dialing in the stroker ?

[bartlett]

So I got my motor all broke in and it runs great ! I would like to dial it in a little better

idles perfect at about 900 out of gear warm 800/850 in gear. 

It wants to  be rich on idle, I have it at about 12.5 air fuel idle hot. Leaning it out brings cold blooded into play.

Cruise at 65 is 12.7-13.3 ish area  got 9.8 mpg highway .. Thinking of dropping a jet on the pri.

Seeing a lean spike right off throttle when hot, It does not do it for the first 1/2hr of driving. Its not a big spike but you can tell its there.

the carb is a new 750 holley single pumper . 

 whats the best way to get this single pumper to richen up right off idle. its running a 30cc pump and stock squirters.

thanks ....

[ScotiaFE]

The pump cam.
It's the plastic cam under the pump lever.
Here's enough info to get you started.

https://www.google.ca/search?q=holley+cam+chart&tbm=isch&tbo=u&source=univ&sa=X&ei=CyKqUeHIKYfgqAH5v4DIAw&ved=0CCoQsAQ&biw=1589&bih=774

[My427stang]

It could be a couple things and there are a couple of ways to fix it.

- If you stomp it and it goes lean, its generally accel pump. 
-- Make sure its adjusted properly
-- You could go larger squirter to come on quicker but have the same amount of fuel
-- You could go with a blue cam to add fuel and come on quicker (there are others, but the blue usually works pretty well)

- If its a lean spike during a more gentle acceleration it could be PV or transition circuit
-- Make sure you don't have too tight of a PV, a vac gauge will help.  If it opens at 6.5 and its stumbling as it passes 7.5, its too tight go up
-- Make sure your float level is high enough.  Its not a fixed setting, raising it starts all circuits more quickly, so raising a little can get main jet fuel moving a little quicker, as well as all the other circuits
-- Low speed air bleeds can be made a little smaller, this will get transition fuel moving a little quicker, make very slight changes.  .001 makes a difference in % of area
-- Primary throttle blade adjustment can be wrong too, if you are too deep in transition when you hit it, it wont enrich until the mains come in, also leaning things out.
-- You can even mask those issues with a good? pump choice, but that is sort of fixing a watch with a hatchet.  Accel pump fuel is very coarsely metered and if its a PV or transition circuit problem, bathing it in accel pump fuel isn't a great fix, even if it works sometimes

- As far as fuel consumption, I would look at a few things
-- Make sure you have some timing at cruise RPM.  Should be quite a bit, maybe up to 50, but low load, and lean, like at cruise, you need a lot for a good burn
-- If you reduce main jet size, realize that WOT may, not will, need more PVCR fuel, so if you jet down and your bog gets worse, odds are your PV is late or the PVCRs are already too small
-- Its perfectly fine to lower main jet if you offset with PVCR fuel, and often can help mileage quite a bit

Remember, WOT under power is easy, some combination of main jet and PVCR pretty much does what you need.  Its the part throttle tuning that changes the rest of the curve and ends up where you need it at WOT that takes all the finesse.

Do a change at a time, take notes, and you'll get it to do whatever you want it to do

[KMcCullah]

It sounds like you may need to go with the 50cc pump kit. I've had similar issues before.
I left my rich idle alone because I don't have a choke. Maybe your choke could use a little tweak?
Have you tried playing with the diaphragm spring on the secondary side? Your highway fuel mileage may improve with a slightly stiffer spring.

[bartlett]

I cruised it at 60 and pulled a plug.. at cruise I was just touching 13 air fuel.... The plug is showing good heat range, and rich on the ring.  Im going to drop the primary some and lean it out.  Im sure this is going to make the off throttle worse. Im going to try uping the squirter size when I can get over to the race shop and grab some.

[zukinut]

Ross,

How does float level affect how quickly mains come in. I could understand have more fuel to use before needle opened, but not sure how that woukd affect quickness.

