VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1937-1945 1940 chevy oil pan removal/oil pump replacement

NO OIL PRESSURE, HEARING A KNOCK in engine.

Do you have to lift the engine to remove the oil pan on a 1940 chevy 216? Looks like there may be enough space to do it without lifting the engine???

Also, can the oil pump be changed w/o lifting the engine?

Thanks

All that is needed is to disconnect the right outter tierod and possibly the little cross member at the back of the engine. Oil pump bolted to main bearing cap and easy to get at. Ol pumps gave very little problem other than by-pass check valve stickng open and loss of pressure. Usually happened in old dirty engines.
Not 100% sure of rear crossmember but I had to remove it on my 1939.
Also make sure all oiler pipes for the rods are free and oiling.

This can help me a lot - Thank you. I'm also not convinced it's the oil pump but...............

I live in Arizona and the car sat for 9 months. Prior to storing, oil and oil filter was changed (I do this annually no matter how little the car is driven). Engine was rebuilt 21 years ago and was spotless when we completed it. There is less than 3000 miles on this car. I do not use detergent oil so I guess sludge build up is possible.

When you mention the bypass check valve - are you referring to the oil distribution valve?? Or a by pass check valve somewhere else?

Also, if there is sludge buildup, can the pump screen possibly be plugged as well?

To check for oil flow at the top end - can I just remove the valve cover and run the engine for a short period of time (seconds) to see if there is flow? And can I squirt oil down the shaft of the push rods? They are all connected to the rocker arms and appear to be ok (no bends etc).

Thanks again for your help!

If the gauge is not registering any oil pressure I would be very cautious about running the engine until that problem is fixed.

It takes a while (maybe 15 - 30 seconds) before oil gets to the rocker arms. In my '37 the gauge will show pressure well before oil gets to the rockers.

There are 2 valves that manage the oil flow in your engine.

There is a relief valve integrated into the oil pump housing. That controls the oil pressure from the pump. If it is stuck open most of the oil output from the pump will dump back into the oil pan.

The oil distributor valve is on the left side of the engine block. It divides the flow between the oil to give priority to oil going to the main bearings and the rocker arms. When oil pressure builds in the system the distributor valve opens to direct oil flow to the oil pipes that feed the spray nozzles and fill the troughs to splash lubricate the rod bearings. The pistons and wrist pins are lubricated by oil spray thrown off the connecting rods.

I agree that sludge build-up can cause problems. When I pulled the oil pan off my car there was 5/8" of sludge in the pan. The inlet screen around the oil pump was so coated that it floated in my parts washer. I was surprised that the bearings were not damaged.

I recommend that you should remove the pan and determine why there is no oil pressure. You should plan to check and adjust bearing clearances while you have the pan removed.

Do not fool around with the oil distributor valve on the side of the block. If therre is no oil pressure do not run engine.
there should be no sludge in enine that short time except a little on the bottom of the pan.
Use modern detergent oil: The oil by pass or slide valve is i the oil pump. It opens up is the pressure exceeds 80 pounds with cold oil. If it opens up and fails to close you will have no oil pressure at normal temps.

Hi 40original

Rather than risking damaging your engine by running it, you can pull out the distributor and use a drill and the shank off of an old screw driver to spin your oil pump.
This will give you lots of time to watch things and try to diagnose your problem.
If your drill is reversible, make sure you have it set for clockwise rotation. :-)

Also, (I fully agree with Gene above) a spotless engine should ALWAYS be run with a good brand of high detergent oil. Sludge will be a non issue from that point on. If it's spotless, why let sludge accumulate in the future?
And high detergent oils have superior anti wear, and anti corrosion characteristics as well.
If you have the pan off and are starting with it clean again, I would highly recommend switching oils to prevent future problems.
These oils are especially beneficial for engines that are used infrequently and sit for long periods of time due to their ability to neutralize the acids that form due to combustion and from condensation.

Good luck! And I hope it's an easy fix!

Or turn it over with the starter for a minute.....there it should show 3-5 pounds of oil pesure.

Man, you guys are good!!! Before I do anything, I'm draining the oil to check for any metal shavings, hopefully I will not find any. If I do - I'm screwed!!! Next, if the drained oil looks good after filtering , I'm going to insert a thin wooden dowel into the oil pan drain hole to see if I can hit the pump tube - if it moves, its disconnected - remove pan and reconnect pump tube. If connected, remove pan and check for sludge. If connected, also remove oil distribution valve and replace - NOS are available, re-assemble and keep my fingers crossed.

Thanks again to all - I will repost my results; give me a few days.

I would follow Stovebolt’s advice and run the oil pump with a shaft in a drill. That will quickly tell you if the oil pump is producing pressure.

Even if it does produce pressure I strongly recommend that you need to remove the oil pan to determine the condition of the bearings. The knock needs to be resolved.

