under bonnet heat

[GATS]

:dude:hi guys, help needed before i kill myself, i have fitted a rover 3.5 to my stag, long story to why !!. i fitted a edelbrock carburetor, wrapped the manifolds with heat tape, new rad fitted with a header tank,16" fan at the back {no room at the front} pushing air to the engine.. I have no problem with the engine /rad, temperature,but i do with the under bonnet heat!!. with the bonnet closed.the heat after a while vopourises the petrol, flooding the carb, if i take the pipe off there is a hissing of gas . my question is -how to over come this problem???.will wrapping the rubber pipes with somethinghelp?. change to steel ones, placing a other fan in the engine bay like the removed engine fan to blow over the top of the engine??. or placing slots in the bonnet. any help please as i just want to use the car. paul

[V Mad]

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I presume the problem is that the car will not re-start when it is really hot and you believe it is due to vapour lock? Does it happen immediately after you switch off or after say ten minutes?

You say the carb is flooding; this is not the same as vapour lock, so you may have a faulty carb.

If it is vapour lock then there are several steps you can take:

1. Insulate any fuel carriers in the engine bay. ie pipes, filters, carb etc. Does the carb have an insulator under it?

2. Make sure the pump is giving out adequate pressure and maintaining it after switch off (the pressure helps to reduce vapourisation).

3. Move fuel lines, filter away from heat if possible. Can you relocate the filter to a cooler position?

Hope that helps.
Chris

[Marco Polo]

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G'day Paul,

I don't have a rover engine fitted but do run a TV8 in high ambient temperatures.

My bonnet has a series of louvres cut in it, I also have an electric fan fitted. When the fan cuts in when the car is stationary,very little air is expelled through the louvres but a massive amount of hot air exhausts just behind the front wheels. The fannever cuts in when the car is moving unlessI'm climbing the local mountain rangeand I haven't talked anyone into sitting on the bonnet while I'm driving so I can't comment on the effectiveness of the louvres at speed.

I also had fuel vapourisation problems and found that the fuel supply line in the engine bay was 1/4" internal bore, I have increased this to 5/16" bore and have had no issues since. It may be worth you increasing the bore diameter of your fuel line.

Hope this helps,

Raoul

[GATS]

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:dude:hi guys, to answer your questions, yes i have a carbinsolator fitted {just yesterday, i thought that will fix the problem } i have 5/16 pipes fitted,I can,t see where to move the pipes to keep them cool, the heat must be at its highest at the top of the engine bay, and thats where the carb is!!. the carb only flood when the engine cuts out. paul

[Camo]

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Not sure if this is going to be of any help but,
My Rover V8 with Monarch exhaust manifold (wrapped) generates a hell of alot of heat, so much so that on a hot day the fan is only off when at 50mph, around town and at 70 mph the fan generally is off and the temp gauge sits at midway between 1/2 and 3/4. This is purely down the the exhaust as it never got this hot before fitting the manifolds. The fan I use is 16 inch placed in front of the rad as no space behind.
I don't have any problems with the SU carbs, fuel pipes are all normal bore.

I will at some point, when money allows get some louvres cut into the bonnet to release the extra heat. seems the only way forward to me..

Stu

[GATS]

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:dude:hi stu, how did you fit a rover in you car with out changing the carbs??. i had to change to a edelbrock, and that justs fit. do you not have the same problems as i have??.paul

[mjheathcote]

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I don't think its the fact you have a RV8, more the case of no mechanical fan to keep a merry breeze around the engine bay especially at low speed/stationary.

Renault's answer to the 5 Turbo was a little fan blowing a breeze onto the carb for the same problem.

[V Mad]

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GATS wrote:

:dude:hi guys, to answer your questions, yes i have a carbinsolator fitted {just yesterday, i thought that will fix the problem } i have 5/16 pipes fitted,I can,t see where to move the pipes to keep them cool, the heat must be at its highest at the top of the engine bay, and thats where the carb is!!. the carb only flood when the engine cuts out. paul

How do you know it is flooding? If you have a problem with flooding, then that is not the same as vapour lock. Flooding is caused by a faulty carb or too much fuel pressure.

[GATS]

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hi, v mad, you could be right on the flooding , i only said it because it only happens when the fuel evapourates. i could check what the pressure is for both engines, paul

[Camo]

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GATS wrote:

:dude:hi stu, how did you fit a rover in you car with out changing the carbs??. i had to change to a edelbrock, and that justs fit. do you not have the same problems as i have??.paul

Hi Paul,
One of the PO'ers did the conversion some 15 / 20 years ago but it seems he got it all in the engine bay quite well, not much clearance on carbs as I have small dents where the last owner used to drop the bonnet to close it :X
I have no issues with restarting when hot though...

Stu

[V Mad]

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GATS wrote:

:dude:hi stu, how did you fit a rover in you car with out changing the carbs??. i had to change to a edelbrock, and that justs fit. do you not have the same problems as i have??.paul

To fit the standard RV8 without a bulge you need to fit a spacer plate between chassis and cross member/subframe. Then shave a bit off the top of the SUs. Still a squeeze though.

[stagowan]

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Paul,
You could try removing the rubber strip from the bonnet and undo the bonnet catch a few turns. This should give a bit of a gap for some of the heat to escape.
Not a permanent fix but it might give you a chance to use your car (if the rain stops!).
Mike.