Proper tuning sequence?

[26ftcobraBBF]

I know you all could help me out with this question..

I'm wanting to dial the Cobra in so I know it's running/ starting the best it possibly can. Please let me know what the proper sequence is for the tasks below.

Ignition timing, curb idle, fuel mixture, choke kick off, and accelerator pump,.....and how the heck do you find the sweet spot on the dash pot?

Let me know if I missed any crucial steps. Thank you

[ArdWrknTrk]

Ignition timing... like just static timing?

Or base timing, centrifugal-curve (slots, weights and springs) , vacuum curve and total ?

Fuel mixture... just idle, or power valve, boosters, secondary springs, secondary metering plate, main jets, etc..

A lot of tuning there is no a-b-c-d.

You make a mixture adjustment, you have to go back and reset the curb idle.

You change the advance springs and you have to either add fuel or back it out of the rattles.

Depending on weights and springs, the centrifugal is coming in not far above idle (not often in our trucks, and less likely in an RV)

Accelerator pump cams can be changed or a different hole can be used.

This is more of something to address if your rig bogs instead of pulling.

You KNOW it isn't going to peel out, tires smoking.

Not sure what you mean by choke kick off.

Lots of chokes have a vacuum pull off, which cracks the choke open more when the engine starts.

You also have a fast idle cam that can have multiple steps.

This will hold the throttle slightly open until the engine is warm enough to idle properly (not full operating temperature)

It takes experience to juggle these settings in order to optimize your tune.

No one can say X carburetor needs to be 1 5/8 turns open on the idle jets in any 460.

Engines wear. Some have a different cam. Winter vs Summer fuel. The phase of the moon, today.

Bill Vose can help walk you through it, but no one can tune your truck over the internet.

It's down to you to understand the subtle clues and accurately report subjective observations.

 

[26ftcobraBBF]

Ignition timing... like just static timing?Or base timing, centrifugal-curve (slots, weights and springs) , vacuum curve and total ?Fuel mixture... just idle, or power valve, boosters, secondary springs, secondary metering plate, main jets, etc..A lot of tuning there is no a-b-c-d.You make a mixture adjustment, you have to go back and reset the curb idle.You change the advance springs and you have to either add fuel or back it out of the rattles.Depending on weights and springs, the centrifugal is coming in not far above idle (not often in our trucks, and less likely in an RV)Accelerator pump cams can be changed or a different hole can be used.This is more of something to address if your rig bogs instead of pulling.You KNOW it isn't going to peel out, tires smoking.Not sure what you mean by choke kick off.Lots of chokes have a vacuum pull off, which cracks the choke open more when the engine starts.You also have a fast idle cam that can have multiple steps.This will hold the throttle slightly open until the engine is warm enough to idle properly (not full operating temperature)It takes experience to juggle these settings in order to optimize your tune.No one can say X carburetor needs to be 1 5/8 turns open on the idle jets in any 460.Engines wear. Some have a different cam. Winter vs Summer fuel. The phase of the moon, today.Bill Vose can help walk you through it, but no one can tune your truck over the internet.It's down to you to understand the subtle clues and accurately report subjective observations.

Awe man!!! (little kids voice) haha..

 

So in terms of basic, I have a new holley that the factory has set, and they say,         "it shouldn't" need any monkeying around with, so setting carb adjustments aside for now, and just talking timing is I have stock distributor from O'Riley's with a vacuum advance ( nothing fancy). This here is probably the dumbest question you've ever considered answering, but with the timing I know it says to unplug the vacuum advance and plug the hose, when doing that should the engine be warm (low RPM), or on start-up (with a higher idle)? I've already set timing 8° btdc as the under hood label suggest. The suggestion is based on all emissions equipment in place, should I set the timing differently than stated due to it not being an emissions ran system anymore? Ok and here's the dumb question since it's already set, if I put my timing light on it to verify where is now, would I need to remove and  plug the vacuum advance hose again to get the correct reading? Man I think I'm illuding common sense asking that, but I'm gonna let it fly..

To be honest I think it runs pretty good now, maybe im thinking that because it use to run really bad and that's all Ivev known from it. I'm thinking it may have a growing issue with the control module that I may just replace because there fairly cheap. It seems to run a little better before it warms up all the way, and also runs a little hot intermittently. I don't know though. That's why I mentioned it. The cooling system seems to be in decent shape with a new water pump, radiator cap, and a new thermostst. The radiator seemed ok.

