How do you remove and reinstall a distributor on a 93 suburban 350?

Answer 1

Hi: My name is John Stroman. I'll do my best to answer this, but please know that I build Ford and Porsche engines and my information should be taken as less than expert in nature - which means it's probably better than most shops.

1. Have complete confidence that you can do the job. It's not rocket science.

2. Don't rely on manuals such as Haynes. They are generally poorly written and the photographs that are included in those manuals are worse than NSA satellite imagery. Asking the question on the Net is a great start. Just remember, there is nothing difficult about the job. If there is any issue, it is that car manufacturers do not publish procedures.

3. Remove the air cleaner. Remove the spacer (standoff) under the air cleaner. These steps will require you to disconnect vacuum lines to the TBI (Throttle Body Injector).

4. Look at the vacuum lines that you've pulled off. Are they cracked, torn, or otherwise damaged? If so, consider yourself a winner even if you do nothing else. You've discovered vacuum leaks that rob your engine's performance. Replace them. The 350 engine is so common, your local parts store will have them for the cost of a Starbucks Triple Latte. I pity you if you don't replace them.

5. Look at the distributor. SEE it. Visualize it out of the truck. Success begins with an intention not to fail. Begin by getting a GOOD Sharpie pen. Sharpie -- magic marker, felt tip pen, pick your term. Fail to get a pen, and yet again, I pity you.

6. Look at the engine. The Number 1 cylinder is closest to the driver side headlight. I assume you are in the United States, where the driver is on the right side of the truck, when viewed from the vantage point of a person about to be run over by an oncoming Suburban.

7. Staring at the SPARK PLUG of the Number one cylinder, trace the spark plug wire for the number one cylinder to the distributor cap.

8. On the distributor cap, mark the number 1 spark plug wire location. Mark the distributor cap and the wire! If all if the wires were to disappear due to a Martian laser, YOU and your marks should unerringly, accurately, and confidently identify to the surviving Earthlings where the number one plug wire goes.

9. Pull all of the remaining wires from the distributor cap. If you know where number 1 was, the rest are easy to place because there is an exact order -- called the firing order -- that defines where the rest go. Even a Haynes manual lists that order. I'm enjoying a nice Merlot and do not wish to rely on memory to list the order. Google 350 firing order. (I think it's 1-8-4-3-6-5-7-2 - whatever it is, looking at the distributor cap top, going counterclockwise, install the plug wires in the correct order)

10. Remover the distributor cap.

11. Note where the rotor is pointing. It's important! Mark the lip of the distributor body (the surface the cap rests on) to line up exactly with the brass contact of the rotor.

12. Disconnect the negative battery lead.

13. Pull the electrical connectors on the back of the distributor. You will need a small screw driver to pry open the locks which GM so lamely designed for the connectors.

14. Grab a 9/16 box wrench.

15. Remove the bolt securing the distributor hold down clamp -- but DO NOT TOUCH (or turn) the distributor!

16. Once the clamp is off, place a mark on the silver distributor body and continue that mark to the intake manifold. The purpose of the mark is to ensure that the clocking position of the distributor body relative to the engine is known and known exactly.

Voila!

You know exactly how the distributor bolts BACK to the engine. You know exactly where the rotor should point (a detail that determines whether your engine will run), and you know exactly how the spark plug wires will go.

17. Pull the distributor. Don't lose the clamp or bolt. Don't erase your marks, and keep dirt away.

18. There's a gasket under the distributor. Peel that off too. It's a good idea to replace it also.

19. Whatever else you do, keep things clean. No dirt should get into the hole. No dirt should get on the distributor shaft.

20. Don't even think about starting the engine or otherwise causing the engine crankshaft to turn -- this will throw off the markings.

A few other comments. Despite the size of the engine and truck, GM successfully will have made you into a gymnast to get to these parts. GM, by intention, does not design for maintainability. Dealing with the discomfort to get to these parts is a microcosm of the Struggle of Life. You shall persevere.

If you erase your marks; if you do not follow these steps; or if some dummy tries to start the truck because they need to go buy a lottery ticket, all is not lost. You must roll the engine to Number 1 cylinder TDC while observing two phenomena:

(with number 1 spark plug removed) a feeling of air being pushed out of the spark plug hole when rolling the engine clockwise (5/8s 1/2 inch drive socket on the crankshaft pulley).

Scribe mark on the pulley lining up with TDC.

With those TWO conditions, you've placed Number 1 at TDC. When you reinstall the distributor, you need not care where it's oriented, so long as you can plug the electrical connectors back to the body.

What you will need to care about is that wherever the rotor points, that will be your number 1 firing position. I cut a hole in an old distributor cap to allow me to rotate the distributor to exactly align the rotor with one of the spark plug holes.

From there, connect the rest of the plugs in the correct firing order. You shall achieve victory in this manner, but to be sure, it's a lot easier to mark things!

You win. The distributor has been removed, and you have procedures to replace it.

Cheers,

John