2.8 ignition timing correct? (Page 1/1)
CSM842M4 JUN 18, 09:15 PM
About a year ago, I bought an '86 GT with known (or possibly only suspected) engine issues, but with a laundry list of new parts. While chasing a no-start condition this week, which turns out to be a bad fuel pump, I found some baffling things kinda goofy with the ignition. First, I found the spark plug wire going to the #4 cylinder was OFF the plug. While researching THIS issue, I found that all the plug wires are out of order on the cap.
I brought the #1 piston around to TDC on compression, and the distributor rotor is pointing to the 3 o'clock position (standing on the driver's side, looking to the passenger side). My Chilton's manual has #1 tower at the 9 o'clock spot. I know it really doesn't matter as long as the wires are in the correct order, but what is the "right" position for the #1 tower? Thanks in advance - Chris
Patrick JUN 18, 09:51 PM

quote
Originally posted by Patrick Here:

Over the years here, I've seen so much confusion relating to setting the static timing.

First of all, the cap position can be anywhere you wish to orient it... as long as the rotor is pointing to the terminal used for #1... and the piston is at the top of the compression stroke for cylinder #1.

The only thing restricting where the distributor can actually be positioned is the wiring harness. Obviously the connection for the ICM can't be pointed away from the coil if you expect to connect the harness etc.

Below is the 2.8 in my Formula. To do the initial static timing, I have the timing mark for cylinders #1 and #4 (the wider mark on a known good harmonic balancer) set to 0° with #1 piston on the compression stroke. If I'm installing the distributor, I drop it down so that when fully seated, the rotor is pointing at the indicated bolt on the upper intake. I then rotate the outer distributor so that the terminal I'm using as #1 (as it could be any which one you want) is lined up with the rotor. The terminal I've selected seems to work best in regards to orienting the distributor towards the coil. The engine is now timed well enough to start, and dynamic timing can now be set with a timing light (or for the old guys like me, by ear). Nothing to it.




[This message has been edited by Patrick (edited 06-18-2019).]

CSM842M4 JUN 18, 10:03 PM
Wow! That was quick! Thanks, patrick. That's actually about where my rotor is pointing now. I do need to confirm that I'm on TDC compression on cylinder 1 - I was using my "digital" compression instrument (middle finger) in the spark plug hole as I turned the balancer with a socket and ratchet, and only saw one mark across the balancer. Updates to come. Thanks again - Chris
Patrick JUN 19, 03:29 AM

quote
Originally posted by CSM842M4:

I do need to confirm that I'm on TDC compression on cylinder 1 - I was using my "digital" compression instrument (middle finger) in the spark plug hole as I turned the balancer with a socket and ratchet, and only saw one mark across the balancer.



Chris, I hope you're not assuming that you have a "known good harmonic balancer" as I referenced above. They deteriorate, and the outer ring (with the timing marks) spins on the inner hub. My first V6 Fiero had this issue, which made timing it for the first time rather challenging ... until I realized what the heck was going on!

[This message has been edited by Patrick (edited 06-19-2019).]

CSM842M4 JUN 19, 10:03 AM
Thanks again, patrick. I've seen the outer rings on the balancers slip before, once on a '78 305 in a Malibu and more than a few times on Chevy 427's. Yes, it makes timing them VERY difficult! So much easier with a new or at least good balancer. I will also confirm that. Thanks for the reminder.
CSM842M4 JUN 19, 06:21 PM
Well, I feel a strange combination of disappointment and satisfaction. The fuel pump is definitely the biggest culprit, and may be covered under warranty. However, the plug wires are on the distributor cap in the correct order and location, and the balancer checks out good. I was really kind of hoping that the wires were wrong, and that putting them right would have cleared up the engine knock. Hooking the #4 wire to its plug may still help, but I won't know until after the pump is in the tank and the tank is in the car. Oh, well. I bought the car as a project anyway. We'll see what gives this weekend. Until then,... Chris