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Author
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Topic: power valve
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RADRIDE
Gearhead Posts: 270
From: Va.Beach, Va.
Registered: Aug 2002
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posted 04-09-2003 06:45 PM
   
OK I gave up on the peanut carb & bought a MightyDemon.It ran good out of the box, but rich.In tuning idle mixture I could run the screws fully in without much trouble,and only 6lbs of vac.So I figure the pv(6.5)is flowing always.I will change to a 4.5 pv. Now will I run into a lean condition?I used a friends Vac guage,is this the best way to adjust air/fuel mix.The cam is CompCam 294s,heads are AFR-185 non-emission,intake RPM air-gap.Should vac be so low?
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Moneymaker
Administrator Posts: 21725
From: Lyons, IL, USA
Registered: May 99
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posted 04-09-2003 08:51 PM
NO.
You will not lean out too much with a 4.5 PV.------------------
Alex Denysenko
Co-Administrator and Moderator NHRA/IHRA/SRA member and licensed Superstock driver
MCA member# 53321
NHRA and IHRA SS/LA National Record Holder '00,'01,'02,&'03
Fleet of FoMoCo products including 88 ASC McLaren Mustang #28
Professional Manwhore
The Barry of BarrysGrrl Quote #1: "I never met a magazine mechanic I liked."
Quote #2: "Make sure brain is in gear before engaging mouth!"
Quote #3: "If you can't run with the big dogs, stay on the porch!"
www.moneymakerracing.com
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BLstangin
Gearhead Posts: 474
From: South Central MN
Registered: Apr 2002
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posted 04-09-2003 08:57 PM
I have a 6.5 pv in my holley 1850 carb. I have between 11 and 12 lbs of vac at an idle, will this powervalve be o.k. or is it causing my surge around 1200-1400 rpm, holley told me my jets were lean, so which one is it? I am running 69 jets in my 302.------------------
1970 coupe restored with the help of my dad. 302 with 600 holley, aluminum intake, headers, pertonix ignitor 2 with matched coil, lakewood bellhousing, 4-speed toploader, and 2.79 open 8" rear. Soon to be 9" 3.25 trac-lok
1986 f-150, 5.0, factory towing package with original c-6 trans
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Moneymaker
Administrator Posts: 21725
From: Lyons, IL, USA
Registered: May 99
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posted 04-09-2003 09:05 PM
quote:
Originally posted by BLstangin:
I have a 6.5 pv in my holley 1850 carb. I have between 11 and 12 lbs of vac at an idle, will this powervalve be o.k. or is it causing my surge around 1200-1400 rpm, holley told me my jets were lean, so which one is it? I am running 69 jets in my 302.
I can't see you being lean at all with 69 jets.
I would definatly try a shorter PV to eliminate the part throttle surge.
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Alex Denysenko
Co-Administrator and Moderator NHRA/IHRA/SRA member and licensed Superstock driver
MCA member# 53321
NHRA and IHRA SS/LA National Record Holder '00,'01,'02,&'03
Fleet of FoMoCo products including 88 ASC McLaren Mustang #28
Professional Manwhore
The Barry of BarrysGrrl Quote #1: "I never met a magazine mechanic I liked."
Quote #2: "Make sure brain is in gear before engaging mouth!"
Quote #3: "If you can't run with the big dogs, stay on the porch!"
www.moneymakerracing.com
IP: Logged |
capri man
Gearhead Posts: 4320
From: doerun, ga.
Registered: Nov 2000
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posted 04-09-2003 09:09 PM
does his vaccum seem kinda low to you guys??
leak somewhere maybe??------------------
mike r
racing is real
everything else is just a game.
81 capri-7.51 @89mph 1/8
1.54 60 ft.
http://prestage.com/site/site_display.asp?SiteID=141
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BLstangin
Gearhead Posts: 474
From: South Central MN
Registered: Apr 2002
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posted 04-09-2003 09:24 PM
capri man, do you mean my vaccum? My vaccum is a little low because my motor has been cammed. I do not know all the specs on my cam, because it was in there when I bought the car, but I do know that it has .448 lift on the intake and .472 lift on the exhaust, checked the lift when I had the intake off last week, and my dad just fixed my intake leak, he put a coat of silicone around the water jackets and around each intake port on both sides of the gaskets to make sure it wouldn't leak as we found about three or four spots where it looked like it was leaking and and we used a new base gasket on the carb too, so I am pretty sure nothing is leaking there. It does run much, much better after we put intake gaskets in it, and the idle is more of a steady lump instead of a eratic jump all over the place type of idle it had before. Holley says my pv is just great, and my jetting is lean, but it did this before I put headers on too. I don't see it lean either as my friend's 500 hp cleveland is only running 71 jets. Does my vaccum sound about right for this cam? 
