrey, Your box is not a T5, the T5 is too small and could not take the torque of the big block. It's a TKO600 with .82 fifth gear. (Road racing version)
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J Jones
USA
39 Posts |
Posted - 30 July 2010 : 03:34:13
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OOPS....
Thank you for the correction, Emmanuel.
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Damien
Belgium
67 Posts |
Posted - 02 August 2010 : 11:25:31
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Dear all,
Thanks for your valuable comments. I used a Glasurit colour (do not remember which, but could find it out). This is very nice, as the colour evolves with the light. with the handles, I meant the dashboard switches, but I found them. These are Maserati ones.
I have also placed an extraction system on the radiator to reduce the heat under the bonnet, and it seems to work. With a big fan and an aluminium radiator, the water temperatures are at a good level, except for this expansion tank problem.
Can anybody post a picture of this second expansion tank and the way it is connected to the cooling system.
kind regards,
Damien |
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CF9
