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Holley 50 cc pump install #1507608 09/25/13 05:52 PM 09/25/13 05:52 PM
Joined: Oct 2003 Posts: 614 ont,canada M mopartuner OP mopar
mopartuner OP mopar M Joined: Oct 2003 Posts: 614 ont,canada	Put a 50 cc pump on my 850 ultra hp carb to try and cure a secondary stumble and just wanted to know if there is pump cams that are 50 cc pump specific?The kit came with 2 cams,a red one that fits and a biege one that the diameter is way off.I have all the other cams for a 750 dp that I have been using up to this point.I changed the pump arm with this install. 410 pump gas solis flat tappet cam 10.95 so far

Re: Holley 50 cc pump install [Re: mopartuner] #1507609 09/25/13 06:22 PM 09/25/13 06:22 PM
Joined: Aug 2003 Posts: 43,204 Bend,OR USA C Cab_Burge I Win
Cab_Burge I Win C Joined: Aug 2003 Posts: 43,204 Bend,OR USA	Quote: Put a 50 cc pump on my 850 ultra hp carb to try and cure a secondary stumble and just wanted to know if there is pump cams that are 50 cc pump specific?The kit came with 2 cams,a red one that fits and a biege one that the diameter is way off.I have all the other cams for a 750 dp that I have been using up to this point.I changed the pump arm with this install. Did you use and change the pump arm to the one for the 50 CC pumps? If not you need to do that first before selecting the pump cam. I have removed the 50 CC pumps and arms from all of my double pumper carbs. that came with them stock to cure bogs, stumbles and flat spots when going to WOT I found the off idle stumble and bog on the starting line to be cause by being to rich What size squirters and motors size and intake are you tuning with now ? Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)

Re: Holley 50 cc pump install [Re: Cab_Burge] #1507610 09/25/13 06:32 PM 09/25/13 06:32 PM
Joined: Oct 2003 Posts: 614 ont,canada M mopartuner OP mopar
mopartuner OP mopar M Joined: Oct 2003 Posts: 614 ont,canada	I have a 410 10.5 to 1 with the 850 on top of a 2 inch open spacer.The cam is 602/624 262/274 @ .050 installed at 104 deg.I have allready changed HS air bleeds,emulsion bleeds,played with 31/35/37 ssquirters,pump cams and the thing still has a huge stumble when going to WOT.I have a wideband in the car and the idle is good and after it does its stumble it goes good and the afr is at 12.9.The transition from cruise to power is crap. 410 pump gas solis flat tappet cam 10.95 so far

Re: Holley 50 cc pump install [Re: Cab_Burge] #1507611 09/25/13 06:34 PM 09/25/13 06:34 PM
Joined: Oct 2003 Posts: 614 ont,canada M mopartuner OP mopar
mopartuner OP mopar M Joined: Oct 2003 Posts: 614 ont,canada	Quote: Quote: Put a 50 cc pump on my 850 ultra hp carb to try and cure a secondary stumble and just wanted to know if there is pump cams that are 50 cc pump specific?The kit came with 2 cams,a red one that fits and a biege one that the diameter is way off.I have all the other cams for a 750 dp that I have been using up to this point.I changed the pump arm with this install. Did you use and change the pump arm to the one for the 50 CC pumps? If not you need to do that first before selecting the pump cam. I have removed the 50 CC pumps and arms from all of my double pumper carbs. that came with them stock to cure bogs, stumbles and flat spots when going to WOT I found the off idle stumble and bog on the starting line to be cause by being to rich What size squirters and motors size and intake are you tuning with now ? Oops forgot the intake is a victor 410 pump gas solis flat tappet cam 10.95 so far

Re: Holley 50 cc pump install [Re: mopartuner] #1507612 09/25/13 11:49 PM 09/25/13 11:49 PM
Joined: Jan 2003 Posts: 5,762 Hot Rod Ridge FastmOp master
FastmOp master Joined: Jan 2003 Posts: 5,762 Hot Rod Ridge	I run 50cc pumps on my 850's. the one on my Chevy 406 is really responsive. The one on my road runner is still getting dialed in but I know it's going to be fine after I fix the breaks and can tune it a little. My Chevy has the dark red (maroon) looking one and the screw is in the bottom hole Not sure on the RR. It's dirty lol I don't run power valves or vacume advance on either lol

Re: Holley 50 cc pump install [Re: mopartuner] #1507613 09/26/13 01:36 AM 09/26/13 01:36 AM
Joined: Jun 2003 Posts: 52,972 Romeo MI MR_P_BODY Master
MR_P_BODY Master Joined: Jun 2003 Posts: 52,972 Romeo MI	Lets go back to the basics here.. whats your timing at, if you use advance whats the basic timing and your total(timing has to be right FIRST before messing with the carb) then is the pump arm touching the cam on the accelerator pump... as soon as the throttle moves you need pump shot

