Tune ’em up—move ’em out
We’re starting to get into touring time and your lovely old LaSalle or Caddy has been in the garage and/or under a cover during the hard, cold winter.
You know, come to think about it, the “old gal” wasn’t really running up to par when you put her away. Maybe we ought to give her a little tuneup.
The question is, how do we go about it? We’re not talking major overkill; just a little ’ole tuneup to make it a little more fun on the tours this year.
First of all, remember this is not a “daily driver” that more or less tunes itself by regular use. This is a car that may get a short or long run and then set idle for awhile.
The place to start is with the spark plugs. Pull them out and look them over good. Are they dirty? Are they all white? What is the gap? Are they all exactly the same? What the hell, plugs are cheap to replace. It is the least expensive improvement you can make to allow your car to run better and it doesn’t take a rocket scientist to replace them. But let’s do it right.
Your good old service manual will give you the right size and proper gap. Some cars will have a specific gap; others will have a range to set the gap. In the ’37 to ’48 (Caddys or LaSalles, of course), it will show .025 to .030.
A good rule of thumb for our Rocky Mountain Region (and many others) is to take 20 percent of the difference and add it to the middle of the range. This means that the proper setting for .025 to .030 would be .028. Please don’t assume they come out of the box with the right setting. You will probably find all of them different. It is important to set the gap correctly, but even more important that they are all the same.
Failing to do so can require faster RPM for a smooth idle.
Also, a little trick to make things smoother is to take a pair of pliers and snug down the little screw ends on the top of the plugs. When you put in the properly gapped plugs, tighten them up snug but not overtight. Overtightening can change your gap. Again, make the same tightness on all plugs. There you go—you did good—now let’s go the next easy step.
Check out the point gap in the distributor. A visual inspection will tell you if they are in good shape.
You can do a world of good with a simple cleaning before you set the gap. Use a piece of clean, stiff paper like the corner of a business card. If you have to use a file to smooth them up, you are much better off to replace them (usually much less than $10). Check your service manual for the proper gap and simple instructions as how to set the gap.
This is a good time to check out the distributor cap. Make sure it is clean and dry inside and out. Make sure there are no cracks or chips in the cap. Clean out the plug wire receptacles with a .38 caliber bore cleaning brush or a Q-Tip® with alcohol or brake and electric cleaner and blow out clean with compressed air.
If you do these one at a time, you will get the wires back in the right holes. Check out the spark plug wires themselves. Make sure no insulation has rubbed off or burned off. This goes for the insulating covers that go over the top of the plugs. Make sure you have at least 1/2 inch of white porcelain showing between the bottom of the spark plug cover and the metal base of the plug.
Next, you want to check and clean all the filters in the fuel system including the fuel pump screens and the screen on the carburetor at the fuel line inlet.
At this point, if you have a timing light and know how to use it, set your timing. It is a good idea to clean and mark the timing marks and pointer well. It makes it much easier to set your timing more accurately.
When all of the above is completed, it is time to “touch” or adjust the carburetor. The two little screws at the base of the carb are adjustments for the low speed and idle circuit of the carburetor and have very little effect over 1,000 RPM. They do have a major effect on low speed, idling, and most important, ease of starting.
Take these screws out and carefully wipe them clean. Blow out the holes they come out of with compressed air and re-install, screwing them in finger tight and back them off 1 1/2 to 1 3/4 turns. Start the car and let it warm up to operating temperature. It is best to hook up a tachometer and then adjust these screws one at a time, screwing them in until the engine starts to slow and back off to max RPM.
Do this about three times on each screw until you are at maximum RPM. Doing anything else to the carburetor should be left to someone very familiar with carbs and who has the right tools.
Congratulations! You have just completed a minor tuneup at the cost of about $20 and a couple hours of enjoyable time. This small investment will pay big dividends while enjoying your car this summer. Your Caddy will run so good you may think you have a LaSalle.
See ya next month.