Moparts
Hemi stumble/sputter on starting line ???
Posted By: Charlie Moore
Hemi stumble/sputter on starting line ??? - 08/31/13 01:25 PM
I have a '65 Coronet with a 514" Hemi, Mopar crossram with 2 Holley 770's. Footbrake car. I have tried 2 converters and the current one will only allow a launch of 2600 rpm. On the hit of the throttle the car stumbles and actually spits back thru the carbs which is visible when we try with the hood off. It will stumble for a bit maybe 100 -150 ft. and then take off like a rocket and run almost 140 mph.
Now for the things we have tried are two different sets of carbs and going lean and fat with both. Different ignition wires. 3 different types of plugs. Different MSD 7al2, Compression test, Leak down test, Crank trigger, crank trigger wire, reroute crank trigger wire to avoid RF. By pass crank trigger and use distributor.
We did find a broken intake valve spring and thought great that's it. Went to a track rental this past Monday ready to make some good hits and had the exact same problem.
We have spoken with several engine builders across the country and they have all taken the time to listen to everything. After they have a while to think about it they have all said it sounds like everything is right.
We degreed the cam a while back and we are going to check it again today just to be sure because it really acts like the intake valves seem to be closing a little late.
I posted this today as it marks my 3 month anniversary since I first took this car to the track and we are no closer to a resolution.
Any thoughts would be greatly appreciated. Thanks in advance.
Charlie Moore
440-846-3777
Posted By: MR_P_BODY
Re: Hemi stumble/sputter on starting line ??? - 08/31/13 02:09 PM
It really sounds like your accelerator pump and squirters
being its right at the hit... is the pump arm moving
as soon as you move the throttle blades
EDIT
Whats your timing at
Posted By: Charlie Moore
Re: Hemi stumble/sputter on starting line ??? - 08/31/13 02:13 PM
The squirters have been replaced with larger and smaller ones. The cams that push on the accelerator pump arms have been replaced and modified to give the major shot after stage rpm. Thank you for the input.
Posted By: Charlie Moore
Re: Hemi stumble/sputter on starting line ??? - 08/31/13 02:17 PM
Timing has been tried anywhere from 29 degrees to 35 degrees.
Posted By: MR_P_BODY
Re: Hemi stumble/sputter on starting line ??? - 08/31/13 02:18 PM
Will it it free rev without the stumble
Posted By: Charlie Moore
Re: Hemi stumble/sputter on starting line ??? - 08/31/13 02:20 PM
When I try to free rev it, it will go to about 4000 rpm and stumble momentarily and then jump up.
Posted By: MR_P_BODY
Re: Hemi stumble/sputter on starting line ??? - 08/31/13 02:25 PM
Quote:
When I try to free rev it, it will go to about 4000 rpm and stumble momentarily and then jump up.
The reason I ask if it will free rev is that will
eliminate the drive line/conv... it still has the
problem but less and at a different rpm.. load just
makes it worse.... have you sprayed the intake for
vac leaks
Posted By: Charlie Moore
Re: Hemi stumble/sputter on starting line ??? - 08/31/13 02:29 PM
I'm not 100% sure what you mean when you say spray the intake? I've heard of it, but what are you spraying it with?
Posted By: MR_P_BODY
Re: Hemi stumble/sputter on starting line ??? - 08/31/13 02:33 PM
Quote:
I'm not 100% sure what you mean when you say spray the intake? I've heard of it, but what are you spraying it with?
Spray it with carb or brake cleaner.. it has to be
a flammable product ... but if its leaking it will
suck in the carb cleaner and you will hear the revs
come up(its burning the cleaner like fuel)
Posted By: Charlie Moore
Re: Hemi stumble/sputter on starting line ??? - 08/31/13 02:38 PM
I really appreciate this. We noticed that the idle air bleeds have been changed to make them replaceable. We noticed that adjusting the air/fuel mixture did not affect the idle much at all. We assumed the air bleeds were just to big but there maybe a leak. I will try this after I put the front of the engine back together. Thanks again.
Posted By: Charlie Moore
Re: Hemi stumble/sputter on starting line ??? - 08/31/13 02:41 PM
With this creating a super lean condition on the opening of the throttle, have you seen it start spitting back like I tried to describe?
Posted By: MR_P_BODY
Re: Hemi stumble/sputter on starting line ??? - 08/31/13 02:49 PM
Quote:
With this creating a super lean condition on the opening of the throttle, have you seen it start spitting back like I tried to describe?
