under bonnet heat

General Chat About Cooling & Overheating

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stagman
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heat

Post by stagman »

Ian Anderson wrote:Or the Zimbabwe Method

Wrap your fuel hose with cloth
Unplug your windscreen washer hose
Attach said hose to the cloth and when the fuel vapourises press you windscreen squirt button

Gives a cool water squirt and evaporation does the rest!

Worked with Ethenol Blended petrol in 40 degree outside temp

But I would also check your floats as the carb should not flood but be lean if the fuel is evaporating. It could be that once the whole carb heats up the float needle or hinge "pinches" tight

Ian
hi ian, i have just been reading the edelbrock manual, quote-excessive under the hood temperature-ensure fuel line is not located too close to heat sources causing expanding fuel to be forced past the needle and seat. unquote. so it seems the fuel line could be the possible cause for both problems.i have ordered steel fuel pipes to see if that makes a different, and some heat wrapping in case that need to be uused as well.paul


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Ian Anderson
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Post by Ian Anderson »

Well that also makes sense re the evaporation causing the fuel to force past the float and flood the carb

In Zim it was always the fuel boiling in the float and hence we cooled the fuel line to cool the fuel and stop the evaporation

Ian
Owner of an "On the Road" GT40 Replica by DAX powered by 3.9Hotwre Efi, worked over by DJ Motors. EFi Working but still does some kangaroo at low revs (Damn the speed limits) In to paint shop 18/03/08.
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Re: heat

Post by Richard P6 »

stagman wrote: hi ian, i have just been reading the edelbrock manual, quote-excessive under the hood temperature-ensure fuel line is not located too close to heat sources causing expanding fuel to be forced past the needle and seat. unquote. so it seems the fuel line could be the possible cause for both problems.i have ordered steel fuel pipes to see if that makes a different, and some heat wrapping in case that need to be uused as well.paul
My fuel line used to come up at the offisde rear of the engine then go along the inner wing (above the tubular headers) to the front where the regulator was situated. Then from the reg, back across the headers (A way above them but they do get very hot) to the side of the carb.

I resited the reg to the rear of the nearside inner wing and rerouted the fuel pipe so that it came up across the front end of the gearbox to the reg, then across the bulkhead and into the back of the carb. This improved matters.

Possibly a simple rerouting would help.

I am also getting a heat insulating gakset (you can get 1/4" and 1/2" ones from Mr Gasket), and have now wrapped the manifolds.

When you have a return pipe, the fuel can circulate and will be cooled as it does.

I am trying all of this because I had the same problem as you do - let us know how you get on.
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ged
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Post by ged »

Hi stagman,

I don't know if this will be of any use to you but this is the setup I used on my SD1 & I don't have any problems with it.




Image

You can just about make out the fuel line going behind the left hand rocker cover & the regulator is mounted behind the air cleaner.

Ged.
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Post by stagman »

hi ian, sorry about the time its taken, had a few other problems, right getting back to the overheating, i have moved the rad back , to enable a electric fan to be fitted on the engine side pulling air thro , the rad , that worked out fine, temp, is on the 1/4 mark on the clock on the move, it moves up till the fan hits in, but stays midway on the clock. but i am still getting vapour problems, so i am now fitting a return pipe to the tank to see if that works. i will report back when done . paul
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Post by DEVONMAN »

Hi Stagman.
Probably not much help but Renault had the same problem with the R5 Turbo and solved it by fitting an under wing fan which blew cold air via a small duct onto the carb for about 5 minutes after switch off. The duct had a spur around the fuel feed pipe to cool that also.
Janspeed never really solved the same hot start problem on their Turbo Range Rover conversions until they went injection.
I had the same problen on my twin turbo RV8 (until I went injection) and in frustration at times poured cold water over the inlet manifold to get it started. I tried wrapping pipes, return pipes, rerouting pipes. carb insulation blocks, but none of those worked. The same applied to my Son's twin turbo RV8 in a Sierra. It seems it's all down to excess heat build up in the carb after switch off. A 10-20 minute stop tended to be the worst, particularily in summer.
Good luck with the problem.
Regards Denis
1950 A40 Devon Hotrod with 5.0 twin turbo RV8.
EDIS8 wasted spark, Holley Injection.
Been as far as the Moon and back in 57 years of driving. Same Car, 5 engine upgrades !!!


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under body heat

Post by stagman »

hi denis, god if you have tried all that i can not see me doing any better. one thing i would like to know more of is the cooling fan by the carb. i have a small fan which pumps air from boat engines, which i could pump cold air on to the carb instead. but what do you use to turn it on for a set time after stopping the engine??. hope you can help cheers paul. ps we have got to be mad , spending all this time on these cars.. :?
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Re: under body heat

Post by Ian Anderson »

stagman wrote:hi denis, god if you have tried all that i can not see me doing any better. one thing i would like to know more of is the cooling fan by the carb. i have a small fan which pumps air from boat engines, which i could pump cold air on to the carb instead. but what do you use to turn it on for a set time after stopping the engine??. hope you can help cheers paul. ps we have got to be mad , spending all this time on these cars.. :?

Sounds silly but look at bathroom extractor fans - a lot are 12 volt and most have a run on timer built in

Ian
Owner of an "On the Road" GT40 Replica by DAX powered by 3.9Hotwre Efi, worked over by DJ Motors. EFi Working but still does some kangaroo at low revs (Damn the speed limits) In to paint shop 18/03/08.
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Post by stagman »

hi Ian, thanks for that i will look on ebay .paul
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Re: under body heat

Post by DaveEFI »

stagman wrote:hi denis, god if you have tried all that i can not see me doing any better. one thing i would like to know more of is the cooling fan by the carb. i have a small fan which pumps air from boat engines, which i could pump cold air on to the carb instead. but what do you use to turn it on for a set time after stopping the engine??. hope you can help cheers paul. ps we have got to be mad , spending all this time on these cars.. :?
There are loads of timer kits if you can wield a soldering iron, but this one looks like it would be easily adaptable.

http://www.jaycarelectronics.co.uk/prod ... eyword2=KC
Dave
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Post by topcatcustom »

Under bonnet heat isn't an issue if your carb is a foot above the bonnet :wink:

I'd get busy with ducting and fans, aluminium tape is handy too
TC
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