38 DGAS, charcoal canister & stock jet sizes

[88Sleeper]

Hey Gus,

So I'm working on the 38 Weber swap. I've got the old stuff out, and have removed the dividing plenum from my intake manifold.

On my to do list still:
- Finish converting the keihin throttle cable linkage to run on the 38.
- Figure out how to hook up the Charcoal canister (keihin had 2 gas lines going to carb, weber only has 1 fuel bowl vent)
- What to do to keep the Cruise control working (and the vac lines running all over the drivers side fender.. what to do about these?)
- Determine a good starting jet/air corrector size to run.

I have the '88 service manual which lists out how the original charcoal canister works, but that had 1 gas line from the canister going to the back of the keihin, and one line going to the thermovalve A on the front, drivers side of the keihin.

So far, I saw that lostforawhile posted about how you can get one of those 'el cheapo scooter-grade vacuum controlled vac valves for ~$10 onlnie, and they are coming, but I still don't quite understand how to get this to work on the 38, since keihin had 2 lines, with 2 different control valves on it, but the weber only has a fuel bowl vent... =\

Also, I heard there was a way to keep the cruise control intact, which I'd love to do, but I haven't started digging on that yet. I would really love to know if that just needs a single vac line, or a full set of input/output solenoids for it to work correctly...

Finally, the place I ordered my 38 DGES kit for the accord seems to have handily did some mods to it in order to help prevent idiots like myself from screwing with the jets to get it work off the bat. They installed 170 Air corrector jets (on the top edge of the carb, next tot he distributing jet) but the 2 main jets in the bottom of the float bowl aren't marked (maybe they're in upside down? )

I read the thread where people listed their jet sizes, but didn't see anything about the 38 webers before my eyes started to glaze and roll into the back of my head
I saw plenty of that stuff out on the jeepforum though.. makes me think the 38 isn't exactly 4-cyl friendly, considering the jet kit I got (the only one available for the 38) says on the front: "For 6-cyl engines" ... Somehow I don't think the a Clifford & A20 are going to compare all that great....

I would greatly appreciate any input or advice. I can post diagrams and descriptions from the 88 service manual for the charcoal canister, if that would help any of the moderators or pro's come to a better solution for these things.

Thanks guys~

[lostforawhile]

you dont have to change anything on the cruise, line simply has to hook up to manifold vacuum, find a FI canister and the extra line and fitting won't be on it

[88Sleeper]

Ok, I'll check out the cruise today then. Does it need the valves and vacuum piping on the drivers fenderwell then?

So would it be sufficient to just plug one port on the canister, and use the other line by itself?

I thought it needed a l one connected to the weber intake filter area to let the trapped gases escape when the canister is "purged".

Do you know by any chance what conditions it's supposed to purge under?

I think your original post mentioned that if I hook up the vac switch to our, it will be purging the entire time the cars running, right?

[lostforawhile]

Ok, I'll check out the cruise today then. Does it need the valves and vacuum piping on the drivers fenderwell then?

So would it be sufficient to just plug one port on the canister, and use the other line by itself?

I thought it needed a l one connected to the weber intake filter area to let the trapped gases escape when the canister is "purged".

Do you know by any chance what conditions it's supposed to purge under?

I think your original post mentioned that if I hook up the vac switch to our, it will be purging the entire time the cars running, right?

the canister can be setup to purge into the air cleaner or intake depending on vacuum, when there is vacuum at the control diaphragm on the canister it allows fresh air to flow through the canister and be pulled into the engine, the big hose on the bottom of the canister is how fresh air gets into it. On the older cars they used the vacuum signal from the PCV system to operate the diaphragm on the canister, as far as the cruise control, there is a simple line going into the canister with a check valve, the control valves are built into the assembly of the actuator. there is a single line attached to one of the metal lines next to it, this is manifold vacuum, leave the actuator right where it is, connect that line to manifold vacuum and you are done. The cruise operates by pulling on the lever attached to the gas pedal arm. As far as your linkage adapters, try pierce manifolds, they should have the specific adapter

[88Sleeper]

Cool, that actually answers most of my questions!!

