FE Power Forums
FE Power Forums => FE Technical Forum => Topic started by: bartlett on June 01, 2013, 05:57:51 AM
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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 ....
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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
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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
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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.
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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.
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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
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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
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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 .....
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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
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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... ;D
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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 ....
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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.
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but what does it do once its up to temp ? just stay open ? I always thought you wanted it to cycle ? ???
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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.
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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.
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I think I would try to bigger squirter; you need more fuel and enlarging the squirter size will give it to you. Have you played with pump cam positions? I assume you got a new pump cam with the 50cc pump?
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well I think Im on the right path ! lol ... I took the carb off and opened up the plates 1 1/2 turns and the carb reacted good ! The idle went upto 2,250 or so and once I turned it back to 900 it idled good and the fast idle cam seems to work correctly again. I hooked up the vacuum gauge, and that moment happend when I said to myself Your DUMB ! My gauge read 6" of vacuum !!! No wonder this this has been a pain to adjust ! This carb has the stock power valve in it(6.5) ! I need like a 2.5 or a 3 !!!! Im betting the power valve is trying to open at idle !
So of course I dont have one here and I wanted to see if the hesitation is gone,So I went for a cruise to fleet farm. Car ran real good ! no flat spot but slightly rich in the transition. ( I can tune that with a pump cam swap) Im happy ... So fleet farm has 91 non oxy fuel ! great ! Im empty and fill it up, On the drive home all my tuning goes out the window ! every thing went from high 12's to high 10's ! lmaoooo can't win ....
:)
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well I think Im on the right path ! lol ... I took the carb off and opened up the plates 1 1/2 turns and the carb reacted good ! The idle went upto 2,250 or so and once I turned it back to 900 it idled good and the fast idle cam seems to work correctly again. I hooked up the vacuum gauge, and that moment happend when I said to myself Your DUMB ! My gauge read 6" of vacuum !!! No wonder this this has been a pain to adjust ! This carb has the stock power valve in it(6.5) ! I need like a 2.5 or a 3 !!!! Im betting the power valve is trying to open at idle !
So of course I dont have one here and I wanted to see if the hesitation is gone,So I went for a cruise to fleet farm. Car ran real good ! no flat spot but slightly rich in the transition. ( I can tune that with a pump cam swap) Im happy ... So fleet farm has 91 non oxy fuel ! great ! Im empty and fill it up, On the drive home all my tuning goes out the window ! every thing went from high 12's to high 10's ! lmaoooo can't win ....
:)
Power valves have nothing to do with idle if the carb is built right and running right. P/Vs are a part of the main circuit and should only discharge fuel while the main cir. is in operation. If there is no fuel flowing out of the booster venturis [main circuit] it is not active. A leaking/defective p/v will dump fuel into the intake manifold via it's vacume port, not the main cir.
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My raid should be here tue/wed.... I got busy tearing it apart tonight and I inspected the old/stock/recored in the 90's radiator. I tore it apart and I'm 90% sure this was my cooling problem. from the very top it looked ok but 80% of the cores were plugged up with corrosion ect. I wonder how it flowed/cooled at all. amazing how well it looked to flow from the top with the cap off. I then took the thermostat in the house and cooked her ! lol ... what I thought I had in there was not the case. I thought I installed a 190 .. Its a 180 ... The old cookie temp gauge said it opened all the way around 200 ! and this was heating fairly slow. So yea it works but not perfect.
Now the waiting game ,install the new raid .... figure out fan clearances and get a new fan .......
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gettiNG FLUSTERED.. ! Brand new 4 core, dual 1,400cmf fans/and shroud. Brand new thremostat,all new hose's, High volume water pump. start motor from room temp and within 5min its got the thermostat open and every thing flowing good. 10min of running and its hovering over 200-215 ! this is in the garage and hood open on high idle ....... the motor seems to build temp real fast, I looked at the head gaskets and I can see the gasket all the way to the end. Is this thing just not broke in yet and runs a little hot ? I got good air fuel and plenty of timing in it ..... I dont get it !
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Often with the hood open the air dont pass trough
the radiator so the car overheat. Try with the hood
closed
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Have you run it going down the road? If it cools OK at 50-60 MPH and then heats up when you slow down, your fans are not cutting it. I learned the hard way that there is a big difference between the various electric fans, and that the ratings sometimes don't mean much...
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thanks... Well Im going to take it out today and see what it does.. :'(
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If it's good going down the road and heats up when idling. Blame the fans.
2800 cfm is about 2/3 of what I like to see on electric fan used as the primary cooling fan, depending on which brand/model/mounting etc, you could even be at 50% of the value you think you are too.
For a street strip car, I much prefer keeping things at thermostat temp, and if it takes an engine driven fan, so be it. I would have to assume as you get up to speed, the amount of drag gets less and less due to vehicle speed, so I doubt the HP gain would be functionally significant to boot.
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Your carburetor experience is a real good example of why I have gone 100% to EFI. I have several boxes of Holley stuff in the back of my storage from over the years, and a few pieces of Weber stuff as well. But nothing works so nicely as just pushing a few keys on the laptop to make improvements!
KS
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Your carburetor experience is a real good example of why I have gone 100% to EFI. I have several boxes of Holley stuff in the back of my storage from over the years, and a few pieces of Weber stuff as well. But nothing works so nicely as just pushing a few keys on the laptop to make improvements!
KS
You can say that again! Matter of fact my current program will log, then offer me its recommended improvements. If I load them and don't like them, I hit undo, and try something different!
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thanks... Well Im going to take it out today and see what it does.. :'(
If it works going down the road and you want to keep the electric fans, get some Spal fans. They are the only way to go, IMO...
