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SLCKREG

  • Karma: +0/-0
How do you know...cam carb Q?
« on: November 06, 2009, 05:49:40 pm »
Long story short, I've went from a 800dp 4150 holley to a 1050 domi(#8082). Ran well except when I stomped it at lower r's. It didn't bog out..it all but died. When I say lower I'm talking like 3k. How do you know if it's dying out from too much gas or not enough?? I guess trial and error. I dunno :-\ When I stabed it at 4500 it was better...but a big pause. I assume I'd want to play with the cam for the squirter on the accelerator pumps. Fwiw fuel pressure is good, timing ect.
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BOOST

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Re: How do you know...cam carb Q?
« Reply #1 on: November 06, 2009, 06:04:36 pm »
  Accelerator pump would be my first check maybe just an adjustment sounds like your on the right track.

65BEAVER

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Re: How do you know...cam carb Q?
« Reply #2 on: November 06, 2009, 06:39:20 pm »
change the pump cam they are the little colored plastic thing that actuates the linkage. They are cheap and only takes minutes to change. After you get that close you can also play with the squirters. They take minutes to change also. Just for reference because all carbs and engines are different. I believe i had a pink cam on a 540 with a 1050 dominater.
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SLCKREG

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Re: How do you know...cam carb Q?
« Reply #3 on: November 06, 2009, 06:52:28 pm »
Thanks for the replys...If I'm not mistaken there is an adjustment by relocating a screw on the existing cam(s). I guess I'll try changing that 1st. I doubt it will/could bog worse. I guess I'll start with just the one on the secondary side 1st,and see what happens.
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65BEAVER

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Re: How do you know...cam carb Q?
« Reply #4 on: November 06, 2009, 07:07:54 pm »
If it's better at 4500 i would think to slow down on the cam? But don't know
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GT Jets

  • Karma: +192/-0
Re: How do you know...cam carb Q?
« Reply #5 on: November 06, 2009, 08:21:10 pm »
You will get the same scenerio if your timing is locked out on an overcarbed application..Carb tuning 101...

It is much easier and quicker to tune it backwards... :screwy:

By that, I mean change the timing to be a bit retarded (like 5 degrees) to prevent a lean detonation condition.
Then get faster (earlier) cams for the accelerator pumps, bigger nozzles and the biggest diaphrams you can get...I am not saying you need the biggest, I am saying tune it bacwards..You can typically adjust in less fuel easier than get more. ;)

I was brought up starting with a setup that runs rich and work backwards, in other words, a lot of fuel damn near spraying the butterflies before they open (with a slight exageration)..Then keep taking away until it goes too far (like a lean "pop").

A vacuum gauge hooked to manifold vac will also answer some questions....If there is very little vacuum at 3K (in the 2-4" range) you went too big on the carb (or cam)...Advancing the cam timing can sometimes (but rarely) help out.

GT
  • Boat #1: 1992 Carrera 20.5 Elite (I/O bitches)
  • Boat #2: 19' Bubble deck Jet BBC Berkeley
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If i get some free time tonight at work, ill play with it and post it for everyone to see.

Time to man up and yank it John!  :banghead:
Ray

SLCKREG

  • Karma: +0/-0
Re: How do you know...cam carb Q?
« Reply #6 on: November 07, 2009, 06:34:04 am »
Thanks GT,,,for the record when I said cam I was talking about the cam for the squirters(I guess that's what it's called). I am locked out and running a crap load of timing. With the 800 dp and stock jets pv's ect, I had no bog what so ever with the same timing,fwiw. As far as being overcarbed I don't think I am with a 557" bbc....I dunno. As far as vac I've got a permanent gauge set up for that, off memory I'm still pulling 10 pounds, or inches or however vac is measured. To be honest the water was so ruff yesterday at wot I couldn't read my wideband(the fact that one of the jolts from a wave knocked the lens out didn't help either) at idle it was right at 11 to 1. I'm having a hard time wanting to fart with timing when it appears to be a carb issue(to me). Someone else also told me to jet up, I guess I could start there. I was pulling my new detailed agressor b cut to the same r's as the old loose set up with an ab cut, so I'm happy with the top end ...just not the huuuuge bog. As far as my squirters go does it sound like they need to be bigger or smaller? There are # 33s in there now.
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SLCKREG