I do have one left though, I was going to hook up the control diaphragm on the control valve to the vacuum tube on the bottom of the weber, where some people hook up the distributor advance. I'm going to hook mine into the tree on the back of the manifold, and I've read that the tube on the weber only sucks good in the lower band of the rpm range. This would open the canister for purging during the low rpm range, when the weber is still on the idle circuit... good idea or bad?

My other option, as you suggested, US to tee into the pcv circuit, on the intake manifold side (if I got that right?) That hose is rather short (the "n" loop), and I don't want to redo that system from scratch. I'm not opposed doing so, as long as I get this done right...

I'll have to pay with it tomorrow some more. Today I got the adapters on, and sealed with Toyota fipg on the outside (just to be safe).

Thank you for info so far!!

[88Sleeper]

Darnit, so hard to catch all spelling errors with tapatalk =( srry lostforawhile...

[lostforawhile]

I'lll have to find the book, but the old systems were t in before the pcv valve, so when there was enough vacuum to open the pcv valve, the canister would also operate. installing it after the valve would be regular manifold vacuum, I'm figuring out how to add a temp control system on mine, so the canister won't purge until after the engine is warmed up. let me clarify though, the purge hose should be t ed into the pcv system, so it only purges when the pcv system is pulling enough vacuum to open the valve, the hose to the purge valve is operated by regular manifold vacuum, it just opens the valve. The original system controlled when the canister purged etc, the canister works just like the early systems did, but without as complex of a control system

[lostforawhile]

basically when manifold vacuum is applied to the purge control diaphragm, it allows vacuum at the purge hose to draw fresh air through the charcoal in the canister and the stored fuel vapor to be pulled into the intake manifold. in the case of hooking the purge hose before the pcv, anytime there is enough vacuum to open the pcv valve, the canister will purge, providing there is manifold vacuum at the diaphragm

[88Sleeper]

Ah, ok. So what your saying is that the purge valve should have manifold vacuum so that is open whenever the car is running, but the actual hose that has the fuel vapors traveling to the carb system needs to be tee'd into the pcv system, on the oil/crankcase dude, so that when the pcv is purged, it will simultaneously purge the canister, right?

My only question here is, wouldn't having fuel vapors capable of traveling into the crankcase, be a bit hazardous? Or does it not matter, because the crankcase already has blow-by going into it...

[88Sleeper]

Oil & crankcase side*, but dude...

I also forgot, but I read that 2oodoor got cygnus x-1's 38 weber, and it was jetted pretty well....

Would that kind of setting transfer from one 38 to the next, or does each particular weber need to be optimized against itself & it's applied entertainment(engine/mods), for best results?

[lostforawhile]

Ah, ok. So what your saying is that the purge valve should have manifold vacuum so that is open whenever the car is running, but the actual hose that has the fuel vapors traveling to the carb system needs to be tee'd into the pcv system, on the oil/crankcase dude, so that when the pcv is purged, it will simultaneously purge the canister, right?

My only question here is, wouldn't having fuel vapors capable of traveling into the crankcase, be a bit hazardous? Or does it not matter, because the crankcase already has blow-by going into it...

thats the way they used to run it on old Hondas, there isnt that much fuel vapor in the canister, it purges pretty quick, it's only absorbing the fumes from the tank

[88Sleeper]

Kk, I'll try it then. To hook it up, I'll probably drill a hole in the plastic pipe that hooks the pcv valve, Gerry a metal insert with a flange through it from the inside, seal it with Fipg on the outside, and clamp the house from the canister to it, that way it should hold. The 16 hr gardening time makes me impatient though ;]

Thank you for your help & great explanation lostforawhile!!

