Carb Tuning with Colortune

In the Knowledge Base, under Resources,  (black bar top of the page)  there is a good article written on tuning webers, by DannyP.

Had to Google "colortune webers." A spark plug that lets you see the color of the flame front inside your combustion chambers! Wow. Looks like a great idea in theory. Reports of its actual performance are decidedly mixed.

Those work best ("best", here, is a relative term) when you can look at the plug, from the end and along the length of it but just off to one side.  Looking at it perpendicular from the side, and especially those two plugs buried at the front of the engine behind the manifolds where you can't see them, would not show you much.

Novel idea, though.  I remember seeing a clear glass plug on a very old car at a show, once.  IIRC a Thompson Flyer or a Brush - can't really remember - but those were pretty novel, too!

OK.

An Innovate LM2 Lamba (O2) meter is $350 new. Nobody wants to buy one, and I get that. But, really-- there's no shortcut here. "Reading" sparkplugs? Perhaps on a '73 Fiat Spyder, but I struggle to get my upper number 1 and 3 plugs in and out without cracking the insulators as it is.

Also: how do you see what's happening during various load and throttle positions? Shut the car off, and coast to the side of the road while you pull a plug to look at it? I'm as old-school as anybody here, and that seems like a ridiculous way to get it done.

In the absence of a meter, a guy is just guessing. There are some pretty good guessers out there-- but if a guy is going to try to use something like this apparatus, then he's looking for help. Help is available in the form of a tool that works.

I'd recommend finding a way to get your hands on it.

Krusty posted:

...I followed the documentation I could find on the web (Mixture screw fully in then 2 turn out) and the plugs are still carbon fooled...

  

Getting Webers very close to right shouldn't require exotic equipment, voodoo, or Doctor Ferguson's Magic Carburetor Elixir and Moustache Wax.

It's a process with clearly defined steps, and focusing on one aspect (like mixture screws) without understanding the whole process is sort of shooting in the dark.

I keep posting a link to this article - right here in the SOC archives - as a great place to start. It's a longish read, but unless you get the big picture, you could be wandering in the desert in search of the promised land for a long time.

Sacto Mitch posted:

Getting Webers very close to right shouldn't require exotic equipment, voodoo, or Doctor Ferguson's Magic Carburetor Elixir and Moustache Wax.

It's a process with clearly defined steps, and focusing on one aspect (like mixture screws) without understanding the whole process is sort of shooting in the dark.

I keep posting a link to this article - right here in the SOC archives - as a great place to start. It's a longish read, but unless you get the big picture, you could be wandering in the desert in search of the promised land for a long time. 

Suit yourself.

But a $350 tool is not exotic, or voodoo, or Doc Ferguson's Elixir. It is, however, a great tool to see what's going on, if a guy is completely in the weeds.

Yeah Stan, not questioning your wisdom.

Just reminding those confounded by carbs to go through the basics first in a logical order. Harney makes the point that a lot of other stuff (like timing and linkage) is at the root of 'carb' problems and should be squared away before the monkeying begins.

I've just discovered that a suspect distributor is probably responsible for a flat spot down low that would be easy to blame on jetting, mixture, or a bad alignment of the planets.

Stan Galat, '05 IM, 2276, Nowhere, USA posted:

Sacto Mitch posted:

Getting Webers very close to right shouldn't require exotic equipment, voodoo, or Doctor Ferguson's Magic Carburetor Elixir and Moustache Wax.

It's a process with clearly defined steps, and focusing on one aspect (like mixture screws) without understanding the whole process is sort of shooting in the dark.

I keep posting a link to this article - right here in the SOC archives - as a great place to start. It's a longish read, but unless you get the big picture, you could be wandering in the desert in search of the promised land for a long time. 

Suit yourself.

But a $350 tool is not exotic, or voodoo, or Doc Ferguson's Elixir. It is, however, a great tool to see what's going on, if a guy is completely in the weeds.

I would give VOODOO a shot as a LAST RESORT

Well said, Stan, but there is no way, on this green Earth (or the eastern Massachusetts sand bar, where I am now), that I'm gonna shell out $350 clams for a meter I'll use once, maybe twice in 20 years.  Just not gonna do it.  Now that I'm retired the budget just doesn't include things like that.

Why?

Because it won't do much to find that flat spot caused by my less-than-par ignition timing advance that wouldn't be found by my el cheapo A/f meter swinging lean or the seat of my pants whenever I gently push the "go" pedal.  I can see/feel what's going on, just not yet sure what's causing it but strongly suspect the less-than-mediocre advance curve on 90+% of the "009" distributors out there.

Would a wide-band be nice to have?  Sure!  (Once every ten years or so.)

Do I need one?   Hell, NO!

More on distributors (mine is the Pertronix that looks like an 009 Bosch):

Setting the timing the other day, I noticed that the timing marks weren't moving at all as I slowly increased revs above idle (while viewed under the timing light's flashes). Until I got to about 2200 rpm and then bam - it went to almost full advance, jumping up again to max advance at about 3000.

I looked up the advance curve for an 009, an 019, and a few others and while they're not linear, the shapes of their curves don't look anything like what I'm seeing.

