4160 carb install and tune (for Mike)

[ArdWrknTrk]

Good evening ArdWrkn Trk, I'm somewhat relieved that I only have to type out your name because I'm not quite sure how to pronounce it to address you in conversation. To answer your question, my mom calls me Michael, to everyone else I introduce myself as Mike. "The Cobra" is what I call my motorhome. It's a 1985 Cobra 26' class C motorhome. Powered by a Ford cutaway chasis E-350 Econoline with a 460ci engine. Hence my user 26ftcobraBBF (26 foot Cobra Big Block Ford).

The history of the Cobra Motorhome, in case you were wondering dated back to the early 1970s, Cobra produced a wide range of recreational vehicle. They produced Class A and Class C motorhomes through much of its three decades of existence, Cobra was also attached to the creation of fifth wheel trailers until 1980. Cobra’s extensive line of motorhomes have been powered by Chevrolet, Ford and Dodge powertrains. Cobra ceased production of motorhomes after the 1994 model year. Forest River Incorporated bought assets of the company soon after it shutdown. Some die hard Ford guys I've ran across in Facebook groups get really sensitive when I mention a 1985 Ford Cobra is why I like to give a little history behind the name.

I've had some time to think about the information I've been requesting, and while you guys did a stellar job fielding my questions I can see why there may have been some confusion (mainly mine), or you guys thinking"what the hell is this guy talking about". It wasn't until you brought to my attention about all the factory, vehicle specific, specs being ," out the window" because of the changes I've made to the motor. That is when I questioned my direction. I now realize I can't rely on factory specs trying to make this run as good as it did new. I didn't even think about that until you mentioned it, which makes perfect sense. Thank you for that. I'm now going to take on a more Ford performance mindset versus a return to OEM mindset. Looking forward to your conversation about Duraspark, and/ or distributor specific information.

Disclosure....:nabble_smiley_grin:I'm a carpenter by trade, not a mechanic. I've got a very mechanical mind that started as a kid with my dad, and through the years I've mostly always done all of my own mechanical work to mine, and friends and familys vehicles. So when I ask dumb questions thank you in advance for just answering and not busting my you know what's to bad.

Good morning Mike!

My name is Jim.... it's right there in my signature.

You have a Cobra and I have a Hard Working Truck.

Just turned 460,000 miles, full of northern rust and never without a half ton of carpentry tools in my two Knaack boxes.

Yep. I'm a carpenter by trade.

Started in high school going to apprentice classes at night, once I quit my night job.

Everyone has questions.

None of them are "dumb questions"

If it helps you, or someone else, understand how their truck works or how to fix it.

That's why we participate in this forum.

It's going to be OUR conversation about the DuraSpark II ignition system.

It's advantages and flaws.

What would you like to know about how it works?

[Gary Lewis]

Good morning Mike!

My name is Jim.... it's right there in my signature.

You have a Cobra and I have a Hard Working Truck.

Just turned 460,000 miles, full of northern rust and never without a half ton of carpentry tools in my two Knaack boxes.

Yep. I'm a carpenter by trade.

Started in high school going to apprentice classes at night, once I quit my night job.

Everyone has questions.

None of them are "dumb questions"

If it helps you, or someone else, understand how their truck works or how to fix it.

That's why we participate in this forum.

It's going to be OUR conversation about the DuraSpark II ignition system.

It's advantages and flaws.

What would you like to know about how it works?

I'm going to "read the mail" for the most part. But we have the section of the factory shop manual on ignition systems on the page at Documentation/Electrical/Ignition. And it has a decent overview of how the DS-II system works.

Mike - Jim pointed out that he has his name in his signature. Would you mind doing the same? That really helps me keep names straight. Thanks!

[Angelo Voltura]

Good evening ArdWrkn Trk, I'm somewhat relieved that I only have to type out your name because I'm not quite sure how to pronounce it to address you in conversation. To answer your question, my mom calls me Michael, to everyone else I introduce myself as Mike. "The Cobra" is what I call my motorhome. It's a 1985 Cobra 26' class C motorhome. Powered by a Ford cutaway chasis E-350 Econoline with a 460ci engine. Hence my user 26ftcobraBBF (26 foot Cobra Big Block Ford).

The history of the Cobra Motorhome, in case you were wondering dated back to the early 1970s, Cobra produced a wide range of recreational vehicle. They produced Class A and Class C motorhomes through much of its three decades of existence, Cobra was also attached to the creation of fifth wheel trailers until 1980. Cobra’s extensive line of motorhomes have been powered by Chevrolet, Ford and Dodge powertrains. Cobra ceased production of motorhomes after the 1994 model year. Forest River Incorporated bought assets of the company soon after it shutdown. Some die hard Ford guys I've ran across in Facebook groups get really sensitive when I mention a 1985 Ford Cobra is why I like to give a little history behind the name.

