Dist Timing Issue

[reddog64]

I dont remember if the balancer is keyed..

You need to point the distributor to the number one plug wire, NOT the number one cylendar... but usually they line up pretty close...

 

[Oilbrnr]

I dont remember if the balancer is keyed..

You need to point the distributor to the number one plug wire, NOT the number one cylendar... but usually they line up pretty close...

Oh there is defiantly a woodruff key in the balancer. Unfortunately there does not appear to be a reference mark from the inner to the outer portions of the balancer to tell if it has slipped.

 

[bp71k5]

Why not just try moving the wires over and see if it really work? It's free and only takes a couple minutes. I'd have to think that it's more likely the wires got put back on incorrectly than the balancer slipping. I've got books that say the wires start in three different locations so it's not hard to see how someone could be off. Not a criticism, I'm just remembering how easy it was to goof mine up when I did it.

 

[Oilbrnr]

Why not just try moving the wires over and see if it really work? It's free and only takes a couple minutes. I'd have to think that it's more likely the wires got put back on incorrectly than the balancer slipping. I've got books that say the wires start in three different locations so it's not hard to see how someone could be off. Not a criticism, I'm just remembering how easy it was to goof mine up when I did it.

Because I've quadruple checked the firing order of the wires, and moving them one tower to the left or right acomplishes nothing that loosing one bolt and twisting the whole assembly achieves.

 

[bp71k5]

and moving them one tower to the left or right acomplishes nothing that loosing one bolt and twisting the whole assembly achieves.

Hmm, it won't fix the problem of your timing mark not lining up on the balancer which is what I thought was the problem.

 

[Oilbrnr]

So after two days of tinkering, I'm down to two possiblilities, neither of which seem probable.

I started by removing all plugs from the PO and doing a compression check. Lowest was 140, highest was 150 and the rest were in between. Plug 6 was totally covered with carbon/oil, so either the wire or plug was dead, or on a 30k Goodwrench I've got a bad valve stem seal.

Next I removed the main pulley and compared the harmonic balancer to a brand new one from NAPA. Timing mark matched the OEM exactly. Sh!t.

Gap the new AC plugs to .045 and put the new Taylor wires in. Made sure I was on #1 TDC Compression and marked the base of the dist. and put the cap on. Started the firing rotation with the second tower clockwise from the tach/wiring node of the cap. Fired truck up at 8* BTDC it ran for a short time, as before, and died. Cranked the dist CCW and she runs fine. Idle miss is gone and power slightly up. WOT miss under load is gone.

Timing mark is at 12'oclock. WTF!!!! I can only think of two explanations. Something changed from 1977 to 1997 RE the crank or harmonic balancer, or my 25 year old Sun inductive timing light is F'd.

Thoughts?

At this point, and the only reason that I care, is that I'm stumped, and I'm never stumped on stuff like this.

 

[bp71k5]

Started the firing rotation with the second tower clockwise from the tach/wiring node of the cap.

If your motor runs smoother when the timing mark is at 12:00 then your #1 wire is not lining up with the #1 cylinder when you timed it. Assuming you really are hooking the timing light up to #1, then the wires aren't on the cap correctly.

Are you sure you started the rotation from the right spot? I know I'm sounding annoying now and I'll butt out if you want.

 

[Oilbrnr]

If your motor runs smoother when the timing mark is at 12:00 then your #1 wire is not lining up with the #1 cylinder when you timed it. Assuming you really are hooking the timing light up to #1, then the wires aren't on the cap correctly.

Are you sure you started the rotation from the right spot? I know I'm sounding annoying now and I'll butt out if you want.

No problem!

As noted above, I used the proper tower to start the firing rotation. With the mark on 6* BTDC, I chalked the location of the rotor to the base of the dist. just to double check alignment to the #1 tower. It started at this position, barely and then shortly after died. I advance the dist. and it runs fine.

I think the one thing you're missing here is that the engine runs perfect. No backfires, hesitation or stumble (esp. now that I got #6 taken care of). If there was a problem with the wire position or order it would be noticeable. That said, and assuming that I've hooked the light to the wire that goes to the plug closest to the radiator on the drivers side, the firing order STARTing point is irrelevant, as long as the relationship to the rotor is aligned.

I know that you tried to get me to move all of the wires one tower in either direction. But if you think about it, all that is going to do is advance or retard the timing by whatever number of degrees it is between towers. IE it is the same as rotating the whole distributor. Unless I'm missing something that is directly related to the way the HEI module works in relation to the magnetic pickup.

 

[bp71k5]

But if you think about it, all that is going to do is advance or retard the timing by whatever number of degrees it is between towers. IE it is the same as rotating the whole distributor.

Try thinking of it like this... The basic problem is that when you rotate the distributer to line up with the timing mark on the balancer, the motor runs like crap because the timing is too retarded. You can see evidence that it's too retared because as you advance the timing, it runs noticably better.

Once you rotate the dist though to fix the problem, the timing mark on your #1 wire is firing at 12:00 instead of 3:00. Is that about right?

This means the rotor is now physically lining up with the #2 wire on the distributor but the motor is ready to fire the #1 cylinder instead. As a result, your timing light ends up being hooked up to the wrong cylinder once you rotate it the 1/4 turn.

That's why just rotating the dist only kinda fixes the timing problem. Moving the wires over one spot will move your timing mark over one spot (1/4 of a crankshaft revolution from 12:00 to 3:00).

 

[Oilbrnr]

That's why just rotating the dist only kinda fixes the timing problem. Moving the wires over one spot will move your timing mark over one spot (1/4 of a crankshaft revolution from 12:00 to 3:00).

So move all wires one tower clockwise?

 

[bp71k5]

That's what I did. My timing mark was also reading at 12:00 and this fixed the problem.

 

[Oilbrnr]

I'll give it a try tonight then!

Do you recall if you had to adjust the dist. much after doing that, or did it start right up?

 

[bp71k5]

If you rotate the dist. so the vaccuum advance unit is in about the right spot. (~ 8:00 - 9:00 on mine ) it should fire right up.

If it starts and idles, you should be able to move it a bit to fine tune it before getting the timing light on it. It'll either we way off or just about right.

 

[Oilbrnr]

Made no difference. As I suspected, same scenario, just a different dist. position to get it to run.

Stick a fork in me, I'm done.

 

[bp71k5]

Are you sure you're timing from the #1 cylinder? I don't see how you can be getting that result if you are.

 

[Oilbrnr]

Driver's side, closest to the radiator, yup. Sun pickup attached right at the plug pretty much.

After I gave up, I broke out the old ColorTune and adjusted the idle mixture settings. Engine is now smoother than 'budda!

I'm going to borrow a friends timing light and see if that might be the issue. Otherwise, it has to be something with the way the Crate 350 crank is keyed...