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MG MGB GT V8 Factory Originals Technical - Mike Barnfather cooling ?
|Mike --I was wondering if you had any sucess with your tests of the pancake fans to remove engine heat ?|
I am looking at puting louvers in the hood on both sides and have forgotten if those alone were any help to you ?
I still am having the heating preoblem when standing still due to lack of airflow.
Mike is in France at the moment and probably doesnít have access to a computer.
As far as I know Mike hasnít tried pancake fans but he does say the louvers alone are effective.
Thanks for the reply - I am going to go the louvers route for now and will be interested in results of fans if he tries it .
All the best
|Gil the louvres will have the desired effect provided the fans on your rad are working properly. (I have used a GTV8 with cast iron blockhuggers at 105F without louvres).|
|Properly working fans are a good point. My V8 used to go into the red when stuck in traffic on a very warm day - 90sF. I fitted an uprated rad with a 4th row but it didn't make as much difference as I expected. Then I started looking into the electrical connections for the fans and found I was losing about 1/4 of the voltage at the fans. Some of this was due to old connectors, but the biggest loss was in the ground wiring. Although they have a thick wire feeding 12v to them they only have a thin black wire for the ground, which is probably longer than the 12v wire, and shared with the lights! I added a local ground to each fan under its mounting bracket in parallel with the existing ground, and even when the first fan had its ground and so was helping the 2nd fan, when I provided a similar ground for the 2nd fan as well both fans noticeably picked up speed. Another noticeable boost was to add a thick brown directly between the spare output spade on the alternator and the brown connection on the fan relay, only a distance of a few inches. I can't locate the exact figures but in last summer's heat-wave I shut the car in the garage on a low 30sC/high 80sF day and at a fast idle got the temperature going into the grill up to the low 40sC/mid 100sF and the temp gauge only got slightly mid-way between N and H. No louvres, and I found that because all the hot air has to escape from *below* the engine a significant amount is sucked forward by the fans and recirculated through the rad!|
|Paul, be careful in a closed garage with a running car. Carbon monoxide is a killer, and without your knowing it.|
I've never found a car to overheat when only idling, even fast idle. It is not making much horsepower. The only heating issues I've seen are after coming to stopped traffic after a spirited run.
|Paul, you can make the same thing with the headlights.|
|Edd - the side door at the back of the car and garage was open. The engine is doing quite a lot of work at idle or fast idle as it is acting as a massive vacuum pump generating about 20 in. Hg. This is why introducing an air leak into the inlet manifold increases the idle speed, it is not because the mixture is 'better' but because the engine is doing less work. Block the suction hose on your vacuum cleaner and see if the motor speed increases or decreases.|
IME experience switch an engine *off* after a hard work-out will result in a big temperature rise due to heat-soak and lack of circulation, and possibly vomiting from the overflow. But leaving the engine idling after a workout even under high ambient conditions results in a smaller rise, which stays there and doesn't drop back, and no vomiting. YMMV.
|Roger--I have a 302 Ford engine and headers going out inner fenders --even with fairly large holes there the heat buildup at idle is a concern . So will try the louvers --have ordered some and will report back the results.On the highway the engine actually runs a little cool --around 185F --I try to avoid city traffic -but at times hard to do.|
I have used lagging in the past - reduced the temperature considerably but have some concerns about uneven expansion and am not using it now. The louvres will definately have the desired effect also.
I have a 4 row tube radiator (custom made with copper core)and the standard 2 fans with heavier wiring much like Paul and I have not had a problem in 4 Australian summers.
I even have block hugger exhaust and no louvres.
The radiator is about 3" longer than a factory part.
I see others here with custom built aluminium radiators with push or puller fans still unable to stop the overheating.
Paul is really onto something when he advocates correctly wired OE fans.
My rad is for a 65 Mustang and a 4 core copper/ brass construction and large capacity.I have 3 fans properly wired-1 pusher in front--2 pullers behind rad.Cooling is not the problem --its heat retention in the engine compartment.
I know Dale Spooner has about the same size --but Alum rad and an engine mounted fan and louvered hood and has no probs.
So I feel the louvers should alleviate my problems in traffic .At any rate I shall report back when I get the louvers installed.
|Paul, makes a good point. I have found that poor wiring casues the fan to run slower. I have found that the MGB wiring is not suited for a electric fan, perhaps the newer B's are ok.|
The problem with the B and other British cars, is the cooling area (radiator) and engine bay. engine bay does not have adequate exits for the hot air.
