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Topic Review (Newest First)
04-26-2013 10:16 AM
eric32 Hello fbird one last question here is the link I found but I know they make all different kind of 02 sensors. Do you know one that would work with this clamp?
http://www.summitracing.com/parts/av...0/media/images

Also I know there is wideband and short band etc I really don't know more then this as this type of tuning is all new to me.
Thanks
04-26-2013 09:56 AM
eric32 Hello fbird I did not know that existed so thanks for the heads up and I looked on summitracing and found what I need to get for clamp wise. This will help me get in the right direction. Thanks again sir
04-25-2013 09:17 AM
eric32 I don't own a welder and don't know how to do that but not that I can't learn. Funds to buy one is out of the option's for now. I will try some of the suggestions you posted to start off with before doing anything else such as drilling wise etc.

I am going to start off with re doing my secondary opening a little less and then re set my primary and then check the pcv valve with trial and error and then go from there. I guess I will have to start saving for a welder so I can get a 02 sensor fitting put into my exhaust.

I have seen some decent priced afr gauges at the auto part store so when funds permit I will look into buying one. I should not have to spend a ton on a welder as I have been looking at some for around 150 to 200 bucks and for something like this they would work fine. Thanks for the tips.
04-24-2013 04:11 PM
eric32 I don't have the option yet for using a wide band 02 censor as I have to find someone who can install one for me and I live in a small town and not many around here can do exhaust work etc. As far as the pcv valve goes its a oem replacement type one so I have no idea what it goes too as the parts counter guy asked me what it was for I said a 350 small block chevy and he gives me one and said it covers most gm vehicles so don't know how to get a different one there and thanks for the tips on the pin vice drill bit set I will have to get one. I will try some other things before I go drilling out holes cause I know it cant be changed once done.
04-24-2013 01:49 PM
eric32 Thanks fbird I will try your suggestions. I know this sounds like a stupid question but where can I get drill bits that size to drill bigger in my original metering blocks? And is this done by hand or a hand drill? I have heard about doing that but have not seen it done. I am famaliar with what holes are what on the metering block. Thanks guys you all rock
04-24-2013 12:49 PM
eric32 Yeah this carb is only a 2 corner idle adjustment. Seems the carb is not too compatible with bigger cams then rv sizes. Can't afford a new carb right now and want to do what I have to do to make this one work and I just need to get it fine tuned to do so.

Problem is if I open the secondary's to be equal with the primary's it ends up with too much of a high idle and causes off idle slow speed surging issues but fine once rpm is picked up. Using ported vacuum does make my engine run with a little less throttle response on low speed and also makes it run a little hotter through town in stop and go situations.

But the primary's I can never get to be .020 or close to it without having to open the primary's open more in order for it to idle good and not stall when put into gear but defeats the purpose of getting it to be square and not end up with the idle pulling too much from the transfer slot and making a too rich of an idle.

This carb has a very lean idle circuit and that's why I asked if I use the billet quick fuel metering blocks it has replaceable idle feed restrictions and will allow me to change the idle fuel curve and might allow me to get better adjustability as this cam want's a richer fuel curve in order to idle well.

From what I read the holley 1850/80457 600 vacuum secondary carbs and there street avenger lines are set up with a very lean idle circuit and many people have had problems with these carbs being way lean out of box on anything other then a stock size or rv cam engine.

Even if I give it more timing initial and hooking the vacuum advance up to ported source it does not make any difference and I end up with the primaries open too much but the idle mixture screws still adjust but end up with run on after you shut the engine off.


I have not checked how much vacuum I have but should be around 16 inches so that is not a problem there as far as vacuum signal goes.
04-24-2013 12:11 PM
33Willys77 I am thinking you are opening the secondaries too far. Close them off and set the t-slot on the primaries to .020. I am not a big guru with Holley carbs, but doesnt this carb have 2 idle adjustment screws instead of the 4 corner? If so, then the seconardaries would be closed. F-Bird will set this straight since he is on here already. Others may also charm in, but this is what I am taking out of your post.
04-24-2013 10:14 AM
eric32 Hello Fbird I have tried that before and the engine does not like ported vacuum too well even with the previous smaller cam. From what I have read on the whole ported vs full manifold debate is bigger cams like full manifold for extra timing and a better idle and my engine runs better with full manifold then ported. When using ported I end up with the primary's open way too much and the secondary transfer slot is up higher then the front and making them equal ends up allowing too much air and I can't get the idle down to 900 rpm as the secondaries are open too much and by the time you get them right to work well they are not equal. I will try and see how it goes.
04-23-2013 08:07 PM
eric32
Advice tuning holley 600 vs idle circuit

Hello guys me again I need some basic advice here on tuning my holley 80457 600 vacuum secondary carb idle circuit. I know about basic carb tuning quite well but am by no means an expert like some of you guys on here when it comes to fine tuning a carb. first here is my setup

350 sbc
dart shp 180cc aluminum heads 72cc chamber
lunati voodoo hydraulic roller 270/276 219/227 @ 50 515-530 lift. 112 lsa
holley 600 vacuum secondary
weiand high rise dual plane
9 to 1 compression.
Turbo 350 2200 rpm stall 3.42 rear gears.

Ok here is my dilemma. I got the timing all set and with vacuum advance hooked up I have around 30 to 32 at idle and around 18 degrees initial timing and all in by 3000 rpm.

Motor runs excellent from 2000 rpm and up but in order to have proper transfer slot position on the primary's at .020 I try to crack open the secondary's about 3/4 to 1 turn past contact on the secondary speed screw but it will cause my idle to be to high and the primary idle won't go down enough but on the flip side of things if I leave the secondary's open too much like that its causing a lean condition and surging at low speed under 1800 rpm from the transition cirtuit and too high an idle and an off idle stumble and the pump shot has all been checked for proper clearance and gets a good shot of gas.

And if I set it back at half a turn then I can get idle to be good and takes off without the bad stumble and backfire from lean tip in and goes just fine but then I have the problem of the transfer slot being slightly more then .020 and say maybe around twice that amount but I still have good tuning of the idle mixture screws and they sit around 3/4 of a turn out.

I know the jetting is not bad as plugs are good and tan and no surging going down highway at 55 mph at 2600 rpm. So I am getting the feeling here but I could be wrong that the holley 600 is a little to lean on the idle circuit for this cam but I want to get this carb to work as getting something else is out of the question and I know a 750 is more power etc but this is something I want to drive and get decent fuel manners with better throttle response.

I do have a set of quick fuel billet aluminum metering blocks both primary and secondary and they have a feature of being able to change the idle feed restrictions from .028 ( which is stock size on current holley blocks) to .031 and would this help me with better idle tuning and needing less transfer slot if I swapped out the holley blocks for the quick fuel blocks which have more fine tuning features and are for this and the 3310 carb as replacement blocks with a more performance type fuel curve which I feel this carb can use. Any opinions? Thanks guys appreciate your help.
Eric

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