Question on '63 L84 Vacuum Advance Control

[Eric V.]

I am missing the vacuum advance control for my '63 FI distributor. According to my '63 and '64 parts books, as best as I can interpret the listing, the applicable part no. is 1116201. But this same part no. is listed for all '63 Corvette applications as well as 283 and 327 passenger cars and ser 10 thru 30 trucks and all '62 Corvettes except spcl hi-perf and FI. Can this be correct? I had thought that the '63 FI engine would require a special vacuum advance control. Any help will be appreciated.

Eric V.

[Duke W.]

Re: Question on '63 L84 Vacuum Advance Control

For some inexplicable reason the '63 FI vacuum advance is "ported". This was "corrected" for '64 and the 8" ...236 VAC was used. It met the "Two-Inch Rule" for the 30-30 cam's 10" idle vacuum.

The '63 340 HP also used the ...201 15.5" VAC with full time vacuum advance, but it didn't meet the "Two-Inch Rule" for the Duntov cam's 12" idle, and my 340 HP engine had all kinds of idle quality/stability problems until I replaced the ...201 with the ...236 circa 1966.

1963 was the first year Chevrolet used vacuum advance on mechanical lifter engines, and they basically screwed the pooch, but corrected their errors for '64.

Convert your vacuum advance to full time and install a "B28" VAC, which is the current replacement for the ...236.

It doesn't make any difference what brand B28 you buy. All, including "Delco" are manufactured by Standard Motor Products.

Duke

[Eric V.]

Re: Question on '63 L84 Vacuum Advance Control

Duke,
Thanks much for the background info and recommendation.

Eric V.

[Nick M.]

Re: Question on '63 L84 Vacuum Advance Control

I have the same year and motor and at a recent Regional event my B15 was judged incorrect and the judge noted that it should be a "201". I changed it over the weekend and the car seems to be running very well.

[John D.]

Re: Question on '63 L84 Vacuum Advance Control

Nick, Very hard to find a real deal 63 201 vacuum advance. They are a two piece affair as we call them. Where the round tube is attached the 63 is unique in the fact that the tube is actually soldered on. But most judges don't know this fact.
In your case though you made a big improvement. The B15 is a strange number. I woulda thought you had a B22 for the 097.
Meanwhile here is what's on my original restored 63 VA that's on my desk. Extreme left side it's stamped 201. Far right side of the "pad" it's stamped 16. In the center it's stamped MS. Tube is neatly soldered on. Very expensive and rare part.
Some repros are not in specs but look good for show. The spring in them is too stiff. This info from Don Baker.

If you are driving your 63 though and don't care about judging get a nice 236 16 and have some fun.
If you are driving an early 64 you are really in trouble as the distributor is a complete screw up. The -063 distributor is 100% '63 except for the 236 vacuum advance. As far as performance with an 063 there isn't any. Wrong: cam, weights, springs, football on shaft, etc. If I had an early 64 I would use a nice '070 distributor and swap out the tag.
RP and GM weren't on the same page with the FI distributors. Took them awhile to realize that the 070 with the 236 made the midyear FI's come alive.
But today we run whatever is supposed to be on the car as most of us are into restorations.
Nice reproduction 201's and 236's are readily available now from Don Baker, etc. Each one is tested and dead nuts. JD

[Michael H.]

Re: Question on '63 L84 Vacuum Advance Control

I am missing the vacuum advance control for my '63 FI distributor. According to my '63 and '64 parts books, as best as I can interpret the listing, the applicable part no. is 1116201. But this same part no. is listed for all '63 Corvette applications as well as 283 and 327 passenger cars and ser 10 thru 30 trucks and all '62 Corvettes except spcl hi-perf and FI. Can this be correct? I had thought that the '63 FI engine would require a special vacuum advance control. Any help will be appreciated.

Eric V.

Eric,

The 201 is the correct original part number for the vacuum control for your 63 FI distributor. They're not difficult to find.

I've owned, driven and worked on a LOT of 63 FI cars over the last 40 years and none had issues with the vacuum control unit or unstable idle.

I wouldn't convert the system to "full time" vacuum. It's absolutely not necessary for 63 FI cars.

[Duke W.]

Re: Question on '63 L84 Vacuum Advance Control

Because the '63 FI has ported vacuum advance it doesn't make any difference whether it meets the Two-Inch-Rule. Since the '63 340 HP is full time vacuum advance the 15.5"...201 doesn't work properly with the 12" idle Duntov cam.

However, the FI engine will idle better, run cooler in low speed traffic, and get better around town fuel economy with a ...236 equivalent VAC with full time advance, and the centrifugal can probably be quickened without getting into detonation to make it more responsive and torquey on the low end and further increase low speed driving fuel economy.

The same situation exists with the '67 L-71 and most emission controlled engines. Converting to full time vacuum advance usually requires a different VAC - one that meets the "Two-Inch Rule" because the OE VACs on most ported advance configurations don't.

