[8LUG]

Whats it for(circled)? 1964 fullsize auto, mine dosen't have it. Any ideas?

[cheese country GP]

It's for the PCV system. Valve is in the back of the carb on the valley cover. Conection on the intake is right in front of the carb & should use a two unit tube for vacum.

[Blackcat]

I think hes pointing out the thin metal tube that runs above it. Pretty sure its either a vaccume tube for the AFB or choke. Seen them before but it's been a while.

[cheese country GP]

If that's what's being pointed to, it's the air inlet for the choke. There's supposed to be two tube's coming from the choke stove on the intake manifold. One goes to the choke housing on the side of the carb to warm the bimetalic spring inside the housing. The other is a vent & goes to the upper rear of the carb just below the air inlet. That allow's for circulation thru the choke stove to warm the spring mentioned before.

[64catdroptop]

The tube should be for a 4BBL rotohydromatic (Slim Jim) car only (in other words a GP or 4BBL Catalina). The Bonneville super-hydro does not use this vacuum line.

-r-

[8LUG]

Thanks ,Ron. It goes to show , that your never to old to learn.

[cheese country GP]

I'm confused. The 4bbl carb is designed the same on any of the full size car's as far as I know. They all require an operational choke to warm up the engine no matter what the tranny is. The tube that run's from the back of the carb airhorn to the choke stove isn't really a vacum tube but more a heat conductor tube allownig air to flow from the choke housing to the airhorn for ventilation.

[Deadhead]

Cheese- I'm with you. There was no vacuum modulator on those transmissions like on a TH400 etc., so they did not require a vacuum port. Not that this line went to the Trans anyway, but why would it only be on roto-hydramatic cars?

Could someone post a Pic of their choke on a car w/o this line?

[mkoser]

my 64 Catalina with the Slim Jim and 4bbl has the tube. It runs from the choke to the top of the carb, just like everybody else's.

MK

[8LUG]

1964 PONTIAC BONNEVILLE, SUPER-HYDRAMATIC 4/SP TRANS

[mkoser]

Originally Posted by 8LUG

1964 PONTIAC BONNEVILLE, SUPER-HYDRAMATIC 4/SP TRANS

You have the tube, but instead of going up and over, yours goes down and under...

[cheese country GP]

That's correct for the tube, down & around the side of the carb to the choke stove just below the base of the carb in the intake manifold. There's a second tube that goes from the stove to the choke housing. If the choke is not operational hard starting will result. The purpose of the choke stove is to let the heat warm up the bimetalic spring inside the choke housing sooner so the butterfly release's quicker & the engine comes' off fast idle sooner. The choke stove is hidden behind the PCV system hose in the previous picture. There's also another part of the equation called the heat riser that's in the exhaust manifold on the right side of the engine. It's spring loaded & if it's not working can damage your engine if frozen shut. It also allow's for quicker warm up of the engine. For best result's, both item's need to be working.

[64catdroptop]

We're talking apples and oranges here.... the tube that John posted a picture of does NOT go into the choke. Yes, all choke tubes are the same for 4BBL no matter the transmission.

The tube that John circled connects into the front of the carb. If you look at your 4BBL carb just to the passenger side of the jet adjusting screw, you'll see that it either has a plug or a tube. I can't remember exaclty where the tube runs (Dist I think), but it's for the slim jim transmission.

When I head to Snyders here in the next couple of weeks,... I take a peak and see if I can clean some cob webs out of the ole' gray matter and remember where that darn thing connects to.

Ron

[mkoser]

Now you've got me second guessing myself.

I will take some pictures of my tube tonight when I get home, It is identical to the first picture.

MK

[cheese country GP]

OK, let's get the proper tube under consideration. The picture first shown had what appear's tp be two tube's showing. The PCV hose that run's from the intake in front of the carb to the valve on the valley cover behind the carb. The smaller tube shown appear's to be a choke tube that run's from the choke stove to the air horn on the carb. There is another tube that run's from the front base of the carb to the dist vacum advance & that IS just used on the slim jim tranny. For some reason unkown to me it's required for that tranny & not the 4 spd hydromatic but it's related to the dist advance & not hooked up to the tranny itself. If you have the 4 spd there's a plug in the hole on the carb base. That tube is very small like maybe 1/8" dia & has a threaded fitting on the front of the carb & vacum hose that attaches it to the dist advance. I'd say the carb end is ported so it only come's alive when the throttle is blipped. I can't even see that tube in the original picture. If the dist tube is the one in question, then it appear's to be routed to the choke stove & that won't help the dist advance curve. So I guess, Ron, we need to find out what tube is in question & maybe get a better picture of what we're dealing with, apples or orange's, but not both as you said.