Any time its super lean the spark tries to chase the
fuel so yes its common to have it spit back and fart
through the carb
Posted By: Dodgem
Re: Hemi stumble/sputter on starting line ??? - 08/31/13 03:02 PM
My uneducated guess is the problems are in the vacuum secondairees maybe opening to fast and maybe too lean or rich at first.
That could be an air bleed problem not allowing enough fuel in right away.
probably opening too fast and too lean combination??
Posted By: MR_P_BODY
Re: Hemi stumble/sputter on starting line ??? - 08/31/13 03:10 PM
Quote:
My uneducated guess is the problems are in the vacuum secondairees maybe opening to fast and maybe too lean or rich at first.
That could be an air bleed problem not allowing enough fuel in right away.
probably opening too fast and too lean combination??
Very well could be... but he has tried 2 sets of carbs...
but that really doesnt mean much if both sets of carbs
were set up about the same
Posted By: Dodgem
Re: Hemi stumble/sputter on starting line ??? - 08/31/13 03:21 PM
So he says lean and fat if it goes lean then fat it sure could be the secondairees coming open too soon lean with no air flow no initial flow from jets then maybe fat because of jetting and or air bleeds??
Posted By: Dodgem
Re: Hemi stumble/sputter on starting line ??? - 08/31/13 03:28 PM
So one easy test would be to go 1/2 throttle at the hit and feed it the rest of the throttle over 60 to 80 feet if that smooths it out it's most likely all in secondary opening and jetting/air bleeds.
Posted By: MR_P_BODY
Re: Hemi stumble/sputter on starting line ??? - 08/31/13 03:31 PM
Quote:
So he says lean and fat if it goes lean then fat it sure could be the secondairees coming open too soon lean with no air flow no initial flow from jets then maybe fat because of jetting and or air bleeds??
I took it that he jetted it leaner and fatter 
Posted By: HEMIFRED
Re: Hemi stumble/sputter on starting line ??? - 08/31/13 03:41 PM
Quote:
Quote:
My uneducated guess is the problems are in the vacuum secondairees maybe opening to fast and maybe too lean or rich at first.
That could be an air bleed problem not allowing enough fuel in right away.
probably opening too fast and too lean combination??
Very well could be... but he has tried 2 sets of carbs...
but that really doesnt mean much if both sets of carbs
were set up about the same
I have seen similar trouble in the past. The carbs were set up for another style manifold and did not want to work with the new one. try returning carbs to out of the box condition
Posted By: Dodgem
Re: Hemi stumble/sputter on starting line ??? - 08/31/13 03:56 PM
Quote:
Quote:
So he says lean and fat if it goes lean then fat it sure could be the secondairees coming open too soon lean with no air flow no initial flow from jets then maybe fat because of jetting and or air bleeds??
I took it that he jetted it leaner and fatter
Oh I thought he had an air fuel and could see it going lean then rich?
I agree with hemi freid call holly and find the stock air bleed sizes and jetting put stock secondary opening springs back in and go from there
some stuff on tuning air bleeds
http://www.quickfueltechnology.com/technical-info/carb-class-air-bleed-basics
http://www.carcraft.com/techarticles/tuning_with_air_bleeds/
Posted By: Charlie Moore
Re: Hemi stumble/sputter on starting line ??? - 08/31/13 05:25 PM
The carbs were set up for a crossram and the second set we tried came off a crossram. We just checked cam timing. Bullet says this cam should be at 109. It was installed at 110.5. It has a Cloyes Hex-adjust cam gear. So I loosened the 3 gear bolts a tried to adjust adjuster cam within the cam gear and sure enough it cracked. I guess I'm done until Tuesday when I can call Cloyes. I greatly appreciate everyone's feedback and suggestions. I'm going to Norwalk now just to watch some cars that actually run. Thanks, Charlie.
Posted By: MR_P_BODY
Re: Hemi stumble/sputter on starting line ??? - 08/31/13 09:24 PM
Quote:
The carbs were set up for a crossram and the second set we tried came off a crossram. We just checked cam timing. Bullet says this cam should be at 109. It was installed at 110.5. It has a Cloyes Hex-adjust cam gear. So I loosened the 3 gear bolts a tried to adjust adjuster cam within the cam gear and sure enough it cracked. I guess I'm done until Tuesday when I can call Cloyes. I greatly appreciate everyone's feedback and suggestions. I'm going to Norwalk now just to watch some cars that actually run. Thanks, Charlie.
