'89 32/36 Weber DFAV rebuild and Conversion

[integratuner77]

Hey guys,

I have been around this site quite a bit researching and reading everything that I could about weber carbs. My car was still running fine, but definitely way out of tune with less than 10 mpg around town and not even peaking at 20 mpg on the highway. The motor still ran strong the carb was just dumping fuel through it. I took a lot of pictures during the process and I hope that I can help someone else in the future.

I stalked ebay or a while for carbs. I ended up buying two 32/36 DFAV carbs. One for 30.00 that had been sitting for a while that I was mainly using for parts and another for 70.00 that was on a running vehicle but missing the choke assembly. I also bought the adapter plate and carb rebuild kit and got to work. I inspected the running carb from top to bottom and cleaned it thoroughly. Then I took the choke assembly off the carb that had been sitting, revamped it, and installed it on the good carb. In the end, I had one complete carb.

Then I got to work on removing the stock carb. It was basically a tornado of ripping out vacuum lines and it felt o so good. Basically any vacuum line attached directly to the carb was removed. Here is what I kepts:

1. Brake booster vacuum line from manifold to the brake booster (left as stock)

2. PCV (positive crankcase ventilation) system hooked up. It has one vacuum tube that runs up through the intake manifold and I looped it back to a vacuum source on the manifold.

3. The vacuum advance on the distributor. I tied both of the lines together and connected them to the vacuum tree on the back of the manifold.


For the dreaded TV cable and throttle cable I took the stock carb cable plates off. I used both the plate for the throttle cable and the TV cable. I modified them with a dremel to fit on the shaft of the Weber carb. It is the exact same shape (circle with two flattened edges) just larger. Then I threaded a nut halfway onto the Weber carb shaft and loctited it like no other. I modified a bolt to have the two flat portions that fit into the modified stock carb plates and cut off the bolt head. It was basically a stud that replicated the Weber carb shaft. I then threaded this into the bolt that was halfway threaded onto the Weber throttle shaft and also loctited it. I was able to slip on the two stock carb plates and put a nut on to tighten it all down. This turned out to have the perfect amount of rotation and accepted both the TV cable and throttle cable with ease.

Then for the throttle cable and TV cable braket. I hacked off the ends of the stock brackets that hold the cable to reuse. I did some modifying and welding to create new brackets to hold each cable. I will post pictures of these so you can better understand it. The throttle cable holder uses the two front mounting points for the carb. The TV cable holder uses two unused bolt holes on the intake manifold. This setup has smooth actuation and goes all the way to WOT with ease.

I removed the EGR as well as the AS valve. I created a block off plate for the AS valve and removed both tubes coming off of the exhaust header. Royal pain for anyone trying to do this. The nuts going into the exhaust manifold have been through many heat cycles and make it a giant paint to remove. I had to remove the radiator to have enough room to get the bolts off. Once off I welded a plate over the opening of the nuts and threaded them back in with some high temp RTV on the threads.

Today I'm waiting on my last puzzle piece. My fuel pressure regulator will be showing up today so I can install it and attempt to start it. I will be sure to updated this with any findings and how it goes. I will also upload tons of pictures of the whole process. If anyone has any comments about my process or questions feel free to let me know.

Thanks!

[2oodoor]

you really shouldnt need the regulator, they run fine without it but having one is ok , probably hold back any foaming issues and smells.

The DFAV is backwards for the primary side so the carb linkage will be on the passenger side. Ive used both DF and DG on mine and really the biggest difference other than being backwards is the chokes and airhorn are considerably smaller on the DF and also use a different air cleaner base.
Another thing to look out for is assuring the thottle is capable of full opening with the gas pedal.

There are some coolant plumbing issues to work out as well. I block off one of the heater hose nipples on the right side. Also block off the water jacket that comes up under the carb base, if you dont then it can put coolant down intake to the cylinders. If you chose to bypass the intake plumbing then remember the guage wont work then because it reads off the sensor screwed in the intake manifold.

[integratuner77]

you really shouldnt need the regulator, they run fine without it but having one is ok , probably hold back any foaming issues and smells.

The DFAV is backwards for the primary side so the carb linkage will be on the passenger side. Ive used both DF and DG on mine and really the biggest difference other than being backwards is the chokes and airhorn are considerably smaller on the DF and also use a different air cleaner base.
Another thing to look out for is assuring the thottle is capable of full opening with the gas pedal.

There are some coolant plumbing issues to work out as well. I block off one of the heater hose nipples on the right side. Also block off the water jacket that comes up under the carb base, if you dont then it can put coolant down intake to the cylinders. If you chose to bypass the intake plumbing then remember the guage wont work then because it reads off the sensor screwed in the intake manifold.

I have full range with the gas pedal so that is all good. The air cleaner base came with the carb so thats all good.

