I recently aquired a trans am with a 383 stroked engine. I been diddly daddling with it for a while trying to fix whatever is making the engine run so rough. It acts like it has no power. If you give it gas, it will rev very slowly. If you give it alot of gas it will shoot a nice fireball out of the carb. It must be valve related. Ive replaced the plugs, wires, distributor cap and rotor and a new hi output HEI coil. Ive tried adjusting the valve preload, but thats not doing much for the problem. Im getting low vacuum (around 9-10hg) at idle. There really isnt many things that can leak with a setup like mine which i will list below. Mainly just the intake manifold, carb gasket, and lines from the carb. Ive replaced the intake manifold with a new one, new quality intake gaskets, new carb gasket and all rubber hoses have no holes or leaks.

So im assuming that my valve timing is off. Ive never really worked with a sbc before.. how can I check the valve timing? If you have an suggestions for me to try, im all ears. Ive tried alot, so most likely ive already tried it or checked it out.. but hopefully there will be that one person that finally puts this mystery to an end.

Its a 383 stroker, with a brand spanking new holley 750 w/ 4 corner idle and a proform main body, new edelbrock performer rpm intake, msd distributor with accell coil. These are the cam specs: Comp camshaft 510/520 lift 230/236 Duration 112 LSA. I currently have vacuum advance disconnected and running a little less than 38 degrees all in by 3000 rpm. If you need any addition info just let me know and ill inform you.

Thanks for looking.

 

Sounds like your ignition timing is off, not your valve timing.

 

Ignition timing is right on.

 

Define your idea of "right on"
38 total tells nothing, except your total is a few degrees too much. What initial? What vacuum advance? What vacuum source did you connect it to?

 

Its at 14 initial and 36 all in at 3k. Verified balancer is correct. No advance hooked up for now

 

have you tried advancing the ignition timing just to see what happens? you can check compression to see if valve timing is off.

 

Does anyone else have anything to say?

 

no

 

you just did ya hoebag

 

you do know you need your vac advance right? do you know what it does? maybe if you learned how and what it does you may sovle your own problem, no need for the name callen, people are trying to help you. you said your not familiar with the sbc, take these peoples advice we are familar with the sbc, check my car out.........in my profile page....

 

Perhaps you should break out your mechanic certificate from Wyotec (as stated below) and see if that helps?

Or maybe you managed to fix this problem back in mid-April when you posted "It's running like a raped ape" thread and claimed to have fixed it below?

Or perhaps it was running ok back when it had your self-described Edelcrap carburetor on it, before you got that nice Holley?

I suggested you take your car to a real mechanic a long time ago.
By now you could've been past all of these problems and avoided your last 100 or so posts on here.

At this point I'm going to have to change my suggestion and say that you may be better off by passing your car along to someone who is not a self-proclaimed certified mechanic.

 

game1939- Sorry, i just got angry because I typed a really long post back to the other guy and it didnt send, so i just asked "Does anyone else have anything to say? But anyway, you have a really nice car!

and to 305sbc... Who do you think you are? Theres no reason to attack me, ive done nothing to you. Who said anything about wyotech and why link posts that have nothing to do with me.

 

Oh BTW, I took the distributor out and changed the acell coil out for a different coil. I also loosened the valves enough that they are just clacking, so I can make absolutely sure that they are not to tight. So now the backfiring through the car is gone, but it will revs extremely sluggish. What else should I check out?

