The Stovebolt Site Forums The Shop Area Engine Shop No oil for valve train

Fresh re-built 235. Using a drill, I can show 80-100 psi oil at the oil feed for the by-pass filter. No oil is making it to the valves. Where should I start ??
Thanks

Bob,

I think you need to know what year engine it is. There are two ways for the oil reach the center oiler on the rocker assembly. One method had a small tube hidden under the side cover. The little fitting going into the block was prone to plugging.

The later version utilized an internal route through "the magic head bolt..or not". I am going to leave the rest of the explanation to others, as this subject seems to be controversial, at best.

Stuart.

Not quite right... all versions used drilled passages through the head. However, if you put an early head on a late 235 you need the custom headbolt to get oil to the lifters, or you can use an external line. Can you give us the casting numbers for the head and block?

Does that sound right to anyone else to get such high psi with a drill?

No, it doesn't sound right, normal running psi for a 235 is 23-35 lbs.

that makes more sense I got about 27 psi or so when I used a drill on mine.

Maybe the pressure is so high because the oil is going nowhere. Do you suppose that the engine could have been modified for full flow filtration and will get no oil to anything unless the oil goes through the filter?

If the bearings are still full of assembly lube they may hold pressure better than a running engine, the only way to know is to bar the engine over a couple of turns and check it then.

I just thought of something else, in later engines the top end gets oil through the cam bearings, and if they are installed wrong the bearings, lifters, and head don't get oil. I would pull the side cover and check the lifter gallery for oil.

The oil pressure relief valve in the oil pump opens at around 45 psi,it must be stuck in the closed position.I've cranked many oil pumps with a drill,the pressure builds up to the relief valve rating at even low drill speeds if all is well inside the engine.
If your block in a later version with a 1/8 inch pipe under the lifter cover near the center top,remove it and have a look.I just got done messing with a 58 block,there's a drilled restriction in there of .060 or so.These later blocks get the rocker oil from a passage that leads from the two center most lifters.The lifters must be the type with a relieved area around the middle for oil flow.The wrong lifters won't allow oil to flow up to the head.Earlier blocks are different,a tube under the side cover picks up oil from one cam bearing.
Some heads,depending on the year,also have a drilled restriction under the pipe plug on the head side.

Thanks for the replys.
Found two things. The oil line in the lifter box was pluged. The relief valve was stuck.
The machine shop apologized and is getting me a brand new oil pump. I might still have a problem, the block is a '57 and the head is a '55.

I think the change happened in '58 so you may be ok.

I have a 51, 235 car eng in my 52 1/2 ton. I'm pretty sure I'm not getting oil to the head. There is a barely noticable oil film on the rocker. The inside of the valve cover is dry. The hyd lifters don't have much oil on them either. Is this normal in a low pressure engine?

Glenn,

Glenn,

Although this might be "not quite right", it's my favorite tip...so here goes again! Under the side cover is a small tube that leads up to a passage through the head. I have found that this tube, with its small ID fittings is prone to plugging.

The rocker assembly should get a ample supply of oil. Although it won't "squirt", it will dribble, (won't we all) and I think some of this should fall down and wash the lifter area.

The fitting that goes from tube/head in the direction of flow toward the rocker assembly can get so plugged it has to be removed and drilled out.

Stuart

Stuart,
I have unplugged it once but will check it again. I have the side cover off right now.I'm replacing the pushrods. My big concern is that it is plugged lower down. I have good oil pressure. What ya think? Also, my new pushrods are the right length but the foot is a bit smaller than the originals. Any problem there? I have hyd lifters. Some one mentioned cutting a slot in the foot to allow for air escape. Does it make any difference. My old ones have slots. Thx.

Glenn,

Glenn,

I really don't know about the slots in the pushrods. I would think if the old ones had them, and they appear to be factory, then it might be wise to modify the new ones.

That whole supply system to the rocker arms is pretty marginal when it comes to crud in the oil.

I have seen the rockerarm shafts themselves so plugged that you almost thought it was a solid rod. I would crack fittings in sequence as I walked toward the center oiler and verify each was leaking. When you reach a fitting that doesn't burp oil, you know the restriction in downstream.

From a technical standpoint, I don't know if new pushrods on old lifters is kosher..especially when you indicate the "foot" is a little smaller.

The sidecover area is inconvenient to work on to say the least. You don't want to have to revisit it anytime soon.

I thought I had seen mention of blasting the passages with compressed air (in reverse) in an attempt to clear them. I hope these suggestions help, maybe the pushrod guru's will be along shortly.


Stuart