I did block off the water jacket that comes up through the carb base with liquid metal.

I'm going to have to take a closer look at the intake plumbing you are referring to. I didnt realize that the gauge sensor is on the intake, I just assumed it was on the thermostat housing like most other cars..

I did have to block one coolant tube that previously connected to the carb. Is this the one that you are talking about will affect the gauge?

I'm about to start it here in a few minutes or at least try. I will update this after.

[integratuner77]

I found what you were talking about on the diagrams. I did not remove the routing of the coolant through the intake manifold so the gauge should still be in good shape.

[2oodoor]

great!
a few more areas to think about... what kind of condition is your pvc valve retainer that goes up on top of the oil separator? Source of problems there because it is plastic and most Ive run across are pretty crumbly. I replace the whole thing with a mopar v8 heater bypass hose since it is rubber and the same size. There is usually a little of the plastic left to salvage enough to slide into the rubber hose so there isn't too much adapting for the pvc to fit.

Also the vacuum advance, only one of those nipples is used and I have seen those things have intermitent leaking issues that will cause stalling. If you have those in a couple of days that is something to check.
The plates I never had trouble with leaking because i put a very thin coat of permetex hi tack , it is purple w/brush in can type. It is possible to warp those though if you keep turning the base nuts with the whole stud moving on ya.

[integratuner77]

What is the PCV valve retainer that you speak of? Is this the piece that comes up through the intake manifold?

When port is used for the vacuum advance? I thought it was both of them...

Lastly.. the big news.. SHE RUNS! I got it started and have the idle tuned. Seems to be running pretty strong and hopefully a lot more efficient. I'm about to button up a few last things then take it out for a test drive. I'll update this later tonight and start uploading some pictures.

Thanks for all your help/advice thus far.

[integratuner77]

SUCCESS! It runs beautifully. Pulls harder than I haver ever felt. It actually accelerates now and it is a beautiful feeling. It still seems to be running a bit rich though. I have some more investigation to do on that. However, overall I'm very satisfied. Here is a bunch of pictures. I'm not going to comment on each of them, but if you have a question feel free to ask.

[integratuner77]

[integratuner77]

[Buzo]

Sweet! Every time I see a good job like yours here I just want to do the same to my car even though I love all the sensing stuff on it. I would like to do the swap not because I'm having problems with my carb, Its just that I want to feel the power you guys mention you get with the carb swap.

Tell us more, Is it cold in your city? how is this carb at cold start?

[ADRIANFARINA]

[2oodoor]

very nice work!

yes the pvc plastic thing that stick up thru the intake manifold, but you probably didnt see the whole thing since you didnt remove the whole manifold. Ive always removed the whole manifold because of cutting and porting on the carb flange area. Have to wash out the shavings etc..

I like how you utiilized the oem cable hardware, it is always interesting how many ways that can be done. There are two different sets for the TV cable, some models have that on the gas pedal assy. some up on the throttle. It takes some fine tuning adjustments to get that TV set just right to suit your driving style and to keep it set where it stays in lock up at interstate speeds and not drop out constantly.

[integratuner77]

Thanks for the comments guys.

I considered port matching the intake manifold and that may happen in the future, but I only had a week and a half to get this project done before I need the car again. Headed back to college on a 4 hour drive, so we will see if my economy improved.

The plastic peice coming up through the manifold for the PVC system seemed to be in good shape so I just put another piece of hose on it and looped it back to a vacuum source.

Currently, its about 25 to 30 deg F here in the mornings. I have not yet tuned the cold start and plan to this morning. I think the choke needs some adjusting as well as the fast idle control. I will let you know how it goes.

I have tons of pictures of tearing apart the carb if you guys would like me to post those as well.

[integratuner77]

So new problem... It still wasnt running quite right on idle and would diesel after turning it off. I decided to check ignition timing and found that it is pretty far retarded which is why it was running rich with the idle adjustment screw just about all the way in. Unfortunately the distributor adjustment is at the max for advance so I have to go into the internals and turn the disc in there to get more adjustment.

I have a question though... which vacuum advance should be hooked up? The front one or the rear one if I was standing at the front of the car.

I'll continue to keep this updated. Thanks.

[Buzo]

I have a question though... which vacuum advance should be hooked up? The front one or the rear one if I was standing at the front of the car....

I'm going to speak based on what I have read in the book only.

You should use the one CLOSER to the distributor. The one in the back works only during the engine warming up since it is connected to the thermo valve C that opens when the car gets hot enough and relieves the vacuum, leaving the other connection alone the rest of the time.

Forgot to say that I'll love to see the carb disassembly pictures.

[cygnus x-1]

So new problem... It still wasnt running quite right on idle and would diesel after turning it off. I decided to check ignition timing and found that it is pretty far retarded which is why it was running rich with the idle adjustment screw just about all the way in. Unfortunately the distributor adjustment is at the max for advance so I have to go into the internals and turn the disc in there to get more adjustment.