 

no prob. thanx 383. now since you losened your vavles try adjusting them the right way and see if it helps...... and to 305 edelbrock is not crap i had holley on mine before and hated it,got me the edel now and lovin it......
Here are step by step instructions:

1. Remove the valve cover.
2. Identify the number one cylinder. Turn the engine over until you see the number one cylinder exhaust valve rocker arm JUST START to move from the closed position to open. You may need to turn the motor over a couple of times to reach this point, but do not turn any further.
3. Locate the intake valve.
4. Loosen the rocker arm adjustment nut until you feel some obvious lash or clearance in the adjustment.
5. Using the thumb and index finger of one hand, grasp the intake push rod below the rocker arm, and rotate it back and forth (clock-wise and counter clock-wise successively to be sure there is no remaining pressure on the push rod from the rocker arm as you loosen the rocker arm adjusting nut.
6. Using the other hand, while continuously performing step 5, with a 5/8 socket and ratchet, tighten the rocker arm adjustment nut slowly until you feel a resistance of motion on the push rod.
7. This will be the zero lash adjustment point. For hydraulic lifters, tighten the rocker arm adjustment nut 3/4 of a turn. For solid lifters, back off the rocker arm adjustment nut until your feeler gauge just fits under the contact point between the valve stem and the rocker arm. Fine tune the adjustment by checking it with a feeler gauge just slightly thicker than the preferred clearance to be sure the clearance is not greater than it should be. If the larger feeler gauge will fit, it needs to be re-adjusted. A lash tolerance of 1-2 thousandths of an inch in the valve adjustment for solid lifters would be acceptable since it may be difficult for someone who is in-experienced to be more precise than that.
8. Turn the engine over until the intake valve opens and then is almost closed.
9. On the exhaust valve, repeat steps 5 through 8 for the exhaust valve adjustment.
10. Repeat this procedure for each cylinder. Be sure to do each cylinder sequentially, either following the firing order, following the cylinders numerically, or in the case of a V8 doing one side of the engine at a time. I prefer to do one side of the engine at a time.

 

Thank your for the detailed guide! I have an account on another site and one of the people told me that the lifters i have are special and can only take 0-1/8 of a turn after zero lash. Im going to try that out today and see what happens. Im also going to make absolutely sure that the balancer isnt off today while the plugs are out. Ive never pulled the timing cover off a 350 before, what all will i have to take off to remove it? The only vehicle ive changed a timing chaine, well belt in this cars case, was on an 86 supra and it ran great when i was done. That car was having just about the same problems im having right now so im thinkign maybe the valve timing is off, i really am.

On the supra it was an inline so i could basically just put a long screwdriver in the spark plug hole and find tdc really easy since the plug was straight up, can i use a screwdriver in the sbc also?

 

14 degrees initial is probably a bit too much. 38 total probably is, unless you're using old heads from the '60s or '70s. With your vavuum advance connected to manifold vacuum you'll find a much better idle with at least 26 degrees oif advance at idle. 10 of that initial, the other 16 vacuum.
Eliminating the vacuum advance is a racing trick, but does NOT work for street driving.

 

the balancer has a bolt, i use a puller to remove it, after timing cover off you see a chain, the bottom and top sproket that runs chain has a dot on them, point them to each other the crank one will point up while the cam one will point down to line up with crank dot.......as far as the lifters 3/4 turn.. im running very high dollar lunati vodoo cam and lifter set and 3/4 it is.......

edit: there not solid lifters are they? if so they need the specs

 

no, no its a hydrualic roller setup. and my luck just got worse, the damper bolt is completely rounded so i cant turn it over by hand now. geez this sucks really bad. I took the plugs out and they are black as coal, theyve only been in there for about a month. The new carb started overflowing today so now i have to figure that out

 

^listen to him.

 

thats a holley for you pita.....adjust the floats..... better yet get e edlebrock

 

LOL

https://www.thirdgen.org/forums/elec...possessed.html

^
You're going to have to make yet another screen-name at this point.

You know if you spent as much time reading informative write-ups and posts as you spent starting new threads, you'd probably have a good understanding of what you're doing by now.

Or better yet, do as I suggest and find someone who knows what they are doing to get your engine tuned for you, then never touch it again.

 

I had an issue with the dielectric/thermal compound under the ignition module drying out and causing the car to run like crap and have a hard time with idle tune and hot restart. Pull it and check if its been in there for a while or if its a new dizzy, they don't always put that stuff under them when at the factory.