C1 FI 250HP 1959 Vacuum Advance Fitting

[Dave Sly]

I've got a vacuum advance (hex style) with a threaded female hole in the end (as opposed to a nipple that the hose should fit to). Is there a fitting that goes in the threaded hole? Anyone know where to find such a thing?

Also, the assembly manual shows a T fitting in the vacuum line (I have Windshield Washers). Is this T fitting plastic or metal, and what color is it? I think the part number is 3699042.

I was surprised that I could not find another posting on this.

Thanks in advance,
Dave

[John D.]

Re: C1 FI 250HP 1959 Vacuum Advance Fitting

Dave, The fitting is a simple matter to make up. Just buy yourself a short length of brake line-3/16 I believe. Then bend one end into a 90 degree.Then cut if off leaving a couple of inches sticking out from the bend. Then run a ribbed rubber hose over to your T fitting. The T fitting is typically a white fitting. Originals are aged and off white plastic or yellowish looking. I don't think any catalogs list this fitting-repro catalogs that is. It is listed in the auto store catalogs though or used to be a few years ago. I may have one around that you can have as this ain't ebay. Not sure though. I believe your vacuum take off for the VA is a weird 45 degree fitting that screws into the air meter. I don't know if this fitting is supposed to be bare brass or zincad. I have seen both. It's a hex fitting but you can't use a typical socket on it. It's a crescent wrench fitting. Anyhow this fitting may still be available from weatherhead or I may have it. Again I am not trying to sell parts. Just trying to help you out as you hardly see the same set up twice on the show cars. Most of the low HP cars I see have Rube Goldberg set ups so I can appreciate you wanting to do this correctly.
Hardest thing is finding the ribbed hose. You can buy it from the good Dr.though. Dr. Rebuild that is. He may have the T fitting also. Look in the aims. Don't know which year to tell you to look in. Probably the 59 aims. But if I recall that isn't correct. You may have to look in the 60 or 61 aims also. If you have trouble let me know as I have all the aims for FI's.
Plenum fitting above the bellcrank. Yours is not typical. Meaning it's not like the high HP. Look in the aims again. Notice its hex fitting with a fat 1/4" tube bent into a 90 soldered into the center of the fitting. I did a study on these fitings. I assume you have a 4900, a 7300R or a 7200 unit.When you post it would be helpful to tell us the year and model of your unit as there is some variation. JD

[dave sly]

Re: C1 FI 250HP 1959 Vacuum Advance Fitting

Thanks a lot for the detailed description. I've got a small white plastic T fitting, and I'll make the vacuum can nipple just as described. I'll post a picture this weekend. They will be on the URL below.

http://12.216.41.72/corvette%20present.htm

The car is an April 30, 59 build date. The injection unit is a 300R. I can't remember the serial number.

Dave

[Don Y.]

Re: C1 FI 250HP 1959 Vacuum Advance Fitting

Engine looks great Dave!

[dave sly]

Re: C1 FI 250HP 1959 Vacuum Advance Fitting

Thanks a lot. By the way, there is a FI part on this engine which is not correct for a 1959 car (I am replacing that part this week with the correct one). Can anyone find the incorrect part?

Dave

[Mike E.]

Re: C1 FI 250HP 1959 Vacuum Advance Fitting

The blue return spring is a) in the wrong location and b) the wrong color. Apparently Podell redid your injection unit.

[dave sly]

Re: C1 FI 250HP 1959 Vacuum Advance Fitting

Good catch. Also the return spring bracket is incorrect. In 1959 and later it was angled at the top.

Dave

[John D.]

Re: C1 FI 250HP 1959 Vacuum Advance Fitting

Rule of thumb: All 57-65 used one accelerator return spring. If in doubt refer to all of the aims and you will see that this is fact. 58 to 65 ALL used one spring going from the bellcrank itself (not the stud) to the accelerator return spring bracket. 57 used one spring from the throttle shaft lever to the bellcrank stud.
Problem: Down thru the years some major repro parts catalogs list the accelerator return springs as primary and secondary. Well this is miss-information. If you disagree then please present documentation to the contrary.
There may be one exception to this rule and that "might" be a few of the 57 air box cars.But since so few of those cars were made let's not go there.
Anyhow Dave you have a nice looking engine. As you mentioned you need one proper spring going from the 59-62 accel return brkt to the bellcrank. The spring is silver paint.
Now if a fellow says that he can't get the car to return to idle properly so his solution is to put a 2nd spring on then his problem is he has a weak repro spring. Some of the repro springs work good for a few months or so and then they loose their tension. Springs in general can be a major problem with FI restorations. You see a ton of cars at the shows with multiple return springs, various colors, and incorrect hardware and brackets. Some of the repro accelerator pedals are soo stiff that one spring won't work. Solution is to find a good accelerator pedal.JD