The Stovebolt Site Forums The Shop Area Engine Shop 1953 216: Vacuum advance install tips?

I have ordered a new vacuum advance for the distributor on the 216 in my 1953 Chevy 3100.

Any tips on the install? Process looks simple enough, but I figured some of y'all may have practical experience with this job.

Thank you.

Bolt it on, hook it up. No secrets to reveal, at least none I'm aware of.

Can you install the vacuum advance without pulling the distributor?

The distributor must be taken out. Just use some way to ensure that you replace it in the same position you removed it. I mark the rotor in relation to the dist body and the body to a point on the engine.

I agree with Forty9 about the markings. Also I believe as you pull out the distributor the rotor/distributor shaft will rotate some as the distributor gear comes up and out from the camshaft. Make a mark here also. You need this to go back in exactly as removed so distributor shaft lines up with oil pump shaft. Maybe use your phone to video how things come apart.

x2. I take the distributor cap off and rotate the motor until the rotor is at 12 o’clock to the motor. I mark the distributor body right at the lip where the rotor is pointing with a paint marker. Pull the distributor, with a black magic marker, scribe a line at the top of the clamp all the way around the distributor body shaft. The reason you want to do this is that it is entirely possible to get the distributor installed and the motor running, without the distributor tang engaging the oil pump slot. So the black line helps you confirm the distributor is in at the same depth as it was when you took it out.

install the new advance On the distributor, leave it loose, install the distributor, install the hold down bolt and center the octane selector to 0. body and rotor pointed to 12 o’clock, tighten the clamp screw. You have this!

You guys are awesome. Thanks for the detailed advice and tips.

If the distributor doesn't drop all the way in, never fear, the oil pump drive gear just has not dropped in yet, do NOT hammer on the distributor, just turn some more until the oil pump drive drops in the slot. If one looks at it, one can figure out on your own.

Ed

I do everything involved with the distributor by starting with aligning the timing marks to no. 1 cylinder. Check the position of the rotor, it should generally point to the 5:00 o'clock position. Disconnect the vacuum line. Pull the cap out of the way. Remove the hold down bolt and loosen the screw holding the advance to the list. shaft. Slide the list out. Remove the old advance unit. life the new one on. re insert the dist. in as close to the same position as possible. If the List. doesn't go all the way down, back it off and turn to rotor one way or the other to see if you can get it to easily slide in and retain the 5 O'clock alignment to the Distributor. body. This may take several tries. If all else fails, jog the engine until the shaft slides in and you have no.1 cylinder and the rotor aligned to No.1 cylinder at the 5 o'clock position. Install the bolt, align the octane lines to the center mark, tighten the screw but not complete yet , and install vacuum line. Static time the engine by hooking a test light to the Distributor side of the coil. turn on the ignition switch, adjust the distributor by turning it until the light just comes on. Lock it down. start the engine and use a timing light to get the final timing perfected. Insure to time the engine in accordance with the recommended RPM.

I didn't remove the distributor to replace the advance on my '38 216. I see no reason why you would???

On a 38 the vacuum can unbolts from the bracket.

Yep. I'm assuming from the discussion that they all don't.

Thanks, Dave

I cannot find a reproduction unit as you describe.

But, does the earlier vacuum-advance unit 1937 spark control unit) have the handy knurled adjustment screw. I have been looking for one of those units.

Tim, Are you referring to the octane selector? If so, I'm not on the computer with my pictures on it. Tomorrow I'll post a picture of my 38's adjuster.

It depends on the unit some cannot be separated from the hold down bracket. Some are bolted the the bracket

Tiny, in my post above, I added a link to an adjustable unit.

Yep, that's it. Do you want to see a picture of one in the flesh? If so it'll be tomorrow.

Yes, you might as well post a photo or two, Tiny - Thanks

If you ever see one for sale, please let me know. I regularly check here, eBay, and a few other discussion boards' parts-for-sale listings.

What are you planning to do with it Tim?
I believe that setup mounts to the block different then a 235.
Maybe Tiny can verify that with pictures.

If I cannot use/adapt it for my high-pressure 235s/261s, I will keep it in my "curiosity parts" collection.

Here are a couple of the selector and one of the "how to use it" instructions.

Thanks, I'll add those to the photos that I have.

I'll keep looking for a unit.

This is interesting, never seen that type of octane adjuster. Guess I have just been working on the late models. Does anyone use this with timing their 216/235? I never have, but would it be worth the effort to try it?

I found another. I took this when the engine was out to be rebuilt. You can just see a bit of the mounting bolt Dave referred to peaking out from the distributor.

Makes me wonder sometimes why engineers find it necessary to fix what isn't broke. The most current version of the Octane selector is a pain to set, and when the rivet wears out, there is slop in the whole works.
They should have stayed with Tiny's version.

[img]https://photos.app.goo.gl/S7NywVCkNrqGRfQcA[/img]
Final follow up on this thread, in case it might help others in the future. Photo shows the distributor, clamp, and my replacement vacuum advance that is made with the octane selector. The tips in this discussion thread were very helpful. In addition, here are a few of my personal notes.
1. Many comments in this thread provided tips to enable reassembly afterwards. I did those things. Specifically... I removed the distributor cap and turned the engine by hand until the rotor pointed at the 12 O'clock position. Then took lots of photos and a video, to help document position for reassembly. I also tried to mark the depth and position of the distributor with a paint pen, but the caked on grease made that difficult, so I just used the caked grease as my depth marker!
2. While the distributor was out I cleaned up the grease cap coming off the side of the distributor. It was locked in place, so I used gentle persuasion from channel lock pliers to remove it. Scraped out the dried up grease, cleaned up the threads, regreased the cap, and reassembled the cap to the distributor
3. The distributor reassembly to the engine was slightly tricky. I noticed the distributor did not lift straight up on disassembly, but rotated clockwise a bit. This appears to be due to the counterclockwise spiral gears on the lower end of the distributor shaft. For reassembly, I dropped the distributor straight down until it hit the ends of those spiral gears, the slightly lifted and gently wiggled the distributor, while rotating it just a bit clockwise until the gears meshed, and finally let the distributor drop into place with a slight counterclockwise rotation. Took a couple of tries to get it lined up. Made sure when I was done the rotor was pointing at 12 O'clock position.
4. Then set the depth using the caked on line of grease.
5. I set the octane selector to 0 and bolted that down.
6. I set the static timing based on the BB on the flywheel and timing pointer.
7. For the first run after reassembly, I removed the valve cover, to watch oil flow and provide independent verification that the distributor shaft was engaging the gear of the oil pump down below.

Thank you all for the helpful advice. I hope my follow up summary may help others who tackle this job in the future. Not a tough job, and does not require any special tools or training, but it does require some care at the start, to help with correct reassembly at the end.