I bought an ARP HD oil pump shaft.I assume the washer that stops the shaft from pulling out when the distributor is removed goes at the top of the shaft where the block narrows down.With the washer at the lowest it will go against the thicker part of the shaft the oil pump will NOT bolt up to the block.In other words its still not in far enough by about 1-2 inches and the washer cant be moved any further.On the original shaft is the washer at the top under the distributor or at the bottom near the oil pump?The washer on the original is bigger than the ARP one and will NOT enter the block at the bottom because there is a slight shoulder about 2-3 inches in.It will go in enough to bolt up the oil pump and not pull out at the top.Has anyone else had a problem with the replacement ARP shafts?

  

I have found on some Canadian blocks the hole for the oil pump drive has not been drilled clean through and a ridge has been left behind from casting at the lower edge of the block where the pump drive shaft passes through the block.



I have had to drill that ridge out that was left behind for clearance of the HD oil pump drives.



That is likely stopping the retainer from passing through.



You do have the distributor out? If not the hex may not be lining up with the distributor

marv

ARP installs the washers on the wrong end for some reason. Put it on the other side of the shaft. The washer goes on the oil pump end of the shaft so that the shaft doesn't pull out when the distributor is removed.


Lawrenceville, GA

Charley is right. The oil drive shaft nominally goes in from the bottom. The clip is on the bottom part so that the shaft is kept from coming out with the dizzy if and when you pull it. The clip isn't necessary to the actual working of the drive shaft though.

This is a US motor.I figured out the washer(clip) should be on the other end however the washer is too small and passes right through the ridge.If it was used on the top end of shaft it would work fine as the opening for the distributor is smaller than the opening in the bottom where the washer should go.Using the original washer which is bigger solves that problem.Where should that washer be positioned?Against the thick part of the shaft or how do I figure out where to position it?The original and replacement shaft are identical length so the distributor should automatically engage the oil pump drive shaft as much as the original setup-correct? I am reassembling this motor on a stand so there is no problem as far as seeing how the shaft engages at both ends.Am I correct that there appears to be  a slight difference in  size between the 2 ends of the shaft? Marvh I took your advice and had the oil groove in the cam deepened  to .032.I appreciate the input from everyone.

  

On the drive shaft that I have (aftermarket -  Mallory), you can see little ridges at the position where the washer is supposed to be pressed on. To answer your question-- I know the clip is nearer the bottom than the top, but I don't know the exact location off the top of my head. I may have a spare shaft somewhere in my workshop. I will look for it and see if I can measure at which point the washer was positioned.

In theory, yes. But in reality one should be careful. For instance, with my Mallory distributor + shaft, the shaft wasn't exactly right and if it all wasn't carefully put together you could easily get some slippage. I called the vendor and he said this was a problem they were having at that time with a batch of Mallorys.

Gee, I've never come across one that wasn't virtually the same dimension all the way down...but then again I have never used ARP HD, so I guess it's possible. Do you have a micrometer? How much difference is there?

 I may have a spare shaft somewhere in my workshop. I will look for it and see if I can measure at which point the washer was positioned.

Thanks.I cant check my old shaft because the clip has been moved around.

  

Found it--that was reasonably easy. The shaft itself measures 8 inches in length. The clip washer is exactly 1-3/8 inches from one end.

Hope this helps. 

Thank you Joey!

  

 I’ll summarize what I know on the ARP oil drive shafts.  The washer being installed at the top of the shaft is on the incorrect end and the washer being used by ARP is too small in diameter to be effective.  This particular washer arrangement is fine for the SBF, BBF, and FE engines but not correct for the Y engines.  I’ve sent a snailmail note to ARP in the past but I’m sure I was dismissed as just someone not knowing what they were doing as I received no response back and the washers continue to be installed on the wrong end and still too small to be effective.

 

I simply remove the ARP washer and install a larger tight fitting washer at the bottom end of the shaft so that the pointed end of the drive still faces to the top.  Reusing the original larger washer from an original oil drive works just fine if the washer is removed without damaging it.

Lorena, Texas (South of Waco)