Here’s a how-to that will help you align your timing (distributor, rotor, No. 1 cyl. at Top Dead Center (TDC) on a 1997.
This will be most helpful when:
1) your distributor has been out it’s housing and it wasn’t marked properly for re-installation
2) you cranked your engine while the distributor was out
3) you think your distributor may have jumped a tooth
*Top Dead Center refers to when your No. #1 piston in the firing order is at the top of it’s compression stroke – when the piston is furthest from the crankshaft.
http://en.wikipedia.org/wiki/Four-stroke_cycle
STEP 1:
Disconnect negative battery cable. **This is not just a precaution. If this is not done, you might actually crank and start your engine manually when turning the crankshaft ---- very dangerous.
For extra precaution, disconnect the ignition coil.
STEP 2:
In my case, I thought my distributor had jumped a tooth after replacing my lower intake manifold gasket (turns out it did, due to a loose hold-down bolt). I was determined to pull the distributor without taking off the air-intake and the whole top of the engine to access it.
It is possible. I was able to pull out and re-install my distributor with this special socket I made without removing all the stuff on top.
As you can see in the pictures below, there is not much clearance between the distributor housing and the hold-down bolt. To loosen and tighten the hold-down bolt, I made my own shortened socket by sanding down a sacrificial 10mm socket. See the pictures below.
STEP 3:
Now on to setting TDC ...
Looson wheel lugs on front drivers-side wheel. Jack up the left front of the truck. Remove wheel lugs and tire.
STEP 4:
Remove your #1 sparkplug (drivers side front-most plug). If your air intake is still on (like mine was), this is best done from the front wheel-well. Wobble extensions are extremely helpful here.
STEP 5:
Now, get under your truck and look at the harmonic balancer behind the crankshaft pulley. You should see two white marks. Both of these need to line up – on at about 4:00 o’clock on the balancer which lines up with on the plastic, and another one on top of the balancer at about 1:00 o’clock which lines up with a notch (see pictures).
Put a ratchet and socket on the crankshaft pulley and rotate the crankshaft to make them line up.
Now, the marks can be lined up and still be 180degrees off which means -- your truck still won’t go. Everything has to be lined up on the compression stroke. To do this, you’ll need to put your finger or thumb into the open No. #1 cylinder spark-plug hole while turning the crankshaft (an assistant can help but I was able to do this easily by myself). When you feel air coming out of the cylinder, that means it is on the compression stroke. At that point, you know you are on the compression stroke – begin to watch the marks and align them slowly.
STEP 6:
You are now at TDC. Time to line up the distributor shaft and rotor.
Here’s the distributor
Two small Torx screws hold the rotor to the distributor. This picture was taken on reassembly.
The rotor only fits on one way. It’s not possible to attach the rotor 180degrees off. Here’s an underside picture of the rotor. Note the dimples next to the screw holes. They are displaced – one is closer to the screw-hole than the other. This is why it’s only possible to attach the rotor to the distributor in one way.
Step 7:
Now attach the rotor to the distributor and rotate to the number 6 which is embossed on the plastic distributor housing (there is a number 8 as well for eight-cylinders – us 4.3 guys want the 6 of course).
Here’s the 8 – don’t align with this though
STEP 8:
Now you are at TDC, your rotor is attached to your distributor properly. Now, the trick is to slide the distributor back in (use a gasket if you have one) so that the hold-down bolt lines up and the rotor stays lined up with the number 6 embossed on the plastic distributor housing. If you don’t get it the first time, you’re probably off by just a few teeth – pull the distributor out and try again.
Here’s a picture of everything lined up.
STEP 9:
Re-install hold-down bolt
And distributor cap
STEP 10:
Now re-connect ignition wires. Note the order on the cap (3, 1, 5 front-to-back).
Reconnect the harness electrical connection on the distributor. Re-connect coil as well.
STEP 11:
Re-connect spark-plug and wire.
When I reconnected the spark plug, my socket got stuck on the tightened spark plug. I had to use a pair of channel locks to grab it and pull it out.
Next time I’ll use a longer socket that extends farther than the exhaust manifold heat sheild like this one on the left.
STEP 12:
Put your tire back on. Re-connect your negative battery cable and you’re good to go.
Re: How to find Top Dead Center and set your distributor and rotor when it has been out
