VCCA Home Forums TECHNICAL - GENERAL Radios, Tools, Accessories School is in session (Contd)

Excellent point! I worried about that, too, as I was typing my novel there.

How complete were the engines when they left the engine plant? How many engine plants were in operation in 1928? Which parts got added at the ASSEMBLY plants?

TIME OUT Go back to the picture on post Nov 01, 2002, 00:35.

From that picture alone we can determine that the cover was NOT painted on the engine, for if it was, the "L" shaped wire loom, the plug wires and probably the spark plugs would be covered with engine color paint. Also the retaining nut and washer would be engine color.

If it were not painted on the engine does it assume the character of the air cleaner where a jobber in accordance with Chevrolet specifications paints it? I think not. Therefore, it is most likely to have been painted OFF the engine and with a more easily obtainable color: BLACK.

Back to the ”˜28 TA who says black and we give him the big bucks to make that determination.

Hey Ray

I respect your opinion and the one of the 28TA but I'll bring my documentation with me when I get it judged. Living in Eastern PA I get to Hershey a few times a year. I will return to the library and try to get more info. They have some great info like original sales literature and articles from many magazines for almost any car and year. I noticed that even the CHEVROLET sales literature differs in description of exterior colors for the 28. For the 4 door sedan one ad says the exterior color is Faunce Green Duco with Dunsmuir Gray trim and the other says Paul Revere Green. Same car, same year, same model, Same manufacturer!!!!! GO figure! And then I go to another sorce and it says the Faunce was an early color and the Paul Rever was a later color.

Until I have further research, let's get back to the rebuild and get this school back in session. I really enjoy learning about the rebuild and everything else involved. It would be great to meet you all at a tour or event. You certainly have much to share. Until then, I am going outside for recess!!!
mromano

mromano, read a little further down or maybe up, it also says they was a change, early 28 sedans were Faunce Green and later 28 sedans were Revere Green

and..................
Mromano, please be patient, our teacher likes to keep us in suspension or suspense whichever, then dump a ton of stuff on us!

Are you all sure that the sparkplug wires are black on a 28?
I bought a new set to get away from black and they were manila colored cloth covered and has a red tracer thread in them. I want to be sure, before I paint them. Maybe I should get some off a VW bug, the red transparent plastic ones that you can see the sparks going down the wires!

Yes, it is odd for the 1928 block casting part # to have a “- 4” following it? I have seen this “Change Order” or “Drawing Level” number on pre 1928 blocks. I have a bare 28 block sitting by my driveway [a garden decoration?] that I just went out in the rain to check … it’s is serial #4098681 with a casting date of B 21 8 [February 21, 1928] …and it has what I take to be the Change Order #16 cast-in to the right of the cast-in Bowtie.

It is possible that Chevrolet did source FERRO Blocks [1928 castings] in addition to its own in-house Gray Iron Foundry in Saginaw? The Sept 30, 1927 FERRO cast 1927 Coupe block [serial # 3802580] I sold to Michael a few years ago was the latest FERRO block I have taken note off … it didn’t have the Bowtie cast-in.

I think I can shed some insight as to why the 1928 engine valve cover was not installed at the Flint Motor Plant #4, the world’s sole source of the 1928 Chev 4. I seen a 1926 GM document that outlines the late Series V passenger car Assembly “Sequence of Operation.” The following in part is the engine sequence:
1. Assemble transmision support to transmision
2. Check timing on engine
3. Assemble transmission to engine
4. Remove cover plate on trans., fill with oil & mount shift & brake levers
5. Assemble universal joint & bolt to transmision
6. Tighten cylinder head bolts on engine
7. Mount ignition coil and wire
8. Fill engine with oil
9. Mount engine in frame
10. Assemble spark plugs in engine
[Then after the body is dropped and mounted on the chassis]
11. Connect gas line to vacuum tank & gas line to carburetor to tank
12. Assemble suction pipe … manifold to tank
13. Prime vacuum tank & atttach vent pipe
14. Fill with gas and water
15. Start up engine and adjust valves
16. Mount valve rocker cover
17. Shut down engine

So the reason the valve cover were not installed at the Flint Motor Plant #4 but at the various assembly plants was the need to both tighten the head bolts before the engine was mounted in the frame and adjust tthe valves hot after the engine was started at the end of the line.