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Re: How do you know...cam carb Q?
« Reply #7 on: November 07, 2009, 08:01:00 am »
I've been sitting here reading the directions(now I'm dangerous) and it says the larger pump shooters .035-.037 should be used in a vehicle where engine speed will increase rapidly. Is it just me or does that sound likea jet boat application :-\. Someone out there must have played this game before, any one running a 1050 on a simular sized engine, that can help a brother out?? The cam thing has got me pretty lost as well. Sounds like 2 part #'s 20-80 and a 20-81. What are you guys with domi's running. I think I'm paying the price for saving money on getting a "street" carb instead of forking out a couple hundy more for the marine version.
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GT Jets

  • Karma: +192/-0
Re: How do you know...cam carb Q?
« Reply #8 on: November 07, 2009, 10:24:33 am »
I've been sitting here reading the directions(now I'm dangerous) and it says the larger pump shooters .035-.037 should be used in a vehicle where engine speed will increase rapidly. Is it just me or does that sound likea jet boat application :-\. Someone out there must have played this game before, any one running a 1050 on a simular sized engine, that can help a brother out?? The cam thing has got me pretty lost as well. Sounds like 2 part #'s 20-80 and a 20-81. What are you guys with domi's running. I think I'm paying the price for saving money on getting a "street" carb instead of forking out a couple hundy more for the marine version.

If'n it were me. I would go bigger on the squirters (find out what squirters come in the marine version and go up one) and bigger on the accel pumps. you may have to get bigger cams for the accel cams also, the last time I bought some, there was a package available with all the popular cams from Holley.

I can get you some part numbers in a bit if you want (I still have all my Holley books). Also take the time to check what power valve is in your setup, I would be willing to bet it is open almost all of the time and you have nothing left when the throttle is pinned at 3k. I am thinking a 6 or a 6.5 should get you in the park.

I am a bit hung over right now  :thumbdown:  Me and some red wine got pretty familiar with eachother and it kicked my ass, but give me a couple hours.... :thumbup: 

Get me a list number and I will get some notes from the riverboat. I have been right were you are before.

GT
  • Boat #1: 1992 Carrera 20.5 Elite (I/O bitches)
  • Boat #2: 19' Bubble deck Jet BBC Berkeley
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If i get some free time tonight at work, ill play with it and post it for everyone to see.

Time to man up and yank it John!  :banghead:
Ray

SLCKREG

  • Karma: +0/-0
Re: How do you know...cam carb Q?
« Reply #9 on: November 07, 2009, 10:47:35 am »
Sweet..thanks GT..as far as the list # it's a 8082 2 circuit. I'm not sure what pv's are in there, but I was kind of suprised that it had pv's both front and rear.
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GT Jets

  • Karma: +192/-0
Re: How do you know...cam carb Q?
« Reply #10 on: November 07, 2009, 10:58:16 am »
Sweet..thanks GT..as far as the list # it's a 8082 2 circuit. I'm not sure what pv's are in there, but I was kind of suprised that it had pv's both front and rear.

If your stuff is out of the box stock...You have 84/84 jets and 6.5/6.5 PV's

I would go down on the PV's depending on what kind of Vac you have at over 2,000 RPM...I can get more info later. Also the 84's sound close to me, I gotta go get my book from the attic from the rock dodger and see where we were..I do think we were running the max ignition timing at 35* BTDC and had a retard module on the dash and we never adjusted it over 3* (Meaning 32* total)., also had a full retard switch for starting...it would run 15* (total of 20*).

Hope that info is helpful.  :-\

GT
  • Boat #1: 1992 Carrera 20.5 Elite (I/O bitches)
  • Boat #2: 19' Bubble deck Jet BBC Berkeley
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If i get some free time tonight at work, ill play with it and post it for everyone to see.

