santiagocabral

Well, on all the engines I have ever built (I lost count) the routine is to change out the oil before the first 500 miles due to any metal particles that might be in the system. This was only a precaution back years ago for all the after market muscle car builders that did their own machining. In reality there should not be any metal particles in the system if the engine was machined and assembled correctly. it is assembled in the same manner as a Doctor does surgery, very sterol and clean. I have never had a engine go bad because of not changing the oil nor have I seen one wear out before its time. Now I have seen engines that I have pick up from people that never changed their oil. You can believe this or not but every one of those engines showed the least among of wear then all those where the owners were so religious in changing their oil ever 3,000 miles. I had one ford v-8 engine that had one owner, he stated that he never once changed the oil from the first day he bought it brand new from the dealer ship. that engine had over 200,000 mile on it. I took it apart and was shocked at what I found..... that was only a max of .001' wear on the rod and main journals and no ridge at all on the top of the cylinder walls, "it wes like brand new-no wear any where". there was caked burnt oil all over the inside of that engine that I had to chip off with a hammer and chisel.

Now I would like to believe the by now the engineering group at the manufacturing plant has their **** together on these area. I mean... come now, its no longer rocket science!!! its a routine now/procedure. I HOPE To God!!! LOL.... The assembly processes has all of these concerns and issues of the past already corrected with procedures in place to insure the engine is clean and free of any machining metal particles, besides, that is what the oil filter is doing, cleaning every drop before it goes to any bearing. Now if there is any particles in the system then they came from the moving part them self and are all ready in the bearing.

I believe we can be rest assured that running these engine up to 15,000 mile will not place any more wear to any of the bearings or cylinder walls then it will by doing oil changes every 3,000 mile. Doing all those dry start-ups that do cause excessive wear to the engine bearings is a bad thing and will cause excessive wear.

Just a word of wisdom. never do an oil change on a cold engine. run it first to a normal operating temperature to get oil on all of the bearings, then change it. It is far far better to have a little old oil with the new then it is to start a dry cold engine.
Although there is some oil on the bearings before a normal start up it is not enough to protect the bearing or the crank, it still takes more then a second to get the oil moving. That is alot of time and due to the high torque/HP of the engine design there is an extreme amount of friction, there is not enough oil to protect the surface of the bearing as it does when the engine is running. this will cause wear to the engine, this is part of the expected life and wear of the engine.

Now when the oil is drained and a new filter is installed the time it takes to move the oil from the oil pan to the first bearing has now increased dramatically there for has also multipled the normal wear by more then five time, especially if it was done on a cold engine in the first place. The oil has to travel up through the oil pump and then to the empty oil filter (fill it) and then to the first bearing, then more time to the last bearing and cylinder walls, cam lifters and valve guides and seals. I hope you get the picture.

Never ever do an oil change on a cold engine, run it first to normal operating temp. A cold engine means that the oil has had more time to run off the bearings. Old oil is better then no oil!

never high rev an cold engine during the cold months.

The only exceptions to the 15,000 mile oild change set by the manufacture would be to the driving conditions the engine went through. example: If the engine spent 70 % or more of the 15,000 mile at a crusing speed at normal running temp. then the oil should be in good shap and some what clean. this means the viscosity of the oil is still maintaining no less then 10-W and is still protecting the engine as if it was new oil. It just has some carbon mixed in it, carbon at the particle size that it is does not hurt the engine nor cause excessive wear. The particles are small enough to go through the filter then it is not going to do any harm to the bearing or journals. Now with filters- they do not stop working just because they may have, lets say they have 20,000 miles on them, they are still filtering just as good as a brand new one. if it stops filtering then it will plug up and the element inside would collapse. You can install a new filter every day for the next year and the oil will still turn dark as if there was only one used.

Example II: Now if the engine is going through more then 50% of stop and go driving conditions and also harsh environment and has seem high temp then yes the oil will need to be changed more often. Even with these types of driving conditions of stop and go, as long as the engine has not over heated or seen high temp on a daily bases then the oil should continue to protect, it would be best to go by the color at this point. infact if any engine that should over heat the first thing that needs to be done is to change the oil ASAP, there is a very good chance the oil has broken down.

Again; engine that have seen a cold dry start-up every 3,000 will have far more excessive wear then an engine that has 50,000 mile with the same oil in it, just with small fill ups to maintain the level. I have seen this so many time over the years.

Now oil presure on a modified pro stock engine works different. the bearing clearance is greater then stock. The oil pumps on Pro stock and bigger engines have higher volume pumps to acount for the greater bearing clearance, but not always high psi. This creates less drag but lower pressure at an ideal then a stock set up. But then these engine will not last on the street for very long. Street rods go stock. drag engine normally never see the street. Oil Pressure pump system in all engines is the same as any hydraulic system, it is applying a pressurized oil barrier between the bearing and the journal surface trying to floot the crank journals away from the bearings. With out any oil pressure the journal surface is rubbing hard against the bearings.