One thing that really helps is the rear lip of the hood, between the hood hinges, should be flaten, next is to remove the rubber seal and flaten the lip on the cowl, this will create about 1/4 to 5/16 of an inch gap.
with the fan running at idle you can feel the hot air exit the engine bay.
In one of the conversions the fan would run all of the time during idle, keeping the temp to about 200 on a hot day of 95 degrees. with the hood open it would run about 3 minutes and stop, with the hood closed it would run all of the time.
With the mention modifications, the fan would run for about 4 minutes and stop, temp to 185 on the gauge and 190 on the thermo gauge on the engine (test purposes)
The fan sw was set at 195.
I have pictures of the mod, if interested.
|I did the flat rear hood lip several years ago, & went a step further & adjusted the hood hinges to increase the gap. As Bill indicated, this does work when the car is stationary.|
Unfortunately, when the car gets moving, the air over the hood hits the windshield then rolls back through the gap, into the engine bay, adding to the pressure, restricting the release of hot air even more.
If you want to know what is happening to the air flow when your car is moving, tape some ribbons on the bumper edges, various spots on the hood & go driving with a friend in another car. Another way is to dribble some motor oil along the hood & bumper, take a drive & see where it winds up. We found that the rubber bumper is VERY restrictive & allows very little air through the radiator compared to the chrome bumper.
I also found that the ST style spoiler reduced my temp at driving speeds by 3-10'.
|Jim, the lip on the cowl between the hinges, this area also needs to be flaten out and the lip facing downwards tours the engine. This creates a suction (out)while driving, thus evacuating the hot air at low and mid speeds.|
Elevating the hood to increase the gap will only create a low pressure and forces the hot air to remain and re-enter the bay.
|Sorry, chaps, Just got back from France yesterday.|
No progress on the fan front.....I got two 'hamster' style fans (from Rover heaters) before I went away ....but they are too large for the job.
The weather was hot.(particularly Le Mans)....fans working at each set of traffic lights and tolls, but the combination of 4 core radiator, 19 row oil cooler and ducting under the car seem to keep the temp under control......I still intend to fit two motor-bike type fans under the louvres, and do smokle tests however.
I did find that removing the lagging around the exhaust pipes (to fit the Lambda sensors) has resulted in a much higher transmission tunnel temp, and the gearbox seems to be getting V hot, so I will have to re-lagg up to the 'Y' pipe at least. I guess it's because I've got big bore stainless exhaust, I cannot recall the old mild steel system being so hot....or perhaps hot-wire systems run hotter than flap-valve ones (leaner perhaps....I certainly got fantastic MPG on a couple of long runs last week).
|I saw an interesting website on the Sunbeam Tigers webpage regarding cooling issues and the relative effects of different variables. No doubt the same issues will apply with V8 MGs. It is at http://www.teae.org/tech_tips/hot_air.html|
|mmhh I too was at Le Mans in V8, std radiator, mesh chrome grill, twin rubber bumper style fans (OE) and running "forlife" |
even when we go stuck in heavy traffic (including in Paris) needle never reached the solid white bit at "h"
no extra holes in car, no lagging. Std Rover SD1 motor. Fans on most of time though....
But would like to reduce temp a bit -- but dont want to alter outer appearance of car...
Any how most of the rest of the year car is driven round Scotland... not so much of a problem..
Mine's always runs cool (just below middle of gauge) until it comes to a stop, then it soon reaches hot, Ive set the fan to come in at 90c, but it always stays on until I'm on the move again, then it takes anything up to 5 mins. to go back to normal.
The engine's a heavily modded Vitesse with 45mm trumpets,and 65mm throttle, I guess about 220bhp, and it gets REALLY hot under the bonnet when stopped.
I'm going to re-lag the exhausts tonight to try to get the transmission tunnel a little cooler. I've bought some more Fibreglass 'wicking' from the local plumbers merchants (TVR development dept use it as their exhaust wrap)......it's a lot cheaper than the stuff Frost sell, but seems effective.......you could try this on your manifolds, Derek, it does reduce underbonnet heat.
Excellent photos, well worth saving. Very neat workmanship.
|As my gauge packed up early this year I have not tested the RV8 style exhaust in very hot UK weather.|
With Ali rad twin Pacet fans RV8 style black satin coated the new gauge reads 180f and 190 f in traffic immediately dropping back to 180 when on move, without Water Wetter. So waiting for 2hour M3 jam on a very hot day to test current system.
might try to get some fibreglass wicking locally and see how it goes.
