Holley carb experts needed!
Thread Starter
Race Director
Joined: Oct 2000
Posts: 15,108
Likes: 79
From: central FL, near the beach.
Re: Holley carb experts needed! (HeaderDesign.com)
0-6498
Wow! just went on a short test drive! This totally transformed it. The idle, and every point above idle was awful :lol: most of the time it was off the scale lean. Oddly it didn't ping, but it was nearly undrivable; had to pump it to get it moving :crazy: and at that 1/3 throttle point i was trying to fix, one side was 13:1, the other off the scale lean. Is this a great hobby or what?
As i pulled in the idle improved to normal, guess that was just cold.
i'm glad it doesn't take long to experiment.
Mabe if that .023 wire hadn't fallen out, it might of been pretty close.
Wow! just went on a short test drive! This totally transformed it. The idle, and every point above idle was awful :lol: most of the time it was off the scale lean. Oddly it didn't ping, but it was nearly undrivable; had to pump it to get it moving :crazy: and at that 1/3 throttle point i was trying to fix, one side was 13:1, the other off the scale lean. Is this a great hobby or what?
As i pulled in the idle improved to normal, guess that was just cold.
i'm glad it doesn't take long to experiment.
Mabe if that .023 wire hadn't fallen out, it might of been pretty close.
Instructor
Joined: Mar 2002
Posts: 239
Likes: 0
From: Fredericksburg VA
Re: Holley carb experts needed! (Matt Gruber)
Sounds strange to have the manifold sides so different. Manifold wetness might be out of whack. What pump cams are you using? Also, how much of the primary transfer slots are showing under the throttle plates (like 0.040")? What about the secondary transfer slots (throttle plates should be like 1/4 to 3/4 turn off the seated position)?
The original carb specs are:
59 jets primary, 60 jets secondary
8.5PV primary, 6.5PV secondary
0.025" shooter primary, 0.037" shooter secondary
The original carb specs are:
59 jets primary, 60 jets secondary
8.5PV primary, 6.5PV secondary
0.025" shooter primary, 0.037" shooter secondary
Thread Starter
Race Director
Joined: Oct 2000
Posts: 15,108
Likes: 79
From: central FL, near the beach.
Re: Holley carb experts needed! (HeaderDesign.com)
thats all for today. once it warms up i quit.
i suspect that at 1/3 throttle i am actually opening the rear slightly and i am not aware of it. pretty hard to tell without a microswitch to warn me.
#5 and 7 have often been listed as the leanest in ths SB. #5 is my leanest, i'm not sure if i want to compensate for it on the primary. i did on the back. i guess it is worth a try, in the spirit of making it a more interesting hobby.
could run, say, a .023 wire on one side and .028 on the other and see if it evens up.
Don't have those measurements for you. But i'm pretty sure the slots are not exposed at idle. Cam is .218 @.050
i will add this note to my web page:
When evaluating the primarys, always disconnect the secondary linkage, as they may open slightly and you won't realize it.
[Modified by Matt Gruber, 3:53 PM 5/29/2003]
i suspect that at 1/3 throttle i am actually opening the rear slightly and i am not aware of it. pretty hard to tell without a microswitch to warn me.
#5 and 7 have often been listed as the leanest in ths SB. #5 is my leanest, i'm not sure if i want to compensate for it on the primary. i did on the back. i guess it is worth a try, in the spirit of making it a more interesting hobby.
could run, say, a .023 wire on one side and .028 on the other and see if it evens up.
Don't have those measurements for you. But i'm pretty sure the slots are not exposed at idle. Cam is .218 @.050
i will add this note to my web page:
When evaluating the primarys, always disconnect the secondary linkage, as they may open slightly and you won't realize it.
[Modified by Matt Gruber, 3:53 PM 5/29/2003]
Le Mans Master
Joined: Mar 1999
Posts: 6,744
Likes: 1
From: delmont pa
Cruise-In I Veteran
Cruise-In II Veteran
Re: Holley carb experts needed! (Matt Gruber)
if the idle transfer slots are not exposed you will have a hesitation because you need fuel flowing till the accerator pump shot catches up when the butterflies start to open. :chevy
Thread Starter
Race Director
Joined: Oct 2000
Posts: 15,108
Likes: 79
From: central FL, near the beach.
Re: Holley carb experts needed!
set it back to stock pvrc and 13" pv. car drives flawlessly. :D
to give an example, i'm cruising at 40 behind a slower car in a 45 zone, i give it 1/4 throttle and it drops into 2nd, ANTICIPATING that i will be passing :cool: no pinging, just ready to go like a racehorse. :D
It is still 12.3:1 or more(in the low speed 1/4 throttle pass mode), so that is the only flaw if i want to be picky. Had that .023 wire not have fallen out, i might not have got sidetracked.
for now i'm just going to ride around and enjoy it, but, next time i have it apart or get really bored, i'll have another look at that circuit. Would be nice if i could rig up an externally adjustable screw that i could use to pinch off the pvrc pathway. i have a spare that i may have a look at. Maybe i'll drill out the spare and see if i can screw a jet in there. i don't trust this wire trick.
Thanks for your comments guys. A perfect tune is lots more work than an excellent tune :yesnod:
to give an example, i'm cruising at 40 behind a slower car in a 45 zone, i give it 1/4 throttle and it drops into 2nd, ANTICIPATING that i will be passing :cool: no pinging, just ready to go like a racehorse. :D
It is still 12.3:1 or more(in the low speed 1/4 throttle pass mode), so that is the only flaw if i want to be picky. Had that .023 wire not have fallen out, i might not have got sidetracked.
for now i'm just going to ride around and enjoy it, but, next time i have it apart or get really bored, i'll have another look at that circuit. Would be nice if i could rig up an externally adjustable screw that i could use to pinch off the pvrc pathway. i have a spare that i may have a look at. Maybe i'll drill out the spare and see if i can screw a jet in there. i don't trust this wire trick.
Thanks for your comments guys. A perfect tune is lots more work than an excellent tune :yesnod:
Thread Starter
Race Director
Joined: Oct 2000
Posts: 15,108
Likes: 79
From: central FL, near the beach.
Re: Holley carb experts needed! (clem zahrobsky)
clem
what if i countersink the hole with about a 1/8 bit. with it upside down(to keep it from flowing inside) JB weld the hole, and then drill it the next day?
To drill and tap would be nice, but there is not much room, 6/32 threads max, then i need jets like you have or maybe a brass setscrew from a hobby shop? something i can drill easily.
what if i countersink the hole with about a 1/8 bit. with it upside down(to keep it from flowing inside) JB weld the hole, and then drill it the next day?
To drill and tap would be nice, but there is not much room, 6/32 threads max, then i need jets like you have or maybe a brass setscrew from a hobby shop? something i can drill easily.
Thread Starter
Race Director
Joined: Oct 2000
Posts: 15,108
Likes: 79
From: central FL, near the beach.
Re: Holley carb experts needed! epilog
the silver lining: http://community.webtv.net/MATTGRU/H...lve/index.html
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