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timing my sbc with vortec heads

7K views 15 replies 5 participants last post by  addictivewoodworks 
#1 ·
Here is my issue. I got this car on a trade. The guy I got it from traded it for a truck, so he wasn't the builder and didn't know much about it.. He told me it was a 383 stroker with a 750 double pumper. after looking it over after I got it, I think he was either lying, or didn't know much about it... So I had no information about the motor. It ran like crap when I brought it home, and had no get up and go. Spark plug wire broke, oil leaking everywhere, didn't want to start, because the timing was so retarded, (the dizzy was turned 180 degrees so the vacuum was facing the firewall), pcv hooked up with (yes with) the brake booster, vacuum advanced on dizzy to timed port was not hooked up...
What I have that I know is vortec heads, 1.6 roller rockers, 670 street avenger, lunati voodoo cam 10120701 (Formerly Part Number 60101) double roller timing chain, etc. I do not know the compression, piston size, etc. I do know when I pulled of the balancer, it was missing the key. The cam was advanced 4 degrees.
After getting it back together, and timed it at 12 btdc, my total was all over the place, all the way up to 54 degrees. it started up good, and drove ok, but when I hit the gas quickly it wanted to bog on me... I adjusted the floats, idle mixture screws ( about 2 1/2 turns out), adjusted the acc cam, still nothing... I should mention its in a 87 trans am that had the fi, so the pump is in the tank. The guy had a mechanical pump on the motor with that, and NO fuel regulator... I got rid of the mechanical and blocked it off, and hooked up a regulator. I'm at about 4 psi right now... ( I'll adjust the regulator to about 6 psi).
My question is, how can my timing be all over the place??? I have been chasing my tail for 2 weeks now. where I'm at now is I just ripped apart the distributor ( which was new), and replaced the pick up coil. I havent put it in yet, but I just feel like I'm chasing my tail. I know someone that knows about motors would probably have this motor adjusted and running great in an hour, I just want to drive this car and enjoy it before the snow starts to fly....

 
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#2 ·
A cogged alternator belt? Wow. That must be a 10,000 amp alternator! :thumbup:

Although timing lights are very simple devices, there is a slim possibility that yours is acting up. Perhaps borrow another from a gearhead neighbor?

When you had the distributor apart did you notice any play in the shaft? That can account for erratic timing.
 
#4 ·
I have a inductive light that is about 30 years old lol.. i do notice that when i rev it to 3000 rpms, the light flickers eratically.. i thought maybe my vacuum advanced was staying open in my dizzy. Yes i plugged the timed port on the carb when i timed it. However i did not plug the port on the dizzy, i just left the hose one unattached. One thing i will point out is i have a summit balancer cover on, and i was timing it off of the degree marks on the cover to the 0 tab on the timing tab, i might have to just go off the tdc matk on my balancer and time it off the tab on the timing chain cover. I wish i had a dial back light so i can tell the advance on the dizzy...
 
#6 ·
I'd suggest a new light. Dial back from the parts store is about $100 but you never have to guess again. Before you remove stuff, buy/make a cheap piston stop to verify tdc. Get an Old spark plug and and hollow it out till you just have the metal part that threads into the head. Tap it or weld a bolt through it so it sticks out INTO the cylinder. Rotate motor slowly by hand till piston touches stop. Mark balancer with marker or nail polish or paint pen. Now rotate other way 360* till you hit the stop. Make mark on balancer. Remove piston stop and divide space between marks in half. Thats your new timing mark. Some balancers have wrong tdc marks for certain engines. It's nice to verify.
 
#8 ·
MSD Street fire Dist you mean? No....that wouldn't cause your jumping around, the MSD box's and many timing lights don't always play nice together.
Firstt, leave the fuel pressure alone. As tech1 is about to tell you, more isn't better.....4.5 Max,likely your 4psi is fine.
Check the dist to see if the vacuum advance can is hanging up. I chased this with one last year, initial timing would be fine, then after the motor saw any kind of rpm it would jump a bunch and hang there. The little arm at the bottom (yes guys im sure there is an actual name for this ) wasn't all the way seated, and it was getting stuck on the pad at the base of the dist that it moves on. This foolishly took me 2 days to figure out....and I'm the dummy who did it.
I opened it up, pushed the arm up into the the arm more, added a touch of dielectric grease to the pad, and that was the fix.
bTW, even dissconnected it still did the same thing as the arm was simply getting dragged open and sticking there.
 
#9 ·
I bought a new pick up coil, and replaced the old one. I cleaned up all the contact points on the dizzy, the vacuum advanced is not binding up.. i checked it and it moved smoothly. What should i set my timing at initial for this setup with the vortec heads... i was seting it at 12 advanced...is that good, and what should be the total...
 
#10 · (Edited)
I would go 16 with a 213/219 @0.50 cam, vortec heads dont usually want more then 34* total so you may want to limit it a couple degrees if its a stock 20* curve.... Maybe bump it to 18 and see how it responds, 36* total isn't gong to hurt it. Its just a couple degrees more then likely nessicary.
Not arguing at all, but just a heads up, the vacuum advance appeared to move freely on mine as well when manipulating it by hand. The only reason I even caught it was when I went to remove it to reinstall the stock one and I noticed a tiny scuff mark from it rubbing underneath.
 
#12 ·
this is what i would do if it was me, im with ben ,, 1st thing is to verify #1 cyl is at tdc compression stroke, next remove the distributor check the gear teeth and contact pattern cant remember is this was mentioned, once engine is verified at tdc then mark your balancer , drop the dzzy in , once its in verify if the dizzy shaft has up and down play, if it does thats what cause to jump around , find out why it has alot of play .., if it doesnt ,
i drop mines in at 10 deg before tdc ,, as a starting point,
leave the vac advance disconnected , and start the engine, once its running then u can tune your timing , ( with vac disconnected)..
see if this helps, .....i know this might sound stupid but verifi timing light is connected to correct cyl #1 ,,,,, i know i know,, but ive done that also ..
hope this helps
 
#14 · (Edited by Moderator)
****.... please dont tell me i just blew my rear main seal... i have oil leaking out of the back upper oil pan when the car is running. Are these known for going. Its a 87 block one piece. I have to jack it up and look closer, hopefully its the oil pan gasket... when the car is running it just pours out... *******.....
Your positive its not coming from higher and just running down?
Check the back of the intake.....
And man, your luck sucks.....sorry for that.
 
#15 ·
You have NO idea. It started by my son and I bought a 67 firebird. We are doing a full frame off restore on it, so I figure lets get something we can cruse in while were building this, so we wouldn't lose interest, because it will more the likely take 5-8 years for the 67. So I bought a 78 firebird and after I got it home, I found the sub frame was completely rotted out on the sub frame mounts, so I bought a new frame and as I was digging into that car the more rot I found. so I put that one on the side for a rainy day, and we ran across this 87... I think you know the story from there....grrrrrrrrr...... yes it is the rear main seal, just my luck, so now I have 3 cars (67 firebird, 78 firebird, 87 trans am), and NONE of them are drivable....VERY FRUSTRATING........ I just wanted to cruse around with my 14 year old son and have some fun as we were doing the 67, Now we have 3 projects instead of one......Here's a pic of the seal, it should be flush in the housing.....
 
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