I will assume that cam is a 112 LSA and they said to
install it at 109... bummer you broke the gear but
thats better to do it now then later... if it is a
112, I would advance it a bit more than the 109...
but thats me.. it would make more low end torgue and
it would help increase the stall on the conv a little...
but being that its falling on its face right now you
dont really know what the stall is because you arent
making the torque
Posted By: tubtar
Re: Hemi stumble/sputter on starting line ??? - 08/31/13 11:25 PM
Quote:
Quote:
I'm not 100% sure what you mean when you say spray the intake? I've heard of it, but what are you spraying it with?
Spray it with carb or brake cleaner.. it has to be
a flammable product ... but if its leaking it will
suck in the carb cleaner and you will hear the revs
come up(its burning the cleaner like fuel)
I have had good luck using an unlit propane torch. Crack the valve and wave it around the intake flanges and carb base.
If you get near a leak , the rpm's will take off.
Posted By: MR_P_BODY
Re: Hemi stumble/sputter on starting line ??? - 09/01/13 12:13 AM
Quote:
Quote:
Quote:
I'm not 100% sure what you mean when you say spray the intake? I've heard of it, but what are you spraying it with?
Spray it with carb or brake cleaner.. it has to be
a flammable product ... but if its leaking it will
suck in the carb cleaner and you will hear the revs
come up(its burning the cleaner like fuel)
I have had good luck using an unlit propane torch. Crack the valve and wave it around the intake flanges and carb base.
If you get near a leak , the rpm's will take off.
That works fine also... like I said .. any product that
is flammable will work
Posted By: HEMIFRED
Re: Hemi stumble/sputter on starting line ??? - 09/01/13 02:09 AM
A smooth way to find a vacume leak is to lay a nice bead of shaving cream across the intake's edge
Posted By: poppaj
Re: Hemi stumble/sputter on starting line ??? - 09/01/13 03:57 AM
I think you are the fellow. That had the nice black 65' coronet. We talked to you about installing hoses on the vent tubes. We also enlarge the pump shot hole to help with a car that stumbles like yours is. Larger squirters might cure it as well. Also have you tried running it on the front two barrels of each carb? Might rule out a problem or find a problem with secondarys. Might try a set of mechanical secondary carbs to see if it solves the stumble. Poppaj
Posted By: dodger mope
Re: Hemi stumble/sputter on starting line ??? - 09/01/13 02:41 PM
those cross ram hemi holleys had a tuff job back in the day,low rpm stall and long duration cams.they used unrestricked idle channels.that will help your stumble but will create a low speed rich cruise condition.i had to deal with it when we put them on street driven cars.the original holleys also had very small idle bleeds.
Posted By: ro23car
Re: Hemi stumble/sputter on starting line ??? - 09/01/13 03:35 PM
hope you get it figured out.
Posted By: OUTLAWSSAA
Re: Hemi stumble/sputter on starting line ??? - 09/01/13 07:47 PM
This may or may not help, because you have already tried another set of carbs. I had the same problem and chased it for a whole season. After replacing just about everything imaginable on the car I found it at the end of the season. It turned out to be one of 2 things. Because of time restraints at a race I changed the vacume pod diaphram and spring at the same time in both carbs. I made a pass with the car and that was the last time I had the nightmare stumble. I'm leaving off a brake so there is a difference there. Good luck!
Posted By: ro23car
Re: Hemi stumble/sputter on starting line ??? - 09/01/13 08:37 PM
Quote:
This may or may not help, because you have already tried another set of carbs. I had the same problem and chased it for a whole season. After replacing just about everything imaginable on the car I found it at the end of the season. It turned out to be one of 2 things. Because of time restraints at a race I changed the vacume pod diaphram and spring at the same time in both carbs. I made a pass with the car and that was the last time I had the nightmare stumble. I'm leaving off a brake so there is a difference there. Good luck!
hey don how are ya?
Posted By: Dodgem
Re: Hemi stumble/sputter on starting line ??? - 09/01/13 09:32 PM
So how big is this motor and what are the cam specs?
TQ stall??
Posted By: Charlie Moore
Re: Hemi stumble/sputter on starting line ??? - 09/01/13 10:20 PM
Quote:
I think you are the fellow. That had the nice black 65' coronet. We talked to you about installing hoses on the vent tubes. We also enlarge the pump shot hole to help with a car that stumbles like yours is. Larger squirters might cure it as well. Also have you tried running it on the front two barrels of each carb? Might rule out a problem or find a problem with secondarys. Might try a set of mechanical secondary carbs to see if it solves the stumble. Poppaj
We tried routing the vent tubes that day and it changed nothing on our car. We have tried squirters ranging from 30's to 55's. We also held the secondaries closed to make sure they were not opening to fast. I've thought about trying a set of mech. secondary carbs but my play fund has dried up with everything I've tried over the past 3 months.
