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'60 rotten choke pipe

Started by David Greenburg, September 20, 2016, 12:07:46 PM

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David Greenburg

So I have read the numerous postings on this issue, and understand the options for repairing or bypassing.  In my case, someone plugged the passenger side hole and left the line to the carb resting on the manifold, and when adjusted carefully, the choke works ok, at least here in N. Calif.  But after reading all the posts, it seems like I need to be sure the other end (driver's side) hole is also plugged, to eliminate the small exhaust leak and also, apparently to reduce the risk of fire (although I'm not clear on how that arises). My question is whether there is a way to confirm that the driver's side hole is plugged without having to remove the manifold.  I don't think it makes a difference, but my car is 3x2.
David Greenburg
'60 Eldorado Seville
'61 Fleetwood Sixty Special

Dan LeBlanc

Lots of light and an inspection mirror?  One of those little snake camera thingies with a light?
Dan LeBlanc
1977 Lincoln Continental Town Car

Steve Passmore

Fire threat is if you had a dribble of fuel out of your carb then you have the exhaust flame coming out the manifold choke hole.
Steve

Present
1937 60 convertible coupe
1941 62 convertible coupe
1941 62 coupe

Previous
1936 70 Sport coupe
1937 85 series V12 sedan
1938 60 coupe
1938 50 coupe
1939 60S
1940 62 coupe
1941 62 convertible coupe x2
1941 61 coupe
1941 61 sedan x2
1941 62 sedan x2
1947 62 sedan
1959 62 coupe

David Greenburg

Thanks.  Since at least the choke end is blocked off I'm not driving a major fire hazard. And if need be, perhaps I can shove some JB Weld into the hole without having to lift the manifold.
David Greenburg
'60 Eldorado Seville
'61 Fleetwood Sixty Special

russ austin

You can repair it easily.  Chips Caddys has the tube to put in there, with simple instructions.
R.Austin

David Greenburg

Russ-  Thanks; at that price is be more inclined to repair rather than just plug the hole. Elsewhere I'd seen a replacement kit for over $100.
David Greenburg
'60 Eldorado Seville
'61 Fleetwood Sixty Special

fishnjim

I don't think there a factory direct connection to the exhaust gas.   Common misconception.  Unless your exhaust manifold rotted away.
There's what they call a "choke oven" that creates hot air from the manifold heat that feeds the tube by convection.   One end of the tube ends slips in there.   The other goes to the choke connection.   They all rust out from hot moist air.   

David Greenburg

But if I understand the set up correctly, the end of the choke pipe opposite the choke is open to the atmosphere.  If that is the case, if the pipe rots, it creates an exhaust leak by allowing the exhaust gasses to leak to the atmosphere through that end of the pipe (or what's left of it). In order to stop the leak, one needs to either replace the pipe or be sure that the openings on either side of the intake manifold are blocked off.
David Greenburg
'60 Eldorado Seville
'61 Fleetwood Sixty Special

76eldo

Exhaust is all sent out through the exhaust manifolds.  The choke tube only brings hot air from under the intake manifold and directs it to the choke coil.

Are you referring to the tube with the spiral insert that is in the manifold, or the pipe with the threaded end that attaches to the choke on the carb?

Brian
Brian Rachlin
Huntingdon Valley, Pa
I prefer email's not PM's rachlin@comcast.net

1960 62 Series Conv with Factory Tri Power
1970 DeVille Conv
1970 Eldo
1970 Caribu (?) "The Cadmino"
1973 Eldorado Conv Pace Car
1976 Eldorado Conv
1980 Eldorado H & E Conv
1993 Allante with Hardtop (X2)
2008 DTS
2012 CTS Coupe
2017 XT
1956 Thunderbird
1966 Olds Toronado

Ken Perry

Exhaust deffinatly runs through the intake and if the tube is gone it will leak and sound like a crop duster air plane. Exhaust is live under the carb also. When the heat riser is closed it sends more exhaust through the intake to warm the carb and choke tube. I would fix it with a new tube. The tube has a swirled metal piece running through it. But if you are not going to run a choke,just block both ends and make sure the choke is open ALL the way on the carb. And I always get rid of the heat riser in the exhaust,they are a problem child ! They couse broken exhaust manifolds and cracked head,drivers side. And Over heating ! Where they have real winters a choke is a must,but here in California,we don't need no stinking Choke !! Ken Perry   
Cadillac Ken

76eldo

I stand corrected.
I guess there is a port that allows exhaust to run into the intake which explains why the paint burns off near the choke opening on the intake.