KenK

Good evening class. We have a lot to cover this evening so clear your desk and get out your notebook and let’s get right to it.

Perhaps now is the best time to discuss how the engine is oiled while it is disassembled. Of course the center of attention for the oiling system is the oil pump. A pointed discussion of the pump will be the subject of another session. For now, lets assume we have a good flow of oil under “X” pounds pressure.



You are looking at the oil distributor with pipes part number 348460. It is important that we understand just how this device functions and where the oil is sent and under what conditions. Notice the fitting in the upper right center. This fitting is connected to the oil pump by a copper line. Oil enters the distributor at this fitting. Notice the chalk line I have drawn. The spring-loaded device in the picture is the oil distributor valve assembly. When this device is installed in the distributor it is secured by the oil distributor fitting directly below. Now let’s continue the path of the oil. It enters the distributor ABOVE the valve. The valve directs the oil through the oil distributor fitting where it takes two paths. Note the provisions for two fittings. One path leads the oil directly to the oil pressure gage. The second path leads the oil to the opposite side of the block and through the oil filter. When it leaves the oil filter it is returned to the fitting on the lower right of the picture. The path now is unobstructed through the oil distributor and into the four pipes. From the four pipes the oil is directed into the 4 troughs, one under each rod. Notice that the oil distributor valve assembly was not involved in this operation so far other than preventing the oil from making a direct path to the oil pipes. So when does the valve assembly come into play? Assume the oil filter is plugged with debris. The oil is blocked in one path to the oil gage and on the other path to the oil filter. With both paths blocked the oil pressure overrides the spring pressure and oil is allowed to flow into the 4 pipes. (In some other threads on the Chevy Chat a question was ask about what happens if you shut off (bypass) the oil filter. As you can see this would force the valve to function continuously. Therefore it would be best to remove the valve if you removed the oil filter).

So, we have lots of oil in each trough now, but how do the bearings get lubricated? Unlike, for example, the 1925 engine, there is absolutely nothing in the ”˜28 engine that is pressure lubricated. (In the ’25 engine the center main is pressure lubricated).

Now let’s examine how the three main bearings are lubricated. Above each of the three bearings, and permanently cast in the block, are reservoirs.



Look closely and you can see that I have laid a small mirror in the block so you can see the reservoir. This reservoir is filled by ’splash’ oil. As indicated previously, all four troughs under each rod have been filled by the individual pipes. As the rod ”˜tang’ hit’s the oil it is splashed throughout the interior of the block. Over a period of time all three reservoirs are filled.



This is the rear main block ½ bearing. Note the nice Chevrolet Bowtie. At the top of the picture is the ”˜locator’. This protrusion fits is a depression in the block to prevent movement of the bearing shell. The hole at the bottom of the bearing matches a hole in the block that leads to the oil reservoir.



This is the other side of the bearing as it is mounted in the block. Note the entry hole for the oil to lubricate the rear main. Put your finger on the page right there. Where is the rear main seal? No seal? Then what keeps the oil from running out the rear of the engine?



This is the other ½ of the rear main. Note the three concentric groves that are near the rear (top) of the bearing. Any oil that has worked its way past the main bearing surface migrates into these groves. Note the hole in the groves. Any excess oil goes through the holes rather than out the back of the engine. But where does the oil go?



At the very bottom of this picture you can see a hole that connects to the hole in the rings. This interconnecting tunnel dumps the excess oil back into the pan/sump.



