77' T/A 400cid won't start! Help!

[nanswah]

I am having a frustrating time with my T/A. It has a Pontiac 400cid engine with a 4BBL Q-jet carb. It started running poorly and I had the timing checked and reset. It ran good for a day or so and then badly again. I had the timing rechecked and it seemed to be the timing chain.
I replaced the timing chain and gears, reset the distributor, replaced the
cap and rotor as well as the plugs and plug wires. I even changed the water pump while I had it off the car. The Damn thing will not start. I am getting spark, the engine turns over but will not start. I also did a rebuild on the carb to no avail. It has a new battery, also.
I am soooo frustrated. Please, any help would be greatly appreciated.
HELP!!!!!!!!!!!!!!!!!!!!!
Could it be the cam???

[Philo]

First I would make sure you are getting fuel to the engine.

You went from running badly to not running, so recheck all your work. The distributor could be 180 degrees out, or the timing chain may have been installed incorrectly (the gears not lined up proberly with each other) . Taking your time, check that the NR 1 piston's valves are closed when it is at the top of the compression stroke, and the distributor is pointing to the wire that goes to it's spark plug at that time. On an engine that has been running, all you need is ignition, fuel and correct timing.

Good luck, and let us know how it goes.

[nanswah]

As to the timing chain, I had the timing marks facing each other/coming together in the middle. A friend that has been helping redid the sprockets to where the bottom one (crankshaft, I believe) is facing up and so is the top sprocket. I am not sure how they are supposed to line up, although there is a keyway to where both gears can only fit in one way. In my chiltons, it says to line up the timing marks b4 removing the gears, but if they are a tooth off, they will not line up.
How can you tell when the piston's valves are closed?
Is that when the first valve moves up and down, then the second valve moves up and down, and then they stay up while some other valves move? Because that is what my friend did when he lined up the timing marks on the timing gears.
Also, does it matter where your number 1 spark plug is if you follow the firing order and point the rotor to number 1 on the cap?
And, fuel is getting to the engine.
Also, the distributor has a keyway, where it can only go in 1 way, so in this case, is it possible to be 180 out?
I am so frustrated and confused because the chiltons is just not any help.
Thank you for your help.

[Jm93]

hmm, remember a engine needs 3 things to fire,

Fuel
Compresion
Ignition

make sure it is getting all 3. then come back

[Philo]

Originally Posted by nanswah

As to the timing chain, I had the timing marks facing each other/coming together in the middle. A friend that has been helping redid the sprockets to where the bottom one (crankshaft, I believe) is facing up and so is the top sprocket. I am not sure how they are supposed to line up, although there is a keyway to where both gears can only fit in one way. In my chiltons, it says to line up the timing marks b4 removing the gears, but if they are a tooth off, they will not line up.
How can you tell when the piston's valves are closed?
Is that when the first valve moves up and down, then the second valve moves up and down, and then they stay up while some other valves move? Because that is what my friend did when he lined up the timing marks on the timing gears.
Also, does it matter where your number 1 spark plug is if you follow the firing order and point the rotor to number 1 on the cap?
And, fuel is getting to the engine.
Also, the distributor has a keyway, where it can only go in 1 way, so in this case, is it possible to be 180 out?
I am so frustrated and confused because the chiltons is just not any help.
Thank you for your help.

************************************************** *
I got all of this info from the "Motor" manual:

The timing marks should be aligned as follows: Top gear, mark at the bottom. The bottom gear, mark at the top. This will be called the valve timing setting. Now install the chain before turning the engine.

Next, set the distributor as follows: (The easiest way in the long run is to remove the valve cover from the side where the NR 1 piston is). Tap the starter, and note the direction of rotation (if you don't know, or are not sure). Rotate the engine slowly in the direction of rotation (not with the starter) until the intake valve opens, then closes. Then continue turning slowly until the timing mark on the camshaft gear is on top.

Now you are ready to install the distributor. (If is is already installed, that is ok, you are just going to line it up with the NR1 piston.) To do this, first with a piece of chalk or tape, mark the location of the NR 1 wire connector on the distributor housing so you will know where the NR1 wire enters after you remove the cap. Then remove the cap. check to see if the rotor is pointing to the chalk or tape mark. If not, remove the hold down bolt and clamp from the distributor and slightly raise the distributor with one hand, while attempting to turn the rotor with the other hand. When you raise it (about one inch or less), you will be able to align the rotor pointer to the point you marked with tape. Then lower the distributor back into place, and recheck that the rotor is still pointed to the chalk or tape mark. The gears on the rotor base may be cut at an angle, so you may have to lead a little to get it to end up in the correct place (pointing to the chalk or tape mark). Now replace the cap and the hold down.

Now it should at least run roughly. These adjustments are 'close' but not perfect. You need to get a timing light on the engine to set it exactly (remember to remove and plug the vacuum hose from the distributor (if equipped) to eliminate any built in vacuum advance.