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went to car craft and it got hot 250 hot ! .... We let it cool and headed home, pulled the fans and shroud off and installed the clutch fan. Now it runs 200 down the road and 220 idling around the fair grounds. Never got hotter than that but still on the hot side. Im not worried about 200/220 ..
Going back to car craft in the am .. I need to get some miles on this thing so she loosens up some ... lol....
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220 isn't too hot, but keep in your hip pocket that no clutch fan runs at pulley speed (other than modern vehicles with locking electric clutches)
So if you decide you want even more wiggle room, a stock sized Flexalite with a standard spacer works really well.
I only HAD to use them when I lived in the desert, where they were amazingly efficient, but you can use them anywhere you need some good idle airflow
Here is the style I grew to love in Las Vegas, they move a TON of air, but aren't noisy like the big flex fans
http://www.summitracing.com/search/part-type/fans-mechanical/rotation/clockwise/blade-type/standard/universal/yes/hub-color/black/clutch-required/no/blade-material/steel?keyword=flexalite
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Worked on it this morning and I think I got it working good now. I had to modify my stock shroud just a little bit to make it work on my aftermarket radiator. Now in the shop it heats upto 180 and just sits there. (thats the thermostat temp) before it would goto 200 and creep up slowly.
final setup is
5 blade stock style fan clutch
Stock fan shroud relocated mounting holes
4 core radiator
if the weather calms down I will be testing today .....
thanks for all the added info .... ;D
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shes running pretty cool now ! ( happy)
I switched to a 50cc pump and my hesitation is still there right off idle and now it's rich lazy through the squirt length. It still spikes lean right off idle and if I just goose it from a cruise speed. It does not cough or stall out ect just lean spikes and catches and goes .. I have opened the secondaries some to keep my idle up and primary plates proper. Do I need to up the squirter size and drop the pump cam back down to a 30cc cam? The air fuel was perfect before with the stock pump cam butt I had the hesitation. This motor has been tricky to dial in .... Help !
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I'd try a .031 squirter and a blue pump cam with the 30cc pump. I can't imagine that you need all that pump volume
If you look below, you will see the blue cam in #1 is pretty aggressive, it tends to work well without flooding. The solid blue line comes in quicker and with a little more
(http://theamcforum.com/forum/uploads/119/HOLLEY-PUMP-CAMS-POST3.jpg)
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ok Ill give it a try .... From what I'm told the 50cc kit will act like a 30cc kit with a 30cc cam installed ... Im going to order a few squirters today...
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I am not sure what that means, 30 cc cam...
Every one of those curves in my last post are cams for a 30 cc pump and you can see they are all different
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they make some cams for the 50cc pump and a bunch for the 30cc pump if you put a blue/30cc cam it should pump the same shot no matter what cc size is.
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I don't know that's true, although I don't know it's false either. I have seen on the net that guys sometimes use a 50cc pump with the small cam, but I am not sure it is the same output as a 30cc pump. Although the sweep and rise would be determined by the cam, seems to me the dimensions of the 50cc pump might do something different.
Regardless, I have done a ton of Holley work, and I don't use those 50cc pumps. I honestly have never found a need for one. The only time I can imagine that I wouldn't be able to tune it with cam and squirter would be for an alky carb when it needed much more volume or if there is a significant issue in the transition and main circuits.
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2X on never having to use a 50cc pump on a streeter or say an under 500hp engine. Usually fellows who would bring me their cars after adding a 50cc pump realized that something else in the carb was off and the new pump merely masked the real problem.
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switched just the squirter to a 31 and the car runs real good just a tad lazy/rich during the pump. ran the car a good 30 miles last night and it just ran good. This morning I switched back to the 30cc pump and installed a blue cam in the #1 slot. and readjusted the pump arm. I'm doing a 2hr drive to sleepy eye for a family gathering and will see how she runs.. just free reving it,it seems to be leaner and crisper so far ... Im happy that Im getting close on the setup. It's fun when they run good.
p.s. ... she runs 190 90% of the time now ! motors happy Im happy.. ;D
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drove 140 miles to sleepy eye and it ran GREAT ! 12mpg 3,000rpm 60mph 70oil psi Its perfect now and time to enjoy it !
thanks everyone for all the help ! ;D
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Glad to hear it worked out!
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drove 140 miles to sleepy eye and it ran GREAT ! 12mpg 3,000rpm 60mph 70oil psi Its perfect now and time to enjoy it !
thanks everyone for all the help ! ;D
Attaboy! How's your water temp on the freeway?
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280 MILES ! FANTASTIC ! Ran perfect !
Jay the temp just hovered around the 190 mark all day ... most it saw sitting was 200...
Here she is in sleepy eye mn at the farm ....
(http://i178.photobucket.com/albums/w279/bartlettracing/DSC01264_zpsd0995e91.jpg) (http://s178.photobucket.com/user/bartlettracing/media/DSC01264_zpsd0995e91.jpg.html)
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So got alittle crazy last night and she runs pretty good ! 1,2,3 across the light lol ....
http://www.youtube.com/watch?v=Vw6HH37vtsU
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I got a friend that built a Boss 302 clone with a NASCAR real deal Yates headed/Ford racing block and for good measure stroked and roller cam'd it. Started out with a Griffin radiater, dual killer Spal elec fans/shrouds etc. it would over heat. Upgraded to the largest Griffin he could have made. went with flex fan and eventually went to a FoMoCo Boss 302 fan and after talking to Griffin about it still over heating he finally swapped out the low temp thermo and went with a hot thermostat and THAT finally cured his over heating. Supposedly the low temp thermo defies logic and lets flow pass to fast or something. I know it's Voodoo/defies logic but it worked