 

On Sun, Dec 13, 2020, 11:49 PM ArdWrknTrk [via Bullnose Enthusiasts Forum] <redacted_email_address> wrote:

 

 

 

 

 

[ArdWrknTrk]

I see I'm not the only one working overnights!

If you've read the emissions sticker you know that all adjustments should be made at operating temperature.

i.e.fully warmed up on the gauge is reading... whatever is a normal reading.

Often I will take a small mosquito hemostat and just clamp the rubber line going to the distributor.

This saves messing around pulling the line off and finding a piece of masking tape to cap it so you don't have a vacuum leak.

Yes, any time you check the static timing the vacuum advance must be disabled.

You've got an 80457-S, correct?

That carb should be close.

If anything Holley sends them out safe (a little rich) IME.

When you say "runs hot intermittently" that would have nothing to do with the module.

But it is worth it to purchase a quality replacement.

Many of us know about modules with no cranking retard or no heatsink contact for the transistor.

On the distributor, is it something specific to an E-350 motor home?

Did they ask you for the calibration code before handing it to you?

Or is it a generic DSII distributor?

The slots, springs and vacuum pot could be for anything, if they didn't.

And a 3,500# Mustang is NOT a motorhome.

[ArdWrknTrk]

I see I'm not the only one working overnights!

If you've read the emissions sticker you know that all adjustments should be made at operating temperature.

i.e.fully warmed up on the gauge is reading... whatever is a normal reading.

Often I will take a small mosquito hemostat and just clamp the rubber line going to the distributor.

This saves messing around pulling the line off and finding a piece of masking tape to cap it so you don't have a vacuum leak.

Yes, any time you check the static timing the vacuum advance must be disabled.

You've got an 80457-S, correct?

That carb should be close.

If anything Holley sends them out safe (a little rich) IME.

When you say "runs hot intermittently" that would have nothing to do with the module.

But it is worth it to purchase a quality replacement.

Many of us know about modules with no cranking retard or no heatsink contact for the transistor.

On the distributor, is it something specific to an E-350 motor home?

Did they ask you for the calibration code before handing it to you?

Or is it a generic DSII distributor?

The slots, springs and vacuum pot could be for anything, if they didn't.

And a 3,500# Mustang is NOT a motorhome.

If you are just making basic settings and not taking a dive into recalibrating everything, probably the best thing you could do for power is to install a 'straight up' timing set and bring the base ignition timing to 10 or 12°.

You say the water pump was just replaced....

Too bad, because you were 90% of the way to the best $50 upgrade you can ever do to a 460.

https://www.amazon.com/dp/B001EHBYVC/ref=cm_sw_r_cp_awdb_imm_t1_JO01Fb7M9T2MY

[Rembrant]

I don't know how well this correlates to an '85 carbed 460, but I talked to Scott at Parkland Performance about mine (460 EFI) and the two things he suggested were to set the base timing to 13* btdc, and install a 180F high flow thermostat. Not sure what the timing advance is the EFI trucks...but Scott would have a good recommendation for what it should be.

Edit: Below I'm referring to my carbed 302. Above I was referring to the 460 EFI in my RV (now sold).

I'm no expert, but with a warm engine I set my timing and then played around with my idle mixture screws and idle adjustment, and a couple times had to go back and adjust the timing again. I was using a vacuum gauge, and I also had the benefit of having an AFR gauge installed.

This was also with a new Holley 4160, which had previously been re-jetted from the stock #66 jets to #68. I could probably swap a set of #66 jets back in there now but it's running so well I don't want to screw with it.

[ArdWrknTrk]

I don't know how well this correlates to an '85 carbed 460, but I talked to Scott at Parkland Performance about mine (460 EFI) and the two things he suggested were to set the base timing to 13* btdc, and install a 180F high flow thermostat. Not sure what the timing advance is the EFI trucks...but Scott would have a good recommendation for what it should be.

Edit: Below I'm referring to my carbed 302. Above I was referring to the 460 EFI in my RV (now sold).

I'm no expert, but with a warm engine I set my timing and then played around with my idle mixture screws and idle adjustment, and a couple times had to go back and adjust the timing again. I was using a vacuum gauge, and I also had the benefit of having an AFR gauge installed.

