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Offline kerryann

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Flat spot with Holley 350 carb
« on: April 17, 2014, 07:31:40 PM »
hi, we have a 1980 pinto, 2.3, automatic.  42k original miles.  i did the holley 350 swap and also the ranger header.  we have the aluminum ford carb spacer under the carb and we also used the racer walsh power valve restrictors.  i read that good baseline jetting is 56-58, we went with 57 since i didnt have any 56s.  started with a 5.5 power valve as that was what i read to have the most success with this combo.  we have a flat spot off of idle through the mid range.  most noticeable when you ease into the throttle vs flat footing it from a stop,  once its on the main circuit it recovers and runs smooth.  the plugs are clean with slight white residue indicating we are pretty lean.  i tried many different pump cams and now have the orange in position 2 which gives quite a bit of pump shot and long duration.  went with a 25 squirter with the extensions to try and lengthen pump shot as well.  have idle mix screws set to 1 1/4 turn out.  i played with the accelerator pump timing and air gap on the lever, it helped initially but cant cure it.  we went to a 6.5 power valve to no avail and now today went to a 7.5.  no change.  ive attached a vacuum gauge, we have 15" in drive with brake on with motor hot.  this would indicate the 7.5 is right on the money.  driving around with the gauge i notice the flat spot occurs at part throttle once vacuum drops just about to zero, the car seems to flatten out and then recover. it is driveable but it bothers me that its not right.  im worried that the racer walsh restrictors are cutting the mid range fuel flow too much, i dont want to drill them and be stuck if it wasnt the right thing to do.  they will be fairly difficult to get back out as well. when installing i drilled the metering block, cleaned out burrs, and blew out chips with air.  we then pressed the inserts all the way in until they stopped.  hoping that was the right thing to do.  if anyone can help please let me know.

also vacuum advance is on full manifold vacuum, both catalytic converters are removed, smog pump is removed, pcv is hooked to port on the spacer.  valve cover has only a breather.  the kick down works as i should as well.  the only thing i have not done is put a timing light on it.  i have no reason to believe the timing is off as the car ran fine in stock configuration with the weber but it is worth checking.  ive attached some pictures of one of the plugs for reference.

Offline kerryann

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Re: Flat spot with Holley 350 carb
« Reply #1 on: April 17, 2014, 07:33:59 PM »
another picture

Offline jeremysdad

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Re: Flat spot with Holley 350 carb
« Reply #2 on: April 17, 2014, 07:58:08 PM »
That insulator looks cracked...have you tried a heat range colder?

Thanks for all the good info! Someone better versed in the 2.3 will be along shortly.

Welcome aboard! :)

Offline amc49

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Re: Flat spot with Holley 350 carb
« Reply #3 on: April 17, 2014, 08:16:29 PM »
What intake used there?

Don't mess with the restrictors, if it occurs at low amounts of throttle then you are nowhere near the power valve open. If you can get it to hiccup while sitting in drive then have someone do it while watching the exhaust pipe for any possible puff of black smoke. If concerned about PV opening then plug the hole with commonly available plug and then test for the flaw again, but DON"T PUSH THE ENGINE HARD, you can damage it. It will drive at light load and low throttle though so you can test more. If plugged at least you know it's not PV. You can disable the accel pump as well and SLOWLY ramp rpm up to see if it does it. Which accel pump check valve in the fuel bowl under pump cover, the ball check or a silicone disk type? Has to do with how fast the accel pump activates.

You need to verify the timing, timing slow will make it flat spot. The plugs often cannot be read for a while until they color up, it doesn't happen instantly. Look up very high inside, they begin to color up high where the porcelain meets the steel first. You really need to know idle timing and total full all-out as well. The vacuum advance is closely hooked to that depending on which unit you have, it may or may not need to be manifold vacuum. If less vac adv, you use more initial timing lead if more vac adv you need less lead, the two are hooked together and have to add up to make sense on the total, why you need numbers of all of it. If you don't have enough timing you could easily be working on a carb with nothing wrong with it. 

Leaving carb where it is idle setscrew wise, pull the carb and look underneath to see how far up on the slots the throttle plates are, you are only supposed to be either just barely exposing the bottom of the slot or maybe .020" or so, if higher you are too rich then it goes super lean when you run out of transfer slot, think of it as mini-accelerator pump until both the shooter gets working. You don't have the mixture screws very far open which leads to believing  possibly too far up in the slot, a common mistake. The mixture screws are not set by turn amount, rather by vacuum, one may end up different from the other but if too far one circuit is clogged.