Unless you have an oil analysis done I doubt if there is much to be learned by draining the oil. The chances of you being able to see metal shavings is pretty slim. There are lots of places for metal particles to settle in the pan and the rod dipper troughs.

Think of it this way. If you do happen to see metal in the oil, you will need to pull the pan. If the pump produces pressure and you still have the knock, you will need to pull the pan. Is there a scenario where you would decide it is ok to drive the car without removing the pan?

I also strongly endorse the use of detergent oils. These old engines run well on them.

Rusty - I will be pulling the pan - I believe I really need to inspect the bearings and find the cause of the knock. What amazes me is how this happened just because the vehicle sat for 9 months and I started it to get it ready to drive. This is the mystery to me.

Great to hear that you re taking the conservative approach.

I understand your thinking that it is unusual that this has happened after period of the vehicle sitting. It will not surprise me if there was some internal rusting in the cylinders due to oil draining away. Or a bearing got dry and scraped metal on metal during the first few revolutions.

What I do know from multiple experiences in the last 3 years is that the worst thing you can do with a vehicle is let it sit. Operating it for just 20 - 30 minutes once a month really helps keep everything in good condition.

It would not explain the no oil pressure but a stuck valve from sitting can bend a push rod which can then hit the side cover. It does make a lot of noise.

Dave

A couple of things I do when I know an engine won't be run for a while:

I always make sure the engine is well warmed up before it's shut down.
Otherwise condensation will form on parts (particularly on the cylinder walls).
Tests done at the U of S decades ago showed condensation not even visible to the eye, which led to a very very thin layer of corrosion, was responsible for most of the start up wear that occurred in engines that were frequently started and not fully warmed up during winter months.

I always run the engine at a very fast idle for a minute or two, then completely close the throttle and cut the ignition.
Slow idling is an enemy of engines as it throws the least oil around in the crankcase to lubricate and coat cylinder walls and cam lobes.

And whenever possible, a fresh change and refill with the top quality diesel engine oil with a high TBN (a rating of it's ability to prevent corrosion by neutralizing acids).

Seems to have worked so far, as we have many old and new engines on the farm that sit for long periods unused, and restart trouble free... so far! :-)

PS
I fully agree with Rusty.
We just have so many engines on the farm that I never get around to doing it!

Good point!

Excellent - Thanks again to all who replied!!!!

So here is the verdict - I pulled the pan (by the way, no need to drop the tie rod, it drops out easy). amazed at the sludge at the bottom of the pan -I change the oil annually with less than 500 miles on it, never missed a year!!!! Started by feeling through the sludge - found 4 good sized pieces of thin metal that collectively would cover a dime. Pretty much done with this project. Looks like this classic may be hitting the market soon. After 5 years learning and spending for parts, 5 years of on and off labor to restore and 21 years of enjoyment, time for someone else to enjoy the ride.

Thanks again everyone!!!

All of that sludge is a very good reason to only use detergent oil in these old engines!!!

Uncle Ed - you are correct Sir

Uncle Ed - you are correct Sir

One other question - the metal I found is not magnetic - pliable and seem almost like lead?? Could this be an alloy of some sort perhaps associated with the rod bearings??? I'll be checking the rod bearing in the morning to see if any are real loose. Still doesn't explain the oil pressure problem.

Just trying to figure out what metal part is breaking down.

Thanks guys!

The rod bearings are not pressure fed and have no affect on oil pressure. Most likely from a main bearing and the lower half. The top gets no contact or wear.

I agree with Gene’s assessment. If there was no oil pressure the main bearings would immediately suffer.

Or the other way around. With missing main bearing babbitt the oil pressure will be very low.
If you ae lucky you can replace just the bottom insert. May be a problem determining thee size of the cranlshaft if the engine was rebuilt. The crankshaft probably was turned to an undersize,
thick babbitt of poor quality used resulting in failure.
This also could have been caused by an out of balance engine.

I would like to go back to the discussion where there was talk about deterget and non-detergent oils.
I have been using Joe Gibbs racing Driven Conventional 10W-30 motor oil in my 1938 216. It was reccomenden due to the fact that it is a high zinc petroleum. I have been told that it is a detergent motor oil.
There is no mention on the container about it bing detergent or non detergent.
Looking for feed back.

First a 1938 engine does not need any zinc and oils in 1938 had no zinc. The cam to lifter pressure is so slight on the 6 cyl. engines cam lobes never wore off. A detergent is more important. The container the oil was it should list the additives. Generallly racing oils have no detergents because the are used for short racing events and not designed for day to day driving.
If you was zinc there is more than enough in common 10w-30 oils rate for SN or SM service. Zinc only "works" on steel or irons surfaces when under high pressure and very hot......iT DOES NOTHING FOR BABBITT SURFACES BECAUSE IF THEY GET THAT HOT THEY WOULD MELT..The heat makes it bond to the surfaces when the oil film breaks down.