vortec timing
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my boat came from the factory with a votec 5.7 an 2 bbl carb,with no advancement for timing.I was told the modual has 8 degrees built in.I just refreshed the engine an added a 600cfm on the dual plane intake an it wont run with this distributor setup.How much advancement is to much,,will hei ignition suit an if i have a lean issue at #8 can i go up to say 65 or 66 jets in the mains,it has 63 from the factory.I just re-valved 6 an 8 intake,it only took bout 4 hrs to suck them in with the current set up.
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What do you mean it doesnt run? Does it try to start, just wont idle? Is there any obnoxious popping when you are cranking? I did a Vortec head swap onto my 5.7L and my Thunderbolt IV worked just fine. I would post more symptoms and information so people can help out a bit more.
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If you are running thunderbolt ignition then initial timing may call for 8 degrees btdc, module should provide 22 degrees for a total of 30. I assume this is what you have.
I would set advance for total timing of about 32 for a vortec motor, doesn't matter what initial is. On thunderbolt v ignition there is a wire you have to ground to set the timing.
Too much timing on these motors will tulip intake valves. Number 6 and 8 cylinders are the lean cylinders.
What carb? 600 should be close out of the box (edelbrock or holley)
This is a little generic, but you were not specific in your 1st post.
I would set advance for total timing of about 32 for a vortec motor, doesn't matter what initial is. On thunderbolt v ignition there is a wire you have to ground to set the timing.
Too much timing on these motors will tulip intake valves. Number 6 and 8 cylinders are the lean cylinders.
What carb? 600 should be close out of the box (edelbrock or holley)
This is a little generic, but you were not specific in your 1st post.
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ok sorry for not being specific enough.i have a 1999 24ft baha cruiser,it has the vortec 5.7 with 2bbl carb.In 2003 it froze an busted block,so a new short block was installled.I ran the boat another 5 years with no problems,recently we pulled the engine an went thru it,no mods where done for higher performance just back to original specs.I did however go back with a 600cfm holley,which matched up to the dual plane intake once the restrictor plate was removed.Once i started the test an tune soon realized that the distributor would not advance but 8 degrees,called volvo an they said thats all this distributor was meant to do,this is new to me but ok.I have asked around an some say yes i need to go with a new hei single wire to get full advance an some say no that because the boat is always under load that the advancement will tulip the intake at 6/8,,so im at a draw,,,,i know good an well the motor needs advancement but at how much an should i bump up the main jets to go along with the higher timing advancements so not to have these leaning problems.
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So are you saying that the initial timing is 8 degrees before and that as you rev the motor there is no more advance? That is not right.
Small block chevys should run 8-10 degrees initial and 30-34 total in the 3000-3500 range (stock engines)
I think you need to figure out the ignition problems before you worry about the carb. If it is a new marine version holley it should be fine.
Small block chevys should run 8-10 degrees initial and 30-34 total in the 3000-3500 range (stock engines)
I think you need to figure out the ignition problems before you worry about the carb. If it is a new marine version holley it should be fine.
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what im saying is if i set base time at 10 an rev the engine it will only climb to 18,no more,,,im only getting 8 degrees of advancement from the distributor.Yes its a brand new marine holley 600cfm with vac 2nds.Wot on my engine is 4400 rpm
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You should set the all in timing at 32-33 and don't worry about initial timing. Make sure you are grounding the jumper wire as mentioned and that you are revving high enough to have all timing in.
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There is no jumper wire to ground this distributor has a two wire pin connector that plugs into the module one wire pink the other brown ...what I need advice on is what type of hei works best for a stock vortex 5.7 with 600 Holley with throttle range to 4400rpm,,,,because this outlaw junk distributor just will not get the job done