Re: Holley 50 cc pump install [Re: MR_P_BODY] #1507614 09/26/13 05:37 AM 09/26/13 05:37 AM
Joined: Oct 2003 Posts: 614 ont,canada M mopartuner OP mopar
mopartuner OP mopar M Joined: Oct 2003 Posts: 614 ont,canada	Quote: Lets go back to the basics here.. whats your timing at, if you use advance whats the basic timing and your total(timing has to be right FIRST before messing with the carb) then is the pump arm touching the cam on the accelerator pump... as soon as the throttle moves you need pump shot The timing is set at 14@idle and 32 deg totat all in at 2000 rpm.The pump arm is good.The car ran well with the 750 on it but I think it has more with this 850.The transition from cruise to WOT is garbage.AFR flashes to lean and the car goes silent when you mash the gas. 410 pump gas solis flat tappet cam 10.95 so far

Re: Holley 50 cc pump install [Re: mopartuner] #1507615 09/26/13 06:25 AM 09/26/13 06:25 AM
Joined: Jan 2003 Posts: 32,394 Q Quicktree I Win
Quicktree I Win Q Joined: Jan 2003 Posts: 32,394	Quote: Quote: Lets go back to the basics here.. whats your timing at, if you use advance whats the basic timing and your total(timing has to be right FIRST before messing with the carb) then is the pump arm touching the cam on the accelerator pump... as soon as the throttle moves you need pump shot The timing is set at [Email]14@idle[/Email] and 32 deg totat all in at 2000 rpm.The pump arm is good.The car ran well with the 750 on it but I think it has more with this 850.The transition from cruise to WOT is garbage.AFR flashes to lean and the car goes silent when you mash the gas. what are you working on? timing is low?

Re: Holley 50 cc pump install [Re: Quicktree] #1507616 09/26/13 07:56 AM 09/26/13 07:56 AM
Joined: Jan 2003 Posts: 17,918 Akron, Ohio ProSport I Live Here
ProSport I Live Here Joined: Jan 2003 Posts: 17,918 Akron, Ohio	I know it sounds crazy but I had this problem twice before, the first time I ended up drilling out my dominator squirters to .050 and the car started yanking the front tires off the ground. Second time, the bowl gaskets swelled and blocked part of the hole in the metering block. New gaskets and back to good launches.

Re: Holley 50 cc pump install [Re: mopartuner] #1507617 09/26/13 08:26 AM 09/26/13 08:26 AM
Joined: Aug 2003 Posts: 43,204 Bend,OR USA C Cab_Burge I Win
Cab_Burge I Win C Joined: Aug 2003 Posts: 43,204 Bend,OR USA	Make sure the bolt on the pump arms diaghrams are adjusted properly, they should squirt immediatily as soon as you move the throttle a tiny bit and they should have .015 clearance at WOT from being bottomed out It also sounds like your transition circuit may be not functioning correctly Check the float level also, make sure fuel is not splashing out of the front vent tube into the carb. flooding it Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)

Re: Holley 50 cc pump install [Re: Quicktree] #1507618 09/26/13 10:01 AM 09/26/13 10:01 AM
Joined: Jun 2003 Posts: 52,972 Romeo MI MR_P_BODY Master
MR_P_BODY Master Joined: Jun 2003 Posts: 52,972 Romeo MI	Quote: Quote: Quote: Lets go back to the basics here.. whats your timing at, if you use advance whats the basic timing and your total(timing has to be right FIRST before messing with the carb) then is the pump arm touching the cam on the accelerator pump... as soon as the throttle moves you need pump shot The timing is set at [Email]14@idle[/Email] and 32 deg totat all in at 2000 rpm.The pump arm is good.The car ran well with the 750 on it but I think it has more with this 850.The transition from cruise to WOT is garbage.AFR flashes to lean and the car goes silent when you mash the gas. what are you working on? timing is low? I agree... base timing is low for that cam... I would move base timing up to about 20* and change the advance so it goes to 32* or more(to me even your total is a bit low).. but testing will determine the total... I think that the timing will correct most of your issue

Re: Holley 50 cc pump install [Re: MR_P_BODY] #1507619 09/26/13 05:13 PM 09/26/13 05:13 PM
Joined: Feb 2007 Posts: 5,080 organ M maximum entropy master
maximum entropy master M Joined: Feb 2007 Posts: 5,080 organ	50cc pumps have dedicated cams, BUT, you CAN use 30cc cams with 50cc pumps. i do. i drive my car to the track, so my rule is external carb adjustments only. if it gets real cold, i sometimes have to run the 50cc cams, but keeping it JUST rich enough to keep from bogging (you can tell when your r/t gets erratic that you're getting too lean) is fastest. too rich hurts your 60', but can still be consistent enough to be raceable. control the duration of the shot using the combination of cam and squirter size. study your incremental times to figure out what you need to do for any given weather conditions. this all assuming that your timing is dialed properly. for what is the good life if not doing things thoughtfully?

