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

Perhaps just a bit of refresher information is in order. Last session we talked about the engine number, date and casting number. This information is located on the passenger’s side and near the rear of the block. The stamped number is the engine number.



To tie this all together the car number on the small plate located on the right end of the seat riser is: 6 AB 2324 This number tells us that the car was assembled in Oakland, CA, the AB indicates a 1928 National and the last number is the sequential assembly number at Oakland. This very low number corresponds with the low number on the engine and the casting date of 1927. I’m still waiting for one of our absent students (KenK) to raise his hand and tell us all about these numbers and dates.

Hot tanking the block turned out to be difficult too. That is to get it thoroughly clean. When the rear soft plug was removed it took a drill bit to remove the ”˜crud’ packed around #4 in the water passages. It was obvious that no water had circled #4 in many years. The reservoirs above the front and rear mains were packed with black gook. It is even more obvious that this car was not well maintained and now I even question the engine builder.



From the picture, which is the right side (passenger), you can easily see the discoloration around #3 and #4 as was mentioned in an earlier post. What, with the plugged water passages, poor oil changing practices, and perhaps the bad piston, it is no wonder that I decided to tear this engine down for inspection.

Here is a view of the ”˜crud’ on the center main bearing support. This same material was all over the inside of the engine and in all the reservoirs.



At this point the rods have been modified at the small end to accept the pistons I have selected. This is a view of our setup on a milling machine to ream the small ends. This provided a rough cut and they were finished up with the hone on the rod-resizing machine. Notice in the picture that a piece of metal has been clamped in the open space on the rod. This is necessary to prevent the reamer from catching the edge of the gap. This also insures that we have the exact size necessary when the bolt is released.



Next will be fitting the big ends of the rods to the crank.

All the cars are back in the barn after a madhouse weekend. Had one of my cars in the Big NW Car Collectors Show and Swap Meet. Our local VCCA Columbia River Region had a club display that featured my ”˜41 and another ”˜41 that I maintain for a customer. One of my ’28s was in the Ghost Stories presentation. This is a major production on Officers Row in the historic Vancouver Barracks in Vancouver Washington. So now we can start school again.

The best time to fit the big ends of the rods to the crank is while it is out of the block. This is kinda practice on this job as we have already fit the rods before we tore the engine down. However, as a check we will do it under these ideal conditions. By fitting the rods with the crank out of the block we can swing the rod completely around the throw and find out if there is any unusual wear in the throw. As we have mentioned earlier, it is typical for the throw to wear into an oval shape. This is because the force is at the top of the travel on the throw and then again at the bottom as it changes direction. There is very little force and therefore very little wear when the throw is at a 90 degree angle. Granted, we could make the same determination by use of a micrometer. You will note that I have not mentioned using plastigage for this fitting. If this was the first time around it could have been used, however a practiced feel is more accurate.



Each rod is fitted to its specific location on the crank. That is #1 rod is fit to the #1 throw and so forth. As each rod is fitted it is advisable to make written notes as to how many shims are used and their location. As the rod is removed small plastic ties can be used to keep the components in their required location until the final assembly is started.

Even from the factory assembly, components are liberally marked as to their location. Pistons are marked as to ”˜front’ and to which hole. Rods are generally marked by numbers at the factory. It has become custom in engine rebuilding to remark the rods. This is usually done by hash marks. These marks designate in which hole the rod will be placed and which rod cap goes to that rod.



Note in the picture that this rod is marked by #4 on both the rod and cap and subsequently remarked #4 with hash marks. Unseen in the photo, but the bottom, or cap, is also marked with 4 hash marks. It is safe to say that when we do the final assembly this one will go in #4 hole.

Okay, we will have recess while I go put out some fires in other locations. Wouldn’t it be nice if this were all I had to do?

Ray, this '28 block you have is the earliest '28 block I have run across. As you know the date code of K 16 7 indicates this block was cast on November 17, 1927.

The Bowtie casting mark shows it was cast at the Saginaw Foundry that GM had turned over to the Chevrolet Division several months before. The cast in number 348532 is the part # of the 1928 bare Cyl Block. The bare block was not serviced, since you had to by a #361157 Cyl Block with Caps and Screws for $24 in 1928.