I've had some time to think about the information I've been requesting, and while you guys did a stellar job fielding my questions I can see why there may have been some confusion (mainly mine), or you guys thinking"what the hell is this guy talking about". It wasn't until you brought to my attention about all the factory, vehicle specific, specs being ," out the window" because of the changes I've made to the motor. That is when I questioned my direction. I now realize I can't rely on factory specs trying to make this run as good as it did new. I didn't even think about that until you mentioned it, which makes perfect sense. Thank you for that. I'm now going to take on a more Ford performance mindset versus a return to OEM mindset. Looking forward to your conversation about Duraspark, and/ or distributor specific information.

Disclosure....:nabble_smiley_grin:I'm a carpenter by trade, not a mechanic. I've got a very mechanical mind that started as a kid with my dad, and through the years I've mostly always done all of my own mechanical work to mine, and friends and familys vehicles. So when I ask dumb questions thank you in advance for just answering and not busting my you know what's to bad.

Did someone change the bowls on that thing? 4160s don't usually have a fuel feed like that.

[ArdWrknTrk]

Did someone change the bowls on that thing? 4160s don't usually have a fuel feed like that.

My 750 Angelo?

They don't usually have a quick change secondary or a Stub Stack either....

[ArdWrknTrk]

Did someone change the bowls on that thing? 4160s don't usually have a fuel feed like that.

How else would you set it up if you wanted adjustable center hung floats and jets plates instead of metering blocks?

I'm obviously not as into this as you.

So I'm sure you could help me understand

[LARIAT 85]

I have to get the engine to high idle while the choke is on and the fast idle cam in place.

When it starts I check the float levels are good and I try to set the throttle stop screw for about 1,600 rpm.

By setting it this way, I think you are going to find that the fast idle speed is going to be much too high when temperatures get warmer again. The fast idle adjustment works much better when it is set at full operating temperature. That is how Ford set them when they were new.

1600 RPM is when the choke should come OFF. You wouldn't want it that high on a stone cold engine that has just been started in the middle of December. That speed is a bit too high under those conditions, and it will climb even higher as the engine builds up heat. And then you have to blip the throttle much too soon to get the idle to come down. And that kind of defeats the purpose.

If you set the fast idle speed to 1600 RPM when the engine is fully warmed up, it will never need to be re-adjusted. When outside temperatures are coldest - like in December - the fast idle cam will initially hold the throttle at about 1200 RPM. (Just like on most modern fuel-injected vehicles.) If you sit there and let it idle, you will find that fast idle speed will start to increase as the engine begins to warm up. When the fast idle speed climbs to 1600 RPM, that tells you the choke is ready to come down to the next step on the fast idle cam - which is usually about 1200 RPM in cold conditions.

But, you do not have to sit there and let it "warm up." 1200 RPM is enough to keep the engine running smoothly and you can drive away on the choke, if you like. As the engine warms up from driving, the choke will automatically come off gradually. This practice is actually *better* for the engine. A cold engine will warm up faster in mile of [conservative] driving than it does sitting at idle for 10 minutes.

When the outside temperatures are warmer - like in July - the fast idle cam will initially hold the throttle a bit closer to 1600 RPM. That's because a warm engine needs very little choke and for a much shorter time period. Fast idle speed will rise to 1600 RPM much faster, and the fast idle cam will completely drop off when you blip the throttle.

I have found that chokes can work very well when they are set correctly. In the end, there should be very little difference between driving a cold carbureted vehicle compared to a cold fuel-injected vehicle.

 

[ArdWrknTrk]

I have to get the engine to high idle while the choke is on and the fast idle cam in place.

When it starts I check the float levels are good and I try to set the throttle stop screw for about 1,600 rpm.

By setting it this way, I think you are going to find that the fast idle speed is going to be much too high when temperatures get warmer again. The fast idle adjustment works much better when it is set at full operating temperature. That is how Ford set them when they were new.

1600 RPM is when the choke should come OFF. You wouldn't want it that high on a stone cold engine that has just been started in the middle of December. That speed is a bit too high under those conditions, and it will climb even higher as the engine builds up heat. And then you have to blip the throttle much too soon to get the idle to come down. And that kind of defeats the purpose.

