: Need timing help!!!!



JTraik
06-07-04, 08:29 PM
68 DeVille

Hi, im still a begginner mechanic. What i did was change the timing chain and sprockets. I had the new sprockets on there with the teeth with dots pointing directly at each other. Someone came over and he turned the crank shaft till the piston was up in the number one chamber then we put the distrib back on and had it pointing at the number one plug. I went to start it up today (and yesterday) and all it does is keep turning over and no firing. Now i took the air cleaner off and the carb was spitting out the vaporized gas, should it do that?

The same guy is coming over with a timing light. Did i do anything wrong or out of sequence here? thanks!

lux hauler
06-08-04, 05:50 PM
Assuming the timing chain and gears are installed correctly.......

The number one cylinder is on the passenger side at the very front of the engine. Bring that piston to top dead center (TDC) on the compression stroke (pull the spark plug out of the number one cylinder, turn the engine over by hand with a finger over the spark plug hole. When you feel air pushing around your finger, you know that is the compression stroke. Bring the piston to the top and align your timing mark on the crank....the engine is now at TDC on the compression stroke).
Now the number one position on the distributer can be anywhere you'd like it to be, you just have to follow the firing order (in the direction the rotor turns.....clockwise, I believe) the rest of the way around the cap with your plug wires. But whatever post (on the dist. cap) you choose as number one must line up with the tab on the rotor, with the cap installed, while the engine is at TDC on the compression stroke.
Hope this helps.....? :hmm: I'm not very good at 'splainin' things.:helpless:

BTW.......disconnect the coil wire before trying to turn the engine over by hand. We want you to finish the job with the same number of fingers you started with.:eek:

Angela Desmond
06-08-04, 07:24 PM
Just one more thing to mention. When you say you had the timing marks on the gears lined up, you did have the dot on the cam gear at the TOP, not the bottom of the gear, right? On Chevys it's at the bottom with the crank dot on top, but cads have the cam mark at the top when lining them up. I didn't see you mention that, so I was just checking....

Dead Sled
06-08-04, 09:52 PM
Just one more thing to mention. When you say you had the timing marks on the gears lined up, you did have the dot on the cam gear at the TOP, not the bottom of the gear, right? On Chevys it's at the bottom with the crank dot on top, but cads have the cam mark at the top when lining them up. I didn't see you mention that, so I was just checking....


WHAT?

the dots should line up crank at top cam on bottom

unless your cam is ground 180 degrees off or you like serious advance

JTraik
06-08-04, 11:58 PM
Yeah it turns out my distributor was off by one cylinder. It fires nice now and its MUCH more responsive with the new timing parts :)


Just one more thing to mention. When you say you had the timing marks on the gears lined up, you did have the dot on the cam gear at the TOP, not the bottom of the gear, right? On Chevys it's at the bottom with the crank dot on top, but cads have the cam mark at the top when lining them up. I didn't see you mention that, so I was just checking....

Umm...the cam dot should be at the bottom and the crank dot should be at the top.

Another thing about those sprockets...before i took the cam sprocket off i noticed a tooth missing and i was like...what the heck. Then i took it off and realized it was nylon!!! :bonkers: Not a very good choice IMO

Angela Desmond
06-09-04, 06:23 AM
That's the way the book shows it! After installing the Cloyes roller chain, Al at MTS told me I can do it with the dot on the bottom, but the manual shows cam dot on TOP. Don't have a scanner to print a picture here. If you want I'll mail it to you! BTW, I just timed a 425 using a degree wheel, and unless someone has pulled a fast one on me and switched the intake and exhaust vavles, then the dot on top works perfectly..... :rolleyes:HT4100 is shown in manuals as timed with the cam dot on the bottom.

Imprl59
06-09-04, 10:23 AM
Another thing about those sprockets...before i took the cam sprocket off i noticed a tooth missing and i was like...what the heck. Then i took it off and realized it was nylon!!! :bonkers: Not a very good choice IMO
They did that to help reduce the noise of the timing chain. Many of them would break off all the teeth leaving you stranded after about 100k miles. Sounds like it is a good thing you found it when you did!

Steve B.

caddycarlo
06-09-04, 11:23 PM
it does not matter if the dot is up or down the cam has 720 degrees of rotation and the number one piston is at top dead center with the dot up and after the crank turns 360 degrees the piston is again at tdc but the cam now has the dot down either way will put the cam in right ...... with the dot up the intake and ex valve will both be open and the rotor in the dist is pointing at number 4 wire with the dot down both will be closed and the distutor will be pointing at number one cyl ...........

Dead Sled
06-10-04, 01:37 AM
what he said

its a helluva lot easier to connect the dots and point the rotor to the #1 plug wire

JTraik
06-10-04, 04:25 PM
what he said

its a helluva lot easier to connect the dots and point the rotor to the #1 plug wire

I think it has become more of a debate on right vs wrong here. But yeah the dots are there to make it easy.