Quote:
Originally Posted by Vegas69
Is this something we all should worry about, or only in specific applications? Or only a cast core?
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This is a specific brand & material incompatibility issue; combining a Comp cast core roller (-8 core, the standard core Comp grinds their hydraulic rollers and "Street Series" solid rollers on) with MSD's melonized distributor gear (their standard provided gear) is a nearly guaranteed failure regardless of oil pressure or other outside influences.
The solution is to get a GM Melonized gear and have it honed out to fit on the larger .500 MSD distributor shaft; the GM gear and the Comp -8 core will "play nice" together, but that doesn't fix the potential problem of the soft -8 core eating the lobes up with higher spring pressures.
Ned, Mike Lewis usually keeps a dozen or so honed GM gears in stock and can ship it out same day. The other solution is to buy the GM gear locally and have a machine shop hone it out from the GM stock ID (.491" I believe) to .500" to be a nice slip fit on the larger OD MSD distributor shaft. Any local machine shop can do it, I know Walt (Performance Machine) could for sure. All he has to do is put it on the Sunnen hone and open up the ID.
Quote:
Originally Posted by DRJDVM's '69
The one thing that still worries me.... the no oil pressure..... if the dist gear is trashed but the rotor still turns and the timing marks werent off, shouldnt I still be getting some oil pressure ???
That bugs me.....
What are your guys thoughts on the "high volume/high oil pressure" as being the cause ??
Like I said, my car has like 70 psi of oil pressure alot of the time.....
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If the distributor gear is trashed, then the distributor isn't turning and thus the oil pump isn't spinning, so no oil pressure.
As far as the HV/HP pump... a new engine that has been built with proper bearing clearances has no need for an HV pump and it's just taking extra HP to bypass the unneeded oil. I do like the high pressure Z-28 pump spring though for any performance build. The HV pump does increase the load on the distributor gear and probably expedited the demise of your gear. The gear failure is a material incompatibility, but excessive load on the gear certainly speeds up the failure.
The only time I would think about using an HV pump is if the bearing clearances are really loose or if the block has piston squirters or valve spring squirters installed, and even then I would consult with those with more experience to see what their recommendation would be.