HOT 440

[ALEX]

HI I OWN A SECOND HAND VOLVO 440 WITH I THINK THE SAME ENGINE AS THE RENAULT 21 SOLEX CARBU AND ALL THE CAR HAS 125000KMS UP AND RUNS VERY WELL BUT THE ENGINE CUT OUT WHEN THE WEATHER IS HOT NOT UNUSUAL FOR THE SOUTH OF FRANCE ALL THE ELECTRICS HAVE BEEN CHANGED PLUGS HT WIRES DISTRIB CAM AND CAP AND THE RENIX HT UNIT SAME PROBLEM
THE NEW FUEL PUMP AND PIPES HAVE MADE NO DIFFERENCE
A COMPLETE REBUILD OF THE SOLEX CARBU HAS NOT HELPED EXCEPT THAN WHEN THE OUTSIDE AIR TEMP IS OVER 25C THE PIPE WHICH RUNS EXTRA PETROL BACK TO THE FUEL TANK IS FULL OF FROTH AIR OR FUEL????
HELP. THIS IS A GREAT CAR I DONT WANT TO CHANGE.

[Dan F]

Hi.
Get the carb float chamber ventilation system checked and cleaned.
It helps the car run correctly when hot. There is a solenoid valve that opens and closes for a set period of time when the engine is warm.
The line that feeds fuel back to the tank is just for petrol vapour and any over fuelled petrol etc. (will only be small amounts of actual fuel though).
You should get the Haynes manual as you will find it will be very useful in this respect.

Cheers,
Dan.

[ALEX]

FIRSTLY THANKS FOR YOUR TIME AND YOUR HELP.

SOLENOID VALVE OK AND ALL LINES CLEAN BUT SAME PROBLEM.
THE FUEL PUMP BODY IS AT 90°C WHEN CAR HAS BEEN RUNNING FOR 20MINS OR SO. FROM WHERE THE PUMP IS FITTED THIS SEEMS NORMAL AS ENGINE TEMP MUST BE OVER 100°C. PETROL BOILS? AT 70°C.
I RAN A LONG PLASTIC PIPE FROM THE BLACK FILTER UNIT TO THE FLOAT CHAMBER VIA THE WINDSCREEN. THAT WAY I COULD SEE THAT WHEN THE ENGINE STOPS THERE WAS NO PETROL IN THE PIPE.
? IS THERE A FILTER UNIT AT THE PETROL TANK END OF THE SYSTEM?
IF I BLOCK OFF THE RETURN PIPE ALL GOES WELL BUT ITS NOT CORRECT TO DO SO AS THE PUMP MUST SUFFER CHEERS ALEX

[Dan F]

Hi.
There should be a filter at the tank end, under the car I believe, although, having said that, it might just be injected models.....There should be an in line fuel filter that could be blocked though.
You could always get your carb removed and cleaned, that could solve a lot of probs.
Perhaps your solenoid isn't working properly on the float chamber venting system.... Can't be expensive to replace and eliminate...

Haynes do a manual for the Solex Carb used in the 440. May I suggest you get a copy?
I have a copy of it somewhere for when I had my carb fuelled 440.
If I can find it I will give you the number on the book.

Cheers,
Dan.

[Oldgit]

This sounds like the old "V" engine problem, fuel too hot in the pipes and the pump gets a mixture of gas and fluid, which seems to be proved by the visible pipe.

On "v" engines we used to fit a small electric pump at the back of the car, and use this to feed either the mech pump or directly to the carb. The reason we did this was to ensure that there was in fact a flow through the return pipe, this means that the fuel is not subject to high underbonnet temp all the time, the excess flows back to tank and helps the fuel to remain cold enough to prevent boiling.

Only issue with this is that you need to ensure that the pump is turned off in the event of an accident to prevent it from pumping fuel all over. Our chosen method for this was an inertia switch that cut off the power if knocked.

Another issue, If the pipes to the carb are reversed, the carb would be starved of fuel as the return system has a restrictor somewhere usually in the form of a metered hole, usually in the carb but not always. If the pipes are reversed, it could be that you are trying to feed the card through a restricted supply.

[srtames]

Sounds like you have a vapour lock in the petrol pump.
My 340 pump has a smaller outlet return pipe . you could try using a 12v computer fan to cool the pump as 90deg is rather high. I assume you have the thick gasket fitted on the pump.

good luck, Steve