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Pump cams on 1050 3 circuit domi

Posted By: 602heavy

Pump cams on 1050 3 circuit domi - 02/15/09 08:20 PM

Anyone had problems with these cams (buff colour) , just seems to pour the fuel through the shooters , this carb is out the box & runs wayyyyyyyyyyy rich between 1500rpm & upwards , heard theres some tuning issues with these 3 circuit carbs but the motor is flooded with fuel through the rpm range , changed carbs & the motor runs sweet , this motor is a 605" , will change the cams & see what happens , what does'nt help is the throttle linkage is a 1:1 ratio , so when you open the throttle both primary & sec shooters are activated@ the same time.

If the motor was a 440" i could understand it not working out the box , but this is a 605" so would think the volume/duration of shooter would be near the mark. I've got two other 1050 2 circuit dominators that run fine on the 605" , the volume/duration of fuel out the shooters does'nt even come close to the 3 circuit , just thinking what motor would require that ammout of fuel out the shooters to perform ok.

TIA
Posted By: cudabunch

Re: Pump cams on 1050 3 circuit domi - 02/15/09 08:28 PM

Not sure what your asking? What is buff color cam and I guess you are looking for less of a shot?
Posted By: 602heavy

Re: Pump cams on 1050 3 circuit domi - 02/15/09 08:37 PM

Sorry , modded my post.

The pump shooter cams are yellow , just wondering if any of you guys change the cams out before you fit the carb , just seems to flood the motor with these cams , i realise the shooters may need changing out but just asking if this is a common problem with these 3 circuit carbs out the box?
Posted By: cudabunch

Re: Pump cams on 1050 3 circuit domi - 02/15/09 08:51 PM

Quote:

Sorry , modded my post.

The pump shooter cams are yellow , just wondering if any of you guys change the cams out before you fit the carb , just seems to flood the motor with these cams , i realise the shooters may need changing out but just asking if this is a common problem with these 3 circuit carbs out the box?




Well my motor is tiny compared to yours,but I had to move down to 28's or 25's on the shooters and the yellow cam iam still trying to figure out how to move it to the 2 position.I think there is a brown cam that comes on later.
Posted By: Anonymous

Post deleted by Defbob - 02/15/09 10:34 PM

Posted By: 602heavy

Re: Pump cams on 1050 3 circuit domi - 02/15/09 10:46 PM

What's the point of 50cc pumps/.050 discharge nozzles/big tan cam , on a 3 circuit dominator? , can't see why holley fitted these mahoosive shooters , considering this carb is a 3 circuit which meters itself fuel between idle & main circuit (intermediate).

Any thoughts?

TIA.
Posted By: Cab_Burge

Re: Pump cams on 1050 3 circuit domi - 02/15/09 11:51 PM

What list number, if it is a stock Holley carb, and dash number is the carb your having the problem with? If it is a custm made Dominator from some other comapny than Holley I can't help you on it,sorry
Posted By: 602heavy

Re: Pump cams on 1050 3 circuit domi - 02/16/09 12:28 AM

Part~8896-1 , this carb is direct from Holley so out the box , will try a smaller pump cam in there first.

Can easily modify to a 2 circuit with a 4150 metering block gasket , but really want to try to get this to work.

Any more info?
Posted By: 70blackfish

Re: Pump cams on 1050 3 circuit domi - 02/16/09 12:32 AM

take the middle air bleeds out of the top of each of the four holes, and see if that helps.
Posted By: 602heavy

Re: Pump cams on 1050 3 circuit domi - 02/16/09 12:44 AM

Quote:

take the middle air bleeds out of the top of each of the four holes, and see if that helps.



Thanks , removed the intermeiate air bleeds already , did'nt help any , i was on the same thinking as you are , thinking it would lean the intermediate.
Posted By: sixpackgut

Re: Pump cams on 1050 3 circuit domi - 02/16/09 01:14 AM

are you saying that carb came with 50 squirters? you can get brown cams and that will be a smaller pump shot. reduce the size of the squirter too. the brown cams come in 4150 and 4500 style so pay attention to that if you buy them
Posted By: Cab_Burge

Re: Pump cams on 1050 3 circuit domi - 02/16/09 01:16 AM

Do you still habe the power valves in it? If so try reducing both of the power valve restriction channels down by bushing them and then enlarge it to what size you want I had one of those 8896-1 and sold it after having the front metering block modified by the carb shop and blocking off the rear power valve while testing that carb on a motor on the Carb shsop owners DTS engine dyno In retrospect I could have bushed both PVRC and enlarge them back to .035 to .050 while usig the wide ban as a guide on the dyno Live and learn That carb and another custom built (very expensive )1050 dominator made me end up liking the stock 9375 non HP 1050 Domintors so much
Posted By: 602heavy

Re: Pump cams on 1050 3 circuit domi - 02/16/09 01:25 AM

Ok , for what application are these carbs used on , maybe circuit racing? , Holley do not say which application these are best suited , most guys can't use these out the box , most change the metering blocks out for 2 circuit , why don't Holley have any info on there site stating this carb should not be used on a street/strip motor without extensive modifications , i got no issues working the carb to suit my combo , goes a bit far when you have to rework the complete metering system , been there with a mighty demon , ok i got it dialled in ok , but a lot of time & effort involved.

PVs fitted front & rear.

