Does the Thickness of Your Oil Matter? | Engine Masters FULL EPISODE | MotorTrend

What surprised you most about these tests?

I'm not surprised at all. We run Competition Eliminator and years ago on the dyno we switched out the 30-weight break-in oil for Royal Purple #9 (aka pro stock oil) and lost 20hp. Put the break-in oil back in and picked it right back up. Ring seal is king!

I did a study of oil viscosity versus engine wear. It was suggested by some engineers in Detroit at their customer training school. They said that thicker oil would provide a little better protraction from dirt in the oil. I was looking at a big heavy piece of industrial equipment used around the clock on a schedule. The mechanics thought it wasn't true but went along with the trial. I thought that it did prolong the Ford industrial engine a little longer than the thinner oil. This was 50 weight versus 30 weight. Any way I quit auguring the point and solved the problem, as I understood it, by changing the engine to a Perkins diesel, which was easier to keep the dirt out of. Fun in a big Canadian aluminum smelter!

I agree, we run straight 30 wt. In our hot rod engines with .003 thou. On the mains, .002 on the rods, we use HX bearings with plus .001 thou. Clearance, or grind the crank to our specs. !

The interesting thing to remember is when looking at oil pressure, is that pressure is actually the measurement of two things combined; flow, and resistance to flow. In theory, due to easier pumping, the thinner oil will generate less pressure (as we saw here) and a lot of people see that as less protection. I look at it as more that the oil generates less resistance, creating greater flow, making it so you have more fresh oil being pumped into your bearings, so as long as you arent overcoming your film strength based on the size of a given oil molecule, you are better pulling heat our of your journals, which can only be a benefit to engine longevity. The ring seal thing is a whole other kettle of fish i hadnt considered however.

Bottom line takeaway for me is to run the correct viscosity oil for your engine clearances but, run it warmed up hot so it’s doing its lubrication job but allowing the most power. I think this is what racers have been doing forever even if they didn’t fully understand the science.

In some racing, it is common, and proven to work. Changing both viscosity and the amount of oil, to lower the ET. We can drop two viscosity levels and use 1-2 fewer quarts of oil and see a substantial change. It's part of what we call "switching from bracket mode to heads up mode."

I just wanted to mention that not only does a thicker oil seal the rings better but they also keep fuel out of the oil better for some reason. My direct injection pushes more fuel into crankcase with thinner oils and also the fuel reduces protection so I use thicker than suggested spec oil.

I and a few older guys were running durablend before they even came out with it, we mix are own, It worked quite well; rings love oil it make some seal producing more horsepower moving parts like synthetic oil. The Best of both worlds and the high mileage package.

This isn't hard to understand, because it's 2023, and I'm 51 years old and have always been interested in mechanical stuff. 100 years from now (if YouTube still exists), people will look back at this type of knowledge like it was something special.

I just switched to this (GP1) from the driven HR4. Running 20W – 50 in a small block stroker with high compression. So far so good. It also has a light green tint to it, which, for me, is easier to read on the dipstick.

very interesting video. I really didn't think there was going to be that much of a gain in power just due to the oil temperature, it really made a fair difference. Thanks for putting that together guys!

Awesome job with this 1.. Its amazing how much oil actually affects hp gains aswell as affecting other aspects of how well the engines run and the level of protection they receive with different types(viscosities) of oil

Interesting! Good test! Oil pumps use a lot of power at high pressure... My next step would be to adjust the oil pump relief to find the lowest safe oil pressure for less drag. I went from 70 psi to 45 psi on my boosted 389" SBC and I could feel the difference in the seat of the pants and it picked up about 1 mpg on the street.

This is one of the most informative videos you've ever done. I've been preaching this forever and not a single person seems to hear me. Lower viscosity for fuel economy, higher for lifetime and power.

Full syn 5w40 in everything is the way to go. 5w for winter starts, 40 for summer heat. Buy it gallon jugs for everything and save.

I was driving my mustang earlier today 10.5:1 347 , 6 spd, 4.30s and noticed when it has been running for a while with 20w50 in it it seems happy . Oil temp is at around 200-210 degrees and water temp at 170-180. It was around 80 degrees outside. I was sort of thinking it would be hot but it definitely seems happy and running really good. Derale dual fans and champion radiator.

The correct oil level in your crankcase will give you far more horsepower than thinner oil. 35 years of swinging a wrench: oil level in the middle of the add/full range = perfect. Heavier oil complementing ring seal is very real, so is high rpm scouring and scoring protection from higher film strength oils.

I saw a display and sat thru a briefing about oil weight. I saw that 5-30 was better than 10-30. That was for engines that require a 30 weight oil. The demonstration was impressive. This was 20 years ago.

Great informative video. That Driven GP-1 oil is some good stuff. Thanks guys.