eugene Posted July 25, 2002 Share Posted July 25, 2002 I'm having trouble timing my engine: late model 350 w/ stock cam, holley 600 vac sec, HEI w/ adjustable vac adv How much vaccuum should my ported signal have at idle? Shouldn't it be little or none? Mine has 9 in. at idle and 22 in. on accel. This is causing extreme timing advance at idle(14 deg. above initial timing). The only way to get a decent timing curve is to retard the initial timing. Is this a carb problem or a vac adv diaphragm problem? It's a new Accel adjustable vac adv unit. I don't get any change in the advance at idle after adjusting the diaphragm back. Also, I need a good Holley tuning book. I bought one by Dave Emanuel that ended up being more of a history lesson. I need one that's heavy on the tuning and troubleshooting. Any recommendations? Quote Link to comment Share on other sites More sharing options...
660Z Posted July 25, 2002 Share Posted July 25, 2002 your right ported vacuum( above the throttle plates....and on the side of the metering block on holleys)should have little or no vacuum at idle and become stronger with acceleration.sounds like you have a bad metering block gasket... a tip:at least with the older gaskets.rub liquid soap on them and they become reuseable and seal better.....the holley new blue gaskets i don`t think this tip applies,haven`t worked with one so i really can`t say.....mark Quote Link to comment Share on other sites More sharing options...
Mike C Posted July 26, 2002 Share Posted July 26, 2002 Also make sure that you haven't uncovered too much of the idle transition slot because your primary throttle blades are cracked too much. This is the trouble Pete was having with his car, not enough airflow at idle so the idle had to be turned up which caused the mixture to be too rich. Quote Link to comment Share on other sites More sharing options...
eugene Posted July 27, 2002 Author Share Posted July 27, 2002 Thanks for the tips! Any recommendations on good books for tuning and troubleshooting Holleys? I work on fuel injected vehicles every day, carburetors are new to me. I think you may be onto something with the transfer slot because the car runs way too rich. I can't get it below 2% CO at idle or it dies returning to idle after acceleration. I need an information resource to help me start over with it and select jet size, power valve, etc. to get this thing running efficiently. I may go EFI someday but the novelty of working with a carburetor hasn't worn off yet, and it's so damn easy to work on that any changes would be quick and easy, I just need a guide to help me troubleshoot. I've found a lot of books and manuals, I guess I just want to know which ones have been helpful with other people. Quote Link to comment Share on other sites More sharing options...
pparaska Posted July 27, 2002 Share Posted July 27, 2002 Jason, Go here for Holley info to find the jets, PVs, etc. the carb came with: http://www.holley.com/HiOctn/ProdLine/CarbList.pdf Find the list number on the choke horn front and look it up in that file. Oh, and Dave Emanual's book on tuning and modifying Holley carbs is a good place to start! Good luck! Quote Link to comment Share on other sites More sharing options...
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