I know a higher heat range (hotter) plug will cause this to happen sooner, but it the plug itself does not add heat to the engine to cause this increase. Are you saying the engine runs coolest at the optimum timing?Īlso, I thought advancing the timing will cause a hotter spark plug (not heat range, but actual temperature) because the cylinder temperature itself gets hotter due to higher combustion temperatures and/or pre-ignition. Have a look at the Wikipedia page on Ignition timing for more detail.Thanks for the response. tuning up the engine or running on a different fuel to normal. You'd only typically have to adjust it manually if you have changed something, e.g. Most adjustment is done automatically, either be a mechanical or vacuum system in older cars, or by the ECU in modern vehicles. 10 degrees before TDC), and adjustments are noted relative to that (so 9 degrees would be referred to as "retarded by one degree"). Generally, the manufacturer will specify the amount of advance needed (e.g. Equally, as load increases, you need to advance less, as a larger air/fuel ratio burns quicker. The exact timing needed depends on a lot of factors, such as the engine speed, load, fuel octane rating and temperature - for example, as the engine gets faster, the timing will need to be advanced further, so that the fuel still has time to burn - the cycle is shorter but the fuel still needs the same amount of time. If it occurs too late, you lose power as the piston has already moved some way back down the piston - you'll also lose fuel economy and could get overheating. If the spark occurs too early, you can get the expansion happening before the piston begins to move down, which will cause knocking, and possibly engine damage. Generally the timing is set so that the spark occurs slightly before (in advance of) top dead centre (TDC), because it takes time for the air-fuel mixture to burn and expand - you ideally want the mixture to fully burn by just after TDC. Thanks!Īdvancing or retarding an engine is the term used to describe adjusting the timing slightly to make the spark occur slightly earlier (Advanced) or later (retarded). I hope I covered most of what you wanted to know. Trust me, it's way worse than blowing up your Honda at the drag strip. I've seen Caterpillar do testing on their engines and JUST the right amount will destroy the engine. IF you tinker with it, it could actually be a huge problem. It can also cause the exhaust manifold to heat WAY up.Īs far as for the other methods mentioned, those systems typically come on larger machinery and are installed by the factory. This will eventually eat away at your valves and cylinder walls. This actually causes a "fire" inside the cylinder and probably lots of misfires. When you retard the timing without compensating for it, the combustion chamber will ignite late. I'm saying this assuming you're not adjusting engine cams and things of that nature. What can happen if you don't correctly retard the engineĭepending on your method of retarding the engine, generally nothing catastrophic. Generally you would find it just after your drive shaft, because it is usually a stand-alone unit. These are usually switched on and there are secondary pumps that help assist the hydraulic fluid in stopping what ever it is that you're trying to stop. They serve the same purpose, but are more robust and can do a much quieter and smoother job of slowing things down. I've seen small cars with them, and typically you see large machinery with them. HOWEVER they do the opposite, they help slow down the motion of the drive-train. Hydraulic retarders are essentially the same design as a torque converter in the sense that they have small veins that hydraulic fluid passes through. Reasons for doing this would be for non-computer managed fuel economy, a car that has minor forced induction and non-computer management, if the vehicle isn't performing as desired, and some engines will actually benefit and gain horsepower from retarded timing. Retarding the ignition timing can be useful for a few things, but is generally left untouched. Here is a video of what it sounds like and a video demonstrating it.
Rather than having to use and heat up their brakes while stopping or traveling downhill, this could be used instead. This was done so that large machinery and semi trucks could come to a more quick and even stop. It was designed to open and close the exhaust valves very late to use the pressure from the engine in an attempt to retard the engine. The most famous engine retarder is the Jake Brake. There are several ways to do this and several reasons for it. It just means that in one way or another, you are hindering the engines ability to provide driving force, and in some applications you are actually using a device to work against the engine and vehicle. Retarding an engine is essentially a vague, but blunt term.
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