Holley 94 vaccum port leak

[Steve51]

Is there supposed to be a copper compression ring on the steel vaccum line? The line has a mark around it like you would see from a compression ring. When I slip the steel line in and tighten down the brass fitting the line stays loose enough to pull out. The same fitting on the distributor end has a much tighter fit buy no ring. Is the line at the carb end just "worn" down too much?
I have been getting a steady 20 on the vaccum gauge until I recently pulled the carb off to fiddle with it. Dumb move on my part. Now I have a vaccum leak.

 

[petehoovie]

Is there supposed to be a copper compression ring on the steel vaccum line? The line has a mark around it like you would see from a compression ring. When I slip the steel line in and tighten down the brass fitting the line stays loose enough to pull out. The same fitting on the distributor end has a much tighter fit buy no ring. Is the line at the carb end just "worn" down too much?
I have been getting a steady 20 on the vaccum gauge until I recently pulled the carb off to fiddle with it. Dumb move on my part. Now I have a vaccum leak.

 

[Steve51]

Further investigation tells me the Ford vaccum nut is worn out and will not seal on the vaccum line and the inverted flare portion has seen to many removal/installation cycles. The threads on the carb vaccum port are a bit delicate so I decided to replace the OEM nut with a compression coupling, not using the nut/ferrule on the carb side and using thread seal compound. This way I can take it apart at the vaccum line end of the fitting and don't have to worry damaging the threads on the vaccum port.
The coupling is 3/16 24 thread count.....actually a brakeline fitting I guess.

 

[petehoovie]

Further investigation tells me the Ford vaccum nut is worn out and will not seal on the vaccum line and the inverted flare portion has seen to many removal/installation cycles. The threads on the carb vaccum port are a bit delicate so I decided to replace the OEM nut with a compression coupling, not using the nut/ferrule on the carb side and using thread seal compound. This way I can take it apart at the vaccum line end of the fitting and don't have to worry damaging the threads on the vaccum port.
The coupling is 3/16 24 thread count.....actually a brakeline fitting I guess.

 

[farmertom]

Is there supposed to be a copper compression ring on the steel vaccum line? The line has a mark around it like you would see from a compression ring. When I slip the steel line in and tighten down the brass fitting the line stays loose enough to pull out. The same fitting on the distributor end has a much tighter fit buy no ring. Is the line at the carb end just "worn" down too much?
I have been getting a steady 20 on the vacuum gauge until I recently pulled the carb off to fiddle with it. Dumb move on my part. Now I have a vacuum leak.

Hey Steve,i'm having the same issue with the vac. line wanting to walkout on the old carb vac.port nut.well im useing the old vac. port nut on new carb.my old carb had gotten worn out,leaking everywhere plus the throttle accelrator pump link was worn to the point of the lower pin and pin hole were slipping out. i decided to go for the Chinese carb on that jungle site. it comes with a brass plug in the vac.port. i know,i know,but dennis carp and of course no one else has a Ford/Holley 94 and if they did it would run you $750. so the knockoff was looking like the deal at $120.i think my nold carb was looking so bad seems like an unlikely rebuild candidate.enough of my rambling, did you get the compression brak line fitting at NAPA or noreillys and what was part #if you don't mind. good luck and thanks in advance, Tom

 

[Steve51]

Hey Steve,i'm having the same issue with the vac. line wanting to walkout on the old carb vac.port nut.well im useing the old vac. port nut on new carb.my old carb had gotten worn out,leaking everywhere plus the throttle accelrator pump link was worn to the point of the lower pin and pin hole were slipping out. i decided to go for the Chinese carb on that jungle site. it comes with a brass plug in the vac.port. i know,i know,but dennis carp and of course no one else has a Ford/Holley 94 and if they did it would run you $750. so the knockoff was looking like the deal at $120.i think my nold carb was looking so bad seems like an unlikely rebuild candidate.enough of my rambling, did you get the compression brak line fitting at NAPA or noreillys and what was part #if you don't mind. good luck and thanks in advance, Tom

I got it at Ace Hardware but I would think it would be available at auto part stores. The 24 thread count UNF is commonly an auto part fitting. At the hardware store most of the brass fittings are NPT threads so have to search through to find the few UNF fittings. The NPT stuff is 18 or 27 thread count tapered. I took a small thread gauge with me to check. The fittings at the hardware store are often not labled by thread count. One other option I thought about was to replace the carb and distributor fitting with a hose barb and use a flexible vaccum hose. Ideally I wanted a 90 degree hose barb at the distributor but those are harder to find than the straight ones. It was just easier to reuse the existing steel vaccum line. I did not use the ferrule on the carb side because I wasn't sure the vaccum port had the proper flare taper and with the ferrule the nut would only grab two threads. You need a skinny ferrule in there.

