Rt. #4, Box 268, Lillington, N.C. 27546
When beginning an engine restoration, the first thing I do is replace any missing parts and repair any that are broken. It is better to do this kind of work early than to try and do it after you've done the other things like painting, etc. I also try to make sure the engine runs about like I want it to.
It seems that everybody has their own remedy for freeing stuck pistons, and other parts that are rusted together. Here's one the readers might want to try, and that's soaking for three or four days in apple cider vinegar (brown variety). Vinegar is slightly acidic and will dissolve rust that has formed in between the piston and cylinder wall and since it is thinner than oil, it penetrates as well as most penetrating oils. Works good on pot metal fuel pumps like those on some of the I.H.C. engines, too.
Next, I completely disassemble the engine. This is so I can get to all the rust and dirt that can hide in the small parts in any little crack or corner. The major parts like flywheels, crank, head, etc. are put aside for later. Small parts like throttle and governor linkage, mixer, oiler, etc. are put into a bucket or box so they don't get lost.
Bearings are marked with a scratch awl so they can eventually be put back in their original location. Bearings and shims are tied up with wire or string the same way they sat in the engine so they can easily be reassembled. All this seems like an awful lot of work, but I've found that it's about the only way to get a really nice looking restoration.
Now that the engine has been taken completely apart, it all has to be cleaned up. I start with the larger pieces first, such as the main frame, fly wheels and head. For this I use an angle grinder with a wire cup brush. With this outfit you can take off heavy rust, grease, paint and almost anything else. Unlike sandblasting, which seems to open up any surface pitting, the wire brush seems to have a smoothing effect on cast iron. If you want to go a step further, a flexible abrasive disc on the same grinder can really smooth out those old rough castings, but if you intend to use some type of filler material, you may find that you don't need to do a lot of actual grinding on your engine. One important point to remember during all this is that the finished paint job will turn out no better than what is underneath it. For small parts and for those areas that can't be reached with an angle grinder and wire brush, you'll have to resort to sanding by hand or cleaning with a hand held wire brush.
Once you get any one part cleaned of dirt and corrosion you'll need to put on a coat of primer to keep any rust from forming back on the clean parts. I prefer to use a good quality red oxide primer from a spray can, mostly because it is convenient.
Once the parts are cleaned and primed, the next step will be to start filling in those areas that are pitted or are rough from the casting process. One product that I like to use is Martin Senour #3934, Red Oxide, Glazing Compound. It comes in a tube and is about the same consistency as tooth paste. On flat surfaces the best way to apply it is with a soft plastic paddle like body shops use. For corners and any rounded surface the best way I've found is to dab a little on the end of your finger and smear it on. Thin coats of this filler will harden enough to sand in about an hour, thicker coats will require more time. When using this or any other filler, be careful to put on only enough to fill in those pitted and rough areas since a big portion of what you put on will eventually be sanded off in the process of getting all those parts slicked up and ready for final painting. Speaking of sanding, that's what comes next. For this I use Autobody, Waterproof Paper, Silicon Carbide in grits of 100, 220 and 320. To make your sandpaper go further, you may want to do as I do. Cut a full sheet of paper in half and then fold each half sheet in half again. This will give you a piece of sandpaper approximately the size of a man's hand with grit on both sides. Soak your piece of sandpaper in water for five minutes before you start sanding. This softens the sandpaper and makes it conform better to corners and uneven surfaces. Anyone who has ever tried dry sanding on primer or paint will tell you that you can clog up a piece of sandpaper in about two minutes this way, and make it completely useless. As you sand, dip the sandpaper in water every minute or so. This will help to wash away the primer and filler as you sand and keep your paper from clogging. You'll be surprised how long half a sheet of sandpaper will last when used with plenty of water. Water won't hurt the engine castings, but you'll find that rust forms pretty fast on any bare metal that has been exposed by sanding with water. If possible try to arrange this work so that the last thing you do before putting everything away, is to put a coat of primer over any exposed metal to avoid having a lot of new rust to contend with the next day. Make sure that all surfaces are dry before applying primer.
