Questionthanks for answering my questions on the cadillac. you wanted to know what size the engine was. it is a 7.7L or 472cid 4bbl. i think i will use those rapidfire ac plugs you suggested. ac says that would be a Part# 4, Gap: .035. when i or who ever tunes it up what should i make sure is done so that it is tuned up correctly? on the oil you suggested. i live in missouri. can i change from one type to another depending on the time of the year? as in cold and warm months. being a 1973 engine. what type of gas and additives if needed should i use.
AnswerWow... that's a REAL beast of an engine. That definitely needs some good exhausting.
Ok. on the plugs... make sure they don't tamper with the gap. The gap is preset and is always correct for the car it goes into, provided you bought the right plugs.
What I consider a REAL tune up that I do is as follows.
New spark plug wires, new plugs, new cap, new rotor, new PCV valve, new breather for the PCV system on the filter housing (if it has a filter). I'm sure that covers most of the basics.
Some other things could be like buy some carburetor cleaner and clean the varnish off the carb... it's mostly just preventive maintenance that could keep you from having a sticky mechanism on the carb.
Well, additives are not neccessary at any age, but a carb cleaner additive to the gas could not hurt to use every once in a while. I know I use injector cleaner every once in a while on my Fiero and it has 125,000 miles and the engine still works perfectly smooth without hesitations or problems. I think advantages are more noticable with Fuel injection cleaners because of the fact you have an injector for every port but for carbs, the advantages would be mostly internal to the carb, and you might not notice it too much in the quality of idle. On, fuel injection the cleaning is more DIRECT to the quality of explosion of each cylinder, a carb disperses the fuel unevenly so the effect of a cleaner carb jet might not be as noticable.
Absolutely, with the oil you can change it and adapt to you weather. That would be no problem. Normally 20w-50 isn't recommended by the manufacturer because it's thicker an "possiblly" lowers you fuel mileage, since it's more difficult for the engine to push the oil around.
The manufacturers try to get the maximum fuel mileage rating so they use the thinnest stuff without compromising on it's durability too much.
I have never noticed any difference in fuel mileage with using different oils, so I would not worry about that. Anyway, once the engine is at normal operating temp. the oil thickens and at it's hot temp. the 20w-50 is only slightly more viscous than a much thinner oil. At cold temperatures is when you might notice the thickness.
Sometimes if a cold front comes in and my car is sitting outside and it's about 30 degrees when I turn the car on the lifters TICK for a little while because it's hard to pump the oil up there quickly, but it usually goes away after 20 seconds. But if you change your oil depending on the season you can't go wrong.
Carlos