This is the center main bearing. Note the hole in the center of the bearing that connects to the reservoir above it. Oil enters here and is directed down the ”˜crow’s foot’ to the other ½ of the bearing and out each side of the bearing to lubricate the edge of the center main. The thick sides of this center main serve as the thrust bearing.

The front main is lubricated the same as the other bearings, however the front bearing allows oil to go both ways as we have to lubricate the cam and crank gear. More on that later.

Okay students, we are out of time, and Bill only lets me post so many pictures. Next session we will cover how the remainder of the engine is lubricated. Honest, eventually we will get around to “laying the crank”.

Looking at the second photo, the underside of the rear main 1/2. I see some discoloring from heat. Was that gaulling I could see on the actual bearing surface? I didn't see as much or any on the center main cap. This leads me to believe that damage to that bearing was caused by either over heating from the plugged water jackets, poor oil supply or both.

Was it just the "close tolerance" of the bearing that kept the oil in the reservoir from just running out? I suppose that if the oil sat in the reservoir long enough it would suffer thermal break down and just run away causeing oil starvation for that bearing.

Dan.

Hey Teacher

I have a question about the oil system. The oil is sent out the opening through a "t". one line goes to the gauge, the other goes through the middle of the block to the oil filter. There is an adapter between the compression fitting and the nipple of the oil filter. If you look inside this adapter, there is a restriction hole in this adapter/fitting. In other words, the hole through this fitting is NOT as large as the copper tube leading to it. In fact, it is very small. I believe it's purpose is to restrict flow to the filter. Two questions....

1. Why the restriction, it seems it would clog easier??

2. I havd two motors, one with this adapter on BOTH ends of the filter and the other only at the supply end of the filter and NOT the return end of the filter. Which is correct.

Also, do you allow show and tell in your class? I just completed a rebuild of my spare motor dated C 1 8 with a head date of B 29 8 and the stamped number on the exhaust port matches the block. I have pics which I would be willing to share.

thanks
a student sitting in the back row near the window!

here's my reasoning for the restriction,or like some would call it ( an orifice ) .I beleive that it is used to force the oil flow/pressure to the guage.Any fluid would always take the easiest flow path so the restriction would allow the primary flow to the oil pressure guage.I beleive that chevy wanted to make sure that the owner knew the correct pressure in case of a oil pump issue.
You should only need one restriction at the oil filter.Once you restrict a flow once in a piticular direction then the flow is always slowed down no matter how many restrictions are in the oil path.
Does any one disagree or agree with my senarial ? :p

Hey guys, what is the size of the restriction on the fitting ? can any one help :(

Hello Ray,
I am excited to see so many familiar pictures that I can compare with my own notes. My question is this. Had your bearings been damaged, what would have been your course of action? Would you have gone with modern inserts on either rods or mains? Are new rough babbit main inserts available for the 28 Chevy that you can line bore locally?

Thanks,
-R

Quickly, students, take your seats and quiten down, we have a lot to cover in tonight’s class.

First: Q&A

K1dan

Very astute observation. It is really obvious that all the main bearings have been overheated, however they are still serviceable and I will use them. Yes, the bearing clearance (.0015-.002) is what retains the oil in the reservoirs. Ever wonder why you could park a 4-cylinder Chevrolet, have no oil drops on the floor, come back much later and there they are. Also consider that if the vehicle is parked for a long time, engine not operating, that all the reservoirs will drain, so when we restart the engine we have to replenish those reservoirs.

mromano

Why the restriction in the fitting to the oil filter? The restriction is to slow the oil passage through the filter and to provide resistance to the pump in order for the dash gage to read pressure. The restriction goes on the INPUT side of the oil filter.

As to your last question. I think that Show & Tell would be great. You make the decision as to any confusion to the students as to which engine is yours and which is the teaching vehicle. Otherwise, go for it.

28chevrolet

I concur with your explanation of the restriction in the oil filter line. And yes, only one restriction.

As to size, my best measurement was 1/16.