Posted By: Charlie Moore
Re: Hemi stumble/sputter on starting line ??? - 09/01/13 10:24 PM
Quote:
So how big is this motor and what are the cam specs?
TQ stall??
Motor is supposed to be a 514. Cam is a Bullet with actual vave lift on intake of .832 and exhaust of .780. Duration @ .050 is 283/288.
The most I can footbrake it to is 2600 rpm.
Posted By: Quicktree
Re: Hemi stumble/sputter on starting line ??? - 09/01/13 10:37 PM
borrow a couple of doulbe pumper carbs and try them.get away from the vac carbs until you figure it out
Posted By: Charlie Moore
Re: Hemi stumble/sputter on starting line ??? - 09/01/13 10:37 PM
Well I had an Engine builder ask if the intake runners in the heads were black and gummy? Sure enough it's pretty black and sticky. When I told him that Bullet said the cam should be at 109 and it is at 110.5, he immediately asked about the intake runners. He said it really sounds like it's getting a lot of exhaust reversion back in the cylinder and intake manifold. That could explain why when I first start it it seems fine and revs good but after about 2 minutes or so it won't rev smoothly. We are going to advance the cam to about 105 and put it back together. I will post how it goes whether it's positive or negative. Thanks again for all the feedback
Posted By: oldtimer5151
Re: Hemi stumble/sputter on starting line ??? - 09/02/13 01:43 AM
Before you spend any more money, put .028 hsmabs in all bleeds. Take carbs. off and adjust the transition slots the same and re-set the float levels. Then put .035 squirters in and go down, not up, from there on squirter size. Adjust idle screws 2 rounds out and adjust idle.
Posted By: Dodgem
Re: Hemi stumble/sputter on starting line ??? - 09/02/13 02:22 AM
Quote:
Well I had an Engine builder ask if the intake runners in the heads were black and gummy? Sure enough it's pretty black and sticky. When I told him that Bullet said the cam should be at 109 and it is at 110.5, he immediately asked about the intake runners. He said it really sounds like it's getting a lot of exhaust reversion back in the cylinder and intake manifold. That could explain why when I first start it it seems fine and revs good but after about 2 minutes or so it won't rev smoothly. We are going to advance the cam to about 105 and put it back together. I will post how it goes whether it's positive or negative. Thanks again for all the feedback
That cam definitely will like 105 way way better than 110.5 or a 6500 stall speed converter. even 104. So it was dragged down by the converter holding it out of it's power band .
Posted By: ro23car
Re: Hemi stumble/sputter on starting line ??? - 09/02/13 03:03 AM
Quote:
borrow a couple of doulbe pumper carbs and try them.get away from the vac carbs until you figure it out
those wont work.
Posted By: hustlin hoosier
Re: Hemi stumble/sputter on starting line ??? - 09/02/13 04:24 AM
Why won't they work?
Posted By: ro23car
Re: Hemi stumble/sputter on starting line ??? - 09/02/13 12:21 PM
Quote:
Why won't they work?
ok i will rephrase my reply. i know of 5 different people that tried 950hp mecanical carbs and none of them could get them to work. plus my self 4 were on cast crossrams 2 were on sheetmetal intakes.
Posted By: ro23car
Re: Hemi stumble/sputter on starting line ??? - 09/03/13 04:02 PM
did you get it figured out yet?
Posted By: Quicktree
Re: Hemi stumble/sputter on starting line ??? - 09/03/13 05:21 PM
Quote:
Quote:
Why won't they work?
ok i will rephrase my reply. i know of 5 different people that tried 950hp mecanical carbs and none of them could get them to work. plus my self 4 were on cast crossrams 2 were on sheetmetal intakes.
probably because it way to much, I have seen many 750 double pump carbs on tunnel rams.not to mention dominators on applications that need them.
Posted By: ro23car
Re: Hemi stumble/sputter on starting line ??? - 09/03/13 05:49 PM
Quote:
Quote:
Quote:
Why won't they work?
ok i will rephrase my reply. i know of 5 different people that tried 950hp mecanical carbs and none of them could get them to work. plus my self 4 were on cast crossrams 2 were on sheetmetal intakes.
probably because it way to much, I have seen many 750 double pump carbs on tunnel rams.not to mention dominators on applications that need them.
