I'm going to look into getting a Stewart electric water pump for my 91 5.3. Does anyone know the ID of the lower hose ? Thanks
Lawrence

 

I have a 91 5.3. Just wondering why you are doing this? are you having prblems with the mechanical pump?

 

To control coolant circulation after shut down & idle temp control are my primary goals. With that said I must say I don't have a coolant temperature problem. My only "heat " problem here in Florida's heat is fuel rail heat after a restart. I have a 5speed with a aluminum flywheel, add all this together & stalling is a problematic until the hot rail gas is back in the tank, about 2 min. I'm hoping the elec. water pump will help . From dealing with this vapor lock in BB Corvette's I used a electric fuel pump with a tank return line that I could continually run if needed. I read good reviews on electric water pumps in the v12's.
Lawrence

 

I do not believe an electric water pump will solve your fuel rail vapour lock problem and it will hardly affect under bonnet temps. The fuel rail is not directly cooled by the water jacket. Rigging up a push-button activated circuit to do the corvette fuel fix will be a better solution, I reckon. Also, the conditions in the engine bay for any electrical item are pretty harsh, and I have had lots of failures of electronic things I have tried and discarded. The electronic controls for the electric pump wil be less reliable than the OEM water pump, in my experience of electronic devices under the bonnet, anyway.


To answer your question, the exit from the radiator and the inlet to the OEM water pump (presuming your idea is to gut the OEM pump and keep the plumbing) are two different sizes, the rad exit being the smaller of the two. The best idea, I believe, is to use a top quality silicone/nomex reinforced reducing coupling at the water pump inlet to make the connections to a hose of the same diameter via a solid joiner. (The OEM hose is a rather horrible item with one end bigger than the other). The couplers are available from specialist racing places, in the UK at least, and are the best available for the job.


Greg

 

Are you *sure* that this a hot fuel problem?

Lots of V12 are operated in hot conditions without a fuel heat problem. Any other mods on your car that might account for fuel getting unusually hot? Have the fuel pipes been re-routed or anything?

Also, is the fuel temp switch present, and operational?

Cheers
DD

 

Im in sunny, hot, NE Florida and have had no fuel related heat problems to speak of before, during or after shutdown.

 

I have no coolant temperature problem, and realize the fuel & coolant system are not related except through radiant heat temp's . I have two Auto Meter gauges installed in the water rails along with the dash gauge, that reads 210F (the hottest) & bottom of the N in hot FL traffic weather. The proposed electric water pump (EWP) is strictly for coolant circulation after hot shut down. Whatever drop valve seat insurance it takes. Anything else is a bonus. I must add I'm running aluminum rad., electric fans, Lutz 1, Euro exhaust, 180 stats, ALL new hoses.
Doug, no I haven't modified or checked any thing on the fuel rail. I will ! This is really not a big problem, just an inconvenience ! If the stock fuel pump would run continually (instead of that ?? seconds) when the key is turned on it would get rid of the hot fuel in the rail via the return line to the tank before starting.