johns59super88

Before I even ask the question, let me say that I have the service manual (and can recite a lot of it from memory) and I have checked Wild About Cars and am still in need of information. I apologize in advance for the length of this post but I'm trying to be complete and descriptive.

After 2 years, I'm doing the final (hopefully) connections on my 59 394's engine and will try and start it in the next day or two. Here are three questions.

1. I have two vacuum ports coming from the base of the Rochester 4GC. The larger one, 3/8 in diameter which comes out the back of the carb is for the power brakes, goes through a check valve then to the vac booster on the power brakes and the vac reservoir. No problem. Correct?

2. The smaller one, about 1/8 in comes out the passenger side of the base. I believe it is supposed to be fitted with a tee and routed to the vac advance and the throttle return check dashpot although none of the above mentioned sources actually say this. There is one pic in the service manual that sort of shows this. Correct?

3. My confusion is how to hook up the vacuum part of the fuel pump. The manual clearly says it is to provide vacuum for the ventilation/heat system (no ac on this car) when the engine is unable to. This implies the engine vacuum and fuel pump vacuum are interconnected but the diagram for the ventilation system is very clear and complete and shows no connection between the engine vacuum and the fuel pump vacuum. Moreover, the top of the fuel pump (pic attached) has two fittings, one marked "engine" about 1/8 in diameter and another marked "wipers" about 3/8 in. diameter. The car of course has electric wipers. So the third question is how/where do I connect the two fittings on the top of the fuel pump?

Thanks for whatever help you can provide!
John

johns59super88

So, I think I answered my own questions. The engine fitting on the vacuum section of the fuel pump gets tee'd into same vacuum setup as the vacuum advance and the throttle check dashpot. The wiper side of the pump is what will control the ventilation system and should be blocked off until I get all the ventilation stuff hooked up. Assuming all that is correct, do I need a check valve somewhere in the vac system other than the one in the main power brake vacuum line?

oldcutlass

I think this is a schematic for your wiper system, I hope this helps.

lazy394

This much I know, but my setup is different to yours.

The vacuum pump only runs the internal vent controls and enters the inside of the car on the passenger side of the firewall just to the side of the dist.
The 3/8 one is for the booster.
The 1/8 is for the vacuum advance on the dist.
The 59 did not run a dashpot on the carb so im guessing you have a later carb.
hope something in this helps.

johns59super88

Thanks for the diagram Oldcutlass. I'm not quite ready to connect all the washer control stuff yet but that diagram will help when I get there.

Thanks for the info Lazy394. I connected all the vac lines as you described and I think it's now correct. As to the dashpot, I may be (probably am) using the wrong terminology. Anyways, what I was referring to when I said dashpot was the throttle return check which looks like a small vacuum diaphragm. It is at the lower left of the attached photo from my service manual and is what I have on my car. Is yours different?

oldcutlass

Crap that is for the washers. Sorry at a quick glance, I thought it covered both.