Will

[My427stang]

The head pressure, or pressure at the booster, is slightly higher with a higher float level.  When the air starts flowing across the booster, it starts easier.  It's not dramatic, but it is another tuning tool

[bartlett]

my427

Thanks a ton for your help, You have been a big help the entire build.  I Did use your valve adjusting tech and it worked great! much better than my old school way .....

[bartlett]

How does the water flow in the FE ?  My stock radiator is not cutting it IMO . It runs 200 all the time and gets warmer when not driving. never pukes or bucks the starter ect ... Today from cold I fired it up and it builds psi in the hoses pretty quick and once it would sit and idle I rechecked the timing and felt the hose again,It was rock hard and was just as hot as the temp gauge at 160 ... My question is WHY? is the bypass off the water pump doing this ? is my thermostat not working correctly ? It's new with the motor and a 195.  or just normal ... My clutch fan is working correctly.

 I have a big new 4 core coming this week and I would like to be sure all my ducks are right and Im not missing a side problem.

 I got my timing at 16 and 36 total 

[jayb]

Water flows from the radiator to the lower radiator hose, into the pump, and then into the block.  From there some of the water goes into the heads at intermediate holes in the head gaskets, but some of the water goes all the way to the back, up through the back hole in the head gaskets and into the heads, forward to the front of the heads, into the intake manifold passage, and out past the thermostat into the upper radiator hose and back to the radiator.  The bypass hose between the intake and the radiator allows some water circulation in the engine when the thermostat is closed; water can come out of the intake, go back into the water pump, and start its circulation path through the block again. 

Pressure will build in the cooling system regardless of whether the thermostat is open; the thermostat is just a gate, and any pressure in the engine from the coolant heating up will show up on both sides of the thermostat.  However, the fact that your hoses are warm before the rated temperature of the thermostat makes me think that at this point the thermostat is open, otherwise hot water couldn't be in the upper radiator hose.  Or did you drill a bypass hole in the thermostat?

To really find out what's going on I would start the car from cold with the cap off, and watch the coolant flow in the radiator.  You will be able to see the coolant start flowing as soon as the thermostat opens.  Maybe your thermostat is just opening early.

In any case, if you are not holding temperature at or close to the thermostat's rated temperature, the radiator is a good investment.  I think I would pop in a new thermostat at the same time, just to be safe.  Or, take yours out and heat it up in a pot of water on the stove; then you can tell for sure when it starts to open.  My wife loves it when I do that...

[bartlett]

jay any type of thermostat you like and or a temp ?  Im thinking your right being my upper hose is getting hot as quick as the engine. It must be opening to soon or just hung open.  this might also be my temp creeping problem.    I think I will replace it with the radiator install ....

[jayb]

I like to use 160 degree thermostats.  A lot of people don't like going that low, and probably for good reason, but I've always had the best luck with a thermostat that opens quick.  With an FE in a tight engine compartment it's easy to overheat, and getting the coolant running through the engine quickly gives you a little more breathing room than a 180 or 195 thermostat.

[bartlett]

but what does it do once its up to temp ? just stay open ? I always thought you wanted it to cycle ? 

[jayb]

It does cycle if your radiator is up to snuff, and especially if you are driving down the highway.  My temps stay right about 160 in most cases.  When in traffic on a hot day, they will climb higher, but they start their climb from 160 rather than 195.  Gives you a little more cushion before you start having to worry about overheating.

[bartlett]

thanks jay, your a welth of info !

  Working on the car this am trying to dial it in (kinda picky) Im getting close now.  Im not sure what the cause of my just off idle 14/16 air fuel lean spot is from. It's a very quick spike. I can feel it and hear it and see it on the gauge. Im running a 80508s 750 vac sec carb That I have done some work to. It has a 50cc kit and the secondary has been switched to a jet kit.

 My gut say's I might be to far open on the primarys and need to open the secondarys to recover the transition holes. and or up the squirter size by three.

 My question is will enlarging the squirter size fix that instant off idle lean or just add more fuel to the rest of the stroke ?

My cam is a 294s so its pretty big and vac is on the low side.