DANGER! DANGER WILL ROBINSON! The timing shouldn't be that far off. If it really is that far out then your timing belt is probably off a tooth. This is a common thing to have happen when replacing the belt. It also makes the engine run like poop. Check the timing with both vac advance ports unplugged and the idle below 1000RPM. It should be at 0* BTDC. With the vac advance ports plugged in it should be between 20*-25* BTDC.

I have a question though... which vacuum advance should be hooked up? The front one or the rear one if I was standing at the front of the car.

One of those ports is the regular vac advance and the other is for an extra 4* advance when it's cold (I forget which is which). You can just plug them both in and it will be fine.


C|

[integratuner77]

Well I may be fine... I believe the mark that is on the AT is only at 15 deg. I was testing it with both vacuum lines unplugged and it seemed pretty retarded and ran rough.

I'll hook the lines back up and retest. I may also try getting a timing light that I can set the advance to figure out what it is actually at. Mine is the cheapest model that just blinks when cylinder fires.

As I thought about it more, I came to the same conclusion as you. If it is really off that far it would be off a tooth. After checking it with the vacuum advance plugged in then I will decide where to go from there.

Fingers crossed that it is actually correct and its just that I dont have a mark on the AT for the timing it is at with the vacuum advance unplugged.

Thanks for your suggestions.

[integratuner77]

Soo some good news... I pulled the valve cover and checked that my timing belt is correct. All checks out there. TDC mark on the flywheel lines up exactly with the notches on the camshaft gear. I also confirmed that all the marks are clear and clean on the flywheel so I should be able to see them if I do get the timing right.

Basically this narrows it down to the distributor... I think I need to get the timing gun that I can adjust the advance to see what it actually is. Then I will know for sure if I actually need more advance or not.

[2oodoor]

For information generally speaking....There is a vacuum port on the weber that is for ported vacuum advance, you dont use that on these Hondas. They require manifold vac for advance so tee off below the throttle plates or on the manifold.

[integratuner77]

HELP: Current Issue

Known -

1. Timing belt is on correctly
2. Marks for TDC and 15 deg advance are visible/clean (found by manually rotating crank)
3. With vacuum advance disconnected timing marks are not visible (TDC or 15 deg) can see the top of the tab on the AT just below the viewing window
4. Distributor is at the max adjustment for advance

Find -

Problem is narrowed down to the distributor. Is there something internal to the distributor that could advance the timing?

It has been taken apart completely before, so it could have been assembled improperly.

[Buzo]

You can unplug each spark plug cable and change it back one position.
The little number in the distributor will not match the cylinder number, but just don't tell anybody.

[Xaisk]

Your swap is coming along pretty nicely =D I bet it felt so good to rip out all that emission control crap and vacuum lines. I know it did when I did my Weber swap. Mine refused to run with that old one so I said screw it.

Good work on the weber!

[2oodoor]

HELP: Current Issue

Known -

1. Timing belt is on correctly
2. Marks for TDC and 15 deg advance are visible/clean (found by manually rotating crank)
3. With vacuum advance disconnected timing marks are not visible (TDC or 15 deg) can see the top of the tab on the AT just below the viewing window
4. Distributor is at the max adjustment for advance

Find -

Problem is narrowed down to the distributor. Is there something internal to the distributor that could advance the timing?

It has been taken apart completely before, so it could have been assembled improperly.

when you are lining up the TDC on the flywheel , what mark are you using?
the correct TDC for number one up is a faintly marked T scribed on the flywheel, all those other are for the timing light with vac advance hooked up.
If you find it is off a bit at the timing belt you can just loosen the tensioner bolt that sticks out thru the cover, no need to remove anything at all. This is easier when all the plugs are out too btw.

[integratuner77]

Yes there is a little T on the flywheel to mark TDC. This lines up perfectly when the two scribes on the camshaft gear line up with the top of the cylinder head.

Moving each wire back one is definitely an option.. Never thought of that... Maybe its wrong.. I'll have to look into it.

EDIT: My wires are hooked up correctly. From the back of the distributor to the front (if standing in front of the car) it is cylinders 4,2,1,3. This is hooked up correctly.

I'm still mind boggled as to what the underlying problem is...

[integratuner77]

FIXED!

I fixed the problem. I believe that one of the springs or both internal to the distributor were broken and it was causing the distributor to not advance the timing enough even at idle.

I replaced the distributor and it started right up. I set the timing at TDC with no vacuum advance and 15* advance with the vacuum advance connected. All is well. I then tuned it for lean best idle and its running strong.

I'm going to replace the spark plugs, fix an exhaust leak, change the oil, and tomorrow is the true test. I have a 4 hour drive that I will record the fuel economy on to *fingers crossed* see improvement.