The Stovebolt Site Forums The Shop Area Engine Shop oil getting to the head

I primed my oil system this weekend with an electric drill but I am not seeing any oil coming out of the spill over tube on the head. Oil filter is filling up, oil pressure tube is flowing oil. What would cause this? Does it require a higher level of pressure than I am providing with my drill? I need to figure this out.

Thanks,

Tom

Were the rockers wet at all? Did you take the rocker arms and shafts off recently?

No I have not had anything off recently. I put the engine back together 6 months ago, but was out of work and busy with other things so I am just now getting back at finishing this thing.

When I did this, my son watched the oil gauge. With the battery powered drill, nothing. So I switched to a higher RPM plug-in drill, and viola! Pressure!

Jim

were you getting flow as I described with the battery powered drill? I was thinking that I was not spinning the pump fast enough. I would love that to be the case, but I was using an electric drill, not a 14.4v drill. My drill was getting hot, I have worn it out in the past, so I did not spin it up too high.

When I did the prelube on my new 235, I had to spin the makita cordless drill for about 30 seconds to get oil to the rockers. But after that, any rotation at all would bring the pressure up to 30 psi or so.

If you had the engine apart, make sure you installed the correct oil line or pipe plugs in the pushrod cover. 53-55 full pressure 235s used a small line, 55-62 235s had a 1/8" pipe plug blocking a passage in the center of the pushrod galley.

good luck

chip

I used a 12V Makita to spin my oil pump, and it worked OK. I did use extra-thin oil (ATF, actually - I had several gallons given to me and I wanted to sort of flush out everything. Plus it's red and easy to see.) Also, I had (temporarily) plugged the bypass oil filter lines.

I do get oil flow to the rockers. It sounds to me like you have something plugged. Unhook the little tube from the block and see what's flowing....

Good luck!
George

Where exactly should I look for my problem? Inside the push rod side cover?

I am not sure what the flow path is supposed to be on this engine so I am not sure which lines to check and what I should expect. I have a larger line, I think it is a return line coming from the block to my external filter mounted on the distributor side of the block. I have a line that I think feeds this filter coming from the top of the filter and connecting to the front of the block, in the bottom corner (Manifold side corner) by the timing cover. This connector has 3 passes. One threads into the block (Male) and then I am left with an L shape with a female connector on either leg of the L. The line connected to the top of the filter goes to one of the taps and the the other tap is connected to a line that goes to the head.

Does any of this help?

Thanks,
Tom

It sounds like you might have an external line already. A mechanic might have installed it when the regular head passages got clogged. If so, this might be your problem.

What year is your engine? This is a 235, right?

On 235s, there are two oil ports on the drivers side of the motor. Both are right above the oil pan rail and behind the driver's side motor mount on the engine block. They are 1/8 pipe thread holes. One is the main oil galley from oil pump. It will be the hole in a round "riser" running down the length of the block. This is where the supply to your filter, and oil pressure gauge should go. The other is a dumb hole in the block that dumps oil from the filter back into the pan. The 1/8" pipe thread hole on the passanger side of the head is an optional oil supply line to the head. It isnt used unless there is an oil supply problem to the head.

On 54-55 engines, the oil to the rockers was supplied by the rear cam bearing, thru a removable line, to a 1/8" NPT passage inside the pushrod cover. 55-62 engines didnt use this line. The 1/8 npt hole is plugged, and oil is supplied from front and rear cam bearing, thru lifter galley, up thru a drilled passage that leads to cyl head. If the line or the block passage gunked up or was otherwise obstructed/damaged/nonfunctional, you can supply oil to your rockers by feeding oil to the optional 1/8 NPT hole on the pass side of the head. This may be the line you're seeing going to the pass side of head. If it is gunked up or connected wrong, then the rockers will starve for oil.

clear as mud?

chip

I primed part of my my 261 last weekend. I had the push rod cover off but no lifters installed. I just had to see the oil coming out of the galleries since the 261 came with solid lifters but was supposedly drilled for hydraulics. Oil came streaming out the gallery holes on the extreme left and right. I didn't see any oil coming to the head (rocker arms not installed yet) but I didn't let it go all that long. When the engine guy is done grinding the rocker arms, I'll redo the experiment. I'll be interested in what you find.

I believe Tom is working on a 270..

534me is a good man! You are correct. I have a 270 and I will be the first to admit that I am by no means a mechanic, but I sure want to know more about my truck and this engine.

Yes this is a 270 out from a 1st ed. 55 GMC 3/4 ton. What has been said about a line that goes to the head makes sense to me, but I dont see any flow at all on the head. The line going from the lower right of the block, when standing in front of the engine, to the upper left of the head is approximately a 1/8" line. This is consistent with what you have posted, however I do not see any fluid coming up onto the rockers. Should I see this or is the oil actually flowing within the head and then lubricating the rockers from within somehow? My problem is that I did not put my head together, that was done at the engine shop, I just bolted it to the block when I was ready for it.

Again, thanks for all the input so far. I hope that I can get educated well enough by you Stovebolt professors to get this beast back on the road before this wonderful weather is gone.

Thanks,

Tom

Ooops my bad, I assumed you had a 235. But the GMC270s should be somewhat similar in design. Where is the other side of the head line connected to? When needed, it should be connnected to the pressure port that sends oil to the oil pressure gauge and oil filter inlet. Follow your lines. You could also carefully loosen the line at the head, run the pump and see if oil comes out. Thatll tell you if the prob is in the plumbing or in the head.

On engines that had shaft-mounted rockers, the oil flows thru the head, up the oil feedpipe connector to the rocker shafts, thru the inside of the rocker shafts, then comes out a 'weep hole' in the top of each rocker. Then the oil flows down over the valves and pushrods for lubrication. (disclaimer-this is how 235s lube; 270s may be similar)

Proffit claims to be the GMC man, maybe he'll chime in. Step right up, long-motor bunnyman. :p

I took the rocker assembly apart to see if I was getting flow to the passage in the head that flows into the rocker assembly and I found that some time in the recent past, a mud dobber (wasp), had chosen my engine to build a nest for its egg. When I took the rocker assembly off and spun the pump, up popped this egg and mud/oil mixture. I pumped all that out, and kept it from falling back into the oil pan, and then discovered that the same wasp or some other wasp had followed the same path and done the same thing in my rocker assembly shaft and that was preventing the oil from flowing down the shaft to the weep holes and overspill tube.

I am just as happy as a little girl now. I may actually be driving this thing in the next couple of weeks!!!!

Anyway, I just wanted to let you all know that it is fixed and thank you very much for all the advice.

Tom

How the hell did he get in there? Someone must have left the truck with the valve cover off? Or did it come through the vent?

It got in through the oil tap in the front of the head. I was going to refit new lines, never got to it and finally reused the old lines that were already properly bent. It is amazing where these things can get to!!!!!!!!!!!!!

We are bug free now.

Tom

It got in through the oil tap in the front of the head. I was going to refit new lines, never got to it and finally reused the old lines that were already properly bent. It is amazing where these things can get to!!!!!!!!!!!!!

We are bug free now.

Tom