- Joined
- Aug 29, 2010
- Posts
- 47,128
- Reaction score
- 9,299
- Location
- OKC, OK
- First Name
- HotRod
- Truck Year
- 85 K20 LWB
- Truck Model
- Silverado
- Engine Size
- 454 - Turbo 400 - 3.73
but after 30 years, you don't know what still there and what isn't.. so just better to trace what you have.
You're right. I usually find that some idiot has worked over all the vac lines, and also as you point out, many parts missing, like TVS ( Temperature Vacuum Switch) that will be shown in the diagram. In that case just skip the temp switch.
I know one for example that used the temp switch and is not necessary is Vac Advance to the dizzy. The purpose is to NOT ALLOW vac advance until the motor is warmed up. The reason for that is to reduce NOX, aka Oxides of Nitrogen with a cold motor. Known in CA as the first smog device that was REQUIRED to be RETROFITTED to cars of the 60's in the early to mid 70's when the law came about.So in the 70's, I think it was back to 66 models, you had to take your car in, and they put a TVS in between your Vac line to the dizzy, so your car ran like **** even worse until it warmed up enough to advance the timing.
Also going further back in the 50's cars that did not come with a PCV valve, just a vent to ambient air, the vent had to be blocked off and a PVC valve installed. OMG, and you should have heard people bitch,.... all this smog ****. Cuz they added a PVC valve and a TVS. All that smog junk.