This is ODD (305 Vortec issue)

[L31MaxExpress]

I don't think 160k is "low"?...but on a SBC, it's not "high", either. Last Vortec truck I had, sold it with 300k. That's "high" to me, although it still ran and performed like new. I haven't looked at the cam gear teeth, but will before I put the distributor back in. Not much I can do about the cam though; I'd run it until it fails (if it ever does), then change the cam.




And no oil pressure at the same time? Like I said; when you consider ALL the symptoms....
Glad you got yours fixed. Mine's not the cap and rotor, though.

I misread what you posted. I thought you got it fired back up again and it did not have oil pressure. Did not make sense that it ran and did not have oil pressure. Re-reading your first post, realized it never re-fired.

I doubt the cam wore being it is steel. I have seen cast iron cams wear gears, but extremely unusual for 5150 cam to wear the gears. I have gone through a couple LT1s that ate the oil pump drive gear to the point of losing pressure and the cam was untouched.

 

[Tom400CFI]

Copy, I do that all the time; mis-read and/or skip over stuff.

I agree with you that the cam is likely fine. One thing that's weird is that the dist gear is only smeared on one side; the side in the pics. On the opposite side, the teeth look B-RAND new....no visible wear at all! I've seen dist gears shread before, but it was the whole gear...not just one side, of just a few teeth.

Going to get parts now...

 

[rebelyell]

I don't think 160k is "low"?...but on a SBC, it's not "high", either. Last Vortec truck I had, sold it with 300k. That's "high" to me, although it still ran and performed like new. I haven't looked at the cam gear teeth, but will before I put the distributor back in. Not much I can do about the cam though; I'd run it until it fails (if it ever does), then change the cam.

Suggest closely inspect Camshaft; At Your Earliest Opportunity.

If teeth on Cam are bad, it'll wreck any dist gear you run against it.
If Cam teeth are bad, your ONLY practical course(s) of action are:
(1) replace Camshaft; Before you proceed further ... OR
(2) park it until you can replace/repair what's needed.

* if, IF you run extra-heavy weight oil, that does put excessive stress on both Cam & Dist gears.

 

[Tom400CFI]

I doubt that the cam teeth are bad. We'll see.

For now? Runs great. Smooth as silk, no CEL. No power either (same as ever), but it "Gets on down the road" just fine, which is about all one can expect from the 'ol "Grandpa Truck".

 

[GoToGuy]

The gear on my 97 wore down in under 70K to the point it was causing a misfire and shudder at light load and highway speeds. It is a well known issue, failing even before 100K on some of these. The distributor gear is much softer than the cam and the excessive shaft endplay does not help things.

Yes cap and rotor will cause it to go from running fine to not running in flight. Just had that issue on my 97 a while back. Started spitting and sputtering when it went into passing gear on the highway, then stalled out, coasted to a stop. Backfiring while cranking. The cap and rotor both burned through and the spark was grounding out completely to the distributor shaft. I have also had both large cap and small cap HEIs do the same burning through the rotor. When you get the new gear on it and still does not run or run correctly which is probably a 90% certainty, look at the cap and rotor. My rotor burned through in a spot that was not visible from the top as well.

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Could elaborate on the " dimple " on the distributor gear. What i am looking at or checking for. I've read a lot about it but not had a chance to examine one yet. The last 383 in the 93 is flat tappet.

 

[Tom400CFI]

There is a dimple in the gear just below, and about the same diameter as the roll pin. That is used to position the distributor shaft, relative to the housing, before installing the distributor. This is only required on the '96-'99 Vortec. Since you said flat tappet, the TBI doesn't require this step.

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[Schurkey]

All SBC/BBC engines have that dimple on the distributor gear. The dimple aligns with the rotor contact tip. Otherwise the gear is 180 degrees "off", which means 1/2 of a gear-tooth off.

This can be helpful on Vortec distributors that can't be synchronized to the crank sensor. Sometimes the distributor gear is deliberately turned 180 degrees (1/2 gear tooth) which improves the alignment. WHY this is so, is still a mystery to me. It shouldn't make alignment better...but sometimes it does.

All I can say is to try it with the dimple and the rotor contact tip aligned, and see how the cam sensor and crank sensor signals align. If they're good...leave it alone. If they're not good, turning the gear in relation to the shaft is an option--a potential "fix".