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1970 coupe restored with the help of my dad. 302 with 600 holley, aluminum intake, headers, pertonix ignitor 2 with matched coil, lakewood bellhousing, 4-speed toploader, and 2.79 open 8" rear. Soon to be 9" 3.25 trac-lok
1986 f-150, 5.0, factory towing package with original c-6 trans
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Moneymaker
Administrator Posts: 21725
From: Lyons, IL, USA
Registered: May 99
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posted 04-09-2003 09:31 PM
I'm right and Holley is wrong!
You vaccum level seems appropriate.
End of story! 
Next question please.  ------------------
Alex Denysenko
Co-Administrator and Moderator NHRA/IHRA/SRA member and licensed Superstock driver
MCA member# 53321
NHRA and IHRA SS/LA National Record Holder '00,'01,'02,&'03
Fleet of FoMoCo products including 88 ASC McLaren Mustang #28
Professional Manwhore
The Barry of BarrysGrrl Quote #1: "I never met a magazine mechanic I liked."
Quote #2: "Make sure brain is in gear before engaging mouth!"
Quote #3: "If you can't run with the big dogs, stay on the porch!"
www.moneymakerracing.com
IP: Logged |
BLstangin
Gearhead Posts: 474
From: South Central MN
Registered: Apr 2002
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posted 04-09-2003 10:04 PM
Thank you Alex, what number pv would you suggest?------------------
1970 coupe restored with the help of my dad. 302 with 600 holley, aluminum intake, headers, pertonix ignitor 2 with matched coil, lakewood bellhousing, 4-speed toploader, and 2.79 open 8" rear. Soon to be 9" 3.25 trac-lok
1986 f-150, 5.0, factory towing package with original c-6 trans
IP: Logged |
Moneymaker
Administrator Posts: 21725
From: Lyons, IL, USA
Registered: May 99
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posted 04-09-2003 10:10 PM
4.5 should be just right.------------------
Alex Denysenko
Co-Administrator and Moderator NHRA/IHRA/SRA member and licensed Superstock driver
MCA member# 53321
NHRA and IHRA SS/LA National Record Holder '00,'01,'02,&'03
Fleet of FoMoCo products including 88 ASC McLaren Mustang #28
Professional Manwhore
The Barry of BarrysGrrl Quote #1: "I never met a magazine mechanic I liked."
Quote #2: "Make sure brain is in gear before engaging mouth!"
Quote #3: "If you can't run with the big dogs, stay on the porch!"
www.moneymakerracing.com
IP: Logged |
BLstangin
Gearhead Posts: 474
From: South Central MN
Registered: Apr 2002
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posted 04-09-2003 10:21 PM
O.k. I will try that, thanks Alex.------------------
1970 coupe restored with the help of my dad. 302 with 600 holley, aluminum intake, headers, pertonix ignitor 2 with matched coil, lakewood bellhousing, 4-speed toploader, and 2.79 open 8" rear. Soon to be 9" 3.25 trac-lok
1986 f-150, 5.0, factory towing package with original c-6 trans
IP: Logged |
Fastymz
Moderator Posts: 14201
From: Reno Nv USA MEM#1240
Registered: Apr 2001
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posted 04-10-2003 12:54 AM
quote:
Originally posted by capri man:
does his vaccum seem kinda low to you guys??
leak somewhere maybe??
You were talking about RadRide thats alot of cam he's running.But it does seem like low vacuum. BLstangin,everytime I listen to Alex my car runs better.Either he's good or just lucky alot.
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SCOOP
oddly obsessed with big scoops on little Mustangs 2.26 60'S
14.9 @ 90.86MPH 65 coupe,351w,C4,Big Boss 429 hood scoop,8"3.40 TracLoc,Cragar SS,Black Suede. https://mustangsandmore.com/ubb/Fastymz.html
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RADRIDE
Gearhead Posts: 270
From: Va.Beach, Va.