If you set the fast idle speed to 1600 RPM when the engine is fully warmed up, it will never need to be re-adjusted. When outside temperatures are coldest - like in December - the fast idle cam will initially hold the throttle at about 1200 RPM. (Just like on most modern fuel-injected vehicles.) If you sit there and let it idle, you will find that fast idle speed will start to increase as the engine begins to warm up. When the fast idle speed climbs to 1600 RPM, that tells you the choke is ready to come down to the next step on the fast idle cam - which is usually about 1200 RPM in cold conditions.

But, you do not have to sit there and let it "warm up." 1200 RPM is enough to keep the engine running smoothly and you can drive away on the choke, if you like. As the engine warms up from driving, the choke will automatically come off gradually. This practice is actually *better* for the engine. A cold engine will warm up faster in mile of [conservative] driving than it does sitting at idle for 10 minutes.

When the outside temperatures are warmer - like in July - the fast idle cam will initially hold the throttle a bit closer to 1600 RPM. That's because a warm engine needs very little choke and for a much shorter time period. Fast idle speed will rise to 1600 RPM much faster, and the fast idle cam will completely drop off when you blip the throttle.

I have found that chokes can work very well when they are set correctly. In the end, there should be very little difference between driving a cold carbureted vehicle compared to a cold fuel-injected vehicle.

Good point Rick!

But if you see the photo, the choke is wide open.

Cam adjustment is by bending the tab on this carb. (there's no screw)

I successfully got my truck starting with one pump cold (not bitter cold) and it's driving well.

I think it needs a bit more pump shot, but I'm not going to do any more tuning until conditions improve.

[swampedout]

Good point Rick!

But if you see the photo, the choke is wide open.

Cam adjustment is by bending the tab on this carb. (there's no screw)

I successfully got my truck starting with one pump cold (not bitter cold) and it's driving well.

I think it needs a bit more pump shot, but I'm not going to do any more tuning until conditions improve.

You guys are way ahead of me, but Im following this conversation closely.

[ArdWrknTrk]

You guys are way ahead of me, but Im following this conversation closely.

What kind of carburetor do you have on your truck Sam?

Honestly, since this Holley 750 was working well for me a decade ago.

I thought I could drop it on.

Obviously my engine is getting tired, but it does show me that the Thunder 650 was restrictive on top.

I definitely need to do some fine tuning.

[26ftcobraBBF]

I have to get the engine to high idle while the choke is on and the fast idle cam in place.

When it starts I check the float levels are good and I try to set the throttle stop screw for about 1,600 rpm.

By setting it this way, I think you are going to find that the fast idle speed is going to be much too high when temperatures get warmer again. The fast idle adjustment works much better when it is set at full operating temperature. That is how Ford set them when they were new.

1600 RPM is when the choke should come OFF. You wouldn't want it that high on a stone cold engine that has just been started in the middle of December. That speed is a bit too high under those conditions, and it will climb even higher as the engine builds up heat. And then you have to blip the throttle much too soon to get the idle to come down. And that kind of defeats the purpose.

If you set the fast idle speed to 1600 RPM when the engine is fully warmed up, it will never need to be re-adjusted. When outside temperatures are coldest - like in December - the fast idle cam will initially hold the throttle at about 1200 RPM. (Just like on most modern fuel-injected vehicles.) If you sit there and let it idle, you will find that fast idle speed will start to increase as the engine begins to warm up. When the fast idle speed climbs to 1600 RPM, that tells you the choke is ready to come down to the next step on the fast idle cam - which is usually about 1200 RPM in cold conditions.

But, you do not have to sit there and let it "warm up." 1200 RPM is enough to keep the engine running smoothly and you can drive away on the choke, if you like. As the engine warms up from driving, the choke will automatically come off gradually. This practice is actually *better* for the engine. A cold engine will warm up faster in mile of [conservative] driving than it does sitting at idle for 10 minutes.

When the outside temperatures are warmer - like in July - the fast idle cam will initially hold the throttle a bit closer to 1600 RPM. That's because a warm engine needs very little choke and for a much shorter time period. Fast idle speed will rise to 1600 RPM much faster, and the fast idle cam will completely drop off when you blip the throttle.

I have found that chokes can work very well when they are set correctly. In the end, there should be very little difference between driving a cold carbureted vehicle compared to a cold fuel-injected vehicle.

Thank you Lariat85 for you input on the fast idle setting, I've currently have a fairly fast idle that just continues to climb, and find myself having to tap the throttle to calm the beast.

More over before I make that adjustment I need to figure out why she's got what seems to be either a miss, or really rough idle on a cold start up. I almost have to babysit her initially just before the fast idle kicks in and the rpms come up so it won't stall. After rpm's come up to and the fast idle speed she seems to runs smooth.