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I'm trying to remove the AIR tubes on my 77 L48, but stumbed on some problems:
There are three bolts that are almost impossible to remove...
1) One of them is right next to the 'early fuel evaporation' thing, and I don't have enough space to get my wrench in there.
Can I remove the 'EFE' without getting any problems?
There is also a vacuum hose connected between the EFE and the waterneck. Do I just plug it off.
2) On the other side (driver side) I also have not enough space to get a wrench on the two remaining bolts.
Is there a special tool other then an 'Open-End Wrench' to remove these bolts?
Bolt with tube next to the EFE
EFE
To vacuum connections on the waterneck. One from the 'EFE' and one from the Carb.
One of the two bolts by the 'heat stove'. (passenger side)
Do you need to preserve the old part? I used a flare nut wrench for some (this is the special tool, or "crows foot" socket wrenches), Vise Grips for some, and some broke off and are plugged with concrete nails. My AIR tubes were rusted out when i started.
IF you cut the tube, you can use a regular socket, after soaking the nut in penetrating oil.
Last edited by Bikespace; Jun 1, 2018 at 01:11 PM.
You may find that you may need to take the exhaust manifold off to get these out if you are working in an area and can not get tool on these flare nuts correctly.
Cutting the tubes and using a SIX POINT socket may get it. If it does not..then I know I would have to take the exhaust manifold off....like I have done countless times before.
And do not be surprised that IF you take off the manifold that using heat on the casting will help in getting the flare nut to break loose.
Cutting the tubes and using a SIX POINT socket may get it. If it does not..then I know I would have to take the exhaust manifold off....like I have done countless times before.
DUB
There seems to be some 'cement putty' on one bolt. Do you know how to get it off?
Bolt? What bolt are you referring to??? Because you are dealing with the flare NUTS.
You can either...carefully use a heat gun to get the 'putty' hot and allow it to soften and it should be able to get peeled off of this 'bolt'. I know I could use a propane torch to do this BUT not knowing where it is located and anything else about it...that method all depends because I am throwing out suggestion totally blind here.
Remember...GOOD photos ALWAYS work best when you encounter problems that we cannot see.
If you want to check the working condition of your EFE system this is how the vacuum lines are connected on a non CA or H/A 77 L48. If not cap or plug source vacuum.
EFE TVS switch top port vacuum in, middle port EFE actuator, lower port exhaust. The black and white plastic valve between vacuum switch and carburetor is called a spark delay valve. On a warm day, ambient temp around 70 or more it takes about 5 to10 minutes running engine for the TVS vacuum switch to close on my car opening the exhaust heat riser.
Ok, so just to be sure. According to the info that you guys have given me, I will do the following.
Please confirm if it’s ok.
1. I will cap off the vacuum source from the carb. -> Ok? Please confirm.
2. I will decouple both vacuum lines on the EFE TVS switch (the blue nipple and the one under it) and cap both nipples off (I don’t even think it’s necessary these nipples off…?) -> Ok? Please confirm.
3. Can I leave the EFE actuator in in place without it being controlled by a vacuum source?
I ask this because I think that there is some kind of ‘flap/gate’ between exhaust pipe and manifold. Will this ‘flap’ be closed when there is no vacuum source?
Here are some photos.
I made some indications to be clear, on what I’m going to do with the vacuum lines.
*Sorry guys if I’m being tedious. I just wan’t to make shure so I don’t do something wrong and get vacuum leaks or other problems. (Forgot to say I have a California Corvette.)
By taking out the EFE and how it works..It can greatly effect how your choke works on the carb.
The actuator or 'heat riser' with the 'flap' in it...allows exhaust from that side of the engine to heat up the air to your choke and allow the choke to pull off faster.
I can not be 100% sure but I do believe that with NO vacuum on the heat riser ...It is open so exhaust can flow freely.
"Google' a photo of the heat riser and compare where the lever is in the photo of the one you see and your and where the flap is. You can also go to websites of companies that sell Corvette parts and look at there photos of what they are selling.
The photo of your heat riser is in the open position, the little stop finger is pointing left, open. Hose disconnected, If you pull straight up on the actuator linkage rod you will see the stop finger rotate right (if not all froze up) heat riser closed. Now if you disconnect that linkage there is nothing keeping the heat riser open.
SAVE that black and white spark delay valve, they are hard to find that exact length. Black side facing carburetor.
If it were me I would at least see if your parts still work, just run the top yellow stripe hose like mine (Top Port EFE TVS) since you removed the air pump and diverter valve. Middle EFE TVS port to actuator
Last edited by bmotojoe; Jun 24, 2018 at 02:08 PM.
The photo of your heat riser is in the open position, the little stop finger is pointing left, open. Hose disconnected, If you pull straight up on the actuator linkage rod you will see the stop finger rotate right (if not all froze up) heat riser closed. Now if you disconnect that linkage there is nothing keeping the heat riser open.
SAVE that black and white spark delay valve, they are hard to find that exact length. Black side facing carburetor.
If it were me I would at least see if your parts still work, just run the top yellow stripe hose like mine (Top Port EFE TVS) since you removed the air pump and diverter valve. Middle EFE TVS port to actuator
Ok, I will connect the vacuum lines like yours, and check if my EFE still works (I'm 99% sure it works because I've driven the car a couple of times and didn't notice any problems.). If it works I'll leave it like it is for the time being.
What would happen if it doesn't work? What should I notice when I'm driving?
*I'll delete the rest when I go for a new exhaust system this winter.
Hoses connected cold start, just make sure that the heat riser opens after the car warms up, mine takes on a cold start about 5-10 minutes running at 70* ambient.
Heat riser stop finger left open (your picture) heat riser stop finger right closed.
If your selling the actuator & rod + spark delay valve I may be interested.
Last edited by bmotojoe; Jun 24, 2018 at 02:51 PM.
AIR tube removal problem