Registered: Aug 2002
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posted 04-10-2003 11:21 AM
I dont think I have any leaks, everything is new and motor runs real well.Just trying some fine tuning on something I have very little experience at.My motor guy says with that cam,and heads it flows more air than motor(289 bored .040)can handle creates no vaccum.Sounded good to me,and since he knows a stroker is in works hes not worried.I want a 347,but he tells me it will never handle me behind the wheel and he thinks I will be better off with a 331.
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bluestreek
Gearhead Posts: 1460
From: Athens,GA
Registered: Jul 2001
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posted 04-10-2003 12:08 PM
Radride,
Your vacuum does seem low, but a 294S is a big cam. You could probably get away with using a lot of spark advance to get your vacuum up. What's your ignition timing set at and what size Demon do yu have?------------------
1966 Mustang Coupe: Custom glass hood and BIG scoop sits atop a 289 stroked to 331 c.i., Steel crank and girdle, 5.4 H-beams, Forged slugs, TFS alum. heads, ported Stealth 8020 intake, Xtreme 274 Solid Roller, Holley 750 HP, long tubes, 4speed, 9" 3.50 posi.
2nd pass: 12.11 @ 114 mph
DanH
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RADRIDE
Gearhead Posts: 270
From: Va.Beach, Va.
Registered: Aug 2002
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posted 04-11-2003 11:21 AM
Was at 14, just readjusted a/f mixture with new pv.We retimed at 18 (about33at 2500rpm)it seemed to help a off idle stumble and it seemed to help and car still starts very easily.Could probably go higher but since its been raining for a week I dont have a chance to put it under a load.The carb is a 750 MightyDemon,I know a lot of carb,but a new stroker short block is in my future,and didnt want to buy another carb down line.
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bluestreek
Gearhead Posts: 1460
From: Athens,GA
Registered: Jul 2001
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posted 04-11-2003 11:39 AM
quote:
Originally posted by RADRIDE:
We retimed at 18 (about 33 at 2500rpm)it seemed to help a off idle stumble and it seemed to help and car still starts very easily.Could probably go higher but since its been raining for a week I dont have a chance to put it under a load.
Get the initial timing advanced as far as possible before any other changes. Just remember that the octane rating may effect how high you can go. Then work the carb out from there. Sounds like a RADRIDE!! :lol: ------------------
1966 Mustang Coupe: Custom glass hood and BIG scoop sits atop a 289 stroked to 331 c.i., Steel crank and girdle, 5.4 H-beams, Forged slugs, TFS alum. heads, ported Stealth 8020 intake, Xtreme 274 Solid Roller, Holley 750 HP, long tubes, 4speed, 9" 3.50 posi.
2nd pass: 12.11 @ 114 mph
DanH
IP: Logged |
BLstangin
Gearhead Posts: 474
From: South Central MN
Registered: Apr 2002
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posted 04-13-2003 01:34 AM
O.k. Alex you said next question. First I put in the 4.5 pv and it really helped the surging, but it is still there but it is much better, my dad thinks that my idle circuit may be lean as at these rpms I am barely touching the throttle. I set the idle screws with a vaccum gauge for max vaccum though. What do you suggest next? Also my idle mixture screws don't seem to do a whole lot, is this normal for a cammed car or isn't it?------------------
1970 coupe restored with the help of my dad. 302 with 600 holley, aluminum intake, headers, pertonix ignitor 2 with matched coil, lakewood bellhousing, 4-speed toploader, and 2.79 open 8" rear. Soon to be 9" 3.25 trac-lok
1986 f-150, 5.0, factory towing package with original c-6 trans
IP: Logged |
DidgeyTrucker
Gearhead Posts: 1112
From: Greenbrier, TN USA
Registered: Oct 99
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posted 04-13-2003 11:23 AM
If the idle mixture screws don't make much of a change, this would indicate the primary butterflies are open too much and bypassing the idle circuit all together. You should be able to make an adjustment on the secondaries to open them some so you can close the primaries enough to use the idle circuit. It's all in the fine tuning, carb, timing, etc.Tracy
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