Re: Holley 50 cc pump install [Re: MR_P_BODY] #1507620 09/26/13 05:51 PM 09/26/13 05:51 PM
Joined: Oct 2003 Posts: 614 ont,canada M mopartuner OP mopar
mopartuner OP mopar M Joined: Oct 2003 Posts: 614 ont,canada	Quote: Quote: Quote: Quote: Lets go back to the basics here.. whats your timing at, if you use advance whats the basic timing and your total(timing has to be right FIRST before messing with the carb) then is the pump arm touching the cam on the accelerator pump... as soon as the throttle moves you need pump shot The timing is set at [Email]14@idle[/Email] and 32 deg totat all in at 2000 rpm.The pump arm is good.The car ran well with the 750 on it but I think it has more with this 850.The transition from cruise to WOT is garbage.AFR flashes to lean and the car goes silent when you mash the gas. what are you working on? timing is low? I agree... base timing is low for that cam... I would move base timing up to about 20* and change the advance so it goes to 32* or more(to me even your total is a bit low).. but testing will determine the total... I think that the timing will correct most of your issue I value what you are sugesting here,but darn the thing ran pretty good with that timing.Maybe it can run even stronger with the dizzy locked out,that is the easyest for me to do.I run the MSD pro-billet dist.I allready have the largest bushing and the lightest spring in it.I am going to try it I guess,I have tried everything else. 410 pump gas solis flat tappet cam 10.95 so far

Re: Holley 50 cc pump install [Re: mopartuner] #1507621 09/26/13 07:50 PM 09/26/13 07:50 PM
Joined: Oct 2003 Posts: 614 ont,canada M mopartuner OP mopar
mopartuner OP mopar M Joined: Oct 2003 Posts: 614 ont,canada	I locked the timing at 34 deg and with the 50 cc pump and 37 squirters it still has a stumble when you floor it.AFR goes all the way to the lean end and the motor goes silent........This Holley 850 Ultra carb is a worthless pile of junk,dont buy one. 410 pump gas solis flat tappet cam 10.95 so far

Re: Holley 50 cc pump install [Re: mopartuner] #1507622 09/27/13 03:02 PM 09/27/13 03:02 PM
Joined: Jan 2004 Posts: 13,247 Mt. Vernon, Ohio dartman366 I Live Here
dartman366 I Live Here Joined: Jan 2004 Posts: 13,247 Mt. Vernon, Ohio	Quote: I locked the timing at 34 deg and with the 50 cc pump and 37 squirters it still has a stumble when you floor it.AFR goes all the way to the lean end and the motor goes silent........This Holley 850 Ultra carb is a worthless pile of junk,dont buy one. try a smaller IAB and fatten up the Idle you also will probably want to start trying larger squirters also, I am finding that out with the E-85 conversion and a 1050 dominator that it wants ALOT of fuel at the hit to the tune of .059 squirters at Norwalk in the cool air.Oh, I used the E-85 deal as an example as I have been tinkering to get it dialed in also. Light travels faster than the speed of sound,,,this is why some people seem bright untill you hear them speak.

Re: Holley 50 cc pump install [Re: mopartuner] #1507623 09/27/13 04:55 PM 09/27/13 04:55 PM
Joined: Aug 2003 Posts: 43,204 Bend,OR USA C Cab_Burge I Win
Cab_Burge I Win C Joined: Aug 2003 Posts: 43,204 Bend,OR USA	Quote: I locked the timing at 34 deg and with the 50 cc pump and 37 squirters it still has a stumble when you floor it.AFR goes all the way to the lean end and the motor goes silent........This Holley 850 Ultra carb is a worthless pile of junk,dont buy one. Call Holley and have them send you a "Call Tag" so they can look at it and fix it for you I'm assuming you bought it new and haven't modified the heck out of it Have you If you bought it used and it has been worked on by someone other than Holley, good luck Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)

Re: Holley 50 cc pump install [Re: Cab_Burge] #1507624 09/27/13 06:16 PM 09/27/13 06:16 PM
Joined: Oct 2003 Posts: 614 ont,canada M mopartuner OP mopar
mopartuner OP mopar M Joined: Oct 2003 Posts: 614 ont,canada	Quote: Quote: I locked the timing at 34 deg and with the 50 cc pump and 37 squirters it still has a stumble when you floor it.AFR goes all the way to the lean end and the motor goes silent........This Holley 850 Ultra carb is a worthless pile of junk,dont buy one. Call Holley and have them send you a "Call Tag" so they can look at it and fix it for you I'm assuming you bought it new and haven't modified the heck out of it Have you If you bought it used and it has been worked on by someone other than Holley, good luck I bought this carb new.I even call Holley and told them all the info on the motor and car and they told me that the 850 ultra should be the carb of choice.I have called them many times and they allways say they will call me back and never do.This is the last holley carb I will ever buy. 410 pump gas solis flat tappet cam 10.95 so far

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