Most records show the first 1928 production Engine started at Serial #3863596 which would make your #3864000 the 405th 1928 engine built at the Fllnt plant [I would estimate] around Dec 1st 1927. Is the Cyl head the original head for this engine? If it is, you should find the same engine serial # stamped on one of its exhaust port flanges?

The Car No. 6AB2324 was the 1324th 1928 Model passenger or commercial car to come off the Oakland assembly line, since Job #1 was Car No. 6AB0001. I believed 1928 model production started in December 1927 and Oakland built 1741 total units to include pass, comm. and One Ton Trucks. I seem to recall the show room anouncement of the 1928 Models was about Dec 30-31,1927, so I bet most of the December production was built before Christmas to allow the Western Dealers time to receive express shipment of these first of the new 1928 Chevrolet models, so they would have at least one showroom model to display on the 1928 model announcement day.
So Ray, it is a good chance that your '28 Roadster was a showroom announcement day model. KenK

Ray, Thanks for the nice textbook with pictures. I have seen the kind of build up you show on your engine from engines have had two over the counter remedies, in-expensive oil additives that are advertised as "an overhaul in a can" and usually in an engine that had a heat related failure. the other additive was used to stop a radiator leak, that had leaked into the crankcase. Of course the build up may have occured before the additives were added, but the most common factor seems to have been POOR or NO normal engine maintenance.
I used to do work on Chevrolet and IH truck engines in the late 50s and early 60s (I was a mechanic's helper) for a certain dump trucking contractor that used Gulfpride oil. You would not believe the sludge build up on his engines. His drivers never changed oil or serviced the air cleaner. After the mechanic, he used for years, left, he hired a guy out of the Army that was a M.T. mechanic at Fort Sill, Ok. He instituted a PM program and put premium heavy duty air cleaners on the trucks. The results were amazing, even though the drivers continued to abuse the engines and failures occured the engines were noticably cleaner, and they continued useing Gulfpride with out the sludge buildup. This makes me believe it isn't the brand of oil so much as it is the way the engine is maintained and operated. Many times we over look poor operating practices as well as poor maintance programs.

Okay, students what grade would you expect me to give to KenK when the report cards are distributed at the end of this course? Thanks Ken for your contribution.

It appears that some of the students are looking ahead (pun intended) at the class schedule and see that we will spend some time on the head. Don't want to give away the major points yet, as I think that discussion will be very interesting. For now, lets just say that the head is the original one.

Student in the back raising his hand. When recognized he speaks "He is not sticking to the current subject." "I think that he is trying to butter up the teacher." A spit wad sails across the room. Is the class becoming unruley? "Shouldn't we wait and see how much he contributes and what he scores on the final exam?"

There you go again Chipper....!

Time to call the students back in from the schoolyard. Class is gonna start in just a minute.

The block has been thoroughly cleaned and is now ready to be bored for the new pistons. Both the top of the block and the bottom are sanded to insure there are no burrs or imperfections that will interfere with the placement in the boring machine. It is absolutely necessary that the block be in ”˜registration’ with the boring machine. Note the two clamps on each end that will hold the block firmly.



For this machine the cutter is set very carefully based upon the current size of the bore and the size necessary for the new pistons. It is then installed in the boring bar.



To insure that the cutter is directly in the center of the cylinder that will be bored, the bar is lowered into the cylinder and 4 locating fingers are extended to touch the cylinder walls. At this time the cutting bar and head are floating on air pressure. When center is located the air is removed and the cutting head secured for the cut.



The boring bar has been started in number 1 cylinder and continues the boring automatically. When each cylinder is completed the head and bar must be centered as above for the next cylinder.


When all the cylinders have been bored the machine is reset with a different cutting tool and a slight ”˜chamfer’ cut is made to assist in the installation of the piston when the rings are installed.



This procedure has now completed a rough cut of the approximate size for each cylinder. Now the block is removed and placed in a special machine that will hone the cylinders to the specified size based on each individual piston.



Note in the upper left corner you can see the honing head and behind it a digital readout of the progress of the honing.



This is the first rough hone. Course stones are used for a fast cut and to smooth the imperfections left by the boring tool. When the machine nears the specified size for the cylinder the stones are changed to fine and a final honing is accomplished.



Although the digital readout is monitored, the final measurement is made by the bore gage that is set based on each individual piston. (No, all pistons are NOT made equal). As each piston is fitted to a special cylinder it is permanently marked on the face for reference when assembly is begun.



