Engine flush

IMO a flush is not necessary when the engine is maintained with regular oil changes. A flush may be required if you go and pick up a car from a sandy/dusty area and the oil has not been changed in 25,000 miles. But, then, any damage will have already been done.

A flush of an automatic transmission is necessary so that the lines and components of that transmission can get the new fluid.

 

There is a difference between a fuel system flush and a crank case flush. JohnnyS is completely correct about the crank case. With modern oils and proper change intervals the crank case flush is rarely needed. As far as the fuel system goes it depends. Fuel injectors will after many miles start to not really plug up but the fuel pattern and size of fuel droplets will deteriate. The other issue is carbon build up in the intake tract and particularly on the back side of the intake valves. Depending on crank case ventilation and egr systems the build up can be significant. Many newer cars have TSBs relating to intake tract cleaning. I have a 97 Ford Aerostar and I did the procedure to clean the intake tract. It basically requires feeding in a cleaning solution just behind the throttle body (thru a vacuum port). Once the solution is fed in the engine is shut off and allowed to set for a couple of hours. When the time is up the vehicle is started and you basically go and do an Italian tune up on it. On my van there was a notable improvement in the way it ran. I also picked up 1.5 mpg. The other issue is dirty fuel injectors. There are machines that basically put a powerful cleaner thru the fuel system while the engine is running. The concentration is much higher than just dumping a bottle of the cleaaner thru the tank. Since I do not yet own one of these awesome cars I can't speak directly about it!

 

Mike,
bad idea on a hand built engine. The risk to seals, gaskets and other parts is just to high. Change the oil and use a ultra high quality racing 20-50W (SWEEPCO)oil will help milage the most. If the injectors need service, (at this point I think "YAHOO I get to take the thing apart again !!") removal and performing the needed service or replacement is my suggestion. If you think you have contaminents in the fuel delivery system, change the filters. Water contamination is easily gotten rid of by using products that emulsify the water and then run it through the engine. Works very well. As far as the claims made by some products to improve mileage, most of then have large concentrations of alcohol, or benzines or other aggresive solvents which boost octane for a little while, which encourages further use of the product. Steer clear.

I always try to remember, if they were that great they would be additives in the fuel you buy.

These engines were designed to produce power and were not designed to maximize fuel efficiency. As I have posted in the past, these engines consume approx. 5 gals/hr on average. It's the way the system was designed. Go faster, get relativly better milage. Example- around the bay area I get approx 10 mpg. When I drove the car from Tucson AZ to San Fran at approx. 105 mph avg, I got 17 mpg. not bad for a 35 year old engine - 5th gear at approx 3700 revs. The same is true when I drive at 55 mph - 5th gear approx 2300 revs, but the mpg degrades to 12 mph. For a Ferrari V-12 the difference between 2300 and 3500 means very little in fuel flow into the engine. It just takes longer to travel the same distance. Now if we were to travel around in 3rd gear with the revs at 6500 revs, the fuel consumption would be significantly higher. But between 2500 and 3500 - little difference. It is fairer to the engine to place fuel consumption in gallons/hr of operation rather then mpg.

My suggestion, drive that car, change the oil and have FUN !!

 

All the fuels contain additives. The US gov't mandates a generic blend of additives as the low end additive to keep fuel injectors cleaner. The "major" brands have their specialized blends. I recently had a tour of a major Valero refinery. At the truck loading area they had additive tanks with logos from: Shell, Exxon, Gulf, and others. The majors do a lot of research and it may seem like a bunch or marketing BS but they actually work.

There are also machines that clean your injectors on a bench set up after removal from the engine. This has a lot of advantages like the gunk not going into your engine and you can actually see the results in the spray pattern. I had that done successfully on my SVX.

As for benzine being a "harsh solvent", gasoline in Italy has always been called "benzina" for a reason. Until cancer research got the amount in fuel reduced gasoline had a very high benzine concentration.
Ken
Chem Eng.