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  #31 (permalink)  
Old 04-10-2013, 11:30 AM
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Originally Posted by painted jester View Post
The arm couldn't do it there is a spring holding the pump diaphragm down, simple vibration couldn't actuate the pump arm with enough force to pump fuel, or every time you hit a bump on the road the arm would bounce and pump fuel.

jester
A high cycle vibration is nothing like a bump in the road.

A compressed spring is just the thing that a harmonic induced vibration would act on.

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  #32 (permalink)  
Old 04-10-2013, 12:22 PM
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Quote:
Originally Posted by lmsport View Post
A high cycle vibration is nothing like a bump in the road.

A compressed spring is just the thing that a harmonic induced vibration would act on.
Yes the heavy end of the arm with the adjuster could pump (especially the heavy secondary arm) if you hit a bump but the spring in the pump prevents that from happening!!! Especially with the rubber check that blocks the hole to the bowl that the ball doesnt!!

That is something Ive never seen or heard of either, are you talking about the spring on the adjusting screw ( the screw that holds the spring so it can only go up if bottomed out and cant push down on the actuating arm for the accelerator pump diaphragm till the cam actuates it, or the spring that holds the diaphragm to the bottom of the pump? It really seems that after over 50 years of Holley using that style arm on the primary and secondary pumps I would have heard about that problem! Where as the rubber check is a more recent addition. Any one else know about this or has experience with it!

The rubber check has no weight or pressure bearing on it and I can imagine it oscillating at harmonic frequencies, but the pump arm and with the spring pressure on the diaphragm I can't imagine an oscillation there to pump fuel especially at part throttle? Or are you just throwing things out there as guesses?

Because the guessing part is over on my end! Are you a non believer in the check causing this because its been pretty much made clear to me its the culprit
Jester

Last edited by painted jester; 04-10-2013 at 12:44 PM.
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  #33 (permalink)  
Old 04-10-2013, 02:26 PM
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Originally Posted by painted jester View Post
QUOTE=gearheadslife;1664783]I uderstand that,, my question to YOU is, is this REALLY a problem if the engine will not see steady 2800 rpm use(cruise rpm)
while running through the rpm range that "mini squirt" of fuel might happen once if at all.. unlike if you hold the engine at that rpm.. like dyno rpm steps, you found an issue on a dyno. that might not be an issue in real world use.. as the engine would not see that rpm for any lenth of time..
I also understand that every engine combo will cause this to happen at different rpm.. but. we don't race or drive dyno's
on the street/track would this even be an issue at all.. as the harmonics would not have enough time to act on the parts to cause the mini squirt..
in other words running it through the rpm range does this effect power, or is it only when you hold the engine at that rpm.. that when in use, the engine never see's that steady rpm??
now if the drivetrain and tire dia make cruise at 65 an engine rpm of 2800. I can see the need to fix this.. but if not.. you are hunting problems on a dyno that in use. the engine will never see
cause even in high gear, the engine might stay at 2800 of a few tenths if not hundredths of a sec. as it pulls through the rpm range.. making any harmonics fuel squirt unlikely to happen over and over.. it be once and done, if even that.. what was the outcome from a non stepped dyno pull..??



QUOTE=gearheadslife (FURGAL);1664783]I uderstand that,, my question to YOU is, is this REALLY a problem if the engine will not see steady 2800 rpm use(cruise rpm)[/QUOTE]

In the Video I posted it wasn't at 1 steady RPM (it was at varying RPMs)!!!!!, On the 440 on the dino run it started at 2800 that's as far as I had to go to know I had to fix it!!!!!!!!! I wasn't doing a demonstration!!!!!! Once that was fixed I went on with the dino session. That's whats done on a dino run you fix it as it happens and then continue, Or do you think that's the wrong way to do it?

I see you capitalized "YOU" LOL! So I take it you want to make this personel! With no one butting in!!!


Well Im not getting in a pis-sing match but I will state this and be done!!!

