Register and join the largest automotive community online!
Google  
Web AF
Please Register or Login to access: DriverSide DriverSide Home | Service & Repair | Car Prices | Parts & Accessories | Reviews & Advice | My Garage

How to find Top Dead Center and set your distributor and rotor when it has been out


Google  
Web AF

drdd
01-14-2008, 12:56 AM
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.

http://i23.photobucket.com/albums/b390/drdd/Jimmy%20Top%20Dead%20Center%20Distributor%20and%20 Rotor/Wedding015.jpg




For extra precaution, disconnect the ignition coil.

http://i23.photobucket.com/albums/b390/drdd/Jimmy%20Top%20Dead%20Center%20Distributor%20and%20 Rotor/Wedding016.jpg





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.

http://i23.photobucket.com/albums/b390/drdd/Jimmy%20Top%20Dead%20Center%20Distributor%20and%20 Rotor/Wedding025-1.jpg

http://i23.photobucket.com/albums/b390/drdd/Jimmy%20Top%20Dead%20Center%20Distributor%20and%20 Rotor/Wedding006.jpg

http://i23.photobucket.com/albums/b390/drdd/Jimmy%20Top%20Dead%20Center%20Distributor%20and%20 Rotor/Wedding008.jpg

http://i23.photobucket.com/albums/b390/drdd/Jimmy%20Top%20Dead%20Center%20Distributor%20and%20 Rotor/Wedding007.jpg






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.

http://i23.photobucket.com/albums/b390/drdd/Jimmy%20Top%20Dead%20Center%20Distributor%20and%20 Rotor/Wedding026.jpg






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.

http://i23.photobucket.com/albums/b390/drdd/Jimmy%20Top%20Dead%20Center%20Distributor%20and%20 Rotor/Wedding017.jpg






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.

http://i23.photobucket.com/albums/b390/drdd/Jimmy%20Top%20Dead%20Center%20Distributor%20and%20 Rotor/Wedding010.jpg

http://i23.photobucket.com/albums/b390/drdd/Jimmy%20Top%20Dead%20Center%20Distributor%20and%20 Rotor/Wedding011.jpg

http://i23.photobucket.com/albums/b390/drdd/Jimmy%20Top%20Dead%20Center%20Distributor%20and%20 Rotor/Wedding012.jpg

http://i23.photobucket.com/albums/b390/drdd/Jimmy%20Top%20Dead%20Center%20Distributor%20and%20 Rotor/Wedding013.jpg

http://i23.photobucket.com/albums/b390/drdd/Jimmy%20Top%20Dead%20Center%20Distributor%20and%20 Rotor/Wedding014.jpg






STEP 6:

You are now at TDC. Time to line up the distributor shaft and rotor.

Here’s the distributor

http://i23.photobucket.com/albums/b390/drdd/Jimmy%20Top%20Dead%20Center%20Distributor%20and%20 Rotor/Wedding001.jpg





Two small Torx screws hold the rotor to the distributor. This picture was taken on reassembly.

http://i23.photobucket.com/albums/b390/drdd/Jimmy%20Top%20Dead%20Center%20Distributor%20and%20 Rotor/Wedding020.jpg


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.

http://i23.photobucket.com/albums/b390/drdd/Jimmy%20Top%20Dead%20Center%20Distributor%20and%20 Rotor/Wedding009.jpg

http://i23.photobucket.com/albums/b390/drdd/Jimmy%20Top%20Dead%20Center%20Distributor%20and%20 Rotor/Wedding009a.jpg

http://i23.photobucket.com/albums/b390/drdd/Jimmy%20Top%20Dead%20Center%20Distributor%20and%20 Rotor/Wedding028.jpg




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).

http://i23.photobucket.com/albums/b390/drdd/Jimmy%20Top%20Dead%20Center%20Distributor%20and%20 Rotor/Wedding029.jpg

http://i23.photobucket.com/albums/b390/drdd/Jimmy%20Top%20Dead%20Center%20Distributor%20and%20 Rotor/Wedding031.jpg

http://i23.photobucket.com/albums/b390/drdd/Jimmy%20Top%20Dead%20Center%20Distributor%20and%20 Rotor/Wedding002.jpg



Here’s the 8 – don’t align with this though

http://i23.photobucket.com/albums/b390/drdd/Jimmy%20Top%20Dead%20Center%20Distributor%20and%20 Rotor/Wedding030.jpg






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.

http://i23.photobucket.com/albums/b390/drdd/Jimmy%20Top%20Dead%20Center%20Distributor%20and%20 Rotor/Wedding019.jpg






STEP 9:

Re-install hold-down bolt

http://i23.photobucket.com/albums/b390/drdd/Jimmy%20Top%20Dead%20Center%20Distributor%20and%20 Rotor/Wedding021.jpg



And distributor cap

http://i23.photobucket.com/albums/b390/drdd/Jimmy%20Top%20Dead%20Center%20Distributor%20and%20 Rotor/Wedding022.jpg






STEP 10:

Now re-connect ignition wires. Note the order on the cap (3, 1, 5 front-to-back).

http://i23.photobucket.com/albums/b390/drdd/Jimmy%20Top%20Dead%20Center%20Distributor%20and%20 Rotor/Wedding024.jpg




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.

http://i23.photobucket.com/albums/b390/drdd/Jimmy%20Top%20Dead%20Center%20Distributor%20and%20 Rotor/Wedding018a.jpg



Next time I’ll use a longer socket that extends farther than the exhaust manifold heat sheild like this one on the left.

http://i23.photobucket.com/albums/b390/drdd/Jimmy%20Top%20Dead%20Center%20Distributor%20and%20 Rotor/Wedding023-1.jpg





STEP 12:

Put your tire back on. Re-connect your negative battery cable and you’re good to go.

DINO55
01-14-2008, 07:42 AM
Excellent, Write up drdd... (Life Saving for some)
This should end up in the DIY Section...

Dino

ZL1power69
01-14-2008, 11:06 AM
moving to FAQ section

Mopower79
05-08-2008, 11:17 AM
Great write up..
Thanks for taking the time to do it...
You & this thread just saved me a TON of $$$$$$$$$$$
I almost gave up hope on the Jimmy until I "Stummbled" on to this site!!!
Again Thankyou.. :biggrin:

ammike
10-29-2008, 03:55 PM
WOW, i can't tell you how much i appreciate this how -to!! You saved me a ton of hours and money! Tried it and got it the first try with your instruction...2 big thumbs way up!:iceslolan

Add your comment to this topic!


Google  
Web AF