If truly right off idle most likely the transfer slots are too exposed. Drop the idle speed back down too low to get the slots right (while carb is off) and just test to see if the flat disappears, you can bring up idle speed in other ways later.

You can adjust pump cam to have a big space and then none at all and take careful note of what changes. Or bigger shooter vs. smaller and the same. The vacuum gauge WILL drop when the motor dies, normal, an effect not the cause.

If the exhaust manifold has an O2 port you can put an O2 in there to tell if rich/lean by using an A/F ratio gauge.

Offline kerryann

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Re: Flat spot with Holley 350 carb
« Reply #4 on: April 17, 2014, 09:04:44 PM »
it is the stock 1980 intake, not sure exactly which one it is.

i havent tried any different plugs yet.  it could probably stand a heat range colder

i welded up the factory ports on the header so cant do air/fuel unless i added a bung, didnt think id have to be that precise going by rough suggested guidelines for this swap that i read on this forum.

ive never had any luck with the power valve blocker on street cars, only on circle track stuff,  i see what youre saying though.  i will try setting idle screws with the vacuum gauge.  i did it starting at 1 1/2 (factory recomendation) and listened for increase in rpm,  seemed to like around 1 1/4,  i'll verify with the gauge this time.  would you ever this small of an engine like more than the 1 1/2 turns out?

i always tend to set idle speed lower than you probably  should, like the lope sound on a v8, im new to the 4 cyl world but always thought they liked a little more idle speed to stop the shake and vibration and make it a little easier on them off idle getting going. this assumption could be wrong.  we have no tach in the car but i could probably borrow a tach dwell.

accelerator pump shot timing has had an effect on the issue,  i suppose i should focus there, havent tried any bigger squirters yet.  tried a bunch of cams in both positions.  a friend thought maybe going to a 50cc pump might help.  ive tried the holley suggested .015" gap, no gap, 1/16" gap, has been best with slight gap right around the suggested .015"

the plugs were in the car when we bought it.  i was planning on replacing them once i got the carb right but i suppose i may need to get a set now to get an accurate reading.  i will check timing as well.  not sure what to set these motors to.  im used to setting total ith the chevy small blocks at 34-36.  i tried ported vacuum as well as manifold vacuum.  seemed better at manifold.  ive had it explained to me before that manifold vacuum is most beneficial to a street driven motor to have the advance at idle to keep temps down, while ported vacuum was an early emissions strategy to keep exhaust temps upand nothing more than that.  with that being said, what is acceptable initial timing if i run manifold vacuum and what is the number im shooting for total?

Offline kerryann

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Re: Flat spot with Holley 350 carb
« Reply #5 on: April 17, 2014, 09:48:29 PM »
thinking about it further i think the the transfer slots being open too much may be an issue here.  im going to check that first.

Offline amc49

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Re: Flat spot with Holley 350 carb
« Reply #6 on: April 19, 2014, 12:57:39 AM »
Good deal.

The power valve plug is ONLY FOR TESTING, I NEVER advocate leaving them out FYI. A major mistake, leaving it out severely curtails your tuning options and always compromises the carb setup. You plug only to do low speed easy driving to determine your idle, off-idle and cruise setups.

I personally never use any gap in pump cam, I want it on as instantly as I can get it, regardless of what the carb or the car. You will always have a spot in there where suddenly opening the throttle will drop vacuum unless very slowly doing it, the lag in pump shot just adds to any potential flat spot. Most of my experience though was with ball check valve in pump and not much with the silicone valve, the slight gap may be necessary to stop silicone valve from feeding as fuel bowl warms to hot. In my view the ball check taking a millisecond to seal made up for the gap so I didn't set with a gap. Any weight under shooter means less or no gap either. Again, takes time to override the weight.

You may be right with manifold vacuum, I've run into that as well vs. ported. Go by the engine and screw all the theory. Believe what your eyes and ears show you. Ported vacuum was developed simply to kill vacuum at idle to kill NOx emission, NOx raises greatly at any timing before TDC. Old emissions passing trick if failing NOx, you back timing down, car runs like crap of course, pass test and bring it back up again. Backing it down makes HC go up (when tuning the two always go opposite each other) but it can be brought down other ways. Try like 10 and 34-36, higher at idle helps any flat spots provided it doesn't ping. Your vac advance unit may determine your range. Since you're after curing a flat spot then set at idle and let top end power suffer if needed till you sort the flat spot out.