Posted By: sixpackgut

Re: Pump cams on 1050 3 circuit domi - 02/16/09 01:30 AM

Brand: Holley
Product Line: Holley Model 4500 Dominator Carburetors
Part Type: Carburetors
Part Number: HLY-0-8896-1
Number of Barrels: 4
Carburetor Flange: Dominator
Choke: None
Fuel: Gasoline
Secondary Type: Mechanical
New or Remanufactured: New
Fuel Inlet: Dual
CFM: 1050
Carburetor Finish: Dichromate
Ford Kickdown: No
Booster Type: Annular
Throttle Linkage Type: Universal
Quantity: Sold individually.
Notes: Designed for single 4 barrel set ups. Features "soft" progressive mechanical linkage.

Carburetor, Model 4500, 1,050 cfm, Dominator, 4-Barrel, Dual Inlet, Dichromate, Each
Posted By: sixpackgut

Re: Pump cams on 1050 3 circuit domi - 02/16/09 01:31 AM

sounds like your describing a different carb than what is listed there
Posted By: 602heavy

Re: Pump cams on 1050 3 circuit domi - 02/16/09 01:36 AM

Thanks sixpackagut , but that don't really tell you anything , maybe the progressive linkage does'nt help any , bearing in mind the fuel flowing on the intermediate circuit it might fair better if the sec shooters came in when the primary throttle blades are near open?

Thanks for the heads up.
Posted By: sixpackgut

Re: Pump cams on 1050 3 circuit domi - 02/16/09 01:52 AM

the accel pump shot system is the same in most all holleys and has nothing to do with the extra circuit.

the extra circuit does add fuel off idle and that may be the reason why it is so rich but you wouldnt see that happening looking at the carb. what is the squirters in the carb you have? a big squirter will shoot more fuel faster and a smaller squirter will shoot less for a longer duration
Posted By: 602heavy

Re: Pump cams on 1050 3 circuit domi - 02/16/09 02:00 AM

What i meant to say is that both pump shooters work in harmony with each other due to the 1:1 linkage ratio , the 2 circuit 1050 has a progresive linkage whereby the prmary throttle blades are almost fully open before the secs open (pump shooters) , thinking this would help a tad.
Posted By: sixpackgut

Re: Pump cams on 1050 3 circuit domi - 02/16/09 02:09 AM

change the 1 to 1 linkage. in the description i posted, it shouldnt have it anyway. if its not what you wanted then return it. if my engine was 605, my carb would be bigger than 1050 also
Posted By: 602heavy

Re: Pump cams on 1050 3 circuit domi - 02/16/09 02:18 AM

Thanks sixpac , that description you posted was obviously the part # i posted on here , but the holley site give a slightly different description , ie , there part# states 3 circuit...........

Posted By: cudadon

Re: Pump cams on 1050 3 circuit domi - 02/17/09 04:17 AM

What jets are you running? Plug the rear power valve! If that helps, try plugging both and jet it square.
Have you checkedthe float levels? That will change main start up and richness for a given jet.
Let us know, Don
Posted By: 602heavy

Re: Pump cams on 1050 3 circuit domi - 02/18/09 03:23 AM

Thanks

I ended up using a 4150 metering block gasket & punched a hole in it for the IAB , the 4150 gasket blocks the intermediate circuit off , changed the accelerator pumps out to smaller ones also , this motor runs clean & screams through the rpm range , don't think i'll bother messing with the intermediate cicuit , will leave it blanked off.

Those tailpipes smell good , no overfueling & i can pull a chair up , obviously spark lead played a roll also ,will check for any lean issues when i get to the track.

Posted By: Dodgem

Re: Pump cams on 1050 3 circuit domi - 02/18/09 04:04 PM

on my 3 circuit 9375 it definetly runs better through low rpm with 25 shooters. Thought they were way to small when I bought the carb and went 35's sputtered all the way through first. ended up back at 25's on my old 542 they worked best too??
This is because the anullar discharge boosters rain fuel with a low signal so all that extra shot is unneeded.
Posted By: cudabunch

Re: Pump cams on 1050 3 circuit domi - 02/18/09 04:53 PM

Quote:

on my 3 circuit 9375 it definetly runs better through low rpm with 25 shooters. Thought they were way to small when I bought the carb and went 35's sputtered all the way through first. ended up back at 25's on my old 542 they worked best too??
This is because the anullar discharge boosters rain fuel with a low signal so all that extra shot is unneeded.




What color cam did you have on it and was it in the 1 or 2 position ?
Posted By: 602heavy

Re: Pump cams on 1050 3 circuit domi - 02/18/09 09:50 PM

Quote:


This is because the anullar discharge boosters rain fuel with a low signal so all that extra shot is unneeded.



Good info...........the front discharge nozzles are .025 , rears are .035.

I used the pump cams out the mighty demon (purple) , i know there the wrong type (4150) but they work for me till i get the 4500 replacements.
The carb came with the light tan cams , 1 & 2 position did'nt help much with these cams.

Did'nt change shooters out as the motor runs great @ the moment.
Posted By: Bob_Coomer

Re: Pump cams on 1050 3 circuit domi - 02/18/09 10:09 PM

IMO float level is very picky on these. Have you checked it? It might help some. Adjust it to the bottom of the sight hole, were it only has fuel come out if you rock the fender. Then turn it another 1/2 turn down.
I didn't read through all the posts so if these have been mentioned pay no attention.

also sounds like its idling on the primary/intermediate circuit. Back all the idle speed screw out all the way, turn the back idle speed screw in after it touches the cam 3/4 turn, now adjust the front to get proper idle.
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