Running too lean??

Wow. I'm not sure what to say after a buildup like that. Bob, we need to get a cup of coffee.

As much as I'd like to meet you gentlemen, Carlisle is a no-go for me. It's just the wrong time of year to leave the business. That, and I break out in hives if I have to go further east than Ohio or so.

However, Mr. Drake usually rolls through sometime in June on his way to St Louis. Last year we got a few guys together (yeah Rich, I'm talkin' to you) and did a one day get-together in the cornfields and hick-towns I call home. It was a blast, and I absolutely want to do it again this year.

I'll get in touch with Cory and try to iron out some kind of Midwest shindig for this year.

I'd really like to meet you gentlemen. Seriously.

Stan,

You've been on this site for a long time, and you have always been one of the more thoughtful and rational members.  Half the time I don't understand what you are saying - too technical for me - but I feel well assured that what you say is grounded in knowledge and experience.

Hi Stan,

I agree that wide band O2 sensor is the best, however, with the Weber IDF set up where each cylinder has its own (semi)independent adjustment, how do you know which cylinder is running rich or lean.Last time I replaced my spark plugs, the #1&2 is nice and tan, but the #3 & 4 is a bit rich, how does the wide band report since the bung is usually put on the main pipe after all 4 exhaust pipe merge. Just curious.

Eddy

Eddy-

Think of it like this: you're not going to jet the individual cylinders differently, so taking reading after the collector is really the best you are going to do, as it pertains to jetting.

However, that doesn't mean everything is magically the same in all four corners of the engine. Some minor devation is normal, but if you are rich in one bank and burning cleanly in the other (with the same jets), I'd say you probably have a vacuum leak, a linkage problem, or something else going on in one side of the engine or the other. I'd sure dig deeper-- but I wouldn't ever jet an individual bore differently than the others.

Jetting is the last thing I do when I'm tuning the car: after I make sure the valves are adjusted, the timing is set, and the ignition is advancing properly. Paying really, really close attention to the linkage from idle to wide open throttle is equally important-- I've yet to see a hex-bar set-up that is perfect out of the box. Generally, if they are synced at idle, one carb or another leads pretty significantly to WOT. You can straighten this out by re-drilling the holes in the arms of the linkage.

I'm no ace. I've chased a jetting problem for weeks that turned out to be a problem with the CDI box, a bad distributor cap, timing scatter, or some other problem. Somebody a lot smarter than me once said that 95% of all jetting problems are ignition, and I've found it to be true.

one thing that makes me look a lot smarter than I really am is that I monitor all four cylinder head temps. I've found ignition, mechanical, and fuel problems in an individual cylinder long before I would have otherwise with the gauges (when the temp in one cylinder drops off-- there's a problem). If I'm plugging an idle jet or a plug wire has come loose, I know which one it is before I even get out of the car. That alone makes what I'm doing worth it.

+1 Stan.

Eddy, I agree, if one bank is running differently than the other, it ain't the jetting. It is either bad linkage sync, intake OR exhaust leak on one side. Although I would lean toward the linkage first, seems like that is the problem. Definitely the most probable given the symptoms and the most common.

Heim joint crossbar fix is the way, too bad you aren't on the east coast, I'd dial that sucker in for you.

Hi Danny,

Thanks for the offer, however, Larry Jowdy installed my heim joint crossbar fix, so besides the adjustment, I think I am good there. My ignition, I use the CB Performance Magnaspark Digital Distributor, so that should be much better than the standard distributor as it has the advance input to the timing and I am familiar with tuning on the computer.

What I just noticed is that it idles with the same reading on the synchronize meter, however, when I do the WOT, one side as suspected did not open all the way. How do  I adjust that since idle the reading is the same from one bank to the other bank. 

You'll need to think about the geometry of it. There are three arms in a hex-bar linkage--the throttle cable pull arm, and an arm for each carb. The throttle cable arm is fixed- if your gas pedal will pull one carb to WOT, you're good there. One carb's pull arm is going to be fine.

The car that doesn't open all the way is going to take a bit of work on the arm. What I did with mine was to fill the existing heim-joint mounting hole (after removing the joint) with JB Weld. After it cured I re-drilled another hole so that the same amount of movement in the throttle arm pulled the heim joint a little more. If the hole is already pretty close to the end, you can drill the side that DOES open all the way so that it moves it a little less instead.

Moving the hole about 1/8" to 1/4" gets you pretty close, generally.

Eddy, glad Larry did the heim joint fix. The downrod angle is crucial. I ended up using washers to shim the ball on one carb to make the angles exactly the same. Then you can make sure the carbs open the same at full throttle as well as part throttle.

Hi Stan & Danny,

I have re read your post multiple times, but I have trouble seeing what you guys are saying. I am more a visual guy. Maybe, if not asking to much, can you either post a picture or a sketch of what you guys are saying about moving the arm

Thanks,

Eddy

it's the arm on the carb that I re drill,Ive been meaning to make a jig to put the arms on to do it&get them exzactly the same, but havent done it as of yet.also it's possissable the aluminum arms could also be foo a bit.the arm in the center(pulling arm) dosent realy matter at all.the angle does mater but not a lot unless you realy have a lot of angle .and remember there is more than 1 angle, not just left or right but also forward&backward angle need to be the same.. as for the 1&3 cylinders having a diferent plug color I would go up in jet for those 2 cylinders,it's common to jet for induvidual cylinder in performance apps.also if you have heat exchangers that change the exhaust&make those cylinders run hoter they need to have a little fuel, added to them,Ive seen cooked &1&3 cylinders from small heat exchangers&freeflowing header that lets all the heat out of 2&4 cylinders,it's a good way to drop a seat out of the heads.it dont take much jet change but is worth it.or you can use a wide band in each header tube,our race car has that,I shiver just thinking what it cost to have 8 wide bands, but when you figure all the other stuff in a 100thou+ car than it's not too bad.and it can save a very expensive motor if you pay attn to what it's telling you.