950's will work if they are vacuum secondaries.
Posted By: Quicktree
Re: Hemi stumble/sputter on starting line ??? - 09/03/13 07:08 PM
Quote:
Quote:
Quote:
Quote:
Why won't they work?
ok i will rephrase my reply. i know of 5 different people that tried 950hp mecanical carbs and none of them could get them to work. plus my self 4 were on cast crossrams 2 were on sheetmetal intakes.
probably because it way to much, I have seen many 750 double pump carbs on tunnel rams.not to mention dominators on applications that need them.
950's will work if they are vacuum secondaries.
I must be missing something? what does the vac secondary have to do with it? you are only on that circuit for a second.
Posted By: cudaman1969
Re: Hemi stumble/sputter on starting line ??? - 09/04/13 12:20 AM
After years of using Hollys on a crossram you have only one problem- Lean- The idle circuit has to be rich or it will bog or stumble, wiil the engine idle 600 rpm in gear? The secondary's have to be shut with no light visalble around them, adjust the little screw on the base plate bottom. Main air bleeds small .0018 main fuel bleeds large .070 a good place to start. If right, squirters are not needed and if you push pedal down alot you're out of there range anyway. Any vacuum leak is you're enemy 8 is enough. Hope this helps
Posted By: ro23car
Re: Hemi stumble/sputter on starting line ??? - 09/04/13 01:53 AM
Quote:
Quote:
Quote:
Quote:
Quote:
Why won't they work?
ok i will rephrase my reply. i know of 5 different people that tried 950hp mecanical carbs and none of them could get them to work. plus my self 4 were on cast crossrams 2 were on sheetmetal intakes.
probably because it way to much, I have seen many 750 double pump carbs on tunnel rams.not to mention dominators on applications that need them.
950's will work if they are vacuum secondaries.
I must be missing something? what does the vac secondary have to do with it? you are only on that circuit for a second.
yes you are missing something.the secondaries do not open as fast as the mecanicals for one. take a look at the nss hemi cars and see for yourself. i cound not make mecanicals work neither could other people. i footbrake with my 950 vac carbs and have no problem and yes i do have a cast crossram. i know alot of other guys running the crossram carbs on their cars.
Posted By: 68 HEMI GTS
Re: Hemi stumble/sputter on starting line ??? - 09/04/13 01:58 AM
stop by and see me at norwalk if you haven't got it figured out by then. my pops will be there and he is a damn good carb guy. i can leave off the foot brake at idle with my cross ram, and still go on 100 mile round trip drives and cruises.
http://youtu.be/tBwyPmOzqBQ
Posted By: ro23car
Re: Hemi stumble/sputter on starting line ??? - 09/04/13 02:11 AM
wont dale help you?
Posted By: cudaman1969
Re: Hemi stumble/sputter on starting line ??? - 09/04/13 02:22 AM
I had 4780--800- double pumper carbs on my max wedge at one time just to try and had no problem at all. Had no real gain over my set so I gave them back. Like I said the idle circuits have to be right.
Posted By: Charlie Moore
Re: Hemi stumble/sputter on starting line ??? - 09/04/13 02:49 AM
Quote:
wont dale help you?
We have talked to Dale quite a bit. After everything we told him, he said quit looking at the carbs, the problem is somewhere else. I plan on giving these carbs to Dale over the winter. I was told by the previous owner that the Carb Shop had set these up. Oh well.
Posted By: Charlie Moore
Re: Hemi stumble/sputter on starting line ??? - 09/04/13 02:55 AM
Quote:
stop by and see me at norwalk if you haven't got it figured out by then. my pops will be there and he is a damn good carb guy. i can leave off the foot brake at idle with my cross ram, and still go on 100 mile round trip drives and cruises.
I'm sure everyone will be able to find me ay Norwalk. I'll be the guy with the look of total depression. 
Posted By: max_maniac
Re: Hemi stumble/sputter on starting line ??? - 09/04/13 03:50 AM
Quote:
Quote:
stop by and see me at norwalk if you haven't got it figured out by then. my pops will be there and he is a damn good carb guy. i can leave off the foot brake at idle with my cross ram, and still go on 100 mile round trip drives and cruises.
I'm sure everyone will be able to find me ay Norwalk. I'll be the guy with the look of total depression.
Hang in there Charlie - I'm sure you will get it figured out soon. Hey maybe get some Eddy carbs on there and have at it 
Hope to see you at Norwalk once again and maybe if it aint runnin good you will sell it to me cheap!!! 
Russ
Posted By: poppaj
Re: Hemi stumble/sputter on starting line ??? - 09/04/13 04:02 AM
Sure is a nice car Charlie!
Posted By: Quicktree
Re: Hemi stumble/sputter on starting line ??? - 09/04/13 10:07 AM
Quote:
Quote:
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Why won't they work?
ok i will rephrase my reply. i know of 5 different people that tried 950hp mecanical carbs and none of them could get them to work. plus my self 4 were on cast crossrams 2 were on sheetmetal intakes.
probably because it way to much, I have seen many 750 double pump carbs on tunnel rams.not to mention dominators on applications that need them.
950's will work if they are vacuum secondaries.
I must be missing something? what does the vac secondary have to do with it? you are only on that circuit for a second.
yes you are missing something.the secondaries do not open as fast as the mecanicals for one. take a look at the nss hemi cars and see for yourself. i cound not make mecanicals work neither could other people. i footbrake with my 950 vac carbs and have no problem and yes i do have a cast crossram. i know alot of other guys running the crossram carbs on their cars.
he has a lean condition a dp would help. people run them all the time.
Posted By: Cab_Burge
Re: Hemi stumble/sputter on starting line ??? - 09/04/13 06:20 PM
Are you using the newer Mopar two piece crossram intake? If so is it stock or modified some?
I use to tune and drive a stock cast crossram 426 Hemi motor, it didn't like big squirters at all
(it did like either #32 or 35 squirters depending on the track elevation and outside weather conditions
)Bigger squirters would make it hestitate at the hit of the throttle
It did have a 8 inch 4500 RPM stall converter though
I would foot stall it to 2500 to 3000 RPM and it would flash over 4300 RPM at the hit of the throttle
As far as the new Mopar two piece crossram you might want to have someone who knows what to do inside them to fix the fuel distribution help you
What I'm trying to say is I don't know anyone that has ran the stock new Mopar two piece make them 60 ft. well
That or put a stick shift tranny in it, let the clutch out at 7000 RPM and shift it at 8000 RPM
Posted By: Charlie Moore
Re: Hemi stumble/sputter on starting line ??? - 09/05/13 02:32 AM
Well we started it tonight and it ran very well cold but the main problem would develop after the en;gine was good and warm. I let it run for about 6 or 7 minutes and shut it off to heat sink a little. Once the intake was warm and i knew the engine was good and warm, I tried to free rev the motor and it did the exact same thing as before we advanced the cam. I'm pretty much done for the year as I'm really tired of working on it and spending stupid money and wasting the entire summer only to be no closer than I was on June 1st when the car first went out. I truly appreciate all the feed back everyone has given. I hope to see several of you at Norwalk next week. Thanks again, Charlie.
Posted By: B5 Bee
Re: Hemi stumble/sputter on starting line ??? - 09/05/13 04:57 PM
If it is a problem with the secondaries coming in too soon, why not unhook them and see if it will free rev?
Posted By: Dodgem
Re: Hemi stumble/sputter on starting line ??? - 09/05/13 07:47 PM
Did you try putting the heaviest secondary springs in and go from there?
Posted By: ro23car
Re: Hemi stumble/sputter on starting line ??? - 09/05/13 09:08 PM
charlie i dont know if you tried this but put a vacuum gauge on the intake and see if you lose vacuum around the rpm that the stumble is happening at. im thinking that when those intake came out that there was a problem with some of them. the oil you are seeing could be from the face of the intake not square.
Posted By: Charlie Moore
Re: Hemi stumble/sputter on starting line ??? - 09/05/13 10:20 PM
Quote:
Did you try putting the heaviest secondary springs in and go from there?
We did block off the secondaries from coming in and it made no difference. One thing to think about, this problem only seems to come in after the car warms up. When the motor is cold it will rpm very nice. As soon as it gets up to temp it starts to stumble on acceleration.
Posted By: cudaman1969
Re: Hemi stumble/sputter on starting line ??? - 09/05/13 10:22 PM
Are you running a crank trigger? MSD dist. ? timing locked in at say 35 degrees? I don't think anything is wrong with engine if it runs. Just don't give up, things will work out. We have all been there.
Posted By: Charlie Moore
Re: Hemi stumble/sputter on starting line ??? - 09/05/13 10:24 PM
Quote:
Are you running a crank trigger? MSD dist. ? timing locked in at say 35 degrees? I don't think anything is wrong with engine if it runs. Just don't give up, things will work out. We have all been there.
I'm running an MSD trigger and MSD distributor. I can unplug the trigger and plug into distributor and nothing changes. Timing is locked at 31 degrees right now.
Posted By: cudaman1969
Re: Hemi stumble/sputter on starting line ??? - 09/05/13 10:41 PM
Quote:
Quote:
Are you running a crank trigger? MSD dist. ? timing locked in at say 35 degrees? I don't think anything is wrong with engine if it runs. Just don't give up, things will work out. We have all been there.
I'm running an MSD trigger and MSD distributor. I can unplug the trigger and plug into distributor and nothing changes. Timing is locked at 31 degrees right now.
I was leaning toward rotor out of phase but your heat clue might be the line to follow. Coil (what type) or MSD box could be fine till they warm up. Heat affects wires also, plug and power wires. What size jets in the carbs, could be way to rich after warm
up, kinda like a stuck choke. Where the carbs ever run on another car?
Posted By: Quicktree
Re: Hemi stumble/sputter on starting line ??? - 09/05/13 10:44 PM
sounds like another issue other than the carbs
Posted By: Charlie Moore
Re: Hemi stumble/sputter on starting line ??? - 09/06/13 01:08 AM
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Are you running a crank trigger? MSD dist. ? timing locked in at say 35 degrees? I don't think anything is wrong with engine if it runs. Just don't give up, things will work out. We have all been there.
I'm running an MSD trigger and MSD distributor. I can unplug the trigger and plug into distributor and nothing changes. Timing is locked at 31 degrees right now.
I was leaning toward rotor out of phase but your heat clue might be the line to follow. Coil (what type) or MSD box could be fine till they warm up. Heat affects wires also, plug and power wires. What size jets in the carbs, could be way to rich after warm
up, kinda like a stuck choke. Where the carbs ever run on another car?
Coil is a new MSD pro power coil. Ignition wires were replaced, tried 3 different spark plugs. Right now it has 84 and 85 jets. Maybe a bit rich but I wouldn't think it would cause a sneeze back thru the carbs. These carbs were on this car when I bought it in January of 2012.
Posted By: Dodgem
Re: Hemi stumble/sputter on starting line ??? - 09/06/13 02:11 AM
you did not say what springs you tried to tailor the secondary opening rate too fast is bad!
http://www.summitracing.com/parts/hly-20-13secondaries that open too fast cause a momentary lean condition which can cause issues like a bog and Pufft!
Posted By: Charlie Moore
Re: Hemi stumble/sputter on starting line ??? - 09/06/13 02:39 AM
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you did not say what springs you tried to tailor the secondary opening rate too fast is bad!
http://www.summitracing.com/parts/hly-20-13
secondaries that open too fast cause a momentary lean condition which can cause issues like a bog and Pufft!
Dale Cubic had us restrict the secondaries from opening. We actually put accelerator pump springs in so the secondaries would not open. It did not change anything. We have tried several different springs and currently have the strongest spring in right now.
Posted By: sunroofgtx
Re: Hemi stumble/sputter on starting line ??? - 09/06/13 03:38 AM
Charlie, do you have the 8mm or 8.5 wires on it? Did the 8.5's fit better?
Posted By: cudaman1969
Re: Hemi stumble/sputter on starting line ??? - 09/06/13 06:00 AM
Coil is a new MSD pro power coil. Ignition wires were replaced, tried 3 different spark plugs. Right now it has 84 and 85 jets. Maybe a bit rich but I wouldn't think it would cause a sneeze back thru the carbs. These carbs were on this car when I bought it in January of 2012.
We never ran any jet bigger than 76. 74to 76 front. Secondary plate opened to approximatey 87 jet, can't remember drill size, this with 426 cubes 12.5 pistons and crane R296 cam. Recently we tried to fire my buddy's 440 and it would backfire through carb and out headers. Found it was a bad msd dist, tried another and fired up and ran great. Don't like electricity or converters because I can't visibly inspect them.
Posted By: Charlie Moore
Re: Hemi stumble/sputter on starting line ??? - 09/06/13 11:42 AM
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Charlie, do you have the 8mm or 8.5 wires on it? Did the 8.5's fit better?
I tried the 8.5 wires and nothing changed. I plan on bringing them back to you in a few days. I was also hoping you might have a stock dust boot as I have torn one taking the wires off and on so many times.