This was also with a new Holley 4160, which had previously been re-jetted from the stock #66 jets to #68. I could probably swap a set of #66 jets back in there now but it's running so well I don't want to screw with it.

Scott always offers good advice.

12... 13* whatever it will take with no hint of detonation and no laboured cranking when hot.

Right, back and forth, back and forth.

Having a wideband AFR is a huge help.

EFI engines came with a straight up double roller timing set and (IMHO) that is the one best trick for an otherwise stock carbed engine.

Not to mention you get rid of the plastic gear that always clogs up the oil screen.

[Rembrant]

For what it's worth, I've purchased three different Holley carb books. One of them was a decades old reprint, and the other two were much more recent. This one below I found fairly helpful.

https://www.summitracing.com/parts/sad-sa216?seid=srese1&gclid=CjwKCAiAt9z-BRBCEiwA_bWv-HUzlGrXrbaOpl3D-bXVxhe3oPoJp3Pl-nmXr1Z_VcDFJ76akENWQxoCRNEQAvD_BwE

They're not detailed textbooks or anything...they're almost more of a coffee table book if that makes any sense, but they're handy for a quick reference of basic how-to's and techniques. If you enjoy reading up on this stuff, it's worth the 15-20 bucks to have it.

I now have a nice little collection of SBF and Holley books. Now that everything is running nicely of course I don't use them, but they're nice to have if I do need them.

[Gary Lewis]

I agree with Jim. But you may be planning just basic things. So let me suggest a process.

I'd play with ignition timing first, and by that I mean base timing or what Jim called "static" timing. It can really change other things, so if the engine is running fairly well play with it first. Disconnect the vacuum advance and set the timing to what the sticker calls for plus two degrees. Reconnect the vacuum advance and drive it and see how it responds. Especially listen for detonation or pinging. And see how it starts - does it kick back or start normally.

If it liked +2 degrees give it +4. And maybe +6, but depending on what the recommended timing is I don't think I'd go over 14 degrees BTDC or you may have pinging or detonation next summer.

With that done you may have to adjust your idle speed if your vacuum advance is on at idle. And then I'd adjust the idle air/fuel mix. After that the choke since the idle mix does effect the choke.

As for the dash pot, is it the one that slows the closing of the throttle?

[26ftcobraBBF]

I see I'm not the only one working overnights! :nabble_smiley_whistling:If you've read the emissions sticker you know that all adjustments should be made at operating temperature.i.e.fully warmed up on the gauge is reading... whatever is a normal reading.Often I will take a small mosquito hemostat and just clamp the rubber line going to the distributor.This saves messing around pulling the line off and finding a piece of masking tape to cap it so you don't have a vacuum leak.Yes, any time you check the static timing the vacuum advance must be disabled.You've got an 80457-S, correct?That carb should be close.If anything Holley sends them out safe (a little rich) IME.When you say "runs hot intermittently" that would have nothing to do with the module.But it is worth it to purchase a quality replacement.Many of us know about modules with no cranking retard or no heatsink contact for the transistor.On the distributor, is it something specific to an E-350 motor home?Did they ask you for the calibration code before handing it to you?Or is it a generic DSII distributor?The slots, springs and vacuum pot could be for anything, if they didn't.And a 3,500# Mustang is NOT a motorhome.

I try not to work to many nights but my schedule is dictated by my autistic 4 year old, and he's burning the midnight oil these days..ugh...

 

Yes on the Holley carb, that's the one

 

 

Makes sense on the hemostat, here on the west coast I think there called a roach clip for some reason. 

 

 

Module wise that was something I read on the internet about sluggish performance, and running hot( too lean) but maybe they don't pertain to a carb engine. When you say quality replacement are you referring to just motorcraft,bit is there s cheaper aftermarket brand you trust?

 

 

I have no idea about calibration code, and I'm willing to bet the highschool kid who sold it to me didn't know either, but you've got my attention with that where do I find my calibration code, or what it's supposed to be?  Would there be a calibration code stamped on the new one for me to compare to?

 

 

On Mon, Dec 14, 2020, 3:00 AM ArdWrknTrk [via Bullnose Enthusiasts Forum] <redacted_email_address> wrote: