This was on Team Chevelle:
http://www.chevelles.com/forums/showthread.php?t=107027
Distributor "depth" isn't the issue. The distributor housing has two machined surfaces towards the bottom end. Those fit--fairly loosely--into machined openings in the block casting. Part of the oil circuit is for oil to travel AROUND the section of the distributor housing and continue to the lifters. Any oil leaking past the lower machined surface provides lube for the distributor gear. Even so, there could be more leakage than is actually needed by the distributor/cam gear interface. Oil leaking past the upper surface does NOTHING useful. Both of these oil leaks are totally invisible--they are INTERNAL. The oil will just run down into the pan, and be pumped back up again.

This is why you cannot properly prime the oil system of a Chevy without having either a distributor housing in the hole, or a "special primer" that does effectively the same thing as the housing--seal that passage.

MSD distributors for Chevy have two O-ring seals on them. They must be used with a block that is de-burred properly so as to not cut the seals, and then you can positively prevent this oil leak. Note that on any distributor that has these O-rings, there is a tiny drilled passage in the distributor housing casting that squirts a metered amount of oil on the distributor gear. Install that distributor without lining up the oil squirter hole, and you might destroy the cam and distributor gear.

 

Thanks for the info/reply. I am feeling better about putting this thing back together now. I really appreciate the quick reply.....Jon

 

Beth, leave something for the rest of us!

Oh wait, the torn up bearings. Not a clue. What did they say at Team Chevelle?

Well, there was my 1970 LT1 block that had a slight problem. I had it balanced and blue printed when new in 1973. It was a service block from my local dealer and sold to me by my parts-man buddie who also drove my car off the trailer when it was delivered.
Oops, getting long winded. Here's the short story version. Engine was a service short block. How did it get to be a service block? The guy who lined it up on a jig to drill the distributor hole, MISSED. So, instead of pulling the block from the line and getting a demerit, he reset the block and drilled again. The first hole was 3/4" off. It could never be assembled unless he cut another hole. He just yelled "PARTS!" and the block went to a different line and was assembled and shipped to ME! (I ordered it. Drat.)
I installed the good-stuff and put it in my ski boat. You're right. No oil pressure. After trouble shooting for a month my friend and I had no where else to look other than the cam valley. I prepared the engine for manifold removal and drove to his house because he had a primer tool. (see? same situation) Well, the instant the tool was to be placed in the block the trouble shooting was over. They gave me a new short block. But it still hurt, a lot. And no one at the balance shop saw it, nor did anyone else, like me. Who looks for stuff like that?

 

Thats is the odd thing about the whole situation. I had oil pressure at cruising speed and idle. I can not be sure about wot just because I didnt look down at the gauge. Hopefully this solves the problem. The second time I put it together I even primed the motor and then pulled the oil pan off and held a bowl of oil up to the oil pump and made sure that oil came out of the rods and mains. I saw oil coming out so I thought that I was ok. I remember both my buddy and myself commenting about how much oil comes down from the distibutor. That should have been our first clue but you guys probably know how it is. When you are getting close to being on the road you can so excited that you get tunnel vision.

 

You definitely should not use the o-rings unless the block is specially modified for them. Most do not do that mod. Also check that distributor depth to make sure the end of distributor is engage deep enough with the oil pump drive... another very common problem.

mike

 

Since you guys are discussing dist gear oiling, I will share with you what I did about making sure the cam/dist gear got its oil. This may be an old school trick but I just ran across it.

These two gears get oiled by what ever mist or drip in the area but I put a little slot in the dist body lower boss to act as an sprayer channel to feed my billet dist cam gear and the cast iron gear constantly.

Once I determined the correct position my dist would be at the right timing, I put this .010-.015 grove to line up with the gear. This would be an oil pressured stream spraying on both gears mesh all the time.
I still manage to maintain a 55-60 psi supply at cruise. I also have a small pin hole in the center cam lifter galley plug, to feed the torrington bearing on the hex-adjust timing gear with button.

As the second post of this topic mentioned, these dist/block clearances are tight or snug but I can see where an excessive clearance could cause a problem. Also here, the word O rings is throwing me off , do we actually mean the two wide oil sealing faces that have this oil channel in the dist body that lines up with the block lifter gallies? Never seem 0 rings as in rubber 0 rings. Am I thinking wrong?

 

Since you guys are discussing dist gear oiling, I will share with you what I did about making sure the cam/dist gear got its oil. This may be an old school trick but I just ran across it.

These two gears get oiled by what ever mist or drip in the area but I put a little slot in the dist body lower boss to act as an sprayer channel to feed my billet dist cam gear and the cast iron gear constantly.

Once I determined the correct position my dist would be at the right timing, I put this .010-.015 grove to line up with the gear. This would be an oil pressured stream spraying on both gears mesh all the time.
I still manage to maintain a 55-60 psi supply at cruise. I also have a small pin hole in the center cam lifter galley plug, to feed the torrington bearing on the hex-adjust timing gear with button.

As the second post of this topic mentioned, these dist/block clearances are tight or snug but I can see where an excessive clearance could cause a problem. Also here, the word O rings is throwing me off , do we actually mean the two wide oil sealing faces that have this oil channel in the dist body that lines up with the block lifter gallies? Never seem 0 rings as in rubber 0 rings. Am I thinking wrong?

Yep, O rings Don. Both my year old billet and the new crank trigger model. They (MSD) tell you the block must be deburred or do not use the O rings. They don't say why not, but common sense does.
Anyway, my lack of common sense said why-not? We all know what an O ringed shaft feels like when it's sliding home, right? It felt fine and removal last season confirmed that both O rings were great.

Don, somebody stole your idea. The new Chevy MSD's are now made with gear oil holes.:yes:
And how big is your timing gear hole? Seems .030 was the recommended size so that's what's there. Works fine, good OP.

You didn't talk about your dog population.:noway:

 

Sorry Jon,
The problem is your torn up bearings. Is the block seasoned, (old) or new off the shelf like my dreaded LT1?
If it's seasoned, casting sand might have worked it's way free because of the rebuild-work.
I've found a big chunk in the oil filter casting. You'll need to chisel the stuff loose when it's stuck like that. But sand in an oil passage has been know to happen. The oil gallery plugs are removed and an appropriate size bottle-brush is used with your favorite solvent. You probably know all this. What did they say over at Team Chevelle?

 

how bout your pic up screen to bottom of oil pan distance? If its to close its going to starve it for oil.

 

Yeah Fred, I gave him the "Team Chevelle answer" because I didn't have a clue.

Did the rod bearings have a "starved" look- a nice even wear or did they look like trash had gone through (uneven scratches) ? And you shouldn't have more than .0025" clearance on a rod bearing and the same on the mains.