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Tuning the 32-36; things I learned

Bill Blue

Platinum Level Sponsor
After fighting the old carb for several days and a multitude of internet searches, I offer this to anyone tuning a 32-36. No secrets, it's all available some place, but some of it is hard to find.

1. Be sure your ignition system is up to snuff. I had a miss in the mid 4,000 range that was due to a new, but faulty condenser.

2. The idle (or more aptly, low speed circuit) is in full control of events up to about 2,000 rpm. That is with the 2.0. Probably higher with a 1725.

3. The main jets come into full play at about 3,000, once again with the 2.0.

4. The emulsion tubes control the gap between 2,000 and 3,000 rpm.

5. The air corrector jets do not come into play until the upper 4,000's.

How to tune the 32-36:

A. Make sure the float setting is correct. A submerged Weber cannot be properly tuned.

B. Make sure the fuel pressure is correct. A submerged Weber cannot be properly tuned.

C. Tune the low speed circuit as described here:
http://www.redlineweber.com/html/Tech/carburetor_set_up_and_lean_best_.htm.
The .50 idle jet should work fine.

D. Select the proper main jets. Begin with the same (or closely sized) jet in primary and secondary. Pay attention only to operation in the 3,000 - 4,000 rpm range, selecting for optimum performance.

E. Fill the gap between 2,000 and 3,000 rpm with the emulsion tube. A skinny e-tube allows the main jet to kick in earlier. I was running a lean (125) main jet and fat e-tube. At about 2,700 to 3,000 it was pathetic. Changing to 135 main and skinny e-tube made a huge difference, also helping out somewhat as low as 2,000.

F. At this time, it is probably safe to start swapping secondary jets, looking for the best performance. By this time you should be able to feel the secondary kick in. I was happy with 135's and skinny e-tubes in both. I'm sure they are far from optimum.

G. Adjust the 4,500 and up area with the air corrector jets. The larger the jet, the less fuel.

I also had a light throttle surge at low (low teens) rpm. Sometimes it would be barely noticeable, other times very bad. I decided it was probably caused by loose throttle shafts. So I reamed out the shaft bearings and installed brass bushes. It appears that has about eliminated the problem. If you have an old 32-36, a light throttle surge and the throttle shafts can be rattled, they are probably the problem.

I am by no means a 32-36 expert. The 32-36 is a surprisingly complex piece and can be very confusing to tune without some basic information. Knowing the progression of events is critical. This should help you get started.

Bill
 

Bill Blue

Platinum Level Sponsor
Addendum (or I'm a Dum Dum)

A final visit, (I hope) to this subject.

A couple of things I forgot to mention. There seemed to be little correlation between the size of the main jet and the number stamped on it. These were all old Ford jets. But for the most part, that was okay, except for the initial confusion. I drilled them to whatever size I needed. For some reason I had a bunch of jets that were in the 100 range. The numbers on the emulsion tubes make no sense at all. I have the following tubes: 04, 05, 15, 16. I was able to picture I.D. the 16 to be an F50. The 15's seem to be F6. The rest I cannot identify.

I mentioned that I still had some off throttle surge at low rpm cruise. It was much better and not nearly as erratic, but I decided to try to do something about it. I also had trouble getting a decent idle, but throttle response was pretty good. So I purchased a couple of low speed jets, a .55 and .60. Started out with the .55. Did not make much difference at all. Still had to crank the idle adjustment screw way out. So I went to the .60. First off, make sure your new jets do not have chips in them. Guess why I say that. Anyway, some confusing responses and a carb tear down later, I determined the .60 was too small, even with the chip removed. So I went to a .70 (turns out I had it all along, either forgot or missed it). Finally able to get a decent idle, but the idle adjust screw is still way too far out. I'd guess 3 to 4 turns. I have no idea why it is requiring so much low speed jet. I don't think I have any significant vacuum leaks, I can easily take the idle down to 400 or so and then it dies. Off idle response is excellent. Also replaced the skinny primary emulsion tube with a fat one as I now have a lot more fuel being supplied by the low speed jet in the low 2,000 rpm range.

All in all, I am very happy with the results. The engine is very responsive, has considerable urge in the midrange and will now rev pretty eagerly into the 5-6,000 rpm range. My only problem now is one of gearing. I have be going 60-65 for the engine to pull these hills easily in 5th. The limit is 50 and 55 which is only 2,000-2,200rpm.

Bill
 

Chuck Ingram

Donation Time
A final visit, (I hope) to this subject.



All in all, I am very happy with the results. The engine is very responsive, has considerable urge in the midrange and will now rev pretty eagerly into the 5-6,000 rpm range. My only problem now is one of gearing. I have be going 60-65 for the engine to pull these hills easily in 5th. The limit is 50 and 55 which is only 2,000-2,200rpm.

