Thinking Too Much, Endless Possibilities

[Red91]

Basic theory: 20K OCI on a 1992 Buick Roadmaster wagon with a TBI 5.7 V8
Oil: SJ Kendall GT-1 30wt
Variables: unpredictable driving conditions, ranging from long trips to 5 minute sprints with engine on/off/on scenarios
How?: 1 solid 10K run with a filter change and top off at 10K, 1 solid 5K run with filter change and top off at 15K, another 5K run with complete oil and filter change at 20K
Why?: In theory, presuming a full quart for top off at the filter changes, the fresh 30wt oil should be sufficient to refresh the additive package and TBN, without sacrificing the tribofilm antiwear layers already in place with the used oil

Thoughts?

 

[supton]

What is the gain? Less oil used, less waste; or just because you can?

SJ oil?

If it was me, I'd just change it. IIRC this engine was one of those that did well on 3k OCI & dino, racking up miles and miles. Heavy car, low output engine, unknown usage. Lots of gas through the engine. Might not be "severe" but if it was me I'd err towards lower changes.

 

[Bottom_Feeder]

You're replenishing some of the add pack but you're not removing the contaminants.

You're under the car getting dirty anyway. Why not just change the oil?

 

[mightymousetech]

Would be a lot simpler to just change the oil every 10k instead of changing the filter every 5k. I change my filter every second oil change, a dirty filter works better than a new filter.

 

[Cujet]

Unless you are using a micronic filter, and some form of contaminate reduction, that's not a recipe for maximum engine life. Microparticulates do cause wear, and pushrod engines do produce plenty of particulates.

I'd suggest a standard oil change interval, using a quality oil.

In fact, GM warranty repaired plenty of timing and balancer chains due to extended OCI's. The culprit: particulates and viscosity loss.

 

[Red91]

I'm not changing the filter every 5K. The first run is 10K, then a 5K. Yes, to conserve resources. Ideally this would allow the oil to only be changed every 2 years, or 18,000 to 20,000 miles.

 

[TexasVaquero]

Sounds like a recipe for sludge in spite of having some new oil in there. As posted earlier, you wouldn't be getting rid of all the dirt.

 

[Linctex]

I'd run the cheapest oil & filter available and do 10K on each/both.

From my observations on here and personally, I see no need to do anything exotic. My 5.0 (302) has 284,000 miles on it, my 454 has 271,000 - your ol' 350 should do it easily, too.

 

[1JZ_E46]

I'll never understand the fascination with extending drain intervals to ridiculous levels like this. Expect the oil to be the consistency of gear oil by the end of your test.

 

[demarpaint]

Originally Posted By: Red91
Basic theory: 20K OCI on a 1992 Buick Roadmaster wagon with a TBI 5.7 V8
Oil: SJ Kendall GT-1 30wt
Variables: unpredictable driving conditions, ranging from long trips to 5 minute sprints with engine on/off/on scenarios
How?: 1 solid 10K run with a filter change and top off at 10K, 1 solid 5K run with filter change and top off at 15K, another 5K run with complete oil and filter change at 20K
Why?: In theory, presuming a full quart for top off at the filter changes, the fresh 30wt oil should be sufficient to refresh the additive package and TBN, without sacrificing the tribofilm antiwear layers already in place with the used oil

Thoughts?


I guess at the end of the life cycle of a beater which will ultimately end up in the junkyard, why not? If you plan on keeping the car I wouldn't do it. If you plan on selling it don't reveal your oil change regime. Most car buffs will avoid vehicles which have ultra long OCI's, premium extended drain boutique oil or not.

 

[E150GT]

Perhaps put a bypass filter system on it.

 

[Red91]

I already have cheap oil and filters.....

 

[WishIhadatruck]

I have a '96 version of your car, with an updated motor design. Not long after purchasing mine in 2006, I did a number of UOA and none of the oils I tried were happy past 5k miles. Start with a UOA at 5k miles (don't change the oil until after the results come back if you want) and go from there. I realize what you're trying to accomplish, but there is no way to know if this is an acceptable condition unless you monitor the oil somehow.

 

[Cujet]

Originally Posted By: Red91
I'm not changing the filter every 5K. The first run is 10K, then a 5K. Yes, to conserve resources. Ideally this would allow the oil to only be changed every 2 years, or 18,000 to 20,000 miles.


That's fine. It's not necessary. Nor will I make the absurd claim that you will experience engine failure. What you are proposing is a perfect plan for a vehicle you don't care about and don't plan on keeping all that long. Filter changes are seldom required. Oil changes are far more important.

However, as professionals know (such as myself) , via objective data, proper regular maintenance is required for maximum lifespan. My old Ford truck, very healthy at 355,000 miles is a good example of why regular service can save you time, money and hassle.

In a past life, I worked for Mobil oil and was involved in some oil and grease testing. Also worked for Mercury Marine testing oils in race engines. I now work in the high end world of G650 business jets.

The good news is that over 20,000 miles, of zero oil changes, you will have saved yourself about $25 per year.

 

[Cujet]

As mentioned above, the oil change is more important than the filter change. In fact, with healthy engines, filter changes are rarely necessary.

 

[Nick1994]

You haven't said how much it burns.

Replenishing the oil after 10k miles with 1/2 a quart isn't going to do anything. But if it burns a quart every 500 miles you may be on to something.

 

[Dallas69]

Then just do a regular oil change every 5000 miles.
Use your brain cells for more important things.

 

[Red91]

As of now it has yet to consume a discernable amount in several 4K mile OCI's. This is all for the sake of discussion guys, why get so worked up about it?

A member on the previous page mentioned just going to 10K on the oil and filter. That honestly seems more reasonable.

 

[andyd]

This car probably needs shorter OCIs. You have a stash of oil and filters, use them. If you intend to sludge the engine, go for your scheme. This car is almost a classic, or on its last legs. What are your intentions or goals?

 

[Bottom_Feeder]

Originally Posted By: Red91
As of now it has yet to consume a discernable amount in several 4K mile OCI's. This is all for the sake of discussion guys, why get so worked up about it?

A member on the previous page mentioned just going to 10K on the oil and filter. That honestly seems more reasonable.

I would not call 10k OCIs on a 25 year old car using straight weight SJ oil 'reasonable'.