Let me know how it works out...

[burnM]

Shouldn't the #1 cyl be at top dead center before the timing gears are aligned?

[Philo]

Originally Posted by burnM

Shouldn't the #1 cyl be at top dead center before the timing gears are aligned?

No, because this step is setting the valve timing, not the ignition. There is only one place the two marks can be aligned near each other and directly inline with the center of the cam and crank, since the gears are keyed to the cam and crank.

The timing for ignition is then set by connecting the distributor to the cam gear (the one at the rear of the cam) and pointing it to the correct cylinder (NR 1) when it is at TDC.

[burnM]

I just thought about what I posted and...

I'm an idiot.

[nanswah]

Philo,
ok, so when you talk about rotation to set the
distributor, are you talking about rotation of
the engine or the distributor because the
distributor rotates cc and the motor rotates
clockwise? And as to the when the intake valve
opens, then closes, are you referring to the 1st
lifter opening and closing, then the 2nd lifter
opening, then closing on number 1?
I'm sorry to be such a pain, I am just trying to
learn this and most guys are not willing to teach
a woman.
Thanks,
Nancy

[Philo]

Originally Posted by nanswah

Philo,
ok, so when you talk about rotation to set the
distributor, are you talking about rotation of
the engine or the distributor because the
distributor rotates cc and the motor rotates
clockwise? And as to the when the intake valve
opens, then closes, are you referring to the 1st
lifter opening and closing, then the 2nd lifter
opening, then closing on number 1?
I'm sorry to be such a pain, I am just trying to
learn this and most guys are not willing to teach
a woman.
Thanks,
Nancy

On my post of 01-17-2004, 03:32 PM, the idea was: The actual direction of rotation of the rotor does not matter, since it cannot be changed. The Distributor is connected to the rear of the cam on a small gear, and another small gear on the bottom of the distributor shaft. They can only go together one way - with the gears meshed. The only adjustments are: Lifting the distributor up moves these gears apart, and you will then be able to turn the rotor. You would do this to get the rotor pointed to the NR1 sparkplug wire.

For the other question, I was speaking only about the intake valve for the NR1 piston. When you turn the engine, you will see the rocker arm open that valve, then with a little more turning it will close again. This is the time (if the engine was running) that the fuel air mixture has been drawn into the engine. Now you need to turn the engine in the same direction until the piston is at TDC (This would be when the timing mark on the valve timing gear on the front of the cam would be at the top). At this point, both valves for NR1 cylinder will be closed. This is approximately when the ignition would fire the plug. The intake valve is the one closest to the "1" cast into the intake manifold runner. At this point, you work with the rotor and distributor as I mentioned above to get the rotor pointed to NR1.

Ask if you have more questions, or I am not clear.

[nanswah]

ok, now when I try to start it, it throws a big blue flame out of the carb...scared the heck out of me.
I went out and made sure that # 1 was on TDC and pointed the distributor that way. Also made sure that the mark on the harmonic balancer was at 0.
What am I doing wrong?

[Philo]

Originally Posted by nanswah

ok, now when I try to start it, it throws a big blue flame out of the carb...scared the heck out of me.
I went out and made sure that # 1 was on TDC and pointed the distributor that way. Also made sure that the mark on the harmonic balancer was at 0.
What am I doing wrong?

Now you know you are getting fuel and ignition

To protect yourself, put the air cleaner on.

If I remember from a previous post your friend changed the valve timing marks from what they should be - did you change them so they agree with my previous post (Cam gear mark down, crank gear mark up).

If the valve timing is correct, then you are close to right. I don't have information on the '78 400, but the '79 400 advance on this engine is 18 degrees. This means that you need to set it 18 degrees before top dead center (BTDC). This is not easy to get exact without the engine running. What I would do is verify (for your engine) the advance you need (it will be stated in degrees BTDC). Then when your engine is at TDC on NR1 (same as before), look at the timing mark on the crankshaft - where you said you set it to 0. Move it back from 0 to what ever the manual says it should be - or at least most of the way. Then without moving the engine, reset the distributor to point to NR1 again. It may be fine, but is probably one tooth off because you moved the pointer to the BTDC degrees setting for your engine.

Snug up the distributor hold down bolt until you can turn the base of the distributor but tight enough that it won't move on it's own. Now crank it, and if it does not start move the distributor base slightly with your hand to vary the spark timing. It should start. Then get a timing light on the engine and set the timing to the exact setting for your engine. You set it by shining the light at the degree marker and turning the base of the distributor slightly until you see the mark on the pully line up with the correct degree mark. I suspect 18 degrees BTDC is correct, since the '79 400 engines were hold overs from '78, but please check to be sure. When setting the degrees with the timing light, remember to remove the vacuum line (if equipped) from the distributor or you will not get a good reading. Once you get everything set, tighten the hold down bolt on the distrubutor. Recheck with the timing light, to make sure nothing moved, and if OK, reinstall the vacuum line.