Rusty Fender

You ask what action could be taken if the rod or main bearings were so badly damaged they would have to be replaced. Lets take the mains first. If they were damaged the mains would have to be repored into the shells. Several places do this type work. They can be semi-finished to your specifications and then line bored when reinstalled. The crank can also be welded up and reground back to standard. As to the rod bearings. I have at least two sources that can insert the 4-cylinder rods with modern inserts. In talking to one of them I was surprised to find that he does the rods first and then fits the crank throws by grinding. Always been my experience to grind the crank and fit the bearings. Ah, these new modern methods. As to the last question, I always hate to make a solid statement, but the last time I checked, you could still get re-Babbitted mains.

Now for the scary part. I have built both 4-cylinder and 6-cylinder engines by taking the main bearing shells out and poring the Babbitt directly into the block after boring additional holes in the block to attach the Babbitt. The block is then line bored with registration on the camshaft. Every one of them is still on the road and running.

Now that the Q&A’s are taken care of lets get to the new material.

We are gonna backtrack a bit and go back to the oil pump. Initially, we just stipulated that we had a pump and we had some pressure. In reality we don’t really care what our pressure is as long as we have some to move the needle on the dash and sooth our concerns. As mentioned earlier, nothing in a ”˜28 engine is pressure lubricated. What we really need is VOLUME. We want to fill the troughs as fast as possible so splash lubrication can fill all the reservoirs quickly. The OE oil pump on the ”˜28 is a vane type pump. Vane pumps are noted for volume and not pressure. Although the ”˜28 OE pump is normally satisfactory it was my desire to see if improvements could be made.
My objective was to go to a gear pump and overcome the sometimes failure of the vane pump to stay primed and provide more pressure and volume.



Above left is a gear pump and on the right is the vane OE pump. The pump shaft on the gear pump has been modified by threading the end and mounting a permanent extension to mate the distributor.



Ever inspect your OE pump and discover what appears to be abnormal wear on the drive end? Well, that is not wear. That grove is put there to ”˜hook’ the distributor and make the two shafts operate as one. Otherwise the distributor would jump up and down as it rotated. The OE pump is on the right and the NEW pump is on the left.



This is a test fitting to insure that the crank throws will not hit the new pump. Notice even the cap bolts are not installed. Everything looks good at this point. Notice that the pump extends much lower into the pan. This is a major advantage, as a portion will actually be submerged in the sump oil.



I have disassembled the pressure regulator valve to insure thorough cleaning. Never did find out what the exact release pressure was on this pump, but it really doesn’t matter. Pressure could be adjusted by cutting some of the spring off (less pressure) or stretching it (more pressure) or by replacing the spring.



More test runs to insure I could run the pressure line and not have it interfere with the crank throws. Fittings have to be matched to make the pipe fit. First fitting of the pickup shroud to insure clearance with the oil pan.



All the test runs have now been made. All components will fit and operate. Now they must all be removed so we can take up the “Laying of the Crank”. Sorry to disappoint you, but the next class will cover the remainder of the moving engine parts and how they are lubricated.

OK Teach,....... but first to the question about the orifice in the gauge line, it may be to resist any surge upon start-up. The manual states that the upper part of the line should contain air that acts as a cushion and prevents oil from getting into the gauge. OK.....let her RIP!

Thanks Mack,
Your comment reminded me of something that people often do thinking they are really doing good. They bleed the oil line at the gage to make sure the line is clear. Don't do it!!! Two things happen the acids that are in the oil can destroy the gage tube and the oil will act as a buffer in pressure measurement.

Air can move through the tube much faster than oil. As the pressure changes in the engine the air in the gage line can therefore react much faster.

Ever wonder why Chevrolet used such a small line to the oil gage? Now you know. Or you still don't know? To help keep oil from the gage.

Hey, Teach!! <hand waving frantically>

A "Devil's Advocate" question (hope I don't get in trouble for this!).