At, say, 1500-1800, there should be some noticeable advance compared to idle that's not happening with my particular distributor. This is right where my pedal goes a little soft. And I've always felt a little surge of power right around 2200 rpm - where my distributor suddenly wakes up and starts advancing. This isn't the fault of the Pertronix module itself - but of the mechanical weights, springs, and pivot points - which I'm guessing weren't assembled by Black Forest elves named Gunther and Franz.

I could tear my hair out swapping in idle jets, fiddling with accelerator pump settings, and cursing out the carbs. But in this case, none of that is the problem.

And think about it. How many go on about that 'classic Weber flat spot' ?

Mark Harney's article is a great resource to start with, and I completely understand not wanting to spend $350 on something you'll probably never use again once you get this thing right. I made the choice to buy it because for whatever reason, I just couldn't see what was going on without it.

There's no shortage of internet opinions regarding what works when jetting an ACVW. As we all know, "out of the box" jetting is pig-rich for most applications. Mark Harney and John Connelly both advocate for tuning lean of peak on cruise, which is phenomenal when it works. I can guarantee that nobody will ever get to this point without a wideband Lambda meter, and I'm not sure it's worth it to try.

I have.

Sacto Mitch posted:

 More on distributors (mine is the Pertronix that looks like an 009 Bosch):

Setting the timing the other day, I noticed that the timing marks weren't moving at all as I slowly increased revs above idle (while viewed under the timing light's flashes). Until I got to about 2200 rpm and then bam - it went to almost full advance, jumping up again to max advance at about 3000.

I looked up the advance curve for an 009, an 019, and a few others and while they're not linear, the shapes of their curves don't look anything like what I'm seeing.

At, say, 1500-1800, there should be some noticeable advance compared to idle that's not happening with my particular distributor. This is right where my pedal goes a little soft. And I've always felt a little surge of power right around 2200 rpm - where my distributor suddenly wakes up and starts advancing. This isn't the fault of the Pertronix module itself - but of the mechanical weights, springs, and pivot points - which I'm guessing weren't assembled by Black Forest elves named Gunther and Franz.

I could tear my hair out swapping in idle jets, fiddling with accelerator pump settings, and cursing out the carbs. But in this case, none of that is the problem.

And think about it. How many go on about that 'classic Weber flat spot' ? 

Oh, how we agree, Mitch.

One of the most important aspects of how the engine responds and operates (ignition), and 95% of us rely on a $50 piece of absolute garbage. You've got a good one-- it actually advances, at some point, in some manner.  I'm not sure how guys like Jim Ignacio seem to get engines that respond at least as well as a chainsaw motor with a Pertronix distributor, but I've never been that guy. I'm the guy with a drawer full of failed experiments in "distributors of the world." Mallory, OE Bosch, etc.-- you name it, I've probably got one somewhere. Some work better than others, none are very good.

As I've read, then repeated many times-- 95% of all carburetion issues are ignition. The average hobbyist gets an engine with almost no thought given to either tailoring jetting or ignition. The carbs get the jets they came with, and ignition is handled by a $50 east Asian distributor with non-adjustable advance curves.

This is by far the weak-spot in the platform. You want voodoo and elixirs-- playing with advance springs and weights is like throwing chicken bones and hoping to find the path to enlightenment. I really want to like old stuff, but this is where the new stuff is an order of magnitude better. A locked out distributor and a CB "Black Box" gets you the ability to pretty much infinitely tailor the advance curve-- to actually tune the ignition. What a novel concept (something with a reasonable chance of actually working), and one for which we can (again) thank CB Performance for.  

Someday (perhaps as a retirement job), I'd like to start putting together tuning packages that actually work for guys who like the nostalgia of an ACVW Type 1, but who'd like it to work reasonably well. There's probably 15 or 20 people in America left who'd be a good customer base, so there's that.

You'd think a decent shop would be able to do it, but they can't.

Stan Galat, '05 IM, 2276, Nowhere, USA posted:

and one for which we can (again) thank CB Performance for.  

I can actually write better than this. How about,

Stan Galat, '05 IM, 2276, Nowhere, USA wishes he'd posted:

and one for which we can (again) thank CB Performance.  

I'm OK with your wide band thingie, Stan.   It helps me justify the Fluke 561 IR thermometer I bought a while back and have used a couple of times, since.  

And all this talk of weird spark advance - I was actually thinking about that almost a week ago and started to play with timing to see what happens.  Then I remembered that I have a brand new, original Bosch 009 in a box that I got from one of the local 356 guys.   I'll try swapping the electronic module over to that housing to see what difference it makes, but not until I take it to Charlie's Rod Shop to put it on his distributor machine and see what the curve looks like.  That's all I can do as I don't have any different springs to try (and don't know where to get some.)

BTW:  Nobody with an original 356 runs a 009 distributor.  I've heard of a LOT of 010's and a couple really odd-balls, but no 009's.  The 010 brings more advance on sooner than a 009, it seems, and the 356 engines like that.

Bam! Stan is really really right! 95% of carb problems ARE ignition. 009s absolutely suck. The lack of advance, adjustability of any kind, and massive spark scatter add up to something that runs, kinda, sometimes.

