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Auto Go
Auto Go, ASE Certified Technician
Category: Chevy
Satisfied Customers: 849
Experience:  ASE Master certified, ASE certified Undercar Specialist, ASE Advanced Engine Performance certified
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An electronic distributor for a vortec 454 in a 98..silverado..rotor

Resolved Question:

How do you time an electronic distributor for a vortec 454 in a '98 K2500 silverado p/u? There is no rotor to reference, and the mark I made when I pulled the distributor was off. I tried moving the tooth one forward and one back. Did not help timing. I was trying to use timing data for the older 454 to retime the engine, but that did not help since I don't have a rotor in the distributor as a guide.
Submitted: 8 years ago.
Category: Chevy
Expert:  Auto Go replied 8 years ago.
Hello and welcome!

There has to be a rotor in the distributor. I am un clear on the rotor situation...

The proper procedure is to roll the engine on TDC and install the distributor so that the rotor points to #1 on the distributor cap when installed all the way down.

Please explain further why there is no rotor and the problem you are having. Will the engine not start?
Customer: replied 8 years ago.

Ok. The 454 has SFI ignition. In the manual I've been reading, there is a step that mentions that the ignition can not be timed. I did not try to unscrew the cap because it has a bar code seal on the back of it, which I'm guessing is a warning for tampering. The coil is seperate and mounted on a bracket above the distributor.


No, the engine will not start. I figured that the distributor is possibly 180 degrees out on the timing, but I did not want to try that until I know how to verify the position of cylinder #1.

Expert:  Auto Go replied 8 years ago.
Yes, I am very familiar with the 454/7.4 liter. You must remove the distributor cap there is no other way to get this thing timed if you've had the distributor out. Don't worry about tampering. Its a 98, the warranty ran out a long time ago and you can do whatever you want with it!!!Cool get that cap off so you can see the rotor. You will need to know what post on the cap is for the #1 cylinder. If you don't I'll send you a pic. If you do, great! Sometimes its even marked on the cap.

The only way to tell if it's actually on the compression stroke is to remove the number 1 spark plug. It's the first one on the driver side. place a finger over the spark plug hole. Now rotate the engine BY HAND until you feel air start to push against your finger. When you feel this air continue to roll the engine over until the mark on the crank pulley is at the 0 mark on the timing indicator. Now you are at TCD #1. that's where we want to be. Now, you will notice the electrical connector on the side of the distributor. That needs to point in the directon of the driver seat so the wires will reach it. temporarily install the cap back on the distributor. locate the #1 post and follow it down to the base of the distributor and make a mark on the distributor itself so you will know where #1 is with the cap off. install the distributor with the electrical connector facing the driver seat and the rotor pointing at the mark you just made (#1 on the cap). If the rotor dosen't point to #1 with the distributor FULLY SEATED, then pull it out and move it tooth in whatever direction it needs to go and stick it back in. Make sure it fully seats when you put it back in. Sometimes the oil pump drives will give you a bad time getting it in, but just keep wiggeling it and it usually goes in......

Keep in mind that if it's just barely off, you can rotate the distributor a little one way or the other, just don't go to far or the wires to the back of it won't reach or will be pulled too tight. snug your hold down bolt and put your wires and everything else back on. Now here is the fun part

While the truck should run, it still isn't timed properly. The only way to do this is with a scan tool. You must read what's called the cam offset on the scanner. it's basically a timing reading. adjust the distributor until it reads 0 plus or minus 2. Keep in mind it' wont update until you rev the engine over 1500 RPM so make an adjustment and rev the engine before going to look at the cam offset again.

This should get you going! you will have to pull that cap off to get this right.
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