Is the OE pump really so inferior that it is worthwhile to change/update? If we are worried about volume more than pressure? Was this a weak link in the original design, or something that advancing technology just dramatically improved?

I'm sure the change is being made to improve the engine's durability, as the car will see more touring than showing - and, I realize that when completed this modification will be invisible, but I was thinking of the "Preserve and Restore" - "as delivered to the original retail owner" - those type of philosophical concerns....

Thirty years from now, when some future owner opens the engine, what will he make of all this?

My questions are:
(1) When did the gear pump first become available for the 1928 engine?

(2) Is the pump shown the present standard replacement, or is it manufactored for another engine and is being adapted to the 1928 engine?

(3) Is the vane type original pump readily available from the vendors that cater to the early Chevrolet 4 cylinder engine or is the gear type pump your choice because you expect more reliability from this pump?

(4) Is the gear pump ordinally mounted lower in the pan, as you are doing, and an distributor drive extension required for the 1928, or is there another way it is sometimes mounted where the extension shaft isn't required for the Chevrolet engine?

I am in agreement with ChevyGuru. The lucky person who has this car in the future will want to argue that this oil pump must be some kind of option available in '28, not knowing what went on in the fall of 2002. Just my $0.02.

Why would Chevrolet use a gear pump for part of 1928 and then go back to a vane type pump for the sixes? For the same reason they went back to cast iron pistons? Why would you need to increase oil pressure if the bearings are oiled by gravity?
Some aftermarket rebuilt pumps I have seen had only the casting number, all other marks were ground off and the Chevrolet casting number became their part number.

Q&A

MrMac, ChevyChip,

I don’t see anything in the repair manual or the owner’s manual about not bleeding the oil line to the gage. All I find is a picture of the lubrication system and in that picture it points out the air cushion. As to the purpose of the restriction in the line to the filter. If it was not there, and we had a new filter, which would provide little restriction to the oil, I suspect the oil pressure reading would be very low. Perhaps the most interesting thing about the oil pressure gage is the comment in the repair manual: “It should be noted that the oil gage is an indicator only and merely shows whether or not the oil pump is working”. Do I see a futuristic engineer who wrote that, as envisioning the ”˜idiot lights’, which were so popular in the ”˜60s?

ChevyGuru, mromano,

I have been cogitating on your query for many hours now and have concluded that it is a possible set up/bait that could lead into a jumbled thread, as did the famous ”˜battery’ discussion. This begs the question of what you would say if a crumbled distributor on a ”˜25 were replaced with a new body made of much better material? And that item is visible. Quoting from my post of Nov 12 2002 20:54: “Although the ”˜28 OE pump is normally satisfactory it was my desire to see if improvements could be made. My objective was to go to a gear pump and overcome the sometimes failure of the vane pump to stay primed and provide more pressure and volume.”

MrMack, d2d2,

The OE oil pump for the AA and AB (Capital ”˜27 and National ”˜28) is a vane type pump part number 360954. That is the only pump provided for those engines. Assuming your pump was defective I do not know any supplier that can provide that pump. However, a replacement gear pump is available for just less than $200.00 from several vendors. Although I have not personally inspected one of these pumps I suspect it would be very similar to my solution to the replacement problem. My solution is considerably cheaper and gives me the flexibility of selecting the method of mounting. Some inherent problems can be eliminated by my decision to mount the pump as low in the sump as possible.

Now students, our subject tonight is the continued discussion of the internal lubrication of the engine. We have already discussed how the mains are oiled, that is by means of the three reservoirs. The three cam bearings ( not actual bearings but machined surfaces within the block) are also lubricated by their own reservoirs. So at engine start up after considerable time has expired a total of 6 reservoirs must be filled. This is accomplished by the 4 rods/throws contacting the oil in the four troughs. Earlier, we discovered how these troughs were filled by the 4 pipes from the oil distributor. On the bottom of each rod is a tang that hit’s the oil on each revolution and splashes it all over the interior of the block. This oil mist is what lubricates the cylinder walls and piston pins. Excess oil is wiped down the cylinder walls by the bottom, or oil control, ring. The oil being forced through a hole located near the tang lubricates the big end bearings of the rods. This oil is circulated through the bearing surface and exits on top through two holes provided for that purpose.



