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EFE Assembly

  
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EFE Assembly

 
jons jons
New User | Posts: 4 | Joined: 01/13
Posted: 01/23/13
06:49 AM

I own a 1979 corvette (bought a few months ago as a project car). The EFE actuator appears to be faulty (knocks extremely bad when car is warmed up). When I hold the rod to the valve, it quiets down somewhat. I want to remove the assembly and was wondering can I simply remove the valve, cut or remove the butterfly valve and reinstall it as a spacer? Also will plugging the vacuum hose to the EFE cause any problems?  

waynep71222 waynep71222
User | Posts: 181 | Joined: 04/12
Posted: 01/23/13
08:10 AM

i will point you toward several possible solutions...


i am describing this for the other corvette owners who will find this..

the EFE valve blocks on side of the exhaust flow and forces it through the crossover port under the carb to exit the other exhaust manifold.. this heats the intake to help evaporate the fuel sooner .. early fuel evaporation is the name of the system..

with vacuum operated versions... the valve flapper is operated by a vacuum actuator.. but controlled by a thermally controlled vacuum switch somewhere on the intake... on cold start..  there is NO vacuum sent to the EFE actuator.. this leaves the trap door closed and diverts the exhaust flow under the intake..  as the engine warms up.. the vacuum switch changes it's internal position because of the warming coolant expanding the wax pellet inside it..  this allows vacuum to the actuator and pulls the diaphragm and opens the heat riser flap..

so.. lets test the actuator..  

with the engine warmed up...  but shut off..   the rod should be extended...  trap door closed...   when the engine is started.. the actuator rod should retract and pull the flapper valve open..

i have had terrible problems with the aging vacuum hoses to the thermal vacuum valve failing.. swelling and failing to supply vacuum to the EFE actuator properly...

the hoses can be bad...

the thermal vacuum switch can be bad

the actuator can be bad...

please verify the rod is being pulled in when the engine is warmed up... if its not.. the pulsing of the exhaust against the closed trap door will make the whole thing rattle like you describe...

the heat rise valves are available from some suppliers..

ATP Part # 105002    {#355915}
FOUR SEASONS Part # 105  

waynep71222 waynep71222
User | Posts: 181 | Joined: 04/12
Posted: 01/23/13
08:11 AM

i have not found the proper part number for a actuator yet..  

jons jons
New User | Posts: 4 | Joined: 01/13
Posted: 01/23/13
08:45 AM

Do you see any reason this just can't be removed. I've read other forums where vet owners have removed the EFE assembly without having problems occur.  

jons jons
New User | Posts: 4 | Joined: 01/13
Posted: 01/23/13
08:48 AM

The rod itself can be moved up and down freely when the vehicle is cold. The vacuum hose is new (I just replaced it). I'm sure the actuator is bad and I'd rather not deal with it anymore that is why I want to remove the entire assembly.  

waynep71222 waynep71222
User | Posts: 181 | Joined: 04/12
Posted: 01/23/13
06:33 PM

it all depends if you have any problems warming the engine up my modulating the throttle.. instead of it warming up on the fast idle on the choke... and warming up faster...

there is a company who sells to several different suppliers that makes some heat riser valve blocks that DO NOT HAVE THE cross shaft... so its a straight through..

i think i have seen them over at classic industries  or opgi

i don't have any of the various corvette supplier catalogs so i don't know which one has that kind of stuff..

i will look around later tonight or early tomorrow and see what i can scrounge for part numbers...

it also depends if you have to have the car smog tested or are planning on selling the car where it needs to be smog tested...  

waynep71222 waynep71222
User | Posts: 181 | Joined: 04/12
Posted: 01/23/13
06:49 PM

here ... take a look at this list...

so you can narrow down what you need..


rol is a gasket company like felpro  or victor.. they are available through some parts chains...

http://www.hamiltonmanufacturing.ca/hrv.htm