Offline amc49

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Re: Flat spot with Holley 350 carb
« Reply #7 on: April 19, 2014, 01:02:35 AM »
Since just basically a stock motor there I'd use stock heat range or possibly one stage colder. The stock should work though. I use the brand of plug the car comes with, Autolite or Motorcraft for Ford, AC for GM, Champion for Mopar, etc. I see no difference in any plug on the planet except that the OEM will match the heat range requirement better than someone elses', they commonly split heat ranges to fit their product in other cars.

The plugs I loathe are like Splitfire or E-3, use them and you got took brother, no other way to put it. Gimmick plugs are garbage.

Offline kerryann

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Re: Flat spot with Holley 350 carb
« Reply #8 on: April 19, 2014, 08:34:20 AM »
there is a stock motorcraft plug in the car.  i'll get the number.  had the gimmick plugs in a chevy we bought and they fouled up fairly quick.  threw in a used set of autolites and havent had an issue since.

sticker calls for 6 degrees initial but this was a heavy emissions controlled car from the factory.  all that stuff is gone so im going to check and bump it ahead if its that low.  i'll shoot for 10 to start and see what we get.

ive had the carb apart a few times but cant remember if this one is the ball or the rubber check valve.  didnt look to see if the needle/weight under the squirter was there either.  ive had issues with them gumming up before.  can you run without it?

im going to check timing and go after tuning the accelerator pump circuit as well.  going to put a whole new pump diaphragm in and check to make sure everything is working correctly.  i may go to a 58 jet as well and see if the plugs start to color a little more brown.  theres no signs of richness at all so one size i dont think will hurt to try.

don't think we'll need the power valve blocker.  the flat spot is at an odd time. sometime it isnt right off idle and more from a slow cruise to 3/4-wide open throttle transition.  it just struggles for a second when vacuum drops right out to get on the main circuit.  we get no lean backfire through the carb but it certainly seems like its getting the air but just not the fuel.  i'll report back after more testing.

Offline kerryann

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Re: Flat spot with Holley 350 carb
« Reply #9 on: April 19, 2014, 02:21:59 PM »
bumped initial timing up to about 11 degrees.  total tops out at 32.  with vacuum hooked up i see extremely high numbers idleing in park.  with manifold i'll see about 40 initial and 50-51 total.  with ported ill see my 11 initial and still will get 50-51 total.  i know the vacuum drops out under load so is this something i should be concerned with or is the vacuum doing its job?  never seen my v8s show numbers that high even with vacuum hooked up.  the straight mechanical numbers (11 32) seem ok.

also im assuming the T|C mark is 0.  i have the crafstman gun with the advance dial so i highlighted the T|C as zero and turn my dial up to 11 and line the T|C up with the pointer.  and again turn my dial to 32 to get total.  does this sound right?  driving around i dont hear any pinging.  car starts fine.  my flat spot is almost gone.  think it only needs further accelerator pump adjustment.  closing the gap up helped this morning.

Offline dick1172762

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Re: Flat spot with Holley 350 carb
« Reply #10 on: April 19, 2014, 07:53:44 PM »
Pintos need 34 to 36 total timing to run right, set without vacuum.
Its better to be a has-been, than a never was.

Offline amc49

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Re: Flat spot with Holley 350 carb
« Reply #11 on: April 20, 2014, 06:07:34 AM »
I'll second that, 32 total is too low. No way does idle need 40 degrees, use ported but bump initial up higher to get higher total. That figured and set with no vacuum. You can probably limit the vacuum slot......or even adjust the diaphragm. Used to be a set screw inside the nozzle. May be loctited in place though.

Yes, timing read right. If closing pump cam gap helps then look at shooter size, may need slightly bigger. Using 30 cc. pump I'm assuming, 50 cc. is too much. Need weight (at least one ball) under shooter, the vacuum induced at higher carb flow will evacuate your pump shooter passage if no weight there. Leading to another flat spot if pump not pumped up to refill.

I used to play with cams but after a lot of doing so came to conclusion they all pretty much work the same, and use what comes on the carb, rather use hole size to tune with. Once you stomp it hard enough the 'trying to compress a solid' kicks in and hole the only determinant there anyway. Cam profile means nada.

