Changed The Weight Of My Oil
 

So after reading about the controversial subject "what weight of oil to use" I decided to do my own experiment. Seems its a toss up between 10W-30 and 20W-50. Not sure the consensuses on full synthetic.

When I bought my car a few months ago I changed the oil, used the same as the previous owner 10W-30 full synthetic. I really didn't like the sound of the engine, light lifter noise, more noise under a load, oil pressure was about 25 psi cold and about 10 psi hot at idle.

So the other day I changed it to 10W-40 still full synthetic high mileage and a can of STP (another controversial item) results are 30+psi oil pressure when cold and 20 psi when hot. As far as the noise once the car was hot it was much quieter and ticking under a load was almost completely gone.

Part of the problem with this car is the previous owner ran it for years with no thermostats and it never got hot, at least I could not get it above 130 degrees. Now with new thermostats installed she is running between 180-200 degrees so the oil should work better.

I might consider 20W-50 in the spring. What weight/kind of oil do you use?

Re: Changed The Weight Of My Oil
 

Mobil 1 10 W 20

Re: Changed The Weight Of My Oil
 

Please stop using STP. It will cause more harm than good. Consider it "snake oil".

I'd personally rebuilt NUMEROUS engines in the past decades. It was always easy to tell what clients used STP by the amount of GUNK in the engine galley.
It (STP) held many "garbage" particles in place. In other words, the poopy never got to the filter.
If you are looking to quiet down an engine to sell to some unsuspecting person, use it. If you're looking to increase oil pressure temporarily, perhaps to fool some unsuspecting person, use it. Otherwise, stay far away...

Re: Changed The Weight Of My Oil
 

You're going to get as many differing opinions on what oil to use as there are belly buttons.
I was taught in school (GM) that most critical is to use what the manufacture recommends and stay with the identical brand throughout the life of the engine.
Obviously with today's chemicals and yesterday's (flathead) engines, the factory recommendation doesn't apply apples to apples.
I might suggest you "test" different viscosities and see what works best with your engine and driving demands.
I'd start with a non-synthetic 20/50 in your (used) engine.
Synthetic in an old (used) flathead is a waste of money.

Re: Changed The Weight Of My Oil
 

I agree with Kube for your engine, Personally I use 10W- 30.

Re: Changed The Weight Of My Oil
 

My dad used to run #20 in the 52 Merc back in the days before multi grade oils. I ran 10w-30 for a while but last oil change I went to a 15w-40 diesel engine oil. Just because I had some on hand, not for any perceived benefits or advantages. Oil pressure is good cold or hot. Started up at 20 degrees yesterday. Not a recommendation, just how I do it.

Re: Changed The Weight Of My Oil
 

You have solid lifters in a flathead, so changing the viscosity of the oil is not going to change the valve clearance. Whether you can hear the lifters or not the clearance is still the same. I would also suggest a non-synthetic oil what ever viscosity makes you happy.

Re: Changed The Weight Of My Oil
 

The oil topic seems to be a great one. Kinda like if you want to start a fight a Christmas dinner you just ask this question. After reading many posts on this site I moved to VR1 racing oil. It has zinc in it and I took the top 3 recommendations and then did eeny miny moe!

Re: Changed The Weight Of My Oil
 

Well, I knew this would create a stir. I like how my engine sounds with the change and the increased oil pressure. The engine was rebuilt and has been using synthetic since the rebuilt about 3000 miles ago. The synthetic STP is no where as heavy as the original STP, it actually pours like oil. No oil filter on my car, just a lot of oil changes. In the spring if I go to 20W-50 I will opt out of using STP and see how things sound. We grew up using STP in every car and flatheads. I worked at a car garage as a teenager, some lady pulled in off the highway said her oil light was on for the last 8-10 miles. Found oil filter had fallen off and no oil in the pan. The customer had used STP in it, we filled with oil, she drove off, engine was fine. Made me a believer in the product.

Re: Changed The Weight Of My Oil
 

Isn't STP "the racers edge"?

Re: Changed The Weight Of My Oil
 

That is the same exact advice I grew up with, and also the mechanics in the local Ford garage where I was a Parts. Mgr. ALWAYS told people this exact same thing.

Customers that went by that rule were running 200,000 miles PLUS easily on their Ford FE big block engines and Windsor series small blocks and those engines purred like no tomorrow.

Re: Changed The Weight Of My Oil
 

I'm a little late on this discussion but with my newly acquizition ('35), I was told VR1 straight 40w from the previous owner. Of course the temp here is different but the OP hot is midway on the dial at idle and 3/4 driving hot. I'm sticking with what works. I used to be a STP fan back in the day when I didn't know anything!!!

Re: Changed The Weight Of My Oil
 

Don't know what VR1 is but Ford called for 20w oil when it was made. 40w seems a bit sluggish to me. Do you have an owners manual? if not get a hold of one and give it a thorough read.

Re: Changed The Weight Of My Oil
 

I would go with a multi-viscosity oil vs straight viscosity. Are you sure about the 40w rating? "W" stands for "winter" rating on the oil viscosity. Not something you would want to be using if it exist.

Re: Changed The Weight Of My Oil
 

The heavier oil would certainly quiet things. I used to run straight 30 in florida. So I guess my engine is ready for the strap yard. Last change was just 10w-30.


On a rebuilt motor I wouldn't think a thicker oil would be idealistic. Maybe once the bearings are worn. Just a thought. Flatheads are not a high oil pressure engine. It can be harmful but does have a gratifying gauge viewing.

Re: Changed The Weight Of My Oil
 

VR1 20W-50 here

Re: Changed The Weight Of My Oil
 

Definitely a good choice for break-in, but it does not contain enough detergent for year after year. I run four quarts of any good brand of 10w-30 plus one quart of VR-1 to boost the zinc a little.

Re: Changed The Weight Of My Oil
 

What brand is VR-1?

Re: Changed The Weight Of My Oil
 

Valvoline

Re: Changed The Weight Of My Oil
 

Valvoline VR1 20w50. It's been VR1 since new motor in 2005.