OK, recess. Study for the next phase which will be "laying the crank".

Excellent pictures and explanations!
>>I'm curious to know why you went .060 on the bore?
>>How did you know the specs on the 'deck height' of such an old block?
>>Finally, what is the thick shim-like piece between the upper and lower rod caps that's shown in the photos?

Hi lil' johnny,

Thanks for your comments on the pictures and explanation.

>>I'm curious to know why you went .060 on the bore? Answer: The block had already been bored to .020 on a previous rebuild. The pistons I selected for this rebuild are 'standard' at .060 (approx) over the 'standard' Chevrolet block. This required a rebore of approximately .040 over the previous work.

>>How did you know the specs on the 'deck height' of such an old block? Answer: To be honest with you I don't understand the question. If you mean was the block milled or shaved the answer is NO.

>>Finally, what is the thick shim-like piece between the upper and lower rod caps that's shown in the photos? Answer: I assume you are in reference to the picture earlier in the thread showing how rods are marked. When the rod is 'pored' it starts out with a thick spacer on each side in addition to at least 5 .001 shims on each side. This is to permit further 'tuning' of the big end fit as the engine is 'broken' in by removing shims of .001 thickness one at a time.

Thanks for the questions.

Ray,
Thanks for the reply.
>>The .060 bore in a 216 or a 235 is pretty much the practical limit of engine life. Will you do anything "special" to cool your 4cylinder after such a thin bore lining, or is your 28' thick walled and better water cooled on the block?
>>The "decking" is just a general old term for milling the block top. Old engines blocks may have been milled/sanded/machined flat in the past if they have seriously overheated or otherwise warped. I should have refered to it as overall "block height".
>>Keep up the fine work and especially those great pictures!

What kind of variation did you find in this new set of pistons, Weight, Outside diameter of the heads and skirts ? Since you decided to bore and hone the cyilinders to each piston, there must have been over .001 or .002 difference? Why not turn, or grind all pistons to the same value Are they coated or surface hardened? and bore and hone all 4 cylinders the same?.....Will these new pistons raize the compression ratio much with the .060 overbore and the new style piston ? What will be the distance from the face of the block to the topsurface of the pistons at TDC? Did you have any deep pitting on the journals of the crankshaft? are you useing inserted rods? .....Didn't look like inserts from what I could see.

lil' johnny,

It is agreed that .060 is a big jump from a standard bore. However, it must be noted that we are neither hoeing new ground nor plowing a new field. Boring a 4 cylinder out to this size has not proven to be a problem. I have consulted the Speed Guru in Sacramento and he has constructed many engines with this bore. And he races his engines. As to expected heating problems, I do not expect any more problem than with a standard bore. Perhaps Herb can jump in here and comment on the .060.

Mr Mack,

It is necessary to use the boring machine to enlarge the cylinders for the new pistons. Let’s let this machine do as much work as possible rather than going over and setting up the lathe to turn pistons. It is very common in engine building to fit pistons to individual holes. It was even done that way at the factory. As to the new compression ratio, it will be increased some but not enough to make a big difference. Piston pin centers are very compatible, so only the diameter of the piston will change. Crank was in excellent shape and was only polished. Inserts will not be used on this engine, as the rods are useable as removed. My next project, also a ”˜28 engine, will be inserted along with several other modifications to improve reliability.

Thanks for your interest.

P.S. Ditto, great information and I liked the Harley too.

MODERATOR: I'm doing my best to see how this post fits in with this thread?

I remember when I worked in an automotive machine shop in the late '70's, engines would come in for first time rebuild with individual
cylinders .010 or .020 oversize. There was not always consistency-if there was flaw in manufacturing, only one or two cylinders were bored out! I believe U.S. manufacturers had to get their act together because of the import quality of car was cutting into sales.
The type of boring bar being used is the way to do the job-not the type that bolts to the top surface, which as I recall uses another bore and a possible cylinder head bolt hole for clamping purposes.

Ok, I will save my thanks for only those you choose. Your person to person link must be broken.

Good way to build comradeship, not!

Good-by

Hi gator,

Took a lot of looking to discover there was a "harley" in one of the pictures. Looks like I blew that one.