The way transfer slots work, they are needed to feed fuel like accelerator pump, if too high in the slot idle will be too rich, you then artificially lower mixture with the screws to what is actually too lean at curb idle port (the lower hole that feeds idle mixture in). It still seems right since you are adding both curb idle amount plus some of the transfer depending on how deep into it, but problems then as you go for more throttle, you get a lean spot because the transfer enrichening is already gone. So, often you are too rich followed instantly by too lean, the motor just spits its' guts out. Add pump shot being off and even worse.

At slow cruise to 3/4 throttle you should have a PV opening with that, check vacuum gauge reading against your PV rating. I've always wanted light throttle with no PV but anything over half throttle should have it coming open.

Offline slowride

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Re: Flat spot with Holley 350 carb
« Reply #12 on: April 20, 2014, 02:14:56 PM »
I've gone the opposite direction to get away from the "emission" mindset. I swapped to manifold vacuum for a couple simple reasons. More advance at idle brings up the vacuum which improves the idle (and off idle) vacuum signal which should be ESPECIALLY important to you with the Holley. With a fatter A/F ratio at idle it helps cool the engine (as opposed to trying to lean it out) as well as use the considerably greater advance. Off idle response is better, gas mileage has increased considerably, and timing is easier since you aren't trying to set an arbitrary initial advance and hope you total is right.
I have a spare distributor that is being re-curved to get more out of it since the existing curve was designed to work with ported vacuum and emission controls.... this is NOT how an engine is most efficient power-wise. Decide what you are trying to accomplish and commit to it rather than try to limp more power out of mixed technologies.

Offline 74 PintoWagon

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Re: Flat spot with Holley 350 carb
« Reply #13 on: April 20, 2014, 06:52:34 PM »
Did the same with mine, got rid of the shake at idle, better all around performance and better mileage and I'm not done yet..
Art
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Offline amc49

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Re: Flat spot with Holley 350 carb
« Reply #14 on: April 20, 2014, 08:57:54 PM »
Yours and do as you will, I'm just saying the engine does not need 40 degrees at idle.......... ....  You can make carb pull off idle fine easily on race engines with no vacuum at all. In short a patch for other issues.

The norm is a slightly fatter fuel ratio at idle to allay the exhaust dilution at low speed but getting carb into the transfer slot is not the way to do that. You lose the transition fuel to higher rpm. Later emission carbs will have smaller idle feed restrictions to lower emissions, the mixture screws begin to lose effect. You can slightly drill out the restriction(s) and get good adjustability back in the mixture screws if they don't seem to have an easily definable point where the screws really kill the engine going BOTH ways, not just lean. You should be able to see too rich as well but often can't with the leaner carb settings. If like that the transfers may well be feeding mixture that is too lean also. More room for a flat spot there.

Offline jeremysdad

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Re: Flat spot with Holley 350 carb
« Reply #15 on: April 20, 2014, 09:48:40 PM »
Amc49: So, you're saying (and I agree 100%) that a properly tuned 4 cylinder should have the 'shakes' at idle?

They just do. It's how they roll. They sound fantastic when properly tuned! :) lol

Mine does. I can judge the RPM it by ear. It is currently slightly off, timing wise. I attribute that to the thermostat/weather issue. :) It's been a crazy Spring here in TN. lol

Still running ported vacuum to my vacuum advance. Runs good at 6, initial...sooo o...10 is more mileage? I'll do that. Tomorrow. :)

Offline amc49

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Re: Flat spot with Holley 350 carb
« Reply #16 on: April 20, 2014, 10:09:47 PM »
If you mean uneven like miss no. All fours shake though, the forces at TDC and BDC are different because of angles. The reason why so many complaints of vibration on fours. It drives Ford nuts on the FWD cars. That single rubber mount does not work nearly so well as two 90 degree opposed ones like these Pintos have. Only way to stop that shake is with balance shaft. All three zetecs I have shake, you can feel it as they idle, the hydro mount they use there is tightly tuned for idle rpm, the shake immediately disappears as soon as engine goes off-idle. The hydro mounts explode and common, the Chinese ones almost vibrate as soon as installed. I had to rig two of mine to simply quit seeing everything double. Could not find aftermarket mount that didn't shake, the Ford part way too expensive for my liking. On Focus cars that shake will vibrate the entire dash assembly which seems to be tuned to shake at idle. Ridiculous. They dropped one of the engine mounts, when they had 4 point the cars shook much less. They've gone to three mounts now and the cars shake like nobodys' business, all of them, the SOHC, zetec, duratech, crap engine mount design there, they've changed it ten times but all they do is get higher in price, they don't get any better. They get all wrapped up in later technology hydraulic type mounts, when all they have to do is make mounts like old Tempos used, again a ninety degree opposed side mount that imitated the ones on Pinto motors, all rubber and easy to make but no, that would be too d-mn easy. The problem is the mounts used now are single plane pure vertical but the forces doing the shaking are at least double plane and not purely vertical, the Tempo mount addressed that issue much better.