Time to man up and yank it John!  :banghead:
Ray

SLCKREG

  • Karma: +0/-0
Re: How do you know...cam carb Q?
« Reply #11 on: November 07, 2009, 11:07:37 am »
Thanks...sounds like this thing may take a while to get dialed in. When you say try going "down" a size on the pv's does that mean  a smaller #, or bigger? I assume smaller. Sorry for the ten thousand questions.
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GT Jets

  • Karma: +192/-0
Re: How do you know...cam carb Q?
« Reply #12 on: November 07, 2009, 01:19:41 pm »
Thanks...sounds like this thing may take a while to get dialed in. When you say try going "down" a size on the pv's does that mean  a smaller #, or bigger? I assume smaller. Sorry for the ten thousand questions.

The number on a power valve indicates a "rate", as in spring rate, not necissarily "size", the number on a PV is the point in inches/hg that it will "remain closed" or "open" (glass half full vs. half empty type of deal). The lower the number, the longer it remains closed accelleration wise.

I hope that makes sense  :-\  If you have too high of rate (8.5 in./hg) then the valve will be open at 8.5 in/hg and lower and you will not have anything left for mid throttle accelleration, too low (3.5 in./hg) and it wont open until the horses leave the barn.. :).

The accellerator pumps and nozzles fill in the lag time between one throttle position to another, it sounds to me like you have no accellerator pump left at 3K to fill in that void, so if you were to "map" the profile of the pump cams, you are probably all done moving the pump arms at half throttle.. :thumbdown:.

The pumps need to have a later (or longer) profile and will need a larger volume of pump to get the job done and maybe also bigger "shooters", not "hooters", although they may help keep the ambtion to make it work better(IMHO)   ;D .

Is any of this making sense?, I am having a hard time putting it in words.... ???

www.mortec.com    has some killer tuning tips for accellerator pumps, nozzles and power valves. I actually have some books from Holley that have a buttload of info on different carbs, applications, tips and part numbers...A very useful tool.   :thumbup:

GT
  • Boat #1: 1992 Carrera 20.5 Elite (I/O bitches)
  • Boat #2: 19' Bubble deck Jet BBC Berkeley
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If i get some free time tonight at work, ill play with it and post it for everyone to see.

Time to man up and yank it John!  :banghead:
Ray

SLCKREG

  • Karma: +0/-0
Re: How do you know...cam carb Q?
« Reply #13 on: November 07, 2009, 02:55:40 pm »
Thanks again.. I was going to try the shooters 1st, I'm not sure if I need the straight type, or the tube type?
I just went out into the garage and pulled the air cleaner,ect. Fwiw it has shooters for both the primarys and the secondaries(maybe all carbs do, I dunno). It seems to run o.k out of the hole....granted I haven't tried to mat the pedal from a dead stop, but I can live with it there. It seems to me my problem lies when I slam open the secondary side. My initial thought is to make changes just to the secondary side, but a friend of mine tells me that I need to treat the carb like 2 two barrels, and what ever I do to  one side, I need to do to the other. Do I sound as lost as I feel? lol If  Back to the pv thing(If I haven't wore you out yet), do you think my pv(s) are opening too soon or too late, I'm still not sure what direction you'd go from 6.5 :-\      Mental note to self, get holley carb book on christmas list.
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GT Jets

  • Karma: +192/-0
Re: How do you know...cam carb Q?
« Reply #14 on: November 07, 2009, 03:20:29 pm »
Thanks again.. I was going to try the shooters 1st, I'm not sure if I need the straight type, or the tube type?
I just went out into the garage and pulled the air cleaner,ect. Fwiw it has shooters for both the primarys and the secondaries(maybe all carbs do, I dunno). It seems to run o.k out of the hole....granted I haven't tried to mat the pedal from a dead stop, but I can live with it there. It seems to me my problem lies when I slam open the secondary side. My initial thought is to make changes just to the secondary side, but a friend of mine tells me that I need to treat the carb like 2 two barrels, and what ever I do to  one side, I need to do to the other. Do I sound as lost as I feel? lol If  Back to the pv thing(If I haven't wore you out yet), do you think my pv(s) are opening too soon or too late, I'm still not sure what direction you'd go from 6.5 :-\      Mental note to self, get holley carb book on christmas list.