[88Sleeper]

*tosses phone into wall...* I hate this spell checker like nothing... =[

[lostforawhile]

Kk, I'll try it then. To hook it up, I'll probably drill a hole in the plastic pipe that hooks the pcv valve, Gerry a metal insert with a flange through it from the inside, seal it with Fipg on the outside, and clamp the house from the canister to it, that way it should hold. The 16 hr gardening time makes me impatient though ;]

Thank you for your help & great explanation lostforawhile!!

just keep an eye on your oil but you should be fine, I have one of the books that shows a lot of the early emissions systems on vintage Honda stuff, the canister itself really doesn't change much, just whats used to control it

[88Sleeper]

Kk, I just got it hooked in tonight. I realized while I was putting the fitting for the fiat bowl vent in, that even though I trapped it, it was sealed since it hadn't been drilled in the factory...

So being stupid, I did it for them... so in case the canister doesn't work, I just screwed myself, lol!

Btw, I found the one vac line to the cruise cylinder, but there's another huge braided line running from it, a bit higher, and it goes into the fenderwell. Is that a vac line too? Or is the one rubber vac line all I need to worry about?

Can't wait to fire it up again! :-)

[lostforawhile]

see if you can get a picture and I'll mark it for you

[cygnus x-1]

Oil & crankcase side*, but dude...

I also forgot, but I read that 2oodoor got cygnus x-1's 38 weber, and it was jetted pretty well....

Would that kind of setting transfer from one 38 to the next, or does each particular weber need to be optimized against itself & it's applied entertainment(engine/mods), for best results?

For *best* results every carb should be tuned to the engine it's on, but finding a similar engine and carb combination will get you most of the way there. My engine had a mild aftermarket cam in it, so if you used the same jettings I had on a totally stock engine, it might run a little rich. But I bet it would be very close.

C|

[88Sleeper]

Hey Cygnus, glad to get some input.

I finally got it started up with the Weber, wasn't too bad, except it went straight to 3k rpm, and once the choke started opening, kept going up to 3.5k... I gotta admit though, I "tapped" the throttle plates open a couple of times, and WOW, that is one hell of a growl... (to be honest it kind scared me the 1st time since I was half expecting my poor stock motor to throw a rod or worse ) but it's a pretty impressive growl, even with the throttle plates open even a small crack
For the record, before I started it the first time, I bottomed out the mixture stop screw gently by hand, on both sides, and turned them out 1 turn exactly, with the idle speed screw 1/2 way in like it said.
The second time, I did the mixture screws 3/4 out, and the idle screw not turned in at all, and I advanced the timing a little bit, but when I shut it down from 3.5k rpm this time around, it started to diesel, so I got it to turn off by covering the barrel openings by hand

I got some pictures, hopefully they show up below. If not I'll put them onto photobucket and link them in.

To be honest, I'm not quite sure where to start with "tuning" the weber to get the idle down... I'm actually not sure if it's because of a vac leak? I plugged off anything unused, so kind of stumped here if it would be... The adapter plates were also sealed all the way around with FIPG (which turns to a hard rubber after it's dried, and that was 2 days ago)

I know my air correctors are 170's, but I wasn't able to see the main jets in the bottom of the float bowl cause I didn't realize the numbers were on the sides of the screws =\
Now I have a problem, in that the only 38 DGAS jet kit I could find was for "6-cyls" which gives me a pair of: 50, 55, & 60 idle/choke jets, & 170/190, 180/200, & 190/210 main/air corrector jets...
I'm not expecting that "more is better" in this scenario, but what other kind of kit can I use? 32/36 4-cyl kit? (I'm hoping I'm guessing right on this here)

I also have 1 other issue. As evidenced in the pics below, I put a fuel regulator in line between the filter & carb. The base plate is attached to the intake manifold, which (even in 2 mins) warmed up hot enough that it was hard to touch, and also heated up my regulator up quite a bit. The fuel hose from the regulator to the float intake is also hanging only about an inch above the intake ports on the head... My fuel is going to be coming into this thing really hot if I don't move it. I'm thinking I can squeeze it in with one of the screws holding the brake fluid lines right next to the top of the left strut mount, so at least it doesn't heat through direct contact, but before I go off changing my fuel lines again, is this a bad thing to have the fuel getting cooked before it hits the carb? I know we want the intake air to be cold (I'm thinking CAI after this filter needs to be changed) but does that apply to the fuel as well? Is this a plus if the fuel is pre-heated, especially if it get's colder in the winter? Or is Icing not a problem with the webers?