Megajolt people. Accurate, adjustable, and HOT spark. Whatever curve you want, however you want it. Running it 7 years now.

So crank fire or black box with magnaspark?

Rusty S posted:

So crank fire or black box with magnaspark?

Crank fire all the way, assuming it's in your skill set.

Crank fire. Only the best for those of us that are OCD in some ways(ignition) but are still cavemen in others(carbs). Go figure?

DannyP posted:

Crank fire. Only the best for those of us that are OCD in some ways(ignition) but are still cavemen in others(carbs). Go figure?

I don't know, I'm starting to think it's all just degrees of the same restomod disease.

It's like the guy who buys a '69 Camaro because he had one when he was a kid, then drops an LS motor and a Tremec 6 sp in and bolts on a set of dubs and 30 series tires. It's not a '69 Camaro anymore, but then again he's not 19 any more either. We've all gotten pretty used to mechanical devices working well, in the background, without a lot of care and feeding. Everybody wants to update the stuff he doesn't want to deal with.

I'm a bit like you, Danny (not as good, but I try). I like to tinker, and the ACVW is a veritable erector set for middle-aged men. I didn't want to deal with constantly monitoring the body for dings and rust, so the glass body suits me well. I like the fact that the Type 1 can be a docile single-port 1500 or a fire-breathing 4" bore 3L. I like that it allows me to invent, and carry something ancient to a level that was never intended. 

I never got the hang of carb tuning as a kid, and it always bugged me. So I dove off the deep end, and am pretty heavily invested in Dellorto jets, the LM1, etc. Ignition was one of those things just too crude to live with-- it's sort've the equivalent of using a Model T carburetor, except that a Model T carburetor is actually adjustable and an 009 isn't. That and the Model T carb delivers fuel pretty reliably. 

The Black-Box is just an effort to fool myself into pretending I still rely on a distributor, although all I'm doing with it is distributing spark. Mario Vellota pointed out that I could've done that with a crank pickup as well, and just used the distributor as so much extra frippery. I like the frippery, but I like stuff that works. The Black box works. I'm like the '69 Camaro guy, I guess.

Someday, I'll probably go all in and do the full-on MS EFI and spark with all the sensors and cold-start whatnot. I'll still run duals and let that bundle 'o snakes send spark out to the (too many) plugs, but for now I'm still pretending that I like the '60s. Once I do all that, I'll be pretending I'm in the '60s, only with something using fragile Asian parts.

I'm beginning to understand the Subaru guys.

Well, I decided to go for the colortune. My goal here is not to make the car better or get crazy MPG but more to understand how to tune those webers. With the colortune I will at least get a visual feedback if I am doing something stupid. All the literature I could find about the mixture screws on the weber IDF 40 contradicts itself between 2 or 3 turn from seated (they where all 4 at 4 turns from seated before I started this investigation). 

I had a job overseas this week and got it shipped for free to the hotel so I didn't spend that much $$$ on it. I understand the trickiness of installing this device on the front cylinders but I will improvise myself again as a Ukrainian 14yo contortionist to get back there :->. I just put new sparks plugs a few weeks ago and new ignition harness last week so I think I am getting used to the "mechanics hot yoga" technique with some very colorful french Canadian typical swear words used along the way :->

From looking at the thing the wire extension will help me getting it in the front cylinders and the tube with the mirrors will help me see the pretty colors. I will get some picture for the group so you see what i am getting out of it.

will update mid next week.

thanks all for the inputs, I really appreciate this forum. 

jc

First of all Krusty, I don't know if you have Spanish, Italian or the really crappy but somewhat improved Empi Webers that are available now.

I know a little about Webers. I'm wrong sometimes, just like all of us, but here are a couple things you need to know:

Webers run best when the "mixture" screws are around 1 to 1.5 turns out from closed. If they aren't in that range your motor is either pig-rich at idle or has the wrong size idle jets. The mixture screws DO NOT adjust the mixture. This is a fallacy  propagated by people that just don't know. The mixture is set by the jet size, and the air and fuel are mixed due to the size of the idle air holes in the top of the carb and the holes in the idle jet. The "mixture screws" adjust volume only, just like a water faucet.

You should start your tuning with the screws about 2 turns out, and make sure the engine is fully warmed up before you try to adjust anything. I have a plain English article on here about synching the carb linkage and adjusting the idle speed and mixture volume screws. Dells start at 3 or 4 turns out and end up at 2 to 2.5 turns due to the finer threads on their volume screws.

Check what size idle jets you have, and make sure all 4 are the same, as well as all 4 main jets, air correctors, and emulsion tubes. Idle jets can be anywhere from .50 to about .65, most commonly used is a .60. I ended up with a 57.5 in my engine, it runs best that way.

Another thing I've found is about air cleaners. Every time you take the filters off, dirt from the gasket areas falls down and ends up in the idle air intakes, which are open areas on top of the carb.

Also, when these cars aren't used often enough, water residue(especially from car washing) ends up in the float bowls where it turns into white chunks of goo that end up plugging your idle jets.

So keep everything clean, and turn off the fuel pump and run your carbs dry before storage.