Restoring your flathead
It’s time now to start getting deep into the heart of the horses (horsepower, that is).
As you look over the restored parts of your engine, the merits of restoring as you go becomes more apparent. Enough preaching theory, let’s get to it.
Starting where we left off last month, let’s make more room by taking off the distributor tower by removing the two bolts that attach the tower to the block. It should come straight up with a slight twisting motion. This tower needs to be well cleaned and then painted.
Check it for wobble or play in the shaft. If you have any play at all, it should be taken to your favorite machinist and have a new bushing made. Otherwise you have another part for your restored pile.
It’s time now to take out the eight manifold studs. Using a stud puller makes this a fairly easy job. Hopefully you liberally applied penetrating oil a couple of days ago so you don’t break off a stud. If you don’t have a stud puller, use a small pipe wrench, gripping each stud as low as possible to avoid breaking the stud. I prefer to replace these with new ones to avoid future problems.
We now have open access to the valve lifter area. Removing these can be a little tricky, but I am going to share a little secret with you that will make it easier to remove (and later reinstall) the four lifter gangs.
First of all, cut out at least four pieces like you see in the illustration above to hold the valves open. They should be about 1 1/2 x 2 1/2 inches and 3/16 to 1/4 inch thick with the slot about 3/8 inch wide and 1 1/4 inch deep. The best material to use is corded rubber belting. Actually, any heavy rubber stock will work, and in a pinch, you could make these out of quarter-inch plywood or paneling. As you still have the timing chain in place, you can use a socket wrench to turn over the engine.
Starting with the gang for cylinders 1 and 3, turn over the engine and place one of these spacers between the valve seat and the block holding the valves in an open position. Once all four valves are held open, you are ready to remove the first gang of four.
Loosen the three fittings holding the bent “T” oil line and remove it. Clean it and mark it with masking tape so you know the front from the rear one and place it with your restored parts. Now is a good time to remove the rear one and do the same.
At this time, you will find small splash pans under where the oil lines were. These are each held in place by two small quarter-inch bolts. Clean and place them with the other restored parts. Now is a good time to remove the rear oil line and splash pan and do the same.
Now for the lifter gangs themselves. There are two bolts holding each gang unit into the block. These bolts are held in place by a strip of sheet metal 7/8 inch wide by 6 1/4 inches long that have been bent over to lock the bolts in place. Using a screwdriver and small hammer, open these up and remove the two bolts. The gang should come right out, but, if you still have a bind, rotate the engine a little until the cam moves enough to let the gang come out freely. Do not force it!
When the gang is out, mark it with a metal stamp to show that this is the gang from cylinders 1 and 3. You can use an electric pencil or coded punch marks to identify the gang later. Put the gang in the solvent tank and repeat the process with the other three gangs. Don’t try to reuse the metal strips that held the bolts in place. A local sheet metal shop can make you four new ones of the same gauge metal for very little cost.
While these gangs are soaking in solvent, it will be a good time to remove the timing chain tower, clean it well, paint it and place it with your restored parts. After this is done, it is time to start overhauling the valve lifters themselves, one at a time.
There are a few things to remember as you redo these lifters. The first is that if not done right, there will be lifter noise that you won’t like and you will lose some engine efficiency. Second, the various parts and pieces of these valve lifters are not interchangeable and each must remain together as an assembly.
Third, the cleaning and polishing of these pieces is not a cosmetic matter, but to give you an opportunity to perform a good inspection for any minute flaws and/or fractures as well as future smooth operation.
Also, it should be noted that in the 1948 models, there were two types of lifter plungers (not interchangeable). If you are doing a 1948, you should study the service manual very carefully before starting to overhaul the lifters. The earlier engines (pre-1948) had the plungers available from many suppliers and are NOS military surplus packed in Cosmoline. (My earlier article on the fun of Cosmoline should be referred to if you are going to use these type plungers).
Is everybody ready to start on these valve lifters? Good, because this is a slow process, taking an average of 45 minutes to an hour for each of the 16 lifters...if you do it right and don’t run into any problems or broken parts, that is. The first one or two may take longer.
Take one of the gangs out of the solvent after thoroughly washing it. Have a container ready (I use a plastic kitchen silverware separator). Begin to take the lifter assemblies out of the gang body and leave each lifter in the same position that it comes out of the cast part. Remove the small locking ring from the top of the lifter body (by the way, these little rings love to jump and hide, so be careful).
The casting should now be cleaned and may be bead blasted, being very careful not to blast the interior walls. They must be thoroughly cleaned, making sure no abrasives are left in the casting. Each lifter opening can be cleaned using a 12-gauge shotgun cleaning brush followed by a brake cylinder hone set on low pressure. Then use a 12-gauge cleaning swab with a small amount of toothpaste to polish to a bright surface.
After polishing, inspect closely for any flaws or scoring. Be sure to clean again in solvent and coat lightly with oil. As for the individual lifters, you should get a 1948 service manual, as that one has more detailed pictures than the earlier-year manuals.
Polish the walls of the lifter body and inspect for any tiny flaws or fractures. Do not reuse any part of these assemblies with flaws, but replace them. The inside of the lifter bodies can be cleaned and polished using 16-gauge shotgun cleaning brushes and swabs. Follow the manual instructions completely in regards to preloading these assemblies with oil.
After completing each lifter unit, install it in the proper place until all of the four units are done and the whole gang assembly is complete. Do one assembly at a time and after coating them with a light coat of oil, put them with the rest of your completed parts.
That should be enough for this month and there will probably be fewer “students” next month, because some of you may decide to just turn over the rest of the job to a “pro-shop.” For you hangers-on, I say, “Good for you,” and let’s feel sorry for those dropouts that miss out on all the fun and satisfaction of having a really good engine that you rebuilt yourself.
See ya next month.
P.S. The entire community and our Club will miss our Club member Ralph Vance, who was killed in the line of duty as a mountain community volunteer firefighter. I know that wherever he is, he will continue to read The Dagmar and give me guidance as he has done over the years. We all miss you, Ralph.