Very simple, one hose goes to manifold vacuum, the other hose goes to the vacuum motor on the snorkel of the air cleaner.
If you look closely, there is a vacuum actuator on top of each snorkel. The actuators are hidden by the snorkel extension with the "GS455" sticker on it. There is a 3 sided vacuum tee. Manifold vacuum closes the door on the passenger side snorkel. The other actuator vacuum is modified by the sensor to vary the angle of the door to keep the air inside the air cleaner at about 110*. The sensor modulates the vacuum to the actuator so the door admits just enough hot air via the tube that runs from the exhaust stove to the driver's side snorkel. Under heavy throttle, vacuum goes to zero, and both doors in the snorkels go full open. The end of that tee connects to a hose that goes to the open connection on the carburetor, the one right under the word "solenoid" in this picture,
Wow thanks You made that very easy to follow So this system is basically Buick’s way of trying to work with emissions? It appears like the system shows the cat sensing cold air and switching to warm air to start the car. This system changed the following year didn’t it?
No the system was like that for a number of years. It helps with fuel vaporization and carburetor icing in cold weather when you heat the intake air. The sensor modifies the manifold vacuum signal to vary the snorkel door angle so that the temperature of the air stays at 110* or so.
So I might as well lay everything else out here. Your help has been extremely valuable with me entering the Buick ownership realm. Once this car was started I have been working off a list of things to check off as completed and listing my issues so I can address them one at a time. I think as of now I am down to 5 left. 1. When I had this engine rebuilt I had the internals modified a bit, which included more compression, more aggressive cam, and roller rockers. I ended up dynoing at 443HP!. The problem with that is the stock valve covers are too low and the rockers hit. So to compensate for that the rebuilder tried to stack gaskets to get the clearance and obviously they are leaking (I will deal with him later!). My question is are there "tall" covers that will clear the A/C compressor bracket or should I go for pre-made thicker gaskets to get the clearance? 2. There appears to be a leak at the oil filter housing at that gasket. I noticed it is really thin. Is there another brand or type of gasket that you know of that is better? Is this a common leak on a GS? I would think that any part of either housing half that had the slightest deviation from being truly flat would not be compensated for with that thin of a gasket. 3. After giving me that help with the wiper wiring my motor still does not work. Fuse is ok. So I think I just need another unit. 4. Todd at Die Cast Muscle Cars rebuilt my carb. The carb was dialed in at the dyno test and performs great but for one thing. When I start the car in the morning it will not go into high idle. The choke is closed but it still drops right off and wants to stall. Is there something I can adjust myself to get this to work? 5. I cannot get the oil pressure to register on the gauges. The sending unit is the correct one and the wiring harness is brand new. I removed the sending unit and screwed in an actual dial gauge and it shows I have the correct oil pressure, so the problem has to be in the sending unit/wiring/instrument gauge. I know when I put the instrument cluster together I had good ground going from housing to housing. Plus the temp gauge works fine so I would think the ground there is ok. My list was a 46 point checklist so I think I am doing pretty well and thanks to you guys I got this far.