My recomendation just based on the info. that has been presented (hows that for a disclaimer?) I would throw in 5.5 PV's and longer duration accelerator cams with possibly larger volume pumps. Shooter sizes should match from side to side and may need to be stepped up, but the previous recommendations should be followed first (easy and cheap). Being as you have a WB AFR meter, jetting will be a piece of cheddar.  :thumbup:

GT
  • Boat #1: 1992 Carrera 20.5 Elite (I/O bitches)
  • Boat #2: 19' Bubble deck Jet BBC Berkeley
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If i get some free time tonight at work, ill play with it and post it for everyone to see.

Time to man up and yank it John!  :banghead:
Ray

GT Jets

  • Karma: +192/-0
Re: How do you know...cam carb Q?
« Reply #15 on: November 07, 2009, 05:01:16 pm »
After thinking about this for a few minutes....

Here is a free experiment to try..

Go buy a 12 pack of Silver Bullets, go to the lake/river and drive the boat again, but this time get it to run at the afore mentioned 3,000RPM, then let comletely off the throttle for just a half second, then stab it again, if she rockets like it's scared, you need longer cams and or bigger pumps...

Letting off the throttle will reset, or fill the accel. pumps... :sly:

BTW Silver Bullets are optional. ;)

GT
  • Boat #1: 1992 Carrera 20.5 Elite (I/O bitches)
  • Boat #2: 19' Bubble deck Jet BBC Berkeley
  • Like
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If i get some free time tonight at work, ill play with it and post it for everyone to see.

Time to man up and yank it John!  :banghead:
Ray

SLCKREG

  • Karma: +0/-0
Re: How do you know...cam carb Q?
« Reply #16 on: November 07, 2009, 05:32:45 pm »
After thinking about this for a few minutes....

Here is a free experiment to try..

Go buy a 12 pack of Silver Bullets, go to the lake/river and drive the boat again, but this time get it to run at the afore mentioned 3,000RPM, then let comletely off the throttle for just a half second, then stab it again, if she rockets like it's scared, you need longer cams and or bigger pumps...

Letting off the throttle will reset, or fill the accel. pumps... :sly:

BTW Silver Bullets are optional. ;)

GT
I think I follow you here...that way it will get a full shot of both the front and rear shooters. I hope to make it out one more time, I'll try to follow up here with some video of how it runs...and what the wide band has to say. Thanks again GT.
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GT Jets

  • Karma: +192/-0
Re: How do you know...cam carb Q?
« Reply #17 on: November 07, 2009, 11:22:58 pm »
Check out what I be find'n on the net... O0

http://cgi.ebay.com/ebaymotors/Holley-Carburetor-Accelerator-Pump-Cam-Assortment-20-2_W0QQcmdZViewItemQQhashZitem2ea7214799QQitemZ200372471705QQptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAccessories

Scope out the chart on the bottom.  :thumbup:



IMHO you need either the yellow or the brown cam...

GT
« Last Edit: November 07, 2009, 11:25:12 pm by GT Jets »
  • Boat #1: 1992 Carrera 20.5 Elite (I/O bitches)
  • Boat #2: 19' Bubble deck Jet BBC Berkeley
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If i get some free time tonight at work, ill play with it and post it for everyone to see.

Time to man up and yank it John!  :banghead:
Ray

SLCKREG

  • Karma: +0/-0
Re: How do you know...cam carb Q? New
« Reply #18 on: November 08, 2009, 07:35:41 am »
Very cool...Curiosity got the best of me, I pulled one off and it #643 yellow. I went to by some different shooters yesterday,dang 20 buck a piece. I need to buy a bargain variety pack I guess.lol I guess I'll hope the wieband can talk to me.....
edit; you know what's wierd, if you go to jegs and search for dominator pump cams, it only shows 2 part #'s 20 80 and 20 81?   I wonder if the 600 #'s are even suposed to be used on domi's? My owners phamplet only talks about those 2 choices also.  Things that make me go hmmmmmm :banghead:
« Last Edit: November 08, 2009, 08:23:37 am by SLCKREG »
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