I did not post this thread for YOUR Real World!!!! I posted it for HOTRODDERS!! And only the people on here that might be interested in the problem! Not to the ones on here that ask real world questions like "HELP My 2008 farm truck wont start" OR "My cigarette lighter doesn't work?"

If a person is only driving a basic transportation vehicle don't worry about it
Seems to me you don't have to worry from your post FURGAL

Yes! on the Mopar 440 with 4.88s at 2800 with the size tires on it, its a Cruising speed unless your in a school zone
My Vette, 4.11s or 3.73s, 9500 red line, 3500 flash stall, tunnel ram 2 600s, 1/4 mile or 1/8 mile runs it could cost a race, and Money!! A few tenths or hundredths is the same as a mile when you come in second And when I'm cruising it on the street I don't want the problem if I want to play around a little!!

MY Real World? , I wouldn't be tuning a grocery getter on a dino! Or my wifes Aveo, or my F250 Ford, But I do build and tune and work on weekend warriors, drag cars,show cars, off roaders, mudders etc

I don't do roundy rounders or do I do what you call your real world!!!! I retired last year but still keep my hands in it for old customers and friends I think its keeping me alive and well LOL

( I do like roundy rounders just never got into it)

I Dino tune some vehicles (I dont drive the dino as your little quip stated) and then I tune at the track or a stretch of open road!!! The way the vehicle is intended on being driven!!!

This site is "real world" for Hotrodders, we don't deliver grocerys with our hot rods! And we worry about little things that most people in your real world think are silly Like stagger jetting a carb or using rocker stud girdles, or pre loading ladder bars, or porting heads, or installing bigger valves ETC, ETC. Your real world is much different from mine!

The rodders that worry about it may not want it happening even for a split second! I'm not trying to convince anyone to do anything or change anything. Its something that I brought up that I thought was worth mentioning to the few in "my real world" that are interested in what you call a minor problem!

Im almost 67 and worked for Holley at one time, and have been building carbs for 50 years and never knew of this problem until just recently when it happened to me. And this old fart learned something new!!! And wanted others to know! If most people on here were like you in your real world I wouldn't even have bothered! This isn't "ASK THE MECHANIC" its "HOTRODDERS"

SO YES IT CAN BE A BIG PROBLEM TO SOME !!! But you don't have to worry

Jester[/QUOTE]
I asked a simple question. if in the cars use will these be an issue..?? in real world USE.. but got the same b/s answer that this is hotrodders and I've been working on holleys for 30+ years..
if you MISSED it.. I said nice vid...
I was looking for an answer that off a stepped run did it happen?? or was it the steps that gave this problem time to start ..
but got a condisending answer.. carry on..
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  #34 (permalink)  
Old 04-10-2013, 08:42 PM
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people that are arguing with paintedjester,whats wrong with you all?
The guy diagnosed a problem or potential problem that might make your car run better.

Thank you sir for the information,thats one more tool in my tool box or one less step I might need to perform a trouble shoot in the future. I appreciate your video and efforts in this thread.

remember,a carb is nothing more than a controlled fuel leak

or in some cases ,uncontrolled fuel leak
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  #35 (permalink)  
Old 04-10-2013, 10:34 PM
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gearheadslife:

Reread the thread and your questions were answered!

And I take this Quote of what you said I said as a lie If you can't read what I said don't Quote me

QUOTE=gearheadslife: "but got the same b/s answer that this is hotrodders and I've been working on holleys for 30+ years.."[/QUOTE]


I actually said
Jester[/QUOTE]Im almost 67 and worked for Holley at one time, and have been building carbs for 50 years and never knew of this problem until just recently when it happened to me. And this old fart learned something new!!! And wanted others to know! If most people on here were like you in your real world I wouldn't even have bothered! This isn't "ASK THE MECHANIC" its "HOTRODDERS"[/QUOTE]
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  #36 (permalink)  
Old 04-12-2013, 02:34 AM
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I found your post very informative and interesting Jester, and I can fully imagine that phenomenon occurring under certain conditions. Did you mention that the both cases you encountered were on engines with solid mounts? Probably gives more chance for the harmonics to wreak havoc in that situation. I learned something new today, thankyou...