As far as judging is concerned the whole VAC is only worth 3 points - 2 for originality and 1 for condition. I would only take one point for an OE replacement VAC, even it it wasn't the B22, which is the closest in specs to the ...201. Very few judges know what B-number is closest to OE spec, and it's not in the JGs.

It probably wouldn't be that hard to get a VAC stamped "201 15" as were the originals, but have it set up internally to meet the ...236 specs.

Duke

[Michael H.]

Re: Question on '63 L84 Vacuum Advance Control

Because the '63 FI has ported vacuum advance it doesn't make any difference whether it meets the Two-Inch-Rule. Since the '63 340 HP is full time vacuum advance the 15.5"...201 doesn't work properly with the 12" idle Duntov cam.

However, the FI engine will idle better, run cooler in low speed traffic, and get better around town fuel economy with a ...236 equivalent VAC with full time advance, and the centrifugal can probably be quickened without getting into detonation to make it more responsive and torquey on the low end and further increase low speed driving fuel economy.

Duke

Because I assume Eric is restoring his car, I decided to recommend he go back with the correct original "201" vacuum control and leave the plumbing the way it was when it left the factory.
The configuration used for 63 FI is ok and there are no issues.

[Stuart F.]

Re: Question on '63 L84 Vacuum Advance Control

Same goes for possible re-porting internally at the vacuum source. I'm not familiar with the Fuelie connection, but if it is a fitting like used on the Holley equipped engines, that is easily changed while maintaining the original appearance. So, a re-stamped or re-worked VAC together with a "full" port fitting and you're in business - beyond detection except maybe in a performance evaluation where it may run too much better, maybe even as good as an L-76.

Stu Fox

[Eric V.]

Re: Question on '63 L84 Vacuum Advance Control

Gentlemen,
I appreciate all of the good information that has been shared by you in this thread. I do intend to have the car judged, so I will go with the correct VAC, for now, and the correct connection. After I am through showing the car I will be looking forward to trying Duke's recommendations. After reading John D.'s reply I thought I'd better see if I had a 201 among my collection of distributors and parts and I found three, two of which have a silver-soldered vacuum nipple. All three are stamped as J.D. described. So for judging purposes I am set, except I just have to figure out how to restore the cad plating. I was talking to a local restorer last week and he said he just throws VACs in with all the other parts he takes in periodically for cad plating and they come out fine. I would be concerned about the caustic or acidic solutions getting inside the vacuum canister and causing eventual failure, but maybe I shouldn't be. What do you guys do to restore the finish on a VAC?

Eric V.

[Troy P.]

Re: Question on '63 L84 Vacuum Advance Control

I zinc plate them and then give them a quick dip in chromate to protect the zinc. You can do this at home with an Eastwood or Caswell plating set up. 100's of uses in every restoration.

I have a 63 Fuelie too and found this discussion interesting. If you have a spare correct control perhaps I can plate one for you and work a deal to acquire your extra?

[Timothy B.]

Re: Question on '63 L84 Vacuum Advance Control

Can someone post a picture of this 1963 #201 vacuum advance showing the soldered nipple on the front. I have a few originals and would like to know what I am looking for.

[Michael H.]

Re: Question on '63 L84 Vacuum Advance Control

RP and GM weren't on the same page with the FI distributors. Took them awhile to realize that the 070 with the 236 made the midyear FI's come alive.

You make it sound like the 236 vac unit had something to do with making the car faster.

[Duke W.]

Re: Question on '63 L84 Vacuum Advance Control

The ...069/070 SHP/FI distributors also have a much more aggressive centrifugal curve - all 24 degrees in at 2350 rather than 4600.

The more aggressive centrifugal curve also really woke up my '63 L-76. I installed the '65 weights and springs along with the ...236 VAC circa 1966.

The greater low rev spark advance increased low end torque, which was sorely needed on my car with the CR trans and 3.08 axle.

After the change it had no problems pulling from less than 1000 revs in top gear, and normal around town fuel economy increased by about 10 percent, and even with the initial timing set at 16-18 on the tap (about 14-16 true) it didn't detonate on "standard" premium fuel, which was about 99-100 RON.

Duke

[Eric V.]

Re: Question on '63 L84 Vacuum Advance Control

Attached are pictures of the two types of 201 vacuum advance controls I found in my collection - the type with the silver-soldered nipple and the type with the nipple formed as part of the forward half of the vacuum canister. I bead blasted these VACs at low pressure on the front side and on the area where the numbers are stamped so the details would be more apparent. This is my first time posting pictures so I apologize if their quality is somewhat lacking.

In the first picture, the VAC with silver-soldered nipple is on the left, the VAC with formed nipple is on the right. In the second picture the VAC with formed nipple is on top, the one with silver-soldered nipple is on the bottom. In the third picture the VAC with silver-soldered nipple is on the right, the one with formed nipple is on the left. The third picture is my attempt to display the stamped numbers/letters. The characters on the VAC with formed nipple do not show well because they are very lightly stamped. I hope these photos help.

Eric V.