305 rocker oiling problem

[dthela]

305 completely rebuilt. not getting oil pressure at rockers. took off the end rocker support that the oil comes into and there is no oil coming out of the head. 60psi at the filter tho. HELP!!!!!!!!!!!!!!!

[Rich 5150 69]

I believe the oiling comes from the #1 and #2 cam bearing at the front, but lets see if others chime in with something else.

[biohazardbill]

Is this with the motor running or are you trying to prime?

[Rich 5150 69]

If this is happening with engine running I would think that maybe one of the rear plugs in the oil gallery back of the block is driven in to far blocking the port. Is this one side or both...? maybe be on the minor side, could also be mismatched lifters.

[awbrown]

I have no experience with these engines , but in other engines that oil through the shaft , slide a small wire down the oil galley from the rocker shaft mount and see if it goes deep or stops at say where the head gasket would be .. If it goes down past where the head gasket is located then more than likely the cam bearings may not be aligned with the hole ,if you have run the engine and there is no oil then it is one of the 2 I suspect... if you have not run it yet turn the engine over very slowly while you are prelubing it and see if it shows up then....

[dthela]

stops in the same place my old spare engine stops at thought it was the head gasket thats why i checked the old motor. both sides same thing. got the oil diagram, but no oil coming out of head oil hole. wire only goes down to about the head gasket

[dthela]

with engine running.

[dthela]

what could block it at the cam bearings?

[dthela]

Rich, the 305 uses a round shaft will the pressurized oil in it to oil rockers. pushrods arent hollow.

[64fleetside]

The oil holes in the cam bearings may not be lined up properly. On most engines it doesn't matter, but on this one it just might. I've never built a 305V6, just tore a couple down before installing the SBC.

[slorio]

Don:
I saw your question on Stovebolt. Did you check with the discussion group on http://6066gmcguy.org/? I am sure that Pete Chronis on that group can answer your question very definitively. Also, they have an archive where you can search this answer as well. I think the recommendation on the cam bearing is spot on, however, for what it is worth from a novice.
regards,
Steve
New Orleans

[T Herder]

The rear cam bearing is installed incorrectly or is the wrong one. The first and only time this happened to me was in 1970. These rockers basically are pulse oiled, thus each time I remanufacture one of these motors I have a groove machined into the rear cam bearing race to provide continuos oiling.
You have to pull the radiator and grill to pull the cam if you don't want to pull the motor.
Best regards,
T Herder

[62 Barnfind]

I would say that one o more bearing is installed wrong. If the oil hole doesn't line up it will cause low or no oil pressure.

[HEI451]

When I rebuild one of these engines, as I just did a couple of years ago to my own,. I cut the oiling groove into the block, NOT the bearing, so, the metering is altered to full oiling, not intermittent. Then, I add a restricted insert (a Holley main jet) to each rocker stand, to set the volume to the shafts.

The reason I do the groove to the block is, cam bearings can rotate within the block, even if they have the correct press fit, but, the block can't.

[1963c-10]

Were the oil galleys clear? I didn't see the answer to it.

[A.T. RockDriller]

dthela....
I hang out a little around these Vee-Sixes...
Depending on the depth of yer rebuild....you could have one of a couple or more problems....a few mentioned above.

One thing is....keeping in mind that the bottom and the top end of these engines are lubricated via one central oil port....meaning...(unlike most conventional engines) a blockage in any of these ports doesn't always mean the oil stops at that point....It will continue to oil the other ports in a grid fassion.
If the rear cam brg is installed incorrectly...that will only interrupt oil pressure to the rt. (#2, 4, & 6 cyls)....the left side cyl head oils through the front cam brg.

So....if you have problems on oil pressure with both rocker shafts...read this carefully..a bit wordy...but stay with me.
Your rocker shafts are built identically...as far as oiling goes...and they are oiled by their respective oil ports...fed from the left side, bottom of the left rocker shaft....if you are standing on either side of your engine...via the oil port through the cyl head from the block....from the cam brg...blah...blahh.

If your rocker shafts were brand new...they could be mounted on either side...But of course, if they are broke in...ya want to keep them straight...same side to original.
What I'm getting at is that most rebuilds on these rocker shafts, best practices would be to disassemble, clean, inspect and reassemble....set aside for reinstallation.
Well, all four of these end blocks for these R-Shafts all have a hole to match the oil port on the head....but oil only enters thru the left block......the right one just meets up with the deck surface, in essence...ending that oil circuit.
The oil pumped into the shaft oils the assembly and just dissipates through the rockers and other clearance openings.
Most of these, after running fer years, will deposit a kind of aluminum & oil sludge plug in the "dead" end block....the one on the right that doesn't go anywhere. However......if you didn't happen to clean those sludge plugs out...and then lost track and got the rocker shafts swapped....Then you won't get pressure to either.

Long-winded....but I wanted you to understand what I was tryin' to say.
A quick look to check it out and of course you can clean it up with a quick blast of brake cleaner.
I hope it's that simple.

Edit:
However I just read your post #6....that makes my post just a bunch of poetry...
It sure sounds like a head gasket mis-punch.
With the price of these gaskets, I'd consider making a sharp eight inch long punch out of a piece of brazing rod....and poke through that head gasket....it won't hurt anything but the head gasket....and it needs a hole there anyway...
Make it as big around as possible.
In fact, if you have a long drill bit the right size and varify that it's the head gasket...I'd gob some grease onto the end of the bit and clear the port with a slow drill.
I just can't figure out how both sides are starved....unless it is both frt & rear cam brgs....
Or....maybe a new guy at the machine shop figured that those oil ports needed to have an alignment dowell driven into them...
I've seen worst.

[dthela]

I appreciate the info everybody. Someone suggested taking off the ends and squirting oil until passage is full, then crank motor and see if oil pulses out. IT DOES!!!!!! yeah!!! put it back together and now I get the bleading of oil out the rocker holes. Damm it aint much and barely gets any on the inside of the rocker covers, but I guess the system works good. Very noisy though I guess from the solid lifters. Never heard another run in person.

[shortbed70]

I just had this same problem but it was on my 361 sbc motor. Don't know if they are similar but my distributer wasn't down I. The hole far rnough to let oil around the groove (above cam gear on dist) and not letting oil flow to the rockers. Found this by pulling the distributer and re priming motor.
Posted via Mobile Device