383 timing help

[4x4k20]

i have a 79 with a 383 its a 350 bored 30over with 400 crank and rods with vortec heads 10 to 1 compression i had the timing set at 12 initail it ran good and had good power but if you cut it off it would not wont to start back so i set the timing back to 8 it will start but has no power what do you guys that 383 s run you timing at ? i have always had to fool with it it will run good and have good power then i would get some pininging so i would set it back wouldnt ping but wouldnt have any power i have to run 93 octane in it any ideals would be helpful

 

[BorregoK5]

Are you running ported vacuum or manifold vacuum for the vacuum advance? Have you made any runs with the vacuum advance disconnected and plugged off at the carb? Have you set your mechanical advance with the proper springs to give you the best mechanical curve without ping (done with the vacuum advance disconnected)? And if so, did you get part throttle ping after reconnecting the vacuum advance? If its timing related, these questions should help nail it down.

 

[4x4k20]

i have tryed both if i set timing at12 initail and then hook to full vacum it makes good power but will have hard start condition the motor will barely turn over but if i set it at 8 and run full vacum it has no power and pings badly but will start easyly these are partthrottle pings that i have i have had this problem since i built this motor 2 years ago one thing i know is that i have to high of compression i have to run 93 octane i think i need to try another dist i bought one from summit but it was junk i have a jacobs kit it would not work with the summit dist because it had a aftermarket module i had to put my old gm hei back in maybe its old and worn out i am looking into buying a new dist and starter to see if i can fix my problem

 

[BorregoK5]

Do you have an adjustable vacuum advance (and advance limiter plate)? Your scenario sounds much like my 400 was before recurving my ignition. Your 383 is going to want a lower initial advance (2*-4*), your mechanical should be set to provide a gradually increasing advance up the rpm band so that your just barely retarded from full throttle ping and your vacuum to only provide a very small amount more advance when at part throttle but not at wide open throttle or idle (on ported vacuum). It sounds like a vacuum advance kit would fix most of what ales you, barring some other oddity.

 

[chevyracing]

time it with a vacume gaige too. When you get the highest vacumme reading it is timed.

John

 

[4x4k20]

i found my problem well part of it the centrifucal advance is froze up the weights are stuck out at full advance going to try to unstick them for now until i can get a new disturbtor can any one tell me what i should buy i have a jacobs kit on mine so the new disturbtor must have a factory gm module they ,jacobs sold me that kit but didnt say that it has to use a gm module i had bought a new summit hei dist it has an aftermarket module in it so it wouldnt work until i put a gm module in it but i went back to my orginal gm hei dist because the summit hei was cheaply made i will probaly get rid of the jacobs kit because it junk too

 

[BorregoK5]

Those advance weights are prone to siezing like that on original equipment, unstick them carefully or you can damage the main distributor shaft and the dist will be useless. If the main shaft is snug (turns freely but no side to side walk) then you should be able to reuse your original HEI. If you don't already have it, get an adjustable vacuum advance ($29 through summit). It will have new mechanical advance springs for you as well. I bought a Proform distributor off a friend of mine (55,000 volt) ; the Summit was (48,000 volt). It's been very good to me, times solid, consistant and steady. I've had a bunch of Malloy's in the past but have always had little problems with them (poor shaft oiling was one). Good luck!

Oh, and a late add on... I've heard nothing but good things about Jacobs ignition products, might be worth hanging on to it!

 

[4x4k20]

i have the crane advance kit with limiter installed i got my dist. freed up and drove it i still have some pinging at part throttle i will keep fooling with it to i get it rite there is a site called 73-87 .com that has lots of info of how to install the crane kit and lots of other helpful info . also talking about the jacobs kit i bought it because it said it was guarnteed to stop the pinging and add more hp but i havent noticed any difference and about 6 months after i bought it the coil burnt up on it they sent me another one but i am scared of it i keep my old gm hei in my truck now in case of another failer hey thanks for your help with my problem