Bill

Hi Bill
Well a lot depends on how steep those hills are.As to gearing this is when you downshift to 3rd and floor it for that supreme feeling of power.
As to RPM and it seems a touch high for only 50/55 mph .heck in my V6 the cam didn't even come on till around 2500 RPM.If I kept it in that range It was awesome when I floored it
 

Bill Blue

Platinum Level Sponsor
Hi Bill
Well a lot depends on how steep those hills are.As to gearing this is when you downshift to 3rd and floor it for that supreme feeling of power.
As to RPM and it seems a touch high for only 50/55 mph .heck in my V6 the cam didn't even come on till around 2500 RPM.If I kept it in that range It was awesome when I floored it

Yes, it is high. The hills are pretty steep but not long. When I selected the ratio I was living on flat ground and the engine would be turbo'ed. The engine/transmission combination would work well with a 3.89 or perhaps 4.22. The current rear is a 3.55. Maybe I'll just drive the back roads in 4th, 5th is 20% overdrive. This engine is cammed so it really wakes up at about 2700.

Bill
 

husky drvr

Platinum Level Sponsor
Yes, it is high. The hills are pretty steep but not long. When I selected the ratio I was living on flat ground and the engine would be turbo'ed. The engine/transmission combination would work well with a 3.89 or perhaps 4.22. The current rear is a 3.55. Maybe I'll just drive the back roads in 4th, 5th is 20% overdrive. This engine is cammed so it really wakes up at about 2700.

Bill

It's a shame that you would have to pull the head to change the cam, but I think the way you are trying to drive, you would be happier with a less aggressive cam. Or maybe you just need a higher compression ratio to make up for the the missing turbo.
 

RootesRacer

Donation Time
A final visit, (I hope) to this subject.

A couple of things I forgot to mention. There seemed to be little correlation between the size of the main jet and the number stamped on it. These were all old Ford jets.

Bill

You must have a Holley/Motorcraft 5200 huh?
 

Bill Blue

Platinum Level Sponsor
The carb is an early Motorcraft with removable low speed jets on both the secondary and primary. The jet numbering system confusion cannot be due to the difference in flow vs. diameter, as the two do have some correlation. These numbers were off the charts in crazyness. The smallest jet was marked something like 804. Not .804, which would make some sense. Did not pay much attention to the small number-large hole jets, they could have easily been drilled out. Also seemed to have several that were step drilled. Also have a couple of jets numbered "22" and "19". What could that mean?

Yes, the engine could use a little less cam for my application. It has 224* duration @.050" lift. I would imagine 215* would be better. Perhaps I am expecting too much. At interstate speeds, the engine is on the cam and cruises very nicely at 70, taching about 3,000. It pulls good, just cannot handle the hills gracefully in 5th at legal speeds. Maybe it should not. I am comparing it too the Focus wagon which is geared the same and can handle the hills at those speeds, but it is a fuel injected engine with long intakes and 4 valves. The Pinto has none of those helpers.

Bill
 

Bill Blue

Platinum Level Sponsor
Dragging this out for what I hope is the last time.

After driving the car a while after making changes I become sensitive to things I'd never noticed. This time it was a light surge in the dreaded light throttle-mid teens combo.

Checked the low speed idle jet, it was screwed out 2 5/8 turns, 1/8 turn past "spec". So I decided to have another go at the low speed jet. I drilled it out to 90, screwed the jet in 1/2 turn and took it for a spin. The change was good. Could detect no surge.

Two turns on the low speed jet proved to be rich. Ended up at about 1 3/4 turns. The idle speed adjustment screwed ended up unchanged. I now idle at the same speed, just more smoothly. No, I can't figure it out.

Staying true to my theory that you cannot change just one thing, I went through my secondary low speed jet selection procedure. My limited understanding of the Weber leads me to believe that when the engine is floored while in the mid teens, all the carburation is done by the low speed jets. The test I use is how it performs from about 1500 upwards on a hard pull. The road test is an uphill section in 4th gear. Removed the 60 secondary jet, replaced it with a 50. Did okay. No stumbles, actually gained 500 rpm on the pull. Tried a 55 jet. On initial acceleration, there was a stumble at 4,200 @ WOT. WTF was that? Turned around, attacked the hill, had a light stumble on the run, gained perhaps 400 rpm. Reinstalled the 50, the 4,200 rpm stumble left. Once again, have no idea how this could be.

Right now, it is running better than ever throughout the rpm range. It really jumps in the low rpm range. It may have been a little stronger from 3000 to 4000 with the turbo, maybe not.

Now I'm wondering how gas mileage is going to work out.

During all this time, I never noticed an off idle stumble that would make me think the low speed jet was too small. Even when running the 50. The problem has always been low speed, light throttle operation. I find it incredible the engine likes the 90 low speed jet. That is almost as large as some of the main jets I removed from junker carbs I've accumulated.

Maybe all this "screwing around" can help others in their attempt to tune the 32-36.
 

Bill Blue

Platinum Level Sponsor
My wife got off work early today. I could not wait to take her for a trial ride. She was impressed at how, for the first time, the engine is very flexible and smooth, even compared its performance through town to the ZX2.

One other thing I must comment on. For some reason, I had gotten the impression the low speed jet is important at only low and mid range. THAT IS NOT TRUE. The engine runs better now at 5,000 rpm with the 90 and 50 low speed jets than it did with the 80 and 60 combo. I say 5000 as that is where I let off on it. I imagine the improvement can be felt all the way to the top. It really came alive with the 90 primary low speed. The improvements going to larger jets were pretty minor until the move from 80 to 90. That improvement was almost big as the improvements from 50 to 80.

So I will say this: Get the low speed jets worked out before even thinking about the mains.

Bill
 
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