Simple oil change frequency question

[JonB]

The answer to the original post and driving description would be "3000 miles is fine" in my opinion. But consider------

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by luc:
...The only usage that will call for changing the oil more often will be racing.Luc....<HR></BLOCKQUOTE>

I agree w/ most of Luc's points, but the point above. "Only" is not what I would cite.

-- Racing/Track situations, rule-of-thumb 100-150 track miles = 1000 street miles. Obviously, a 12-24-enduro CAN be run, but the motor is shot afterwards.

-- K+N AIR FILTERS = Dirtier oil! Any Viper with K+Ns should be considered a 'heavier-service' use, due to the additional fine particluates that K+Ns admit that OEM does not! Don't fool yourself. Even pollen! Consider keeping a spare set ready, so that you dont take shortcuts when servicicng/cleaning "lifetime" K+Ns. There are filters that claim even MORE flow than K+N... If you select these, adjust your oil change frequency accordingly.

--OIL FILTER CHOICE MATTERS ! Mobil One filters the fine-fine crap! Filter medium can be a factor.....think about it.

-- I hope TomH, FL&OGoR will post his thoughts...maybe temp and humidity discussions, NOS and fuel additives should be considered as well......

 

[Matt M PA]

I hate to disagree with Jon B but, I contacted K&N awhile back when a similar post was made, regarding the actual filtering ability of the K&Ns. while I no longer have the e-mail from them, I do remember that the K&Ns not only flow better....but filter out smaller particles than the paper filters. A search of the board should find the original post quickly. If memory serves me, someone posted the K&N response on the board.

 

[Tom F&L GoR]

If you consider the state of the oil, rather than how you use it, then it's things like:

How hot did it run and for how long? Below 250F is not severe service and is actually fairly typcial, above that is warm, and 300F is OK for a few hours. Yes, the effect on oil life changes rapidly once you get over 250F.

How much blowby? The exhaust that reaches the oil is fairly acidic and initiates corrosive wear. This is one feature diesel oils excel in, since they are treated with more detergent addtives (and result in a higher TBN.) You'll get more blowby at a 60 MPH wide open throttle than at a 120 MPH cruise.

How much particulate matter? Whether past the air filter, soot from the blowby, or anything else, dispersants will keep these little things from clumping and getting large enough to cause wear. Again, diesel oils have lots of dispersants because of the soot that gets into the oil.

How high is the engine speed? Shear rates inside the engine tear apart the viscosity index improvers (what makes it a multi-grade) and the oil will get a little thinner.

How much fuel dilution? Usually racing keeps the oil warm, but should fuel enter the oil, not only will it thin it out, but fuel is not terribly oxidatively stable, it's meant to burn, so it will "use up" some of the oil's thermal stability characteristics.

Fuel additives? The amount in gasoline is pretty small and won't accumulate to an appreciable amount until the end of a longer oil drain. But aftermarket bottles (if one in the tank is good, two is better?) deliver an immediate amount into the oil, and some of them are not compatible with all oils.

A safety factor is the 9 - 10 quart sump Vipers have, that's double a more sedate engine, yet both have the same oil change recommendations? Hmmm...

Considering a lot of the "harm" to an oil comes from the fuel, think of it this way: 3000 miles at 15 miles per gallon is 200 gallons of fuel consumed between oil changes. So for an otherwise healthy engine, consider changing your oil every 200 gallons... (Or do the math from your other cars, and maybe factor in the amount of oil in the sump.)

Sorry, won't go that far on a limb and set a single number of miles, but hopefully you will all get a feel for what is going on with the oil.

 

[JonB]

Thanks TOM! I always read every word of all of your posts.

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Tom, F&L GoR:
A safety factor is the 9 - 10 quart sump Vipers have, that's double a more sedate engine, yet both have the same oil change recommendations? Hmmm...<HR></BLOCKQUOTE>

Those of you with 1996-1999 Vipers, especially ACRs, who have NOT UPGRADED your oil pan to the higher capacity pans, are playing a risky game IF-IF-IF you participate in track or autocross events. The lower capacity of the 96-99 Gen-II motor starves oil at high G-loads. Fact. At a minimum you need trap-door baffles/lazer drain($349) and at best, a new 1.4 extra Qt fan/scraper/gasket upgrade ($599) Both for $899.

A #3 or #2 rod thru your block? PRICELESS !

Street only? Don't waste your $$. Buy a HP mod instead !!

JonBuy Sez........

 

[BWoodbury]

Not all of us autocrossers have to wory about oil starvation, Jon. With my driving technique I'm not sure I would have pulled enough lateral G's to slide a box of doughnuts off the roof of my car.

Rest assured, however, that an oil pan and ACR adapter are going to be ordered real soon. Just as soon as I get that new fan assembly installed...

 

[Henry Cone]

So with my track milage of about 4 MPG I should be good for about 800 track miles...and that's probably about when we change it...

In any case Tom's information is why we use Mobil Delvac 1 5W-40 diesel synthetic in our cars. The extra detergents and dispersants in the diesel oil helps prevent problems from extreme conditions...

As an added benefit, we can run the same oil in our Vipers as in our Cummins Turbo Diesel Dually Ram pickup!!!!

Tom, as always, thanks for all of the great information!!!

 

[Gavin]

Have you heard of the "Kiss Principal" - Keep It Simple Stupid"
Hey I'm not calling anyone stupid.
3000 mile oil changes spoils the average engine and leads to longevity of same.
Hard driving - it isn't, unless you are on a track generating temperatures that will cause even Mobil 1 to start to break down

So in the interest of following the "KISS" principal:

Change the oil every 3000 miles and after every track event.

If you are doing track events then there are other fluids to consider - brake, clutch, tranny, differential.

 

[JonB]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Matt M, PA:
I hate to disagree with Jon B but, ......I do remember that the K&Ns not only flow better....but filter out smaller particles than the paper filters.......<HR></BLOCKQUOTE>

We dont really disagree......the K+N verbiage states a "properly maintained K+N......." I am just believing what old-buds at Team Viper voiced years ago: HiFlow filters are GREAT if the owner can be trusted to maintain em......

(Probably) like many here, I am "GUILTY" of ignoring filter maintenance. Evaporated oil film, or improperly-cleaned media makes it a wide-open invitation to dust and microscopic abrasives. THAT constitutes a severe-use oil change cycle.

 

[luc]

Hard/severe usage is defined by all manufacturers as stop and go driving and a lot of idling,as a taxi or police cruiser.

Towing is also 1 of the definition.

Freeway cruising is the MOST easy usage on oil/engine.

3000 miles oil change is the recommended mileage for severe duty.
Change your oil at 3000/6 months and you will never have a problem with oil.

The only usage that will call for changing the oil more often will be racing.
Luc.

 

[Geoff Green]

I am sure many people will think this is excessive and potentially bad for the environment, however I have changed my Mobil 1 every 1000 miles after my initial 300 mile change. We will see if down the road it made any difference. I have never tracked the car, but have put 8000 miles on this late 98. I also have had the oil anylized every time and track the wear data. Working on the car is just enjoyable.

 

[luc]

If you don't fill the oil filter with oil prior to installation,you are doing more bad than good to the engine.

Before the pressurized oil can do it's job in the engine,it has to fill the filter.

Luc.