Hello guys sorry to post here again but I need some pointers on what to do next.
I have checked everything and there are no vacuum leaks and ignition system is all new and all has been checked along with timing. I am running plenty of initial timing with this cam so its not the issue as was checked before even messing with the carb.
First thing engine 350 sbc high rise dual plane intake dart shp 180cc aluminum heads 9 to 1 cr lunati voodoo hydraulic roller 219/227@50 515/530 lift.
The carb I am using is a holley 600 vacuum secondary with a metering block conversion on the rear. So its jetted 65 front and 72 rear. Float levels checked etc.
First problem I had was the transfer slot being opened up to much but got that solved and is now correctly at about .20 to .030. with the secondary's opened as well and are almost equal with the primary's. Next problem has was getting it to idle smooth but always quit on me so it seemed very lean.
From reading on setting idle mixture screws and idle circuit tuning I got the symptoms mine was way lean and these holley 600 and street avenger carbs are known to have a very lean idle circuit.
I had to also open my primary metering block idle feed restriction from a .027 to .029 cause the idle mixture was lean and having idle mixture screws out almost 1 3/4 turns and turning them in more then a 1/4 of a turn killed the engine and making them richer made no difference so I needed to get more adjustability so after opening the ifr on the primary metering block it worked better and I was able to get it to adjust more so using a vacuum gauge they both sit at 1 1/4 turn out.
Problem I am having is if you are at a dead stop and gently ease into the throttle its fine and if your cruising and your easy getting into the throttle its fine but if you give it a quick shot it will sometimes stall or it will back fire and from reading holley's tech stuff it indicates its too lean.
So I bought a shooter kit and I went from the stock .031 to a .035 and it helped some but still get the back fire if giving it a big shot. So changed the orange pump cam to a blue pump cam to give a bigger longer duration shot and it still did not help either on the number 1 or 2 position.
I called holley tech and they about suck as they said they don't know why its doing this and asked if I went to a smaller shooter and I said how would that help as its a lean backfire? He said to run ported vacuum advance and not full but that makes no difference here as it still does it.
Vacuum advance it limited to 12-14 degrees and from the whole debate of ported vs full manifold setup it does it on either one but from what I get with bigger cams they like full manifold more then ported.
Normally going to a bigger shooter solves this problem and my pump arm is set correctly and has instant shot. I don't have funds at the moment for getting a 02 sensor installed etc so please don't be mean and say get one cause if I could I would but trying to just do one thing at a time so in order to not mess things up.
Any ideas on what to try next? Please be kind guys I am trying to learn.
Thanks all
Eric
I have checked everything and there are no vacuum leaks and ignition system is all new and all has been checked along with timing. I am running plenty of initial timing with this cam so its not the issue as was checked before even messing with the carb.
First thing engine 350 sbc high rise dual plane intake dart shp 180cc aluminum heads 9 to 1 cr lunati voodoo hydraulic roller 219/227@50 515/530 lift.
The carb I am using is a holley 600 vacuum secondary with a metering block conversion on the rear. So its jetted 65 front and 72 rear. Float levels checked etc.
First problem I had was the transfer slot being opened up to much but got that solved and is now correctly at about .20 to .030. with the secondary's opened as well and are almost equal with the primary's. Next problem has was getting it to idle smooth but always quit on me so it seemed very lean.
From reading on setting idle mixture screws and idle circuit tuning I got the symptoms mine was way lean and these holley 600 and street avenger carbs are known to have a very lean idle circuit.
I had to also open my primary metering block idle feed restriction from a .027 to .029 cause the idle mixture was lean and having idle mixture screws out almost 1 3/4 turns and turning them in more then a 1/4 of a turn killed the engine and making them richer made no difference so I needed to get more adjustability so after opening the ifr on the primary metering block it worked better and I was able to get it to adjust more so using a vacuum gauge they both sit at 1 1/4 turn out.
Problem I am having is if you are at a dead stop and gently ease into the throttle its fine and if your cruising and your easy getting into the throttle its fine but if you give it a quick shot it will sometimes stall or it will back fire and from reading holley's tech stuff it indicates its too lean.
So I bought a shooter kit and I went from the stock .031 to a .035 and it helped some but still get the back fire if giving it a big shot. So changed the orange pump cam to a blue pump cam to give a bigger longer duration shot and it still did not help either on the number 1 or 2 position.
I called holley tech and they about suck as they said they don't know why its doing this and asked if I went to a smaller shooter and I said how would that help as its a lean backfire? He said to run ported vacuum advance and not full but that makes no difference here as it still does it.
Vacuum advance it limited to 12-14 degrees and from the whole debate of ported vs full manifold setup it does it on either one but from what I get with bigger cams they like full manifold more then ported.
Normally going to a bigger shooter solves this problem and my pump arm is set correctly and has instant shot. I don't have funds at the moment for getting a 02 sensor installed etc so please don't be mean and say get one cause if I could I would but trying to just do one thing at a time so in order to not mess things up.
Any ideas on what to try next? Please be kind guys I am trying to learn.
Thanks all
Eric