Notice on the picture the hole in the rod-bearing cap. This is the entrance hole for the oil. The tang is located in the picture just below the hole. The hole has been chamfered slightly to funnel more oil into the bearing.

We now have covered the interior lubrication. This still leaves the lubrication of the timing gears and front of the engine and the valve train. This will be done at a later date. Enough for now------Class dismissed.

Two comments from some one who knows very little about 4 cylinders.....This confirms my earlier suspicion about AntiqueMechanics intrest in 1936 oil pumps.I just knew one was going to enter the rebuild.The original '36 oil pump was a vane pump as a 4 cyl. was .The gear pump was first used in 1937.In the later years Chevrolet made a replacement gear pump for 1929-1936 models.It came in kit form and contained The screen.line, and fittings required for the change.A great up-date for those years too.......The first 5 years of the F--d V-8 the main bearings were poured directly into the block and caps as per Rays method.

Hey, Teach-

No intent to bait, set-up, nor defraud here! It was a sincere question.

I think you have answered it. Actually, your answer to d2d2 & MrMack possibly answered it better- you said &#8221;The OE oil pump for the&#8230; "27 and '28&#8230; is a vane type pump part number 360954&#8230;&#8230;.. Assuming your pump was defective I do not know any supplier that can provide that pump. However, a replacement gear pump is available for just less than $200.00 from several vendors. Although I have not personally inspected one of these pumps I suspect it would be very similar to my solution to the replacement problem.&#8221;

That statement, together with the added information in Chev Nut"s post immediately above, answers me.

I guess, therefore, if a guy wanted to rebuild the 4 cylinder WITHOUT this type of update, he would either have to get lucky and find an NOS oil pump somewhere, or just clean up and re-use his old one (possibly not a real great solution for a car to be used in touring).

Now I understand where you're coming from&#8230;

This pump installiation opens up a lot of possibilities for those of us that intend to do a lot of touring of our 4 cylinder Chevrolets. It is apparent that these types of modifications have been around for some time. Access to a few basic machine tools will allow many modifications that should improve the performance and reliability of the engines, I can see why the old four cylinder racing engines did so well, All you need do is get the idea of maintaining originality out of your mind, get to work, and the next thing you know we will have a modern automobile that "looks' just like a 1928 Chevrolet.
:confused: :arrow:

Now T H A T would really be nice to see MM.

The 1936 replacment gear pump must be a modified 1937-39 oil pump because it uses a ball for the oil pump relief valve.From 1940 and up a valve was used.The spring is the same for the original 1937 relief valve thru 1953 (low pressure engine) so the max. pressure relief is the same for all these engines.The oil pump screen and cover is also the 37-39 style so that would make sense..also in those years the support and pipe are not bolted to the main bearing cap as they are in'40 & up....I have the 1934 gear pump unit in my '34 and it produces higher oil pressure than my 39.Often thought it may have been the '40 and up style pump which had larger gears and gave better presure. Its still an improvement over the orig. '34 vane pump. ...........Was a '36 pump chosen because that is the only year the 6 cyl. pump had the female slot on the end of the pump as a 4 cyl. has or wasn't that criticle ????

Gene, I have a pump in my shop that I took out of a 216 engine that outwardly looks idenitical to the replacement Ray is useing including the pickup screen. This pump was a low pressure pump out of the old babbit pounder. The engine number indicated it was a 1951 engine. The ease of fitting the pump to the 4 cylinder is a real eye opener for me, I never considered this method of a modification. I am anxious to see what he does with the head and valve train and rocker arms.