I can't wait to hit the road and see how this thing pulls, but my motor sounded like it was close to it's knees BEFORE I did the swap.. I don't exactly want to kill it 10 ft down the driveway, lol!

As promised Pics! (Let me know what you guys think about the keihin to weber throttle cable linkage adaptation. I was going to suggest doing this to heathzx as well. I tested it, and I have full range of pedal travel from closed (cable has 2-4mm of slack) and will let me pull it open all the way to WOT as is, just a hair above the floor I'm going to have to do a bit of testing to make sure if I stomp the pedal, I'm not going to rip the linkages off the weber...

The pic of the plugged water inlet line "A" -> Is this ok? I just used an excess vac plug , stretched it, and put a clamp on it to hold it... It held even under 3.5k rpm on the water pump, but I'm curious if this is a long-term solution?

I marked the PCV neck, valve, and rubber to plastic line as "B" , about the place circled is where I plugged the red line from the charcoal canister in. I forgot to take pics of this before I put the manifold back in, but the red line touches the manifold as well before getting hooked in... again, not sure if this will cause a heat issue to the fuel vapors?













Here is where that Vac hose I was talking about goes, lostforawhile. It comes off an elbow fitting from the cruise control housing, right above where the small-ish vac line comes in from it's tee fitting.It goes right into the frame though, kind of like the hose on the bottom of the charcoal canister.. breather tube I'm guessing? It's like a 1/2"braided line, so I'm guessing not any vacuum goes into it...

[88Sleeper]

More pics

[88Sleeper]

Last few pics. I also got one of the car itself if you guys are interested what shape mines in.
Yes, I know the body is bad, and I have a second set of doors, trunk, fenders, etc. minus the rear quarter panels, waiting for me to get around to painting and installing.. If I only wasn't so broke all the time on these webers T.T

[lostforawhile]

I know there is an air chamber box inside of the drivers side fender, it really doesnt do anything with the weber ,as far as needing the smaller jets have you contacted pierce manifolds?

[cygnus x-1]

Before you get a jetting kit, I would get a wideband O2 sensor to see where the tuning is at.

I would get something like this:
Sigma Lambda Controller DIY 2 | 14Point7

It's $190 with the sensor and you can connect it to a laptop for data logging. It also includes inputs for other sensors so you can log those too.


C|

[88Sleeper]

Hey Guys,

Thanks for the link. They also have a PP2 sensor as well, for $35 more, doesn't sound so bad if it's got internal logging.

Is it worth being able to log while driving, though?

I already have a jetting kit since I got it at the same time as the carb, I've been running the car since yesterday.

There's no stumble, unless I put my idle under 1k rpm, and if I use the brakes, and the engine fan comes on, it will bog.

I used the idle adjust screw to crack the throttle plates open about 3/16 turns in, and it holds idle at 1k, and doesn't bog. The mixture screws are both set 7/8 turns out, so I think those were set well. However, I feel like it is too lean.

First though, I found this guide to tuning weber/edelbrock/holley carbs: Weber Tuning Methodology

If I understand it correctly, the way the weber works, is that at idle, with the transition fuel holes mostly covered by the throttle plates, the engine runs off the mixture supplied by the mixture screws, and whatever air coming into the carb through the throttle plates (right?)

Assuming that is right, the low speed circuit runs when the throttle plate is opened by pushing the gas pedal, which pours fuel in through the transition holes that are normally covered by the plates. This, of course, is in addition to the fuel already coming through the mixture screws at the bottom of the barrels.

Both of these fuel outlets are fed by the idle fuel jets (in my case, labeled "main choke idle jet" and "left side jet" based off the jetting box).