Brian Rachlin
Huntingdon Valley, Pa
I prefer email's not PM's rachlin@comcast.net

1960 62 Series Conv with Factory Tri Power
1970 DeVille Conv
1970 Eldo
1970 Caribu (?) "The Cadmino"
1973 Eldorado Conv Pace Car
1976 Eldorado Conv
1980 Eldorado H & E Conv
1993 Allante with Hardtop (X2)
2008 DTS
2012 CTS Coupe
2017 XT
1956 Thunderbird
1966 Olds Toronado

Dan LeBlanc

That's correct.  The middle intake runner is the exhaust crossover.  The front two runners feed the front four cylinders and the rear two runners feed the rear two.
Dan LeBlanc
1977 Lincoln Continental Town Car

David Greenburg

Brian - I am referring to the pipe with the spiral piece in it that goes through the manifold, not the section that runs from the pass. side manifold to the choke.  The "port" you refer to is the manifold heat riser; when it is open, exhaust flows from the driver's side head into the exhaust; when it is closed, it directs that exhaust into the exhaust crossover portion of the intake manifold.  But I think if the choke pipe is bad, there is likely still an exhaust leak even if the heat riser is open, because some of the exhaust will continue to be drawn into the manifold crossover since there is less resistance/back pressure for exhaust going out through the leak than for exhaust traveling through the pipes/muffler.

Ken- This is exactly what I'm trying to do; determine if both ends of the manifold are sealed. I have been running without the choke ever since you disconnected it during my ill-fated trip to the Vegas GN.  If I need to pull the manifold, I may replace the pipe, but otherwise I'm inclined to keep going without the choke.

David Greenburg
'60 Eldorado Seville
'61 Fleetwood Sixty Special

wbdeford

#13
Another option is an electric choke, which I am currently running on my '58.  It works quite well, though if your car hasn't been started in a while and it takes a fair amount of cranking to get it going, the electric choke will warm up more quickly than is optimal.  It just needs to tap into a wire controlled by the ignition switch.  In my case, since my power antenna isn't working anyway, I disconnected it and used that spot on my fuse panel.

Still, being an originalist, I am planning to fix the choke stove at some point and reinstall my original choke.

I am finding a lot of the earlier comments confusing, so here is a brief description of the two systems:

Driver side manifold:
thermostatically controlled heat valve (a.k.a. Manifold Heat Riser)
Directs exhaust gas up into the intake manifold to warm the carburetor, by blocking exhaust from going out the driver side exhaust pipe until it warms up.
The exhaust gas then flows toward the other exhaust manifold and out that side until it is warm enough for the valve to close
example: (not from a Cadillac, but similar: http://www.autopartsdb.net/assets/images/ProductImg/g/g023.jpg )

EDIT: Dan pointed out a change starting in '59, where the choke stove comes from the intake manifold rather than the passenger side exhaust manifold.  Editing to correct this.
choke stove heat pipe
Directs exhaust heat up to the choke to warm the choke so that it opens when it should.
1958 Sedan de Ville

Past:
1956 Fleetwood 75 Sedan
1957 Fleetwood 60 Special
1958 Miller-Meteor Futura Landau Duplex
1960 Coupe de Ville
1966 De Ville Convertible
1970 De Ville Convertible
1971 Eldorado Convertible
1979 Sedan de Ville
1980 Seville

Dan LeBlanc

Just keep in mind when referring to the choke stove, in 1959 and onward, it was moved to the intake manifold center port from the passenger side exhaust manifold as seen from 1958 and earlier.
Dan LeBlanc
1977 Lincoln Continental Town Car

wbdeford

Thanks, Dan....I looked it up in the '59 manual and '60 supplement and it didn't say anything about the location, so I just assumed it was where it was before....editing my previous comment to reflect this.
1958 Sedan de Ville

Past:
1956 Fleetwood 75 Sedan
1957 Fleetwood 60 Special
1958 Miller-Meteor Futura Landau Duplex
1960 Coupe de Ville
1966 De Ville Convertible
1970 De Ville Convertible
1971 Eldorado Convertible
1979 Sedan de Ville
1980 Seville

David Greenburg

Happy ending to this story.  I got an inspection camera at Harbor Freight for about $65 and was able to determine that the driver's side end of the choke pipe has also been sealed off. So no exhaust leak. And now I've got a new tool that will undoubtedly be useful in the future.
David Greenburg
'60 Eldorado Seville
'61 Fleetwood Sixty Special

fishnjim

I'll take 50 lashes with the wet noodle.   I assumed you were trying to reconnect the choke tube, not leave it off.   I guess my bifocals didn't clearly read the post.   
I went down and looked at my '59 3x2 manifold which I wasn't thinking of.   I'm with it now, saying the tube rots, exhaust leaks out both the sides.   My bad.
But none are designed to work directly off connection to exhaust gas, the point I was trying to make.   They're always open to air on the cold end to act like an oven, not tapped directly into the exhaust manifold gases.   

David Greenburg

I actually was trying to disconnect the choke.  But since the manifold was sealed at both ends, I've decided it's not worth the expense/hassle of removing the manifold to replace the pipe.  It appears that if, instead  I simply rest the pipe running from the manifold to the choke against the manifold, and set the choke very lean, there is enough choke to help the car start, and enough warmth that the choke goes off.  But living in Northern Californa, the choke is not all that critical. I'll see what happens when it gets colder.
David Greenburg
'60 Eldorado Seville
'61 Fleetwood Sixty Special