[64catdroptop]

Cheese,

Yep, you're right. As I looked at John's picture, you could, in theory, have circled 1. the PCV hose, 2 - the choke tubs , or 3 - the vacuum tube for the slim jim,... or all three. But in the first picture, the choke tubes are not that visable, so I disregarded those, and in the second picture that John posted of his Bonneville engine, both choke tubes are clearly visable.

What you explained is correct. I assumed, since John's Bonneville would have PCV hose #1, and choke tubes #2 anyway, he was questioning the vacuum for the dist(?) #3, which is the small tube that sticks out on the side of the air breather. In the second picture that John posted of his Bonneville engine, you can see the plug in the carb base that I was speaking of.

Also, looking at the first picture, the car in question does have the slim jim transmission (which is also a 4 spd automatic) because you can see the top of the vent tube by the back of the engine.

2 BBL Catalina's had the vacuum tube # 3 also.

So,..... John,..... which tube are you refering to???

One other commet: I noticed in the picture that John posted of his Bonneville carb - manual transmission cars should not have the dash pot installed - they were only used on automatic cars. FYSA
Ron

[Deadhead]

Ron,

I don't believe that there is a Vac. line going to the Slim Jim. Just that tube that was a vent going to that crazy can w/ the 'J' on the end of it. Here is a Pic of mine. This metal line runs from the front of the carb vac port to the vac advance on the Dist. Then there is a 'T' on the back that goes to dashpot on front of carb and to the vac. tank under the DS fender on the rear of the carb.

As you say a 4 spd car would eliminate the dashpot, but would still need the Vac advance tube & the Vac can supply right?

I left everything as-was when I converted to 4Spd. I tried to get rid of the metal line when I rebuilt to eliminate the weird factory T with 2 size lines on it but could not find the right plug for carb. or the one they put a nipple on on some cars. See P. 7c-37 in the '63 shop Man. for a Pic. This Pic is where my confusion came from. I wanted to eliminate that long metal tube that is in question & just come off the back, eliminating the dashpot/throttle return check. Also was not sure that they did not still use the return check on A/C cars.

[cheese country GP]

Yep, that's the set up on my '62 GP. It's got the slim jim but mine is an AC car & didn't have the dashpot. I couldn't find any evidence of it ever having one. No capped tube's, no discarded item's that looked out of place or bracket's that weren't used. The vacum line from carb to dist is quite small & original & doesn't appear to have been cut or disturbued in any way. Have seen other car's like mine that didn't have the dashpot so suspect not all of them did. I had a Le Mans year's ago with the dashpot & it quit working so just took it off, pluged the line & didn't seem to make any difference as to how well it ran.
The only T I could find was off the back of the carb to operate the power brake's, feed the vacum canister, & operate the heater/AC control's. Those would be used on all big car's so nothing special there.
The small canister on the tranny I think is just a vent & has that filter arrangement to prevent debri from entering the tranny.

[64catdroptop]

Bruce,

Must have been my wording... I agree that the slim jim doesn't use a vacuum, but mearly meant that if you look at the picture, you can see that "J" hose thingy sticking up from the fuel filter looking thingy on the slim jim transmission vents.

If you need a plug for your AFB,... I have several. Let me knowa and I'll send you one.

I never notice much difference on the dash pot -no dash pot either. I would just check to see if they worked and then just left them.

Got into a car accident tonight on the way home from work (UGH)... neck and back hurts... talk to you all later,

-r-

[mike nixon]

[QUOTE=64catdroptop;4027082

Got into a car accident tonight on the way home from work (UGH)... neck and back hurts... talk to you all later,

-r-[/QUOTE]

Hope the aftermath's nothing serious.

I have to ask, You trying to compete with Patrick?