There is a member here, Charlie NY who is highly recommended that rebuilds carbs. Maybe some carbs get to the stage of not rebuildable but he would be the one to ask if yours can be fixed. No experience with the Chinese carbs but it seems sometimes they are ok and sometimes not. I wouldn't mind having a second carb on hand....I see them for sale often enough they are not too hard to find. I would be curious how the Chinese carb works.

 

[petehoovie]

I got it at Ace Hardware but I would think it would be available at auto part stores. The 24 thread count UNF is commonly an auto part fitting. At the hardware store most of the brass fittings are NPT threads so have to search through to find the few UNF fittings. The NPT stuff is 18 or 27 thread count tapered. I took a small thread gauge with me to check. The fittings at the hardware store are often not labled by thread count. One other option I thought about was to replace the carb and distributor fitting with a hose barb and use a flexible vaccum hose. Ideally I wanted a 90 degree hose barb at the distributor but those are harder to find than the straight ones. It was just easier to reuse the existing steel vaccum line. I did not use the ferrule on the carb side because I wasn't sure the vaccum port had the proper flare taper and with the ferrule the nut would only grab two threads. You need a skinny ferrule in there.

There is a member here, Charlie NY who is highly recommended that rebuilds carbs. Maybe some carbs get to the stage of not rebuildable but he would be the one to ask if yours can be fixed. No experience with the Chinese carbs but it seems sometimes they are ok and sometimes not. I wouldn't mind having a second carb on hand....I see them for sale often enough they are not too hard to find. I would be curious how the Chinese carb works.

...

 

[farmertom]

I got it at Ace Hardware but I would think it would be available at auto part stores. The 24 thread count UNF is commonly an auto part fitting. At the hardware store most of the brass fittings are NPT threads so have to search through to find the few UNF fittings. The NPT stuff is 18 or 27 thread count tapered. I took a small thread gauge with me to check. The fittings at the hardware store are often not labled by thread count. One other option I thought about was to replace the carb and distributor fitting with a hose barb and use a flexible vaccum hose. Ideally I wanted a 90 degree hose barb at the distributor but those are harder to find than the straight ones. It was just easier to reuse the existing steel vaccum line. I did not use the ferrule on the carb side because I wasn't sure the vaccum port had the proper flare taper and with the ferrule the nut would only grab two threads. You need a skinny ferrule in there.

There is a member here, Charlie NY who is highly recommended that rebuilds carbs. Maybe some carbs get to the stage of not rebuildable but he would be the one to ask if yours can be fixed. No experience with the Chinese carbs but it seems sometimes they are ok and sometimes not. I wouldn't mind having a second carb on hand....I see them for sale often enough they are not too hard to find. I would be curious how the Chinese carb works.

yes i know about Charlie NY. this 94 clone i got the other seems to be working well.time will tell. Tom.

 

[tubman]

yes i know about Charlie NY. this 94 clone i got the other seems to be working well.time will tell. Tom.

I, globalist that I am, would like to know some more details about the carburetor you are referring to. Who made it, what did it cost, where did you get it? That sort of thing. I am sick and tired of dealing with warped castings, stripped threads, worn out throttle shaft bores, and generally beat up and totally used up components. I don't care about interchangeability, because they will interchange with themselves. "GBSisson" on this very board reported having good luck with Chinese repop carburetors for a Toyota. (Please correct me if I'm wrong.) It would be nice to plunk down $150 and have a new carburetor that works.

 

[farmertom]

I, globalist that I am, would like to know some more details about the carburetor you are referring to. Who made it, what did it cost, where did you get it? That sort of thing. I am sick and tired of dealing with warped castings, stripped threads, worn out throttle shaft bores, and generally beat up and totally used up components. I don't care about interchangeability, because they will interchange with themselves. "GBSisson" on this very board reported having good luck with Chinese repop carburetors for a Toyota. (Please correct me if I'm wrong.) It would be nice to plunk down $150 and have a new carburetor that works.

