gta324

Have had the cam in engine since 2004.
MSD dizzy I put in 2007.

So engine had stock dizzy for 2 years then MSD for another 3-4 years

Pulled the MSD a few days ago and here is what the gears looked like




Well put the stock dizzy in and it looked fine! and after been idling a few minuter so I could set the timing it looked like this




You could already see the wear marks on it, so I decided to take the intake of and here is the cam gears...





What could have happend that causes this? something must be wrong ...
Oil pump spinns easy ( I think, will compare with friends car soon)
Camwalk? or lack of cam walk?

fireturd350

iTrader: (8)

What's your cam? Is it a retrofit or are you using roller with retaining plate? Did you check for movement after you stabbed the cam?

gta324

its a hyd.roller LT1 kam in a old block, so I have a cam button in front......

fireturd350

iTrader: (8)

So did you measure walk and shim the button? What timing cover are you using? The stock tin types will deflect.

gta324

been a few years ago but cam button was measured and the cover is a thick Al one, summit i think...

Will check "cam walk" tomorror, how much should it be?

fireturd350

iTrader: (8)

http://www.chevyhiperformance.com/te...lay/index.html

ninetyone

iTrader: (2)

what distributor are you running? TPI one?

ninetyone

iTrader: (2)

More than likely something to do with the type of metal used on the msd distributor's gear. Maybe the metal on the distributor is harder than the metal on the cam gear. Remins me of when i used to work on Ford 5.0 motors EFI, and if a flat tappet cam was used with the stock EFI distributor (roller) (which is a steel gear) then it would tear up the flat tappet cam's gear. Just a thought.

Damon

You didn't use the o-rings on the MSD distributor, did you? That's a big no-no on a street driven engine.

At low RPMs the cam/distributor gears are kept lubricated by oil drizzling down the outside of the distributor shaft body from the oil groove that runs around it on it's way to the passenger side lifter galley (the big groove at the bottom of the distributor shaft). Only at higher RPMs does it get "splash oiled" by the crank whipping oil up onto it from the crankcase. That's why you don't use the o-rings on a street driven engine that sees a lot of idling and low RPMs.

On some aftermarket distributors the fit is so tight in the block, even without o-rings, that those gears can get starved for oil at low RPMs. The recommended fix is to file a little tiny groove down the outside of the distributor shaft with the edge of a file so it drips oil directly from the oil galley cross-over onto those gears. It should not be required, but it is often recommended. Stock distributors are usually plenty sloppy in their fit so that such a modification isn't needed.

The distributor gear material on the MSD distributor (out of the box) is supposed to be compatible with flat tappet and factory-style roller cams. I assume you didn't change it, right?

One other thing that puts extra strain on those two gears is the oil pump (since it's driven by the distributor). A higher volume pump makes it worse, a higher pressure pump also makes it worse. Both together make it doubly worse.

gta324

No O-rings ( see pic) and yes the gears were corrrect (both stock) and should work. I've also read about file a groove in the dizzy, think I will do that.

I do have a HP HV pump in, maybe time to put a stock one in or modify the one I have......