Posted By: 52savoy
Re: Hemi stumble/sputter on starting line ??? - 09/07/13 09:09 AM
Have you thought about seeing how it behaves with a single four intake or street Hemi?
That would tell a lot.
Posted By: Quicktree
Re: Hemi stumble/sputter on starting line ??? - 09/07/13 09:53 AM
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Have you thought about seeing how it behaves with a single four intake or street Hemi?
That would tell a lot.
Posted By: Charlie Moore
Re: Hemi stumble/sputter on starting line ??? - 09/07/13 11:24 AM
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Have you thought about seeing how it behaves with a single four intake or street Hemi?
That would tell a lot.
Definitely thought of that, but I don't know anyone with a single 4 bbl intake manifold that I could try. And honestly right now I can't afford to purchase one. I could come up with a carb pretty easy.
Posted By: B G Racing
Re: Hemi stumble/sputter on starting line ??? - 09/07/13 02:13 PM
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Have you thought about seeing how it behaves with a single four intake or street Hemi?
That would tell a lot.
Definitely thought of that, but I don't know anyone with a single 4 bbl intake manifold that I could try. And honestly right now I can't afford to purchase one. I could come up with a carb pretty easy.
We have a few in stock if you would like to try one.Stop by the shop some day.I don't want to speculate what your problem is but I'am sure you will find the issue.If your at any of the races and we are there just stop by and myself or one of our racers will be happy to help you trouble shoot your problem. 
Posted By: 52savoy
Re: Hemi stumble/sputter on starting line ??? - 09/08/13 04:10 AM
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Have you thought about seeing how it behaves with a single four intake or street Hemi?
That would tell a lot.
Definitely thought of that, but I don't know anyone with a single 4 bbl intake manifold that I could try. And honestly right now I can't afford to purchase one. I could come up with a carb pretty easy.
We have a few in stock if you would like to try one.Stop by the shop some day.I don't want to speculate what your problem is but I'am sure you will find the issue.If your at any of the races and we are there just stop by and myself or one of our racers will be happy to help you trouble shoot your problem.
X2
Your more than welcome to come by my house(shop). Not sure how far off Strongsville is. I have a couple different set-ups you could test.
Fred
Posted By: Charlie Moore
Re: Hemi stumble/sputter on starting line ??? - 09/10/13 11:55 AM
Well I pulled the intake off last night and was lucky enough to have the gaskets come intact on the manifold. I showed that the intake is pretty much sitting on the block rails at the front and back. And is about .070 low on the gaskets. It also appears it was not sealing real well across the bottom side of all the runners. It had .060 gaskets when I bought it, so I didn't think much of it. I'm putting .120 gaskets on to raise it up to cylinder head ports. Then were planning on heading to Norwalk. Hope to see you all there.
Posted By: max_maniac
Re: Hemi stumble/sputter on starting line ??? - 09/10/13 01:27 PM
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Well I pulled the intake off last night and was lucky enough to have the gaskets come intact on the manifold. I showed that the intake is pretty much sitting on the block rails at the front and back. And is about .070 low on the gaskets. It also appears it was not sealing real well across the bottom side of all the runners. It had .060 gaskets when I bought it, so I didn't think much of it. I'm putting .120 gaskets on to raise it up to cylinder head ports. Then were planning on heading to Norwalk. Hope to see you all there.
Great news - hopefully this fix will correct the issue and if not there should be enough people there to help sort it out and get it corrected
Russ
Posted By: jdfpam
Re: Hemi stumble/sputter on starting line ??? - 09/11/13 05:02 AM
Charlie,
I hope that you found your problem. When you called us, I thought that you said your name was Tony! I did not think that you said Charlie. My Dad thought that the intake gasket could be the problem. Did you leave the cam at 105?
By the way, did you used to race a Ford Fairlane?
Jeff Day
Posted By: Charlie Moore
Re: Hemi stumble/sputter on starting line ??? - 09/11/13 11:37 AM
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Charlie,
I hope that you found your problem. When you called us, I thought that you said your name was Tony! I did not think that you said Charlie. My Dad thought that the intake gasket could be the problem. Did you leave the cam at 105?
By the way, did you used to race a Ford Fairlane?
Jeff Day
I now believe the intake was on an engine that had been decked a bit. I needed to raise it up to line up the ports and seal it better. I did leave the cam at 105. Bullet said there was no advance ground into that came and it may work better anyway. I raced a 1963 Ford Galaxie for about 18 years. It is now in southern California.
Thank you to you and your father for listening to my issues and the advise. I will see you this weekend.