oil pressure

I have seen where the tube leading from the valve chamber to the rear main was bent in an attempt to slow rear main bearing leaks . This practice slows oil flow to the rear main bearing and lengthen the time that it takes for the rear main to get proper lubrication .
 
Glenn Thoreson said:
There is a little known thing that can cause a problem with oil level in the valve chamber.
If you look at the "dam" ahead of the oil tube, where splash over lubes the timing gear, you will likely find it eroded down into a rounded looking shape. Ford blueprints show this dam is supposed to be straight across the front ahead of the oil tube. Too low and too much oil will splash over and starve the lifters and main bearings.
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Question: What "erodes" this dam? The only thing flowing over it is oil, which does not erode anything.
 
I guess the purpose of this construction must be to lead the oil towards the timing gear insted of the rear of the oil galery?
 

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I cleaned the sludge from the valve chamber. It was not real bad, but definitely was needing cleaned. I had cleaned the pan previously and drove it around some, maybe 30 miles in sort trips, and then read here about cleaning the valve chamber. This of course is a new to me car. I am an old pro auto mechanic, but other than growing up learning to drive with dads 28AR, I never worked on them before. So now have got a 29 Tudor, am learning a lot, but still confused about a lot. I know if I need major workalike removing engine/trans/diff, I will need to take it to an expert, as I don't have the space or equipment anymore. But my question is, now that I have cleaned the valve chamber, could someone show me a picture of where the drain/feed holes to the mains are. I wiped the area out and blew it with high pressure air (made a mess) but not positive I cleared the holes. I did find a couple holes, and run a wire in them, but only seemed top go in an inch or so. Maybe the hole takes a turn?
 
old-ford said:
I guess the purpose of this construction must be to lead the oil towards the timing gear insted of the rear of the oil galery?
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I haven't seen a block like this before, but it appears the oil goes through the cast in trough instead of having to cast a metal pipe inside the valve chamber to carry the oil forward.

Poke around the rear inside corners to find the holes that oil the mains. Stick pipe cleaners down each one until the wire touches the crank, then pull them out and see if they picked up any sludge. I or someone else has posted pictures of the holes a few years ago.

If you found one in the rear and it only goes an inch or two, that is the one that feeds oil to the rear cam bearing.
 
Thanks. So what would be the approximate diameter of the holes I am looking for? 1/8 inch, 1/4 inch? and there should be 3 , right? How many for the cam bearings?
 
There are three dams in the lifter chamber I don't believe oil should ever flow over any of them. They are used to keep oil in the area's of the main bearing tubes when going up or down long steep hills. The oil flow in the chamber is governed by the lifter cover. Look inside the cover and you will see two small raised bosses that line up with the dams but are much shorter. Oil flows over these bosses and around the dam's the Essex runs down the drain back tube to fill the dipper tray and lube the rods. Oil flow to the mains and cam bearings happens rather quickly after startup oil to the dipped tray takes a little longer.
 
thanks, I will have to look to see if all the holes to the main and cams are open, and didn't get plugged when I wiped the sludge out. Sure would like to see a picture though so I know what I am looking for.
 
Tom Wesenberg said:
A jagged, rounded front hole, right behind the cam gear, is normal, and how Ford built it.
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So, what your saying is the Ford blueprints are wrong? Maybe I don't see straight, eh? I thought my cataract surgery was supposed to fix that. I suppose next someone will tell me they excavated the Grand Canyon with a teaspoon.
Now, to answer an intelligent question: Motor oils of old had a very high sulfur content. So did the gasoline. Add a little moisture and combustion byproducts to it and you had a very corrosive mix. Add to that the the effects of untold thousands of gallons of oil filled with grit and worn off metal rushing over it and you can better understand what happens over 80 years or so. That is one of the reasons manufacturers (i.e. Ford) called for 500 mile oil changes. Acidic oil was responsible for all kinds of problems back when. Pitted and eroded engine bearings being the worst. The oil dam in the valve chamber was a very thin casting toward the top. Easily damaged over time. 'nuff said....
 
So, the oil flows over the front hole and wears it to a jagged edge, then the same oil goes into the dipper tray where oil scoops hit it at great speed and sling it against the cam and cylinder walls, yet none of those three items get any damage. I'm new at this and just learning.
 
Glenn Thoreson said:
So, what your saying is the Ford blueprints are wrong? .
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Are you able to post the portion of the drawing that calls for it to be machined straight across?

I have never seen a block with a straight dam nor have I ever read about it being so. I would like to see the drawing to educate us all.

175546
While this engine has pressure lines you can clearly see the jagged edge.

Still another one,
21273


Can you show us a photo of a block with a nice straight line in the valve galley?
 
oldforder said:
thanks, I will have to look to see if all the holes to the main and cams are open, and didn't get plugged when I wiped the sludge out. Sure would like to see a picture though so I know what I am looking for.
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Here's a link to pictures showing the holes in my very clean and painted block. You need to change .net to .com to make the link work. I thought I had the pictures posted here, but using the search didn't turn them up. I usually have pretty good luck by using the Google Search.
Try a Google search for "main bearing oil holes in valve chamber" and see if that works.

https://www.vintagefordforum.net/forum/model-a/technical-reference/3640-engine-topics

Here's another link that should get you to my pictures:

http://www.ahooga.com/wwwboard/messages/282982.shtml
 
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I am sure I don't know what I am doing, but I can't get to any pictures on any of these links. I got to where you had pic on the vintage ford site, and tried to register to see pix, but not having a lot of luck.
 
oldforder, I got the ahooga link to work. Once you get there you need to click "main bearing feed holes" That will take you to a thread where you need to go to one of the last posts to see Tom's excellent photos.
 
I got that far, but it says I have to register. I did that and have received verification from them that I am registered, and still no pix from Toms post. I am very NOT computer literate. Also I am using a Mac, but I wouldn't think that should matter.
 
oldforder said:
I got that far, but it says I have to register. I did that and have received verification from them that I am registered, and still no pix from Toms post. I am very NOT computer literate. Also I am using a Mac, but I wouldn't think that should matter.
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I don't remember joining that group, but maybe I did. When I hit the link, I don't have a place to register. If you have been accepted, when you get to that page, it should be titles "main bearing hole locations". Then there will be two red lines. Below them it should say "posted by Tom Wesenburg" Near the left margin of that section you should see "Main Bearing Feed Holes" in blue. Clicking on that should take to the thread with Tom's photos.
 
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