On engines that are badly pitted, this priming, filling, and sanding may have to be repeated two, three or even more times depending on how smooth you want the surface to be. But, for a real slick looking paint job, you can count on doing it several times. The first time you sand, you'll want to use a coarser grade of sand paper like 100 grit, and then change to a finer grit, such as 220 or 320 as the surface gets smoother. All this priming, filling and sanding can be a lot of hard work, but remember the rule-'Your finished paint job will look no better than what's underneath it.'
After you've got all parts prepared like I've just described, you'll be ready to start putting on some color. I've used spray paint in a can from several different manufacturers, but I have two favorites. One is Krylon spray paint. It works well and some of their colors are very close matches to some of the old engine colors. Another favorite is Martin Senour Automotive Enamel in a spray can. When applied correctly it has a nice shine and is very durable. Martin Senour offers a wide variety of colors including some of the standard tractor and engine colors like I.H. red and J.D. green and yellow. Many good auto parts stores can mix paint and give a pretty good match to most any color if you can show them some kind of color sample to go by and if you're inclined to use an air compressor and a spray gun to do your painting.
As far as the actual painting goes, regardless of whose paint you buy and whether you use a spray can or a compressor and a spray gun, the one thing you should try to do is put on enough paint so that it looks 'wet' as it goes on, but try and be careful and not let it sag or run. If you do get a run in the paint, go ahead and let it dry and come back later with some fine sandpaper and some water and sand the run oft. Then a little touch up painting over this area should cover it up. If your paint looks dry or ' 'dusty'' when it is being put on it will look even worse after it has had time to dry out.
A little experimenting with paint will help develop your own painting technique. I recommend three coats of paint on an engine to help protect it from handling, weather, etc. I also try to paint all parts before assembling the engine. Sometimes a part may get a scratch as the engine is being put back together, but these can be easily covered with a small amount of paint and a small brush. Some people seem to prefer assembling the engine and then painting it, but I like to paint some of the smaller parts a color that contrasts with the color of the main engine parts. About the only way I know of to do that is to paint first and assemble later. On larger engines of say 6 HP and up, this taking apart and putting back together can mean some heavy lifting, so you'll either have to have some help available or try and figure a way to do your cleaning and painting while leaving some of the heavier pieces in place.
When you're ready to put your engine back together, it's a good idea to have the engine skids or trucks ready, if possible. That way you can go ahead and mount your engine on it and you will have a good sturdy base to work with. If you know someone who has a sawmill, it sure can be a handy source of good material for mounting engines. I prefer to use white oak for skids since it can be made to look good and is strong enough to do the job. On light colored woods, I like to use some type of stain to darken it a little and then after sanding, use satin polyurethane applied by brush to seal the wood and protect it from swelling and cracking due to weather changes. After the engine has been painted and put back together the only thing that should remain will be those little things that will really 'dress up' your engine. Install brass grease cups rather than the painted steel type that probably came on the engine when new. Shop around and try to find brass to replace the original gas line, etc. Polish all brasswork and then give it a coat of clear spray lacquer and that shine will last for years without having to repolish it. Put on the correct decals, and if you want to be a little adventurous, you may want to try a few pinstripes.
The easiest way to pinstripe an engine is with the stick-on type that can be found at many auto parts stores. Basically, it is a thin plastic tape with a adhesive backing. It comes in 1/8, 3/16, ? inch widths, single and double lines and in a number of different colors. Be careful when putting it on and make sure you're putting it in the right location, since it can pull off small pieces of paint if it has been taken off and relocated, especially if the paint is very fresh.
So, basically that's the way I do it, and most of it was learned through a lot of experimenting to find what worked best for me. It's kind of like a fellow I once knew, bought a grain combine that was completely worn out, partly for not knowing any better and partly to save money. When he started using this machine, he didn't pick much grain, but he sure did learn a lot about combines.
In restoring engines there are a couple of important points to remember. Take your time and don't rush. This causes mistakes. Don't spare the elbow grease. Your engine is well worth the effort. Don't forget to have what's under the paint look as good as you want the paint itself to look.