Offline 74 PintoWagon

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Re: Flat spot with Holley 350 carb
« Reply #17 on: April 21, 2014, 10:13:46 AM »
Guess mine is a morphodite then,LOL because it idles smooth as can be after I hooked up the vacuum the right way(not the smog crap way) and I was able to close the butterflies way down leaving next to no transfer slot exposed, better acceleration and better mileage, oh well, LOL...
Art
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Offline kerryann

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Re: Flat spot with Holley 350 carb
« Reply #18 on: April 23, 2014, 09:50:36 AM »
we drove the car with these timing numbers and i can hear what im almost certain is pinging at low rpm cruise, especially going up grades/hills.  thought it was a vibration but its only at certain low rpms under load.  im at about 11 degrees initial and can only get 32 total mechanical advance.  i can easily set it to 34-36, but with vacuum advance hooked up either way im goin to get a very high advance under light cruise.  im worried im going to still have pinging.  36 total will give me about 15 initial.  with manifold vacuum im going to see around 45 at idle.  with ported vacuum it will idle at the 15 but off idle will see more high numbers under load at slow cruise.

with that being said, do i need to recurve the distributor for more mechanical advance?  i know you just grind weights down on the chevys to do this but ive never looked under the cap on this ford so not sure what the mechanism looks like.

i still havent verified the transfer slot position.  i have idle set fairly low.  idle mix screws are 1 1/2 out now.  motor does have some shake to it.

best way i can describe my issue is a wheezing feeling in the mid range.  ive felt it before when running too small of jets in a 4 barrel on a small block.  it doesnt flatten out but stops pulling hard gets kind of erratic.  this feels the exact same way.  on top of it sometimes transitioning from part throttle it does flatten right out to the point of just about stalling and then recovers.  im already at 57 jets.  i have 58s and i think 59s but this is getting past the point of even mini stock circle track tuning guidelines.  it still leads me to believe i have an issue with the racer walsh restrictors not letting the power valve circuit work right.  i will take a picture of where the restrictors sit the next time i have the carb apart.  i drilled until the drill broke through into the passage and stopped.  the inserts are just about a press fit, i pressed them all the way in until they stopped when the contacted the back wall of the passage.  i checked them both for flow by blasting air through them and feeling it at the booster outlet hole.  they both flow, it just seems like not enough.

i did not think of the weight under the squirter possibly causing a problem.  i knew it was to keep fuel from being drawn out but never thought of the flat spot that could cause by being emptied out under vacuum. ill check and make sure that needle weight is there also.

will try some different squirter combinations as well.  still a little confused on timing and what vacuum advance source will work best here but i will see what i can come up with.  i'll report back soon.

Offline jeremysdad

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Re: Flat spot with Holley 350 carb
« Reply #19 on: April 23, 2014, 07:55:43 PM »
Guess mine is a morphodite then,LOL because it idles smooth as can be after I hooked up the vacuum the right way(not the smog crap way) and I was able to close the butterflies way down leaving next to no transfer slot exposed, better acceleration and better mileage, oh well, LOL...

I switched mine this morning before I left for work (by flashlight lol), and filled up on the way to work. Did seem smoother overall, and my gas gauge didn't move as much (as it usually would), but I still have to fine tune my idle.

@kerryann: Sorry we mildly derailed your thread. It'a a bad habit we seem to have. :) lol

Offline amc49

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Re: Flat spot with Holley 350 carb
« Reply #20 on: April 23, 2014, 10:39:11 PM »
You recurve the advance you already have, it does not change the total amount available from stop to stop. When you mess with weights you are going past that but removing weight SLOWS DOWN advance not increases it. You recurve by using lighter springs on the weights you have. You change the total advance by physically altering the weight setup so that the limit to limit distance is increased.

You certainly don't need any more advance if you're already pinging. You recurve when you drop the vacuum unit.

What compression in the motor, what pistons?

You should be aware that the stock intake is hurting you here, it is garbage on a modded motor, it actually does not flow as well as the carb you're using there. They become a problem at around 300 cfm.

Screw the ministock guidelines, they do not go around the track at light cruise. Pretty much dead in it all the time or dead off it. And why they commonly say this or that jetting works but it then doesn't in the real world of slow cruise and slow roll traffic jams with constant on/off light throttle. If you think still lean then make sure of exact size of restrictors then find some fine wire to add restriction. Figure the size of the restriction hole (area of a circle formula) then the wire diameter size do same thing. Add the two areas together and then find a drill bit that equals that area. Drill restrictors bigger using that bit to get more PV fuel, then you can later add the wire to both holes by looping it into both to get back to the original restriction hole size again if you need to. That way you can get bigger PV restrictions yet still get back to square one.

Offline amc49

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Re: Flat spot with Holley 350 carb
« Reply #21 on: April 23, 2014, 10:44:19 PM »
What size hole is in those restrictors????

The ones in the adjustable metering block made for the custom Holley 350 off road 2 bbl. are .042" each. FYI, the main jets vary from a low of 73 to 77 and higher.

Offline kerryann

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Re: Flat spot with Holley 350 carb
« Reply #22 on: April 24, 2014, 04:49:45 PM »
i understand how the weight system works.  ive never had to do it with my v8s but by grinding away some of the stop points on the weight you can increase total advance.  if i had the other problem you can weld to the weights to tighten up the stops and take advance range out.  if there was concern of losing mass on the weight you can always go to lighter springs to quicken the rate the advance comes in at.

why i thought of this was the fact that i can only get 32 total with an initial setting of 11.  this seems to tight of a range.  vacuum advance is a whole different issue.  its always better to run full manifold vacuum on the v8s if possible.  what i am considering in this case with the 2.3 is trying to run ported to limit advance at idle since im seeing 40 initial with no load when using full manifold vacuum.  this just seems excessive.  by recurving the distributor to get more range i can run a much lower initial timing setting.  then when hooked to manifold vacuum it would be back up in a reasonable range.  also when vacuum drops out when opening the throttle up i would have timing come in right at the desired 34-36.  does this make sense?  dont want to pull my distributor apart if this doesnt seem necessary.  can always tack weld to get back to square one but its a lot of work i'd like to avoid if my timing numbers seem reasonable.

these are the racer walsh restrictors:
http://www.racerwalsh.zoovy.com/product/RWA1218/carb-restrictor.html

i dont remember what the spec is on them but they are untouched.  i know i could try drilling and use wire to get back but i figured that they are plenty big enough, especially since they are designed for circle track.  i understand the difference between circle track conditions and street.  i race circle track myself.  very different carb tuning between the two.

the only thing i could think of that could be hindering the restrictors is if somehow when the drill broke through the metering block passage and hit the back wall of the passage it left a divot.  Perhaps theres divots that the ends of the restrictors are sunk into now that they are pressed in and are being further restricted.  not sure if you guys can visualize what im saying.  im probably over thinking things.  it's worth a check, just very difficult to get those restrictors back out.

i am convinced i have an accelerator pump circuit issue at this point.  it may not be the only problem i think i need to make sure fuel isnt getting drawn out through the squirter leaving and empty shot when i need it at part throttle.  certainly seems that that is the case.  as far as jetting, racer walsh recommends a starting point of 56 with a 350 holley and that is for circle track.  usually its safer to run a richer mixture in circle track.  my engine builder sets his up at around 12.5:1 air fuel.  on the street you can definitely run it leaner.  i have 57 jets in now and have 58s to try.  just seems to be getting too far away from what others have found to work on the street.

this is a stock 42k mile motor.  no internal modifications.  stock aluminum intake.  im not looking to eek out every bit of hp possible, just make a nice cruising car that's easy to deal with.  i know there are some better factory intakes out there.  if i could get one cheap i may go that way down the road.  just trying to get what i have tuned up.  the aluminum ford two hole spacer may be hurting me as well.  got it cheap on ebay.  didnt want to spring for the racing open two barrel spacer that speedway sells.  ive always had better luck with the spacers with bored holes in them rather than open on the street anyway.

sorry for the long winded post.  in short, im still uncertain as to what proper timing is here with vacuum advance taken into account.  the carb flat spot i am still working on but im pretty sure its not related to timing.

Offline amc49

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Re: Flat spot with Holley 350 carb
« Reply #23 on: April 24, 2014, 10:51:39 PM »
Hmmm..

You CANNOT recurve the distributor to get more total centrifugal advance range. The stops are the upper limit and if you add spring to bring idle weights in so lower number then the high speed will be slower too and less number then on the upper end. Recurving only moves around what you already have limit to limit. Lord knows I've done enough of them.

Yes the restrictors could be pressed in too far.

You want 12.5 A/F even on the street at full throttle or piston melting time. Lean only when not under full load. All PCMed cars do that when they go open loop at full throttle.





Offline kerryann

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Re: Flat spot with Holley 350 carb
« Reply #24 on: April 25, 2014, 09:08:14 AM »
ok.  i have not looked under the cap here so im not sure what the advance mechanism looks like.  but changing the advance limits by grinding weights is pretty common.  almost all gm distributors will give 24 degrees advance, but there are different shaped weights available, instead of buying these many people grind them down to change the built in stop in their profile and open up the range.

i know this is a ford and could be totally different.  but since this is a 1980 and basically from the height of bad emissions ideas, is there any chance this distributor doesnt advance 24 degrees?  11 initial and 32 total would indicate only 21 degrees. the hood sticker tells you to set initial at 6 degrees.  that will give me about 27 degrees total.  id rather not modify anything if possible.  is there a chance the distributor is worn and hanging up at some point?  just had to replace a gm hei distributor recently because of how worn the pins and bushings were, the weights had grooves worn into them, timing was erratic.

the pinto timing is consistent so it shows no sings of the mechanical pieces being worn out but doesnt seem to give enough centrifugal advance to accomplish 34-36.  UNLESS 15-16 degrees initial is ok.  im open to ideas.

Offline 74 PintoWagon

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Re: Flat spot with Holley 350 carb
« Reply #25 on: April 25, 2014, 10:30:40 AM »
Here's the Ford unit, the numbers stamped indicate the amount of advance it has, they are available with different slots which limits the advance but it's very common to grind them to give more advance travel done it many times, also you can increase or decrease the rounded edge of the weights to speed up or slow down the time it takes the weight to go to full advance, you use the springs to get it to full advance at the rpm you want..

Art
65 Falcon 2DR 200 IL6 with C4.

Offline kerryann

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Re: Flat spot with Holley 350 carb
« Reply #26 on: April 25, 2014, 01:13:45 PM »
ah, i can see it now.  so the stop in your picture is located on the weight that says 21R correct?  this would give you 21 degrees advance?  looks pretty easy to get a little more.  can you flip the weights around to use the 18R and limit to 18 degrees advance?  in my case im thinking i need more.  what are your initial and total timing settings?  where do you have your vacuum hooked and what is your initial and total in park with vacuum hooked up?

Offline 74 PintoWagon

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Re: Flat spot with Holley 350 carb
« Reply #27 on: April 25, 2014, 02:11:09 PM »
That's not mine just a pic I snatched, timing depends on your application but I don't think you want more than 36 total maybe 10-12 initial though just have to try it and see, if it pings then you have to back it down some or run better gas, I always hook up the vacuum to manifold vacuum, ported is for smog. Mine is all out to lunch right now, my initial is around 18 an total 32 and it comes in too late, I'm surprised it runs as good as it does.
Art
65 Falcon 2DR 200 IL6 with C4.

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Re: Flat spot with Holley 350 carb
« Reply #28 on: April 25, 2014, 02:22:57 PM »
im having the same problem.  if i set this car at the initial 6 degrees they recommend id be at 27 total.  id be happy if i could get around 10 initial with 34-36 total but can't do it.  have you ever checked to see what your initial is with no load with vacuum hooked to the manifold?  i was seeing 40 degrees at an idle.  seems a little ridiculous.  this car pulls 15" vacuum in gear at idle when hot and over 20" hot in park.

Offline 74 PintoWagon

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Re: Flat spot with Holley 350 carb
« Reply #29 on: April 25, 2014, 02:38:29 PM »
I never checked it since it's all out to lunch anyhow, but initial and total without vacuum is what I set, mainly total. Even if you have 40 at idle with the vacuum when you get on the throttle it all goes away anyhow and you're on mechanical until you back off the throttle.
Art
65 Falcon 2DR 200 IL6 with C4.