He said these are Vortecs, Rick, and he's got an A and a B version distributor so it is highly UNLIKELY that the distributors spin the same way.....
Mark, while these may be 2000 Vortec Engines, I'll assume that Jim has these carbureted, and will be using the older style YLM 624 AV "VR" Ignition system...... of which I actually prefer.
BTW....., Good move Jim, IMO.
However, I can assure you that the YLM 624
AV and YLM 624
BV both turn CW.
If these distributors did not both rotate CW, the RH engine would require a Reverse Rotation oil pump.........., and to my knowledge, Mark, I don't think that one is available..... at least I have never seen one!
But as per my Mallory experience here, the difference between the BV and AV
is the Helical Cut of the "driven" gear!
While the RH engine camshaft may rotate CCW, the camshaft "drive" gear, and BV's "driven" gear are cut to correct the rotation of the distributor... making it conventional rotation.
It's all done via the direction of Helical gear cut!
I've taken a BV distributor......, replaced the BV gear with an AV gear....., and used it in a Standard LH Rotation application before.
But here's the rub, and what causes the wear issue:
The special Helical cut of the "driven" and "drive" gear, are what causes this "down-ward" thrust on the shaft. If the BV distributor is not equipped with the special thrust bearing/washer at the top of the shaft, then I'm not surprised that he is having issues after a short amount of time.
An oil pump can require quite a bit of power to turn it!
On a Standard LH Rotation engine, the Helical cut of both "drive" and "driven" gears cause a normal "up-lift" on the shaft. This "up-lift" is taken care of via the thrust washer directly above the driven gear. It has worked for years and years in all GM cars.
Now days, the washer is nothing but a plane looking washer. (in the old days, they were bronze, and they had a "tang" on them)
Anyway........, I hope that makes sense, Mark!
................
What I was getting at by "verifying the curve" can be done as Rick suggested.... the trick is getting the curve. I would expect to find it in the service manual (I don't have one covering those engines). It will show the degrees advance vs rpm for the entire RPM band. Usually they only show the advance so you will have to add the initial timing if so spec'ed.
Mark, we fully agree here!
Jim, IMO, best to see the OEM advance curve, but a curve for these can be fairly linear.
Just be sure that it does not come on too soon. The dished pistons don't much care for lots of advance too early.
.