All that you mentioned about your old crusty 8BA carb describes perfectly why i didnt think the old ford/holley was a rebuild candidate.Dennis Carp. not repoping and they were $750. is not acceptable besides out of stock. I went with amazon Thundermingo 94 clone. it was$110.00 plus tax. it came in 2 days. packed well impressive. Looks very well-built and and faithfully reproduced. hopefully your vac.port fitting is still ok.and unbeleavably the 94 clones vac. port is the same as the us made carbs port.on my old carb the vac. line lately wanted to walk its way out of the fitting so for now i have used a drop of red loctite on the close to end of steel vac line and a drop or 2 at the nut.for now it seems to be holding.i have gotten a 3/16 brake line fitting that i think might work that i will try if my red loctite fails.for me it is a pain to reach so if the loctite fix works i ain't messing with it. the old carb was seeping everywhere and the throttle link was severly worn in the 3 hole settings along with the lower pin was sharp and popping out of worn holes. not sure if the aforementioned brake fitting will work i will look at the part number if you like. Right now my *** is parked in my recliner. first off the engine would not hold an idle.i assume that was intended.got the idle bumped up and warmed up the set the the 2 idle mix screws. pulls better than old carb,no surging,no flat spots. Tom.

 

[farmertom]

I, globalist that I am, would like to know some more details about the carburetor you are referring to. Who made it, what did it cost, where did you get it? That sort of thing. I am sick and tired of dealing with warped castings, stripped threads, worn out throttle shaft bores, and generally beat up and totally used up components. I don't care about interchangeability, because they will interchange with themselves. "GBSisson" on this very board reported having good luck with Chinese repop carburetors for a Toyota. (Please correct me if I'm wrong.) It would be nice to plunk down $150 and have a new carburetor that works.

All that you mentioned about your old crusty 8BA carb describes perfectly why i didnt think the old ford/holley was a rebuild candidate.Dennis Carp. not repoping and they were $750. is not acceptable besides out of stock. I went with amazon Thundermingo 94 clone. it was$110.00 plus tax. it came in 2 days. packed well impressive. Looks very well-built and and faithfully reproduced. hopefully your vac.port fitting is still ok.and unbeleavably the 94 clones vac. port is the same as the us made carbs port.on my old carb the vac. line lately wanted to walk its way out of the fitting so for now i have used a drop of red loctite on the close to end of steel vac line and a drop or 2 at the nut.for now it seems to be holding.i have gotten a 3/16 brake line fitting that i think might work that i will try if my red loctite fails.for me it is a pain to reach so if the loctite fix works i ain't messing with it. the old carb was seeping everywhere and the throttle link was severly worn in the 3 hole settings along with the lower pin was sharp and popping out of worn holes. not sure if the aforementioned brake fitting will work i will look at the part number if you like. Right now my *** is parked in my recliner. first off the engine would not hold an idle.i assume that was intended.got the idle bumped up and warmed up the set the the 2 idle mix screws. pulls better than old carb,no surging,no flat spots. Tom.

 

[farmertom]

OOPS,sorry about that.

 

[farmertom]

I, globalist that I am, would like to know some more details about the carburetor you are referring to. Who made it, what did it cost, where did you get it? That sort of thing. I am sick and tired of dealing with warped castings, stripped threads, worn out throttle shaft bores, and generally beat up and totally used up components. I don't care about interchangeability, because they will interchange with themselves. "GBSisson" on this very board reported having good luck with Chinese repop carburetors for a Toyota. (Please correct me if I'm wrong.) It would be nice to plunk down $150 and have a new carburetor that works.

The compression fitting that Steve51 showed that he got from ace hw may be what i purchased from O'Reilly's. part #CF1B.should only have to actually use a portion of this part.

 

[Steve51]

I think the main benefit of using the coupling is not having the risk of damaging the threads of the vaccum port. Having the inflexible steel line and tight access it is easy to get it cross threaded. A few times I caught this before I did any damage. Mine is complicated by the fact that the port is tapped slightly uphill so trying to thread it in perfectly straight cross threaded it. It was not obvious with the short oem nut but with the longer coupling it is quite obvious when viewed from a certain angle. Now I have a fitting that is less likely to cross thread, has replaceable parts, and can be swapped out if needed.

 

[Christopher Salty]

I’m using a knockoff “Holley 94” on Henry because it came with him. It isn’t perfect, but it works well. I haven’t tuned it or checked the float height yet, which I would expect to do with any new carburetor on an engine that isn’t 100% factory. Henry also has a PCV system that creates a controlled vacuum leak, and I haven’t tuned the carburetor for it. I can get him to idle at around 550 RPM, and the idle-mixture screws respond to adjustment. I haven’t tried installing OEM Holley jets to see whether they fit.

I’ve also bought several used Model 59 Holley carburetors from eBay and elsewhere and rebuilt a few. If the throttle shaft is worn, you can install an oversized shaft and hand-ream the shaft bore or bushings to fit.

For those unfamiliar with the terminology, “94” refers to the 0.94-inch venturi diameter, not the model number. Model 59 is one of the versions commonly called a Holley 94.