An observation about which vacuum port to use when bypassing the TCS/TVS system. Edited for corrections: Per Larry's answers below - check the manual and better still check the vacuum at each port in order to determine which one to use when bypassing the TCS. After Larry asked if I was certain about which was which on my carb I used the vacuum gauge that came with a brake bleeder to test each at hot idle. Actually don;t need the gauge. At hot idle pull both lines off and the one with manifold vacuum will hiss like an maniac and the other will do squat. I updated the image labels below to correct my mistake. Moral of the story is never mind what you think or someone else says - test it! Bob
The location of the outlet relative to the throttle plates can be deceiving. On my Q jet, the higher one is manifold vacuum. It isn’t hard to tell the difference. With the engine running at idle, pull the hose off. A manifold source will hiss, a ported connection won’t.
Ahhh - nothing is ever as simple as it seems! Thanks for the info, Larry. I added a note to my previous post to point that out. Cheers! Bob
Which is the proper spot for the vacuum advance on the carb, the pre-throttle or full manifold vacuum?
There is no proper spot, it's a choice. 70's engines used ported. Pre 70's used manifold in most cases. I cover this somewhat in my Power Timing thread, 1st post. http://www.v8buick.com/index.php?threads/power-timing-your-buick-v8.63475/ With ported, you get no vacuum advance until you open the throttle. With manifold, vacuum advance is there at idle. Both ported and manifold vacuum go to 0 at WOT. At part throttle, there is no difference. Try both and see which feels better. They make a special socket for most senders, https://shop.advanceautoparts.com/p...VTr7ACh0mcAzMEAQYASABEgLhnPD_BwE&gclsrc=aw.ds
Well I swear I saw a reference to such in the chassis manual but could not find it when I checked so with the engine at running temp I popped the hood, pulled the air cleaner and both vacuum lines and... yup! You were correct in my mistaken identification. I've updated the image and verbiage to go with my earlier post. Went for a quick spin with the bypass to the manifold port and it felt like it ran a little smoother. Will be interesting to see if this changes how the temperature is maintained come the next 90* day. Cheers! Bob
Ok Larry, Turned the key to the accessory position and the Oil Pressure Gauge bottomed out. After turning the car on, both the Oil Pressure and Water Temp had no reading and the Voltmeter was constantly in the 14 range. I will go over everything again, but I think I have all the wiring correct. Anything you can diagnose with those facts on paper? The lights work and dim if that means anything............. Thank you.......
Voltmeter should read a bit over 14 volts with the engine running. You'll have to diagnose the other gauges yourself if they don't work. Wrong or disconnected wiring maybe.
Is the sender the same for the idiot light as the gauge? When I go to Autozone or Advanced, etc. they list one for the light which is cheap ($10 or less) and the others are made by Autometer and cost nearly $40???? What is the thread size? The Dual VDO sender I have is too small.............. Do they make and adapter male to female that would work?
Paul, I have no idea where you got these gauges, but if you bought them new, they should have come with senders. The gauges won't work at all without compatible senders. Autometer senders probably won't work, and the idiot light sender is not the same as a gauge sender. There are brass bushings that convert hole sizes. The intake manifold is 1/2 NPT. I don't know what your sender size is, probably 1/8 NPT.
Here's what I got from Summit........... https://www.summitracing.com/parts/sww-306bb Looks like I need this........... https://www.summitracing.com/parts/sww-279a/overview/ Looks like it comes with an adapter with it at 1/4 18
Time to place another order to Summit. For the Water Temp Sender, I will go to the hardware store for the adapter for the VDO sender I have. I really appreciate all your help Larry, thanks again!!!!
Gonna check with my local speed shop on Monday to see if they have the Water Temp sender locally. I know I can get the adapter either there or my local ACE.....