1. You have a few options. You can use the 3/8" thick gaskets available from TA Performance, http://www.taperformance.com/proddetail.asp?prod=TA_1702-455B.375 You can use a set of spacers. These are pricey, but well made, https://medicemfg.com/product_view.php?pid=14 I have a set of these that I used for awhile. They worked but I found to make them completely leak free, you have to glue everything together. That makes valve cover removal a big job. The solution I settled on was to use these very affordable tall cast aluminum valve covers. Originally made by Poston Enterprises, Roland Hass has them for 135.00/set plus shipping. Phone number is 970 297 7064 http://v8buick.com/index.php?attachments/postonvalvecovers-jpg.484824/ I painted them Red, http://v8buick.com/index.php?attachments/postoncovers2-jpg.485044/ 2. Replacing that gasket is not so simple. The thickness of that gasket influences internal pump clearances and affects hot oil pressure. http://v8buick.com/index.php?threads/oil-pump-clearances-and-oil-pressure.326597/ If you remove and replace it, you will need to remove the distributor and prime the pump before starting the engine again. I would leave it alone. It is more likely the front of your oil pan, or front crank seal is leaking. It can fool you into thinking it is the oil pump gasket. Been there, done that. 3, Check for power at the wiper harness. Apply power directly to the wiper motor. 4. As the choke rotates closed, it should also rotate a stepped cam that raises the idle speed. There is a screw, that contacts that stepped cam, that adjusts fast idle speed. It is on the passenger side of the carburetor buried in the linkage and hard to see. Instructions to adjust it are in the Chassis manual. Check to see if it is rotating with the choke, and try adjusting it. 5. First, you should have a real oil pressure gauge. You should not rely on the stock gauges. http://v8buick.com/index.php?threads/gauges.197307/ You can run both at the same time. The wiring is different for idiot lights vs. the gauge pod. http://www.buickperformanceclub.com/rallygage.htm
those valve covers are nice. How do you get the holes in them for the oil cap and the PCV? Do you have to drill them yourself?
I have those cover also, I used a good hole saw blade to cut both holes, I can check but I believe 1.25 inch was the size. I used a drill press to make sure i was straight.
that sounds the better way to go rather than having a super think cork gasket that will constantly need tightening. With those covers should I go with cork or rubber gaskets? And they WILL fit under the compressor bracket????
This is the ULTIMATE valve cover gasket, and what I used, http://v8buick.com/index.php?threads/400-430-455-reusable-molded-rubber-valve-cover-gaskets.359633/ I believe they will fit under the A/C bracket. I haven't actually tried that yet.
I want to try those but I have standard cork with no issues. Retightened it once 4 years ago after a couple of months operation.
a question about cutting the holes in the Poston covers. For the oil filler cap on the standard covers there is a recess in the hole that the cap twists on to lock in place. Will just drilling a hole in the Poston covers still hold the filler cap tightly or did you have to do some other modification to the covers or the cap to get it to stay snug?
No, the twist on cap won't work. It may be possible to make it work, but I just used a push in cap. There are screw in caps, but some of them require welding I believe. https://www.summitracing.com/search/part-type/engine-oil-filler-caps/oil-cap-attachment/screw-in This is the one I used, https://www.amazon.com/Spectre-Perf...t=&hvlocphy=9004386&hvtargid=pla-688878103877 I dressed the cap up with a stick on plastic Buick emblem I bought from a company in Ukraine. https://3dcarstickers.com/product/buick-3d-car-wheel-center-cap-emblems-stickers-decals-trishield-logoblack-background-/ (I sized them at 44mm)
Thanks Larry I contacted Roland and he said the big block covers are out of stock and to check back with him in about 2 weeks. I ordered a set of Autometer gauges so I will work on that while waiting for the valve covers.
Old Buick Parts has them if you can't wait. Got mine from Roland. http://www.oldbuickparts.com/product_info.php?products_id=9848
Larry another question for you. I bought an autometer gauge set and I was wondering if the voltmeter could be wired into the stock sensor on the intake. The gauge comes with it’s own sensor already hardwired to it but I have no place to put it and I would like to keep the idiot lights operating. Have you ever heard of this being done?
Second is while keeping the stock oil sending unit in place where should I put the new connector for the oil gauge? Is there a typical spot to tap into?
It's a voltmeter, what sensor are you talking about? You can go right to the fuse block, all you need is ignition on voltage. All you need is a simple brass tee. See the pictures in this thread, http://v8buick.com/index.php?threads/gauges.197307/
I was hoping to keep the original temperature sensor working AND have the autometer temperature gauge as well. I believe they are probably calibrated differently and will not run off one common sensor correct? If I want to keep all of the stock vacuum items on the intake there is no room for a second temp sensor.
