Previously we talked about how to go about an engine tune-up involving older cars with distributors: both contact-point type and those with electronic ignition. The concern on what spark plug to use was limited to using stock or OEM (original equipment manufacturer) spec units. With current engines having longer tune-up intervals because of newer types of spark plugs and ignition systems, some have asked if the older cars could benefit from these newer items. The answer is yes. One of the ways to increase engine efficiency is to burn the air and fuel mixture better. Having a more reliable spark can give the engine a more consistent performance. And also better fuel economy. In the past few years, spark plug manufacturers have come out with spark plugs that can burn better and last longer. Splitfire came out with a spark plug with a notch at the ground electrode. It’s supposed to increase the burn area that burns more air and fuel mixture. Then came the ones with multiple ground electrode. This design also promised larger burning area. Now you the iridium cored spark plug. Smaller center electrode, longer lasting. Then things got more interesting.
For those with older engines, they said that it was bad for your engine because it had a tendency to overheat. True… I agree. But that’s where tuning your engine comes in. The extra heat generated comes from the same amount air/fuel mixture that enters the chamber but this time, more of it is burned. How is that? Lets say an ounce of air and fuel enters the chamber. And upon combustion 90 percent of the mixture is burned and certain amount of heat is also generated. Lets say that makes 9 pounds of force. The 10 percent is thrown out of the chamber as unburned gases. If you increase the burn efficiency by 3 percent, then more air/fuel mixture will be burned. Then more heat is generated, more power. Your unburned gases is down to 7 percent. That’s why your engine temp will rise. More power, more heat generated. For fuel efficiency, you would need lesser fuel to produce 9 pounds of force because you can burn the fuel better. For the ones with carbureted engines, you would need to adjust your primary and secondary jets.
If you want to upgrade your contact point type distributor to an electronic type, you could go to a Japan auto parts surplus store. You just have to bring your old distributor as a sample and go through a stores inventory to look for a matching unit.
Older engines can also benefit from better ignition coils. The theory there is the coils can give a hotter spark. But to make it better would be an MSD ignition system. How? Lets put it this way: I saw a beetle with an MSD system installed. Stock engine, still using contact-points. It was flying on the highway. It passed the emissions test with flying colors. The system could also revive old spark plugs.
If you go around the shops selling surplus engines, you may chance upon a couple of 3K or 4K engines. With EFI or electronic fuel injection. They still have the distributor type ignition system with electronic ignition. This is an example of what the manufacturer did to their older engines. Engines that didn’t reach us. Especially in the ignition department. I had a 1991 Galant, carbureted, but with electronic ignition. It was the model before the MPi version. The engine was the same as the one for the old L300 gas version. Carb was slightly different and the distributor was a contact point type. If you are considering an upgrade, look around first. I am sure there would a system that would work for your engine. The research for me is the fun part. You get a chance to see what ideas other people have. What can work, what won’t work.