detergent oil?

[Guest edalfa]

Well, I yanked the oil pan on my 40 Special today (and the valve cover and side cover, as well)There was plenty of sludge-maybe a 1/3 to 1/2 inch-in the pan. The rest of the valve train looks ok. No real piles of gunk, just kind of a general coating. I also pulled the oil pick up and blasted it with solvent and air. It seem pretty clear. Once I button it back up, I planned on 30w Non detergent. Is this best? I'm worried that a detergent oil will loosen up some pile of gunk that I did not see. Would it really make a difference?

Thanks,

Ed Sheehy

[Mark Shaw]

I believe you are right about using detergent oils.

I am sure others will differ with me, but I use the cheapest non-detergent oil I can find. I only drive about 1000 miles per year in my old Buicks, and I change the oil and filter every year when I winterize my cars.

The additives are in the oil to prolong the life and maintain viscosity well beyond the mileage I put on these cars each year. So why pay extra when any modern non-detergent oil is much better than the oils used in these cars when they were new?

[Guest]

I drive my Pontiac daily (have been since 1959) about a thousand miles a month. I always use the best petroleum based high detergent oil made. Before overhauling the engine 300,000 miles ago I used a quart of oil between every oil change (three thousand miles [about three months]). After overhauling the engine and using new modern pistons and rings from Egge I use about half a quart between changes. The only thing I have found is that my car holds it's oil pressure better with single grade rather than multi grade. With 300,000 miles since overhaul I use ten weight oil and have 20 pounds of pressure at an idle and 35 pounds at 50 mph..

Prior to my starting to drive the car my Grandfather used regular non-detergent oil. It burned about 2 quarts every thousand miles and he had gone to #40 oil to try and stop this. Of course this is entirely the wrong thing to do as the worn rings have more trouble scraping the heavier oil off the cylinder walls. I switched to # 20 weight detergent oil and had no problem at all. The only thing that happened was oil consumption was cut in half.

[critterpainter]

Since you cleaned the pan out you should have no problem with detergent oils. The major thing is to keep your eye on the color of the oil NO MATTER if it is detergent or non-detergent. When it gets dirty change it! even if you have only driven the car 200 miles!

I have an 88 Ford PU that was badly mis-treated before I got it with 48K miles on it. Oil would not flow out of the pan, I ad to pump it out by removing the oil filter and cranking the engine over. The rocker assy was a gooey gross mess. I did NOT remove the pan or valve cover, but I did fill it witha mixture of ATF (VERY high detergent) and oil. I changed the oil every 1000 miles for 3 changes and then went back to normal service. This engine is now spotless inside. ( I had to pull the pan to replace a leaking pan gasket and it showed NO TRACE of its former life). The detergent oils can handle higher pressures and are much improved over the oils of 30 years ago. Don't be afraid of detergent oils if you know the pan is clean.

bill

[Fred Rawling]

All the articles that I have read indicate that you should use new modern oil in your old car.

The newest modern oils have less zinc additive than there used to be. The zinc helps reduce wear.

Detergent in oil is designed to hold the particles in suspension, not disolve them from where they are deposided. If the detergent oil did loosen up some of the deposits, you would see them in the oil and could change the oil.

If you are worried about loosening the deposits, then you should probably be more concerned that the deposits are plugging up the oil passages and reducing the flow of oil to the engine parts; and what ever was loosened up by detergent oil, even if the detergent would loosen them up, is a very minor problem compaired to the reduced oil passages.

[Guest 1937RHDNZ]

I asked this oil question many months ago, with suggestions from both ends of the spectrum. To be honest I am still intrigued about the 'oil question'

I have just put older style Castrol GTX 20/50 in my 1937 47, not sure that I am entirely happy with it, but oil pressure is good driving and idling. Some people hate this oil as they say it foams to much. Any gossip, myths 'been there, done that's' comment appreciated.

How about some of our readers list the brand and type that <span style="font-weight: bold">they</span> use. I would be very interested.

Cheers Neil

[The Old Guy]

The latest info I have seen has Valvoline with .11 zinc ,which is about the best you will find in todays oils. I have used it for 40+ years, and not had a failure due to oil.

[Mark Shaw]

This is all good info, and I am sure it is all correct. But it seems to me that if detergent oils do their job to dissolve, loosen, and/or suspend some of the build up in an old engine that has run all it's life on non-detergent oils, changing to detergent oil would most certainly plug up an oil filter much sooner.

My 13 & 15 Buicks have no filter. The 13 has a once through oil system that needs about a quart of used oil drained every 100-200 miles. Although my later model 29 & 31 Buicks have filters, only a small portion of the oil pump's output goes through the filter in these cars. Therefore, at the very least, you must change the filter more frequently after changing to detergent oils.

I agree that if you have a freshly rebuilt engine, using detergent oil is a good idea. However, in my opinion, changing from non-detergent to detergent oil on an older worn engine will not extend the engine's life and may actually shorten the time when it needs to be rebuilt. Then you can use any oil you prefer...even synthetics. But that's another story.

[Mark Shaw]

Here is a very informative site regarding oils, lead in gas, etc.. Check out what this guy says about synthetic oils for Buick engines in the last two paragraphs....

http://www.harwoodperformance.bizland.com/1941buick/Editorial%2013.htm#Synthetic Oils

[Guest imported_arbys]

A retired antique aircraft restorer recommended to me that I use 5w30 Castrol in my 28 Ford Speedster, I asked why he recommended 5w and he stated that it had better characteristics when cold.

I prceeded to switch to that in my Speedster and my 31 Series 60 Buick. I know that the buick sounded better when cold.

[Guest sherlok]

Oh Lord! Here goes the oil thing again.

From experience I have switched from non-detergent to detergent oils on high milage engines with no problems. It would be nice if high detergent oils were so effective in loosening gunk that there could be a danger in trashing the engine. All the same, as suggested by someone earlier, I change oil on the basis of color (trusting this does not cause any political repercussions) regardless of the milage. There is only so much of the bad stuff that can be held in suspension.

Run 10W30 with confidence. Change often. Drive your classic as much as you can.

Regards,

Sherlok

[Aaron65]

AMEN to that!