Every thing has been going good , on the truck rebuild . This week was spent putting the 272 y block back together , I stripped it down to the short block , cleaned and inspected everything , The motor was very good inside , not much gunk , little carbon on the valves , no ridge on the cylinders , valve seals all soft , timing chain ok , so I replaced the freeze plugs , pressure washed everything , painted all parts , and reassembled the motor , I filled it with oil and put the drill to the pump to pre lube it . Ran it up to 50 lbs pressure and got no oil to the rockers . I did notice the drill would work real hard when the pressure came up . First I pulled the rocker arms off . no oil coming through the heads , Then back off came the heads , no oil coming through the block , I then ran a rod down the holes , did get some resistance but also had fresh oil on the rod when I pulled it out , Put on a bigger drill and got 75 lbs pressure . But no oil . So at this point I have stripped the block and will take it to engine shop and have the go through it . I think when I pressure washed it , blew gunk into a passage and plug something up . So there goes $100 in gaskets and oil . I had planed to have the drive line all back in by today . That's what happens to plans.

 

best laid plans of mice and men.....

sorry to hear, good luck.

 

At least you checked it out before you ran it. I often do things twice, and not because I like to.

 

+1 ... I'd look at it as dodging a bullet, an expensive one. I wouldn't put it on yourself either, Y-block oiling is a weak point. Did you use a 1/2" gear-reduction drill? I have heard it said if you use a 3/8" variable speed drill that you can tell when you get pressure by the smoke coming off the drill. It takes around 1/3 - 1/2 HP to run an oil pump. Could someone have modified the engine for the external rocker oil feed? Was this a running / driving engine?

 

Wow, that is a bit of a set-back. Its already been said but, at least you caught it before you got the engine back in the frame.

Once I was putting a big block chevy back together. I had picked up the short block from the machine shop, finished putting it together and put it in the truck. Then I tried to put a drill on it to pump some oil around....no oil pressure. Messed with it for a long time before pulling the intake back off. I hadn't noticed tha the machine shop had not reinstalled the oil galley plugs along the camshaft journals in the lifter valley.

Hopefully the machine shop can backflow the oil passages or run a rod through them and find your blockage.

Good luck
Bobby

 

We probably all know this but the Y block rockers receive oil from the center cam bearing to the top of the deck on both sides. From the deck, there is a dog leg in the head that serves as oil galley to the rockers on each side.
The dog leg between the deck and head are notorious for blocking with coked oil.
If the Y block has ever been hot or had cam bearings installed by someone un-knowledgeable of the cam bearings, the bearings may not be installed correctly. Quite a lot of written discussion of the rocker oiling problems with the Y blocks. Google is your friend. Make certain anyone working on your engine understands these problem areas.
If I remember right, you had found the rockers to be oiling well when you had initial start up with that engine.

Edit: Pull the cam shaft and blow down through the oil passage from the deck to the cam bearing, should be a straight shot. Also, you can pull the plugs on the oil galley that run front to rear of the block and make certain the galley is clean. If I were doing this, I would pull the engine down to bare block and blow, brush all passages out.
Edit: If you have the block hot tanked in anything caustic, it most likely will ruin the cam bearings.

 

Because of your experience you have a little more work. Without that experience you would have massive amounts of work. Im glad you found out the passage was blocked B4 you went any farther.

 

If you have a cross drilled cam you may not get oil to the rockers until you rotate the engine to line up the oil passage in the cam, then you will only have oil to one side at a time. Unfortunately you cannot push a rod thrugh the oil passages with the heads on as there is a dog leg in them at the block. Even with heads off you can only check down to the cam. Good luck, hopefully it's not too serious.

 

Ditto on the cam bearings. But, they weren't change, so I'd suspect dirt/sludge as others have said. As long as the machine shop has it a good dunking and new cam bearings wouldn't hurt.

 

I, in no way claim to be a Y block expert, have been into a few of them over the years. Personally, I've never seen a stock cam drilled for oil flow. Not saying some are not. Pictured is a stock cam from a 1956 272 CID out of an F1. The cut in the cam journal is where the oil moves from galley to galley and to rockers. You put the front spacer back in when you installed the cam, did you not, Dave?

 

I know little about Y-blocks, but is it possible the head gaskets are flipped, blocking off the ports?

 

I think Dave posted that he has the heads off and still no oil up to the deck. Passage blocked or cam bearing turned would be my swag and if I remember right, he reported oil to the rockers on initial start up and evaluation of the truck. I am betting on trash in an oil galley somewhere. There are screw in plugs front and rear of the oil rail that runs from front to the rear of the engine. The plugs can be a real PIA to remove but just one of those things ya gotta do in this case. I've had to drill one out.
Edit: Just checked, gaskets and heads are interchangeable Gaskets can be put on wrong, blocking the rear water passage.

 

Installing an over head oilier to the rockers may not look pretty but it makes sure there is oil there. Some hose, clamps and a T will get er done.

 

I tried turning the motor over while running the oil pressure up with a 1/2 inch drill . Still no oil . I didn't have the cam out or the chain off . When I pressure washed the bare motor I ran Water back through the oil holes in the block , I thought I could clean out the passages , But looks like I just plugged something up . The shop is run by an old timer that has been building race motors scenes the 60's . He already told me it sounded like a cam bearing problem . Hey live and learn .

 

Did you or did you not have oil to the rockers when you first ran the engine? When water meets oil, the result is usually a coagulated mess.