That isn't just any Harley in the picture........that, my friends, is Springer Soft tail.
Nice class Teacher. Nice toys too!!!!!!!!
Dan.

Looks like the teacher is going to have to spend more time with the pictures. Didn’t realize that I had posted a distraction of a Harley in the background. Will be more careful with additional pictures.

Master Six

I have run into numerous engines that had various size pistons on an initial teardown. The best example was my ”˜25 Roadster engine. All 4 pistons were different. On the face of the block and near each cylinder were markings indicating the characteristics of each piston and cylinder.

The boring machine used for this job is a far cry from units of years ago. As you indicated the type that bolts on was the standard then. I have assisted in boring blocks in the car on many occasions with the bolt on boring machines. Not only that, we even turned the throws with the crank in the block and in the car.

Gator & K1dan,

Sorry about the distraction of the Harley. Will try to screen the future pictures better. However, you should not have been looking out the schoolroom window in the first place. For that, you must both remain after class and dust the erasers and wash the chalkboard.

Class dismissed.

Now how did he know that I wanted to do that! LOL

I have been skipping class but I noticed that you have left all your notes on the board!

My question is whether the crankshaft has counterweights or not ? It appears that it does not. I observed a 1928 Chev 4 cylinder truck at a cruise night this summer and it ran very smoothly.

I'm sorry teacher, I was just trying to be observant. Do I get to clean the Harley too?!

Gator, do you want the board or the erasers?

As they say on SURVIVOR; THAILAND, first things first! I would like to thank Gator and K1dan for their excellent job of cleaning the erasers and blackboard. Not only did they accomplish that chore, but also aliened the desks, pushed in the chairs and empted the wastebaskets. Nice job guys.

Old216

Glad you kept up with the class by reading the notes. No, the crankshaft does not have counter weights. Have talked to several of the old mechanics and the jury is still out on that subject for the Chevrolet 4-cylinder. They have basically the same opinion on shaving weight off the flywheel. Only benefit is a slight increase of ”˜off the line’ speed. A well-built and balanced 4-cylinder engine is a pleasure to listen to. After the change from generator driven distributor to cam driven, and therefore the belt driven generator, and with the use of a fiber cam gear, the 4-cylinder engine just purrs.

Okay students, heads up. We are going to change the lesson plan a bit and head in a slightly different direction. Needless to say, as the engine is being assembled, things are also happening to other components of the engine. Lots of bolt on items need to be cleaned and painted. To paint we need to know what color and that is where we are headed now.

The picture is of a ’28 Touring purported to be bone stock and original. A very reputable VCCA member who I have not contacted for permission to name owns it. The picture is very interesting and tends to bare out some of the comments in a companion thread about engine component colors. I would like to have your comments about the picture as far as colors go. I am sorry I did not take a picture of the driver’s side of the engine. In looking at the engine it is obvious that some modifications have been made. Note the “T” on top of the vacuum tank. One line to the intake manifold (correct) and another line through the firewall to a windshield wiper. This has been added, as the Touring did not have a vacuum wiper. Your comments please on the firewall color. Noting for example that the valve cover is engine color, does this throw out the understanding that only items attached to the engine prior to painting are engine color, or have we now proved that some items were painted engine color and then attached? Several have said for example the air cleaner was engine color and I can’t imagine that it was attached when painted. Same goes for the plug wire metal cover, and I just glass beaded one I swear was black on the inside and had always been black?



Let's have your comments (and keep it clean).

Edited: It has been pointed out to me that a faux pas was made on the picture. That is the driver's side. What I meant was, I wish I had also taken a picture of the passenger side.

Air cleaner brackets are black and encircle the air cleaner and attach to the side push rod cover bolt. according to engineering specs the air cleaner is A.C. make.
All valve covers for 28 that I have seen and examined for original paint were black. Usually the inside has some of the original paint whcih to me is obvious.
Further going back to how much oil in the oil pan - Dry motor 4 1/2 Qts Re-fill 4 Qts. Oil pressure gauge 12 - 15 lbs. This according to engineering specs.

psssssssss.......K1dan, psssssssss, meet you at the cycle parking lot after school, pass it on.

Don't want to offend the '28 owners but I'm glad the '32 motor color is not this. Looks more like a Fo*d color for '28 Fo*ds, which was on my brother's '28 Fo*d roadster. :eek: :eek: