I have a 1985 z-28, I am running a 350 bored.40 over. 1.60-2.02 heads, vodoo cam .507/.507 at 106 deg lube and dual card setup. I put new cam in and lined the dots up on my gear drive dot to dot when my #1 was top dead center. And now when i try to start it it just back fires and blow gas out the carbs. I checked #1 piston and made sure #1 plug were same. I also pulled timeing back off and now my dots are off. crank is at top and cam is at top now. ???????? I dont know how to deg. a cam is that my problem or am i over looking something??????

 

Did you check when you had Cyl #1 at tdc that it was on the compression stroke? Sounds like your timing is off when you stabbed the distributor.

 

I am running a 350 bored.40 over, 1.60-2.02 heads, Lunati cam .507/.507 at 106 deg. lobe seperation and a Edelbrock Performer RPM Dual-Quad Air-Gap with 2- 500 carbs, Accel dual point dist. I put new cam in and lined the dots up on my gear drive dot to dot when my #1 piston tdc. And now when i try to start it, it just back fires and spits gas out the carbs. I turned to dist. 180 out and no luck same thing. I have tried move the #1 plug one to the right and left no luck. I checked #1 piston and made sure the dist. was pointing at #1 plug. I also pulled timing cover back off and took #1 to tdc and moved the dots back together. If I advance the dist. it just back fires and spits gas out the cabs, and when I retard it, it just backfires with a puff of black smoke. I also reset my lifters to lunatis specs. and found that most of my lifters were not working(use Hydraulic Flat lifters) I called summit and they said they would be find once i run the motor(they r new but have been setting in the motor for 2 wks now) Do I need to get new lifters?? Also someone on hear tonight said when i line my dots up on my crank and cam my dist. should be pointing to #6 is that true??? I spent over 6 hrs tring to get my motor to start and nothing, If u can pls help it would be GREAT! I dont know how to deg. a cam is that my problem or am i over looking something??????

 

When both dots are at the top of their gears, you're in the #1 firing position. When they're dot-to-dot, you're in the #6 firing position.

 

I had the same problem with my tpi. It would backfire out the intake (all the vacuum lines would blow off). So after changing cams, my buddy did the dots on exaust stroke. The solution? Pick up the dizzy and rotate the rotor 180*. Then drop the dizzy, bolt it down, and try it now.

 

This is the right way. They have to be just like Apeiron said. He beat me to it.

 

cked timing marks when dot to dot it is pointing to #6 but still wont start!!

 

Thats because when the marks are dot to dot it is in the # 6 fireing pos. To get to number one, the crank gear dot is at 12 oclock as is the cam gear. Not dot to dot.
You want to get them like in the photo. Look at the black dots I marked in the photo thats what you want. Even in the chilton manual will tell you that both marks need to be at 12 oclock

 

You may of put in the dizzy 180*. Just try it. Loosen up the dizzy hold down bolt, slide the holder back, lift dizzy straight up about 1-2 inches, turn the rotor 180*. Make sure you clear the slot in the oil pump shaft because it won't sit correctly if you turn the input shaft in the oil pump. Let me tell you. I was skeptical when our own member "Chevy8588" told me to turn 180* after I told him that my IROC wouldn't start. I told him it was backfiring out the intake and he said "I know what the problem is." So I tried it and there it was. We had put the dizzy in half out when I switched to a 1994 Z-28 LT1 cam.

 

If you do make a "12 o'clock" adjustment, I would strongly advise that you turn the crank with a wrench just to be sure that the timing marks line up. I would hate to find out that the marks don't line up after you put the front of the engine back together.

 

ok I checked and everything is as u said it should be to run but still wont run. Some said it could be that me lifters r not set right. I set them like i have in the past. (when int. starts to close set ext. and when ext. starts to open set your int. valve. Is there a better way of doing them??????

 

Yes there is. Turn the engine by hand to the number 1 fireing posisition TDC
From there you can set exhaust valves #1,3,4 and 8 and intake valves 1,2,5 and 7.
What you do is back the jam nuts off untill you feel lash then tighten the back untill all the lash in gone the turn the nut 1 full turn. Then by hand turn the engine over 1 full revolution only untill you are again at TDC the you will do the same thing for exhaust valves 2,5,6 and 7 and intake valves 3,4,6 and 8. after that turn the engine 1 full revolution untill you are back to TDC and reinstall everything back.start it up and check the lash 1 more time with the car running.

 

Even then, you'll still need to fine tune the lash. Garenteed that your lash will be off on a few rockers. The best way to adjust is by ear. Perform the instructions mentioned above. Then get some rocker pushrod plugs to prevent oil from splashing. Now get a friend to help you. You'll need a tube. Turn on car. Put one end of tube to your ear and the other end to the rocker and listen for a tick. If there is no tick, loosen nut until you hear the tick. Now when you hear the tick, tighten slowly until the tick is gone. Now turn 3/4 turn. Now do the same to all other rockers.

 

THANK YOU ALL, I got car running!!!!!!!!!!!!!!!!!!!!!!!!

 

Killer deal. Now get out and drive it.

 

So what was the issue bro?

 

Ya ^ what Chevy86 said, what turned out to be the problem?

 

Well it looks like donmeca007 is a "get help and " type of person. Fixed his problem then he bailed out. Im curious to know what the issue was. i hope he lets us know.

 

Sorry I'm jacking this thread!
But this caught my attention in regards to the timing marks. I can't say for certain, but I do believe my marks are dot to dot. (As the cam dot was set at 6:00 and the crank dot was set at 12:00.) If this is the case would that explain my previous thread?
https://www.thirdgen.org/forums/tech...se-timing.html
Or if that is true that I did set the cam/crank wrong my engine would not be running at all!

 

No the engine would still start and run, however
that could well be an issue, When the cam is at 6 oclock and the crank is at 12 oclock then you are at #6 fireing posistion insted of #1. Of corse with a high lift cam it could be different it all dependes on what the cam card says is best for that cam, that will tell you where to set the inital degree when installing the cam. If you still have the cam card, see what it says when you tear down the timing cover to re-seal it you can degree the cam to were it should be. Because up to 20 degrees intial timing seems to be to much, even if the car likes it, something to me just seems off with those numbers. IMO.

 

The Car should turn on. When I changed my cam to a 94 Z28 LT1 cam, I made a silly mistake. I got the dots lined up with piston 1 at TDC Compression stroke. I failed to install the dizzy correctly. I had 180* out and she wont start. She would back fire from the intake which would blow off all vacuum lines. After some advice from Chevy8588, I lifted the dizzy and turned the rotor 180* and she sounded like a beast. Fired right up.

 

Update!
I had a old piston stop that's some kind of generic brand, and it was striping out the spark plug threads. So Saturday I picked a Comp. Cam piston stop, and tried it out Sunday night. Well it turns out my timing marks were off in relation to the damper marks. Without touching my current timing of what I thought was 20 degrees, and resetting my adjustable timing tab to true TDC per the new piston stop. I started and let my engine warm up for a few minutes. Then I shut it off, and disconnected the EST. Hooked up my timing light, and started it back up. At about 900rpms the timing now says its at 10 degrees.
I still think I may have set up the cam and crank up wrong in relation to the timing dots. But it is running fine for now. So I'll leave it and enjoy the rest of the year til old man winter sets in. Then I'll pull the timing cover off and see were I'm at, as I have a leak anyways at the cover that I need to reseal.
Thanks for your input guys!

 

They can't be, unless they're manufacturered wrong.

 

now that you know the timing tab was way off and you found it and fixed it, I bet all is well now