Is the reason for insulating the transmisson tunnel only to keep the dirver/passenger cooler???
If anyone needs that foil backed insulation it looks like acoustic sound deadening - try your local car audio specalist - otherwise I can order some in from one of my suppliers and pass it on to you at cost - It costs me (this is trade price no profit here!)
Just ordered some self-adhesive heat reflecting foil (Reflect-A-Cool Ugh!) from Frosts.......4ftx3ft is £64......quite expensive I thought but I'm fed up with hot left arm and foot, will be tested at Silverstone later thsi month.
|In UK, a good source of these materials is Agriemach.|
|Michael--I am using an alum backed heat sheild on floor and tunnel in cockpit and find it works very well.I have installed --yesterday--header wrap which is what I gather you call lagging ,and will see if that helps reduce engine heat at standstill. I have hesitated to butcher the bonnet yet for the louvers.|
I did a 815 mile trip last weekend --car ran flawlessly and no high temps on the road.I also averaged 27 mpg at avg of 75 mph , for a 185 mile stretch,--very happy with that.
Will try this header wrap and report results.
Re-lagged the exhausts (headers) under the car (auto)..it's helped a bit.....Can't wait for the foil to arrive.........2600 miles to Bergerac and back with a hot left arm and leg was no fun......I had to have the hood (ragtop) off most of the time !!!!....hope it arrives in time for Silverstone.
PS Louvres are good, if you can't bring yourself to fit them, at least fold back the rear lip on the bonnet (hood)and scuttle (?)it gave me an airgap of about 30cmx1cm (10"x1/2") at the rear of the bonnet (hood).
PS wish you guys and we spoke thae same language !
|Mike--no problem on car language --I lived in the UK for a year in 1963--and know most other terms as well--LOL.To add to the confusion I am Canadian but have lived in northern New York for the last 30 years, only a stones throw from the Canadian border.|
The header wrap seems to help somewhat --but the louvers are my next step--probably this week as I'm off on a weeks jaunt into eastern Quebec for my annual visit.
The foil should be a big help to cockpit heat --funnily that has never been an issue as I put the insulation in before I drove the car.
Will let you know of my progress.
|My (ex.Florida) car came with some kind of board in the transmission tunnel.......which I scrapped when I rebuilt it to take the LT gearbox........clearly it had a purpose ! |
I already have thick insulation under wool carpet, I'm surprised at teh amount of heat that still gets through !
if you are reluctant to butcher the bonnet - consider the inner wings - there are areas that can take a cut or two and release quite a lot of hot air.
I already have very large holes in the inner wings for the headers, they were made oversize so I can remove the headers while the engine is in the car.
The headers do create alot of heat and the 302 Ford I think may put out more than the Rover/BOP as its close to 300 HP.
Ceramic coating the headers is probably the real solution.
anyway I shall continue trying things until I get results.
|PS the stick -on foil has made a tremendous difference to footwell /transmission tunnel temps......I now have cool air coming in for the first time in years.|
|Mike--thats great news and a big relief I bet !!!|
did you fit (this is such a stupid question) the foil under the car or inside??
Outside, on the floor immediately above the exhausts,and in the transmission tunnel around and above the gearbox.
I only used about 1/2 the stuff which I got from Frosts, it's thin metalised silver cloth with a very adhesive backing, which even stuck on previously Waxoyled surfaces after I had wiped them with white spirit and they had dried.
Most impressed, I even used some on the airbox which has the air filter in, to insulate it from engine heat.
4.6 RV8 so close to 300bhp but as yet not over 190f since RV8 style exit and DIY coated.
looks like a call to Frosts, as my shoes start melting in a jam.
the stuff I have is foil backed bitumen type material with adhesive on bitumen - kinda like the original but perforated stuff in the floor pans.
Well bent the lip down in engine bay last night and folded up the lip on the back of bonnet without any paint chips/ damage visible out side - bonnet was not removed Job was made easier on as I have a door Skining tool ( used to rebuild minis) which has soft plastic pad... will see what difference this makes.
Reading old archive stuff some suggestions that lagging manifolds causes cracks? anyone had this as problem??
Yours wasn't the blue one I saw at Issigeac (Bergerac) last month was it ? That had a 4.6 badge on the back ?
The strong odour from my trainers was being commented upon by Sheila.....so something had to be done.
