| Slant Six Forum https://slantsix.org/forum/ |
|
| Vacuum Reservoir/Amplifier https://slantsix.org/forum/viewtopic.php?t=19131 |
Page 1 of 1 |
| Author: | Robert Deloney [ Fri Aug 11, 2006 6:29 am ] |
| Post subject: | Vacuum Reservoir/Amplifier |
Greetings I have a question about the pull off choke I understand the choke aids the vehicle during cold weather starting what I don’t understand is the (pull off choke and how it works and where to buy one) 1. Do I need to re connect the Vacuum Reservoir/Amplifier? What effect does this have on gas mileage/ power for the super six? 2. Can anyone tell me the price of the Dutra Dual I would like to get a set? 3. Not happy with the 2bbl carb from O’Reilley can anyone give me some pointers Thanks for your help |
|
| Author: | SlantSixDan [ Fri Aug 11, 2006 8:36 am ] |
| Post subject: | |
The choke pull-off is a round vacuum-operated device that looks a little like a flying saucer on its side. It is at the top of the carburetor, connected to the choke lever with a link that has a "U"-bend in it. For operational theory, see Here. Adjustment consists of squeezing together or spreading apart the legs of the "U". Widening the "U" = less choke pull-off action = richer mixture immediately after startup. Narrowing the "U" = more choke pull-off action = leaner mixture immediately after startup. If it's adjusted too wide/rich, the engine will load up, lope and blow black soot after cold startup. If it's adjusted too narrow/lean, the engine will tend to stall quickly after firing from a cold start, and the cold engine will be "gaspy" when you try to accelerate. Testing the choke pull-off itself is done by applying vacuum to its hose (vacuum pump or mouth) then firmly blocking off the end of the vacuum hose to trap the vacuum (clamp or tip of tongue) and watching the pull-off stem. If it stays retracted, the pull-off is good. If it extends, the pull-off diaphragm is ruptured. The vacuum reservoir is not the same thing as the vacuum amplifier. The vacuum reservoir is used on '71-up cars with factory A/C, and provides a vacuum reserve to operate the heater control valve under low-vacuum conditions such as going up a hill. It is made out of black plastic and has bulged-out sides, and is mounted on the passenger side fenderwell. (there are also different vacuum reservoirs, much larger and made out of metal, mounted on the driver's side fenderwell of pre-1967 cars with power brakes). The vacuum amplifier is used on 1973-up cars and is a part of the EGR system. It looks a little like a hockey puck standing upright on edge, and is mounted atop the cylinder head, between the valve cover and the intake manifold. If you are running EGR, then yes, the vacuum amplifier must be connected properly. Dutra Dual information is Here. "Remanufactured" (or "factory rebuilt") carburetors from the parts store are seldom satisfactory...that's not just bad luck you're experiencing, it's a known pattern. Better options are a new carburetor or a careful refurbishing job on a basically sound original. |
|
| Author: | 75duster [ Fri Aug 11, 2006 8:47 pm ] |
| Post subject: | |
dan why is the amplifier needed for the egr? |
|
| Author: | SlantSixDan [ Fri Aug 11, 2006 9:24 pm ] |
| Post subject: | |
The vacuum "amplifier" is just a vacuum relay. The signal for whether or not to open the EGR valve is taken from the vacuum at the carb's venturi, because vacuum at that location is a much more sensitive indicator of engine load than manifold vacuum is. However, venturi vacuum is not strong enough to pull open the EGR valve. So, the venturi vacuum triggers the vacuum amplifier to direct manifold vacuum to the EGR valve, opening it. |
|
| Author: | 75duster [ Fri Aug 11, 2006 10:42 pm ] |
| Post subject: | |
well on my car it was also controlled by two thermostatic valves(i think)that were screwed into the rad and cyl. head near the thermostate housing, and when we took off the vacume amp. we routed the egr vacume hoses through thease valves and straight to manifold(?) vacume. i dont really know if it worked or not but no poblems so far. |
|
| Author: | SlantSixDan [ Sat Aug 12, 2006 6:20 am ] |
| Post subject: | |
Quote: well on my car it was also controlled by two thermostatic valves(i think)that were screwed into the rad and cyl. head near the thermostate housing
Yep, those are thermostatic valves that prevent EGR operation when the coolant is below a certain temperature, so as not to give cold driveability problems.Quote: and when we took off the vacume amp. we routed the egr vacume hoses through thease valves and straight to manifold(?) vacume. i dont really know if it worked or not
Er..."not". Put it back the way it's supposed to be or disable the EGR system altogether, but just randomly changing hose routing like this is a poor idea.
|
|
| Author: | maxracer21 [ Sat May 01, 2010 12:44 pm ] |
| Post subject: | vacuum amplifier |
The name suggests that it should increase vacuum not just relay it from another source, Really glad not to have this on any of my engines........and if it was. I would certainly disable the entire system. looks like something else to go wrong. Thanks for the advice on the ? marks. I shake a lot at times. sgt. ad taylor aka maxracxer 
|
|
| Page 1 of 1 | All times are UTC-08:00 |
| Powered by phpBB® Forum Software © phpBB Limited https://www.phpbb.com/ |
|