Duke
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  #37 (permalink)  
Old 04-12-2013, 03:00 AM
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Originally Posted by thinwhiteduke View Post
I found your post very informative and interesting Jester, and I can fully imagine that phenomenon occurring under certain conditions. Did you mention that the both cases you encountered were on engines with solid mounts? Probably gives more chance for the harmonics to wreak havoc in that situation. I learned something new today, thankyou...



Duke

Duke:
Thank you!
Yes I mentioned the solid motor Mts.

Jester
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  #38 (permalink)  
Old 04-12-2013, 06:11 AM
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The pump arm under the accelerator pump diaphragm dancing against the diaphragm itself would have a much better chance of actuating the pump circuit than the umbrella seal vibrating, IMO. Setting the gap to a minimum might be all that's needed. Adding weight to one end of the pump lever might also bring the frequency outside the range where it vibrates.

But IF it were the umbrella, I wouldn't arbitrarily change back to the ball and bail style check ball in the float bowl. There are several manufacturers of the umbrella check valves. One thing I might do would be to try as many different check valves as possible to find one that didn't dance at the frequencies involved.

Probably the easiest thing would be adding weight to the check valve under the shooter. This should prevent fuel pullover through the accelerator pump discharge nozzles. If there's a ball under the shooter, use a long type check (shown below). If a long check is already in place, cutting a piece of brazing rod, etc. to place atop the check will add weight. Make sure the screw isn't too long, trim if needed.



I would also recommend the check ball seat be checked and re-formed if needed.

More on that here.

Last edited by cobalt327; 04-12-2013 at 06:25 AM.
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  #39 (permalink)  
Old 04-12-2013, 02:46 PM
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Ive found a little on this problem Cobalt and solid motor Mts. increase the likely hood of the problem! The 3 things that seem to work that most use are the washer in the pump, the spring on the bullet check under the squirters or changing to the ball check fuel Bowl, I haven't talked to anyone (the circle track people I know) or read about anything else that seamed to work! I don't know if Holley is working on it or not. Its not pull over, But pull over is what I have to Type in to do a search to find anything on this subject most of it is on the circle track sites that I find. But I do think changing the Bowl if you have an older bowl with the check ball just for a test would eliminate or pinpoint the umbrella check as the problem causer or not and you could reinstall the original bowl and go on with your trouble shooting !

Jester
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  #40 (permalink)  
Old 04-12-2013, 06:41 PM
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Ive found a little on this problem Cobalt
With all due respect, I just gave you the solution(s)!
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  #41 (permalink)  
Old 04-12-2013, 07:58 PM
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Cobalt:

I stated, I tried all the tricks earlier in the thread I'm sorry but your solution didn't solve the problem but the bowl change did, There was no clearance in the pump arm I don't set them with any clearance!I added weight to the bullet check under the nozzles, I drilled a hole, I changed the umbrella check, I changed the nozzles, and changed the accelerator pump diaphragm and spring and the 50 cc housing to no avail nothing worked but when I changed the bowl to the check ball type it quit! There never was any pull over, Holley tech said it was accelerator pump pressure caused from the little rubber umbrella check oscillating from engine harmonics! The secondary throttle plates never opened to cause any air flow past the secondary shooters. Holley tech line told me it was the little umbrella check in the pump, they know about the problem and even suggest going to the check ball type bowl if your running solid mts, or if its happening with rubber mts. do the same thing. The others having this problem suggest a small spring above the bullet check under the nozzles or putting a washer in the pump itself just like in the video I posted! It was real easy to change the bowl to solve the problem!

Jester
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  #42 (permalink)  
Old 04-12-2013, 11:38 PM
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Weird that rubber would let it vibrate at harmonics. It is a insulator.

If the metal pump level vibrated that has mass and would make more sense.

Im sure lots of people racing circles are happy that you have something to offer.
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