Expert: Brad Sears - 1/3/2010

Question
QUESTION: Hi Brad
I have just finished restoring a 58 Buick Special and have a problem that I suspect might be a vapor lock.

Car runs well and is completely reliable with the exception of when it has had a run and then sits for 51 - 30 minutes.  It starts Ok and I drive off but if I stop at a set of lights within a 100 yards or so it stops.  I can start it by cranking the starter motor for quite a long time.  Seems to me that it uses the fuel in the carb and then stops but only under specific circumtances.

I have checked and can find no reference to insulator blocks under the carb of between the fuel pump and block.  All the fuel lines seem well clear of manifolds or exhaust pipes.

Any suggestions?

Thanks in advance for your help.

Regards
Peter

ANSWER: Ok Peter, what parts of the fuel system were replaced or overhauled when you did the restoration? Were the fuel lines replaced? let me know.
Brad

---------- FOLLOW-UP ----------

QUESTION: Hi Brad
Thanks for the quick reply.

All of the fuel lines were replaced with the same type of rubber hose right from the tank to the fuel pump and from there to the carb. A new fuel filter the same as the original was fitted.

The fuel tank was drained and treated with POR cleaner and sealant.

The carb was dismantled, cleaned and a a new kit including gaskets, needle & seat and accelerator pump plumger fitted.

Nothing was done to the fuel pump since it seems to be working OK.

Regards
Peter



ANSWER: If you do not have to stop, will the engine keep running?

---------- FOLLOW-UP ----------

QUESTION: Hi Brad
no problems at all with the car keeping running.  It starts well when cold and also when hot.The stopping problem is only after it has stood for around 15 - 20 minutes.  Even then it starts good and drives a short distance.  I have only had the problem when I have had to stop at a red light -  ithink if I kept the car driving I might not have the problem.

I am thinking of fitting heat insulation on the fuel line in the engine bay downstream of the pump.

Regards
Peter

Answer
Sorry for the delay bit the fish have been biting. I would like you to take a pressure and volume test on the fuel pump. The pressure should be in the 4 to 5 pound range and the volume should be a pint and a half in 30 seconds. If the pressure is low it lowers the boiling point of the liquid that is pressurized. If the pressure is down around the 3 pound level it could cause this problem. Let me know.
Brad