The Stovebolt Site Forums The Shop Area Engine Shop 235 vacuum advance question

This is probably a stupid question, but how the heck do I mount the vacuum advance on the distributor?? heres a picture of the vacuum advance I have. I've looked at the shop manual and flipped through Denny's pictures, and still couldn't figure it out. I bought the engine without a advance on it, so I never got to see how it should be.

Vac advance picture

IInsert the distributor into the assembly and slide the assembly up the distributor post.

Thats exactly what I did, but nothing happens when I put vacuum to the unit. The arm can't be shoved into the advance at all. When I have the unit off the distributor, I can push the plunger in, but it pushes the clamp away from the advance, which than doesn't line up with the hole on the advance.

From whom did you get the advance unit and what is the part number?

I got the advance from classic parts:
http://www.classicparts.com/1947-62-Vacuum-Advance-6-Cylinder/productinfo/83-274/

The clamp doesn't come with it, but I found one in a pile of parts that was with the truck.

It looks to me that the unit you received is not the unit in the catalog.

Call Classic Parts and tell them you received the wrong part. If that does not work, ask to speak with a technical support person and ask him/her if you may send to them a photo of the unit you received and a photo of the unit you tried to buy.

Would someone else reading these posts look at both photos and give their opinion?

Looks like the collar is different to me,you might check that.

I think your onto something. The '54 manual shows the curved collar like I have:
http://chevy.oldcarmanualproject.com/shop/1954truck/54ctsm0619.html

But, this thread says that the '54 manual shows the car, not truck vacuum advance

So I have a new truck vacuum advance, but the collar from a car 235.

The back surface of the "vacuum pot" is not flat on your unit. The back surface of the original pot and the back of the unit in the Classic Parts photo is not the same as on your unit. I have bought two units from Classic Parts and they look like the photo in your catalog, not like the unit your received. I think they sent you the wrong unit.

The collar from a car is different from the collar from a truck but either one will work with the right unit (as long as you bend the vacuum line).

It looks like the clamp collar might interfere with the hold-down bolt on the octane selector. Maybe a clamp from a truck and a vacuum unit for a car? The entire units can be switched (with re-positioning the vacuum tube), but can the collars be switched?
Hoyt

Tim, heres a picture of the vacuum advance without the clamp, and as far as I can tell its the right part:
http://i56.tinypic.com/15f0lrr.jpg

Heres just the clamp I have, Which as Hoyt pointed out, does interfere with the hold-down bolt.
http://i54.tinypic.com/rssf3r.jpg

The other Tim & Hoyt are right. Sorry about my spatial disorientation (just one type of disorientation that I suffer from). The back surface of your unit is flat.

And, you all are correct, if you use the car collar on a truck unit, the ability to rotate is affected. A truck clamp should solve your problem (as Tim and Hoyt have already posted).

I am having this same issue. Does anyone know where I can get a new clamp. My vacuum looks just like the one the OP had.

Or should i return the one I got and try to find one that matches the curved clamp?

Do you need the straight clamp or the curved?

I have the curved clamp, so I think I need the straight clamp. Because I am having the same clearance issues with the new vacuum advance that was stated in the original post.

I'm going to send you a PM.

Any advice guys???

Turn the clamp screw so the nut and head are switched. Screw head should face forward towards the radiator. That worked for me. Easy to get to and still let me sneak a wrench on the bolt. Set the dizzy in the hole and snug at 0. Hook up the line and get it all routed. Loosen the clamp and pull out the dizzy leaving the vacuum advance in place. Then set the timing and line up the oil pump and clamp it in place. Should work.