Around 3-3.5k rpm, the idle fuel jets are unable to supply enough fuel to get the engine to run more, so the main jet's start to kick in. During the transition phase, the engine is actually pulling fuel from all 3 sources, and as the rpm climbs out of the transition phase, the low speed circuit stops putting fuel through the idle jets, and the main circuit compromising of the main fuel and main air corrector jets, does all the work (This is the part I'm not sure of, since I assumed they all keep working all the way to the top, how can you just "switch off" a fuel supply? vacuum signal???)

Also, the guide linked above mentions that the idle circuit has a set of idle air correctors as well? I haven't seen these on my weber, so maybe that's just a holley/edelbrock thing...

[88Sleeper]

Oh, i almost forgot about why I am thinking it's a bit lean. I also have a few questions about timing advance towards the bottom. I get the idea, and I read the manual about why our's have 2 vacuum ports, but something's not "right" .

So , starting with the idle off of choke: I think it's too rich. Not too much fuel, but the choke plates are closed all the way when the cam is released. I'm thinking I should set them to be open a little bit to allow more air in on start, since the belching black smoke problem goes away when it start to open (I assume black smoke = too rich).

Next, the idle is fine. I am not sure what indicates a "lean burn" out of the tail pipe, but I've heard that lean burn = lots of hydro carbons, and my exhaust at idle is very "wet" after it goes through my catalytic convert.. maybe lean??

The low speed circuit runs fine... I think. It pulls ok if I push the throttle in maybe 20-25%. If I start to push it harder, it doesn't really make much of a difference, throughout the low speed circuit, which ends a little bit over 3k rpm (I'm assuming my high-speed circuit comes on 3.5k - 4k rpm).

I'm thinking my main circuit is way lean though. if I "punch" it off of a start, I have less power than my low speed circuit makes. I'm thinking that when I open the throttle plates all the way, there's so much air that the mixture is too rich. With a WOT start, (i.e, I get it rolling in 1st, and then floor it) it has less power than if I'd just crack the throttle open 20-25%.. Kind of lame considering that I heard the weber was "burning rubber in 1st gear" if you'd punch it, lol!

My main question here is... how do I know if it's lean, aside from the wideband sensor and an emissions test?


Timing:

I read some posts from others saying that with the weber, the timing needs to be advanced, maybe 5-10 degrees, if not more?

However, I'm not sure if I'm advancing it properly, since my engine seems to be running weird the first time I "advanced" it.

With my timing light, I found the regular timing mark with my idle set on the Weber, and it doesn't run too bad. Feels a lot closer to how the stock carb is running.

However, seeing as how I have vacuum applied to both ports on the distributor (the lower one, further out from the engine is actually a "cold start" vacuum advance that advances timing when the water is below 51 degrees C) I'm thinking that under higher manifold vacuum, the timing is getting advanced further than before...

When I advanced my timing, I slid the distributor a bit "up" (counter-clockwise, when looking at the cap) and the timing marks went "up" in comparison to the fixed marker on the block. I set it so that the bottom hash mark on the flywheel was about 1/2" higher than where the pointer was at. It wasn't pinging or backfiring at that setting, but when I drove it around, it didn't really feel "right"... The rpm at idle did go up a bit though, which also gave me a bit of a problem when I'd start out at a light, since it seemed like it was bogging down when I was trying to get it rolling in the gear. I assumed at the time that it was just me sucking with driving a stick after 2 weeks of no practice, but now that I reset the timing so that the pointer is on the lower of the 3 hash marks, it is working much more closely to how I expect it to be.

My question here is: A. Am I advancing the timing correctly? I was guessing as to how much travel "5-10 degrees" would actually be on the flywheel, and going off of the pointers, but this isn't really an exact approach here... & B: which way is "Advance", and what kind of effect should I be seeing if I've correctly advanced the timing?

My motor is bone stock, so I'm just looking for how to get the motor running the best, but if the weber does require a different timing point then what the timing markers on the flywheel delineate, then I want to get it right so I don't damage my motor

[lostforawhile]

look at the chariot gauge, it's like 49 bucks, it records the output of the O2 sensor, voltage, oil pressure and temp through external sensors and loads the info to a droid phone by bluetooth, you still need a wideband with a controller for input, but neat little item