That sounds like the sort of stuff I originally had on the inside of the floorpans, I assumed it was to stop drumming as the pans are very thin.
I think rumours of cracking of manifolds are exagerated....I could find no-one to whom it actually happened when I enquired. My manifolds are very thin stainless tube.....about 17.000 miles so far.
Try not to advertise!
In general SS is more likey to crack than mild re wear and tear, but lagging will damage mild but unlikely SS.
You need an offer for the remaining heat-stuff you have from frosts..?
Bought some exhaust wrap and still have about 0.5-1.0 sq.m of the very expensive kevlar foil backed stuff i bought to replace the interior transmission tunnel stuff.
Got cold air feed ducting too... Will see how that works before resoring to louvers etc.
The sheet was 48"x36" and cost £64 !!!!!!!(ouch)
I will measure what I have left (I guess I used about half) and let you know.
Are you going to Silverstone on 23/25th ?
Im still looking for a co-driver with video camera for the 'parade laps'-Sunday 9.20am.
That was the aim - just got the FL bill though... :-<
It was about right, except for i didn't add VAT to my estimate! <sigh>
Anyway let me know and we'll work something out.
|Gil, when you're back from Poutineville, have a look at these nice louvers.|
Checked this weekend.......used a great deal more than I thought........there is a piece 28" wide by 22" tapering to 18", plus a couple of small pieces, I guess it's about 1/3 of the original sheet. It would certainly be sufficient to cover the underside immediately above the exhausts, or the transmission tunnel each side of the gearbox.........yours for £20 !
Go to your local waste tip and take out some of the foil insulation out of the cookers (ovens) there. The modern stuff is quite thin and must do the job otherwise my kitchen would burn down....
Not actually done this yet but 'tis my plan.
V8 in midget - so flow even more of problem
|Bent the bonnet lip at rear and folded down drainage channel|
before - needle to the right of N in normal/fast open road stuff - now sits just on the left of N... only had the car 11 years...
It's amazing how much hot air can escape from there, isn't it ? I wondered if it would make the screen dirty (oil fumes?) but that doesn't appear to happen, but I don't know how much of that hot air finds its way into the air vent and car interior though.
|an oil screen may make it easier to remove midges and flies from the screen... oil loaks a little from sump only so would be worried if it found its way onto screen! |
|My V8's always been a bit fumey, I put a K&N mini-fiter instead of the pipe to the plenium at one stage, and got quite a lot of fumes, particularly when driven hard, so scrapped it. No oil loss between changes, so it's not burning any.|
|The lip from the screen is enough to keep the hot air and fumes from entering the cockpit. If a problem would develop when the hot-engine fumes etc would enter the cockpit via the air vent screen. this can be fixed by raising the front of the screen so that is level with the rear of the screen (horisontal) this will eliminate any heat-fumes at speed to enter the cockpit. I have never had that problem with this mod.|
my V8 is a bit fumey too. Mine is from oil leaking onto the exhaust manifolds. And when I had a split in the manifold there it was dreadful !
Bill - can you explain further please, I don't understand your desciption.
|j w mcglynn|
|"Bent the bonnet lip at rear and folded down drainage channel" |
This section is right in front of the screen that supplies air to the heater. The concern is that by doing that mod the fumes from a tired engine or otherwise, may enter the drivers compartament via the screen.
If does (never experience that problem)then the fix is to raise the front of the screen. If you notice the screen is at a angle that faces the front of the car.
or simply put a deflector about a 1/4 of an inch in front of the screen.
Fumes enters the drivers compartament via the brake box etc. all of the places that leak water into the drivers compartament are the doors for the fumes.
I hope that helps you Jim.
|Makes sense, thanks Bill.|
|j w mcglynn|
|I have had this mod on my car ever since its conversion. I don't think the hot air escapes from there except when the car is stationary.|
When the car is moving the area in front of the screen is a high pressure area and cool air is forced INTO the engine compartment - this feeds the carbs with cooler air and dilutes the hot air surrounding the engine - the air escapes from under the car into the low pressure area in the wheel wells.
There should be no question of any engine bay fumes finding their way into the fresh air inlet.
|Chris at Octarine Services|
|My car only gets fumey when it's at stand still.|
|j w mcglynn|
|Mine used to too......that would suggest that Bill and Chris are right (no surprises there then)|
This thread was discussed between 15/06/2004 and 16/07/2004
This thread is from the archive. The Live MG MGB GT V8 Factory Originals Technical BBS is active now.