I was hoping this question would be answered on my previous post about timing but I'll try again with a new one.

I am missing the EGR vacuum amplifier on my car and I believe that I will need EGR to control knock at higher timing advance levels. This is the device with the 4 hoses coming out of it, leading to the carburetor, the intake manifold, the EGR valve, and the radiator.

Do I need to get one specifically for a 1973 slant six or are they all interchangeable?

Frank

The vacuum "amplifier" is just a vacuum relay. They are all the same.

Just so we're clear, the vacuum amplifier is the device that looks like a hockey puck.

Yes, that is exactly the part I meant. It looked to me like they were all the same but I was hoping someone would confirm that for me. It will make it easier for me to find a replacement. Thanks.

The vacuum amplifier is probably one of the most misunderstood devices under the hood of any car ever built!!!

It's name literally describes it's function. The ported vacuum signal that triggers the EGR is too weak to operate it so mother Mopar came up with the amplifier. There's a vacuum line from the manifold (or full time port on the carb). This signal is what is actually sent to the EGR itself. The ported signal triggers this to happen.

There are normally only 3 hoses on the amp.....ported vacuum, full time vacuum, and EGR.

Often you'll find a solenoid in line which is controlled by the Lean Burn computer, but that's not always the case. Regardless, these amplifiers are usually dead as the rubber diaphragm gets a tear or hole in it. One of several things then happen.....either you get big time EGR operation nearly all the time (which leads to ugly running and nasty deposits on the spark plugs) or you end up with a hesitation or bog.

Gas mileage goes right out the window too.

Have someone who knows what they hell they're doing check this amplifier. A mechanic with more than half a brain should be able to easily figure out how it works by looking at the emission hose diagram under the hood. Good luck!

I do not think the EGR do any "knocking control" but you have to plug the line to the EGR, from the hockey puck.

_________________
Lasse

Signet -66 225
Holley 600 Offy-5270 Dutra Dual,regrind. cam 272 0,420 110, head shaved 0.100 slight.ported
MSD6A
A904
7 1/4 3.23

i have the same set-up on my "74" Scamp. i took a look at mine and the diaphragm was all stretched out. in Tucson they make us go thru emissions but i am told they don't lift the hood (they just want us to be within limits). i haven't taken this car thru yet, so i have no idea if it will pass. if i need a new vacuum amplifier where can i get one? thanks.