528 Hemi help

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cjcx3

cjcx3

Twisted Sundance
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I am making a callout to all you folk that know the gen II hemi and the aftermarket 528 Hemi. I have a 528 Hemi based off of a Ray Barton 750hp crate motor. I purchased all the parts and built it myself to save some $$ and I like to build everything myself. I have checked all the common stuff and ...well Im lost. I have a Pro systems Holley 850 and if I get the engine to idle its way to fat(rich). If I go to a larger air bleed to lean it out then the engine dies when I pull it in gear. I have a MSD6AL with RN9YC plugs gap at .045. Base timing is 20 and full is 33. Fuel pressure is at 7psi. Floats are set a little low. Its really hard to get to stay running when I first start it but after a few minutes it will run ok. The throttle blades are almost out of the idle circuit. Im not sure what else to do. Any help or new ideas out there?
 
how much bigger is the air bleeds you swaped i was told to jump no more than 3 numbers. i jumped mine 2 numbers and never seen much difference.
 
Did you adjust the rear throttle blades per the holley procedure, open them up to help airflow and close the primary down?
 
I have all aluminum 496 Hemi with solid lifters. It does not like to idle when its cold once it warms up its fine. Holley carbs need to have the fuel level set correctly or they will not work.
Fuel level to low it won't Idle correct. fuel level to high it won't idle down and will flood . DO you have a way of monitoring your air/fuel ratio?
 
Air bleeds were 76/76 and I now have 69/69. With the 76 airbleeds it would idle but would die when I put in gear. I have plenty converter. Fuel level is just at the base of the sight glass. Rear throttle is opened up as far as it can go and still be im idle circuit. No I dont have an o2 set up. Im using my nose and the tears from my eyes and reading plugs.
 
I think you went the wrong way on the air bleed size.by making them smaller you get less air into the circuit so you richen it up. to lean the mixture use bigger ones. air bleeds work just the opposite of the main jets. bigger is leaner and smaller is richer.
 
Air bleeds add air to emulsify the idle mixture. I suspect you may need to change the IFR to reduce the amount of fuel available in the idle circuit. This should allow you to choke down on the primary and secondary throttle butterfly opening to get closer to the optimum .020 to .040 transfer slot reveal. If air bleeds are too large then the idle circuit will respond poorly and that is why you get stumble. The balance is the correct IFR (Idle feed restriction) and the correct Idle bleed size to allow for good off throttle response and light throttle running. Even off idle the idle circuit does contribute to fuel delivery on cruise conditions. So it needs to be correct. Keep in mind that IFR changes are more severe than air bleed. So just reduce your IFR by small increments.
 
I didnt go the wrong way on the air bleeds. I know how they work. If I lean out the idle with the air bleeds the engine will die when I put it in gear. I had to lower the air bleed size to get it to stay running while in gear. This IFR is something new to me. What is it?
 
Idle Feed Restrictor....two in each metering block, another orifice to meter the idle fuel. Most billet metering blocks have these screwed in, so they are replaceable.

My Carb is running too rich at idle, did the same when putting in gear. After completely removing the IAB´s it´s running good, that tells me that the IFR´s are too big for my engine....and of course the A/F gauge.....it´s very useful for tuning.

Michael
 
Can you show me a pic of this IFR? my meter blocks do not have anything that screw in
 
The effect of air bleeds is not always predictible. The purpose is to correct the fuel curve on a fixed jet fuel system. Any emulsion is a just a side benefit. Too much air and delivery will be erratic.

Going too big in an air bleed will delay the start of fuel flow. Picture sucking on straw with a big hole in the side. Then it may go rich before settling down, and then will go lean. See the last post here for graphic
http://racingfuelsystems.myfunforum...t80.html?sid=dbfcf9caeea2c04173246204954c4830

The idle system also has a variable air bleed in it. That's the portion of the transfer slot above the throttle blade. See this Chrysler tech booklet for the concept
http://www.imperialclub.org/Repair/Lit/Master/222/Page08.htm
 
How much timing will the starter handle before kicking back. Find that point and set initial timing just short of there.

20 seems a little light for a 750hp 528 engine. I'd guess mid 20's or more.
 
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