An Eventful Evening


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By Duck - 15 Years Ago
Fellas- I was finally able to take the 'bird for a short ride this evening. It was the first time it's been driven on the road since the "Ol Man drove it home from work, (over-heating) one evening in the summer of '64, and parked it for good. Other than I need to re-adjust the clutch and brakes, it was a fun, uneventful, lifetime goal realized for me, and I couldn't possibly be happier! I got to messing around with it when I got home with it, (of course ) and discovered something. When I switched the distributor from full vacuum at idle, to ported vacuum, I instantly fell in love with the way the motor sounded as it idled. Now, I realize the wisdom of running at full vacuum during idle, but that choppy, lopey sound just can't be ignored. I got to thinking about it, and it seems to me the answer to the conundrum is a nicely done install of a properly calibrated thermal vacuum switch- idle the motor with no advance until the temperature comes up and the switch opens and turns loose full vacuum to bring up the idle speed. My truck's 460 uses a similar set-up with the switch installed in the thermostat housing. I noticed a flat boss on top of the t'stat housing on the Y, as well. I guess what I hope I can get some input on, is what would be a good cut-in/ out temperature to shoot for when trying to figure out what switch I need to find/ use? I'd like to make this happen, if possible... -Thanks- /Duck
By crenwelge - 15 Years Ago
Wow! that had to be a thrill.
By GREENBIRD56 - 15 Years Ago
Hey Duck - I'm really glad you got that rig on the road - can't keep that nifty bodywork hidden from the faithful!!!!! Congrats on a long job finally near finished.

My Oldsmobile 442 originally came with a "rapid warm-up" valve that screws into the intake water jacket adjacent to the thermostat housing. It has three ports on it - an inlet from the carb (live manifold vacuum) and two outlets. One goes to the distributor vacuum pot and the other to an additional vacuum pot on the air cleaner that closes a hot air tube up from the exhaust manifold. I don't know the temperature of operation - but when the engine warms up a bit it gets full vacuum advance and a cooler air supply.

It is AC Delco p/n 212582 or 19236477 - about $28 new - so look for one at a junk yard if possible - it was also used on Pontiacs and Caddies. Looks like a pipe plug with a vertical stems - three vacuum sized ports sticking out.    

By Duck - 15 Years Ago
GREENBIRD56 (8/1/2010)
Hey Duck - I'm really glad you got that rig on the road - can't keep that nifty bodywork hidden from the faithful!!!!! Congrats on a long job finally near finished.



My Oldsmobile 442 originally came with a "rapid warm-up" valve that screws into the intake water jacket adjacent to the thermostat housing. It has three ports on it - an inlet from the carb (live manifold vacuum) and two outlets. One goes to the distributor vacuum pot and the other to an additional vacuum pot on the air cleaner that closesa hot air tube upfrom the exhaust manifold. I don't know the temperature of operation - but when the engine warms up a bit it gets full vacuum advance and a cooler air supply.



It is AC Delco p/n 212582 or 19236477 - about $28 new- so look for one at a junk yard if possible - it was also used on Pontiacs and Caddies. Looks like a pipe plug withavertical stems - three vacuum sized ports sticking out.
So, if I read you right, I'd need to cap off one port on the switch, run live vacuum to one port and a return line to a tee, and the ported from carb to the same tee, and the 3rd leg of the tee to the dist. Correct? Any ideas for cut in/ out temps?
By oldcarmark - 15 Years Ago
Those switchs are called "thermal vacuum switch" (TVS).All the manufacturers used them.Different colors indicate different operating temps.There are all kinds listed on Epay.When I worked on the Ford parts counter years ago I seem to recall the temps were stamped on the base(metal part) like a thermostat is.The "basic" Ford # for these was 9D473.As far as where to install I would put it behind the stat housing in the intake manifold.Easy to drill and tap.Hope this info is helpful.
By Duck - 15 Years Ago
Thanks for the kind words and good info- BigGrin I appreciate it...
By GREENBIRD56 - 15 Years Ago
If I understand your intent of the plumbing scheme you proposed......you want the cold engine to run on ported vacuum at idle (thump, thump, thump) and use the valve/switch to engage full manifold vacuum (at idle) when the temp comes up. Thus raising idle speed and cooling things a bit.

Or ....run ported vacuum to the switch so that you are simply using the centrifugal advance only - until the temp comes up and opens the valve - then going to the ported (thump, thump, thump).

By Duck - 15 Years Ago
Steve- It sounds